ascorbic-acid and ferrous-sulfate

Iron deficiency anemia is a hypochromic anemia in which hemoglobin poor synthesis is due to a decrease in the amount of iron in the body. The decrease of iron quantity has many causes: insufficient intake of aliments rich in iron (meat, viscera, green vegetables), increased necessities during growth period, pregnancy, erythrocytes hyperregeneration, high-performance sportsmen, increased loss by digestive way, genito-urinary way, respiratory, hemorrhagic syndromes. Clinically, symptoms and signs specific to all types of anemia and those specific to lack of iron occur besides the symptoms and signs of the underlying disease: atrophic glositis, angular stomatitis, sideropenic dysphagia, pica, skin and nails changes. Laboratory investigations useful for diagnosis are: microcytic, hypochromic anemia, decreased serum iron level, total capacity of iron binding increased, medullar iron store absent, good response to iron therapy. Ferro-Folgamma is one of the most indicated medicines in iron deficiency anemia. Due to its components this medicine has many indications: insufficient alimentary intake concerning iron, folic acid, B12 vitamin, vegetarian alimentation, increased needs during growth period, iron deficiency anaemia secondary to chronic hemorrhages, malnutrition, anemias associated with chronic alcohol intake, preventive treatment of iron deficiency anemia and megaloblastic anemia during pregnancy and lactation.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Drug Combinations; Ferrous Compounds; Folic Acid; Humans; Vitamin B 12

Iron deficiency remains a major global health problem affecting an estimated 2 billion people. The World Health Organization ranked it as the seventh most important preventable risk for disease, disability, and death in 2002. Since an important factor in its causation is the poor bioavailability of iron in the cereal-based diets of many developing countries, SUSTAIN set up a Task Force, consisting of nutritional, medical, industry, and government experts to consider strategies for enhancing the absorption of fortification iron. This paper summarizes the findings of this Task Force. Detailed reviews of each strategy follow this overview. Highly soluble compounds of iron like ferrous sulfate are desirable food fortificants but cannot be used in many food vehicles because of sensory issues. Thus, potentially less well-absorbed forms of iron commonly are used in food fortification. The bioavailability of iron fortificants can, however, be enhanced with innovative ingredient technologies. Ascorbic acid, NaFeEDTA, ferrous bisglycinate, and dephytinization all enhance the absorption of fortification iron, but add to the overall costs of fortification. While all strategies cannot be recommended for all food fortification vehicles, individual strategies can be recommended for specific foods. For example, the addition of ascorbic acid is appropriate for dry blended foods such as infant foods and other dry products made for reconstitution that are packaged, stored, and prepared in a way that maximizes retention of this vitamin. NaFeEDTA can be recommended for fortification of fish sauce and soy sauce, whereas amino acid chelates may be more useful in milk products and beverages. With further development, dephytinization may be possible for low-cost, cereal-based complementary foods in developing countries. Encapsulation of iron salts in lipid coatings, while not an iron absorption-enhancing strategy per se, can prevent soluble forms of iron from interacting undesirably with some food vehicles and hence broaden the application of some fortificants. Research relevant to each of these strategies for enhancing the bioavailability or utility of iron food fortificants is reviewed. Individual strategies are evaluated in terms of enhancing effect and stability, organoleptic qualities, cost, and regulatory issues of interest to the nutrition community, industry, and consumers. Recommendations are made on potential usages and further research needs. Effective fortification de

Topics: Absorption; Amino Acids; Ascorbic Acid; Biological Availability; Consensus Development Conferences as Topic; Diet; Drug Interactions; Edetic Acid; Ferrous Compounds; Food, Fortified; Humans; Iron; Iron Chelating Agents; Iron Deficiencies; Phytic Acid

Ascorbic acid (AA), with its reducing and chelating properties, is the most efficient enhancer of non-heme iron absorption when its stability in the food vehicle is ensured. The number of studies investigating the effect of AA on ferrous sulfate absorption far outweighs that of other iron fortificants. The promotion of iron absorption in the presence of AA is more pronounced in meals containing inhibitors of iron absorption. Meals containing low to medium levels of inhibitors require the addition of AA at a molar ratio of 2:1 (e.g., 20 mg AA: 3 mg iron). To promote absorption in the presence of high levels of inhibitors, AA needs to be added at a molar ratio in excess of 4:1, which may be impractical. The effectiveness of AA in promoting absorption from less soluble compounds, such as ferrous fumarate and elemental iron, requires further investigation. The instability of AA during food processing, storage, and cooking, and the possibility of unwanted sensory changes limits the number of suitable food vehicles for AA, whether used as vitamin fortificant or as an iron enhancer. Suitable vehicles include dry-blended foods, such as complementary, precooked cereal-based infant foods, powdered milk, and other dry beverage products made for reconstitution that are packaged, stored, and prepared in a way that maximizes retention of this vitamin. The consumption of natural sources of Vitamin C (fruits and vegetables) with iron-fortified dry blended foods is also recommended. Encapsulation can mitigate some of the AA losses during processing and storage, but these interventions will also add cost. In addition, the bioavailability of encapsulated iron in the presence/absence of AA will need careful assessment in human clinical trials. The long-term effect of high AA intake on iron status may be less than predicted from single meal studies. The hypothesis that an overall increase of dietary AA intake, or fortification of some foods commonly consumed with the main meal with AA alone, may be as effective as the fortification of the same food vehicle with AA and iron, merits further investigation. This must involve the consideration of practicalities of implementation. To date, programs based on iron and AA fortification of infant formulas and cow's milk provide the strongest evidence for the efficacy of AA fortification. Present results suggest that the effect of organic acids, as measured by in vitro and in vivo methods, is dependent on the source of iron, the type an

Topics: Absorption; Ascorbic Acid; Carboxylic Acids; Diet; Dietary Supplements; Drug Interactions; Drug Stability; Ferrous Compounds; Food, Fortified; Humans; In Vitro Techniques; Iron; Nutritional Physiological Phenomena

Iron (Fe) encapsulation has the potential to help overcome several major challenges in Fe fortification of foods. It may decrease unwanted sensory changes in fortified products and reduce interactions of Fe with food components that lower Fe bioavailability. However, the effect of encapsulation per se on Fe bioavailability is a concern. Rat studies comparing encapsulated ferrous sulfate, ferric ammonium citrate, and ferrous fumarate to non-encapsulated compounds indicate that a ratio of capsule:substrate of > or = 60:40 may decrease the relative bioavailability (RBV) of the Fe by approximately 20%. At a ratio of capsule:substrate of < or = 50:50, the RBV of encapsulated ferrous sulfate appears to be similar to ferrous sulfate. Even minor changes in capsule composition may influence Fe bioavailability. Encapsulated ferrous fumarate given with ascorbic acid as a complementary food supplement and encapsulated ferrous sulfate fortified into salt have been shown to be efficacious in anemic children. For salt fortification, further refinements in Fe capsule design are needed to increase resistance to moisture and abrasion, while maintaining bioavailability. Studies evaluating the potential efficacy of encapsulated Fe in staple cereals (wheat and maize flours) are needed. A potential barrier to use of encapsulated forms of Fe in staple food fortification is the relatively low melting point of the capsules, which may cause unwanted sensory changes during food preparation. Research and development efforts to improve the quality of coatings and their resistance to high temperatures are ongoing. Process costs for encapsulation can be high, and unless they can be reduced, may limit applications. Further research is needed to determine which encapsulation technologies are most effective in ensuring iron bioavailability from encapsulated compounds.

Topics: Animals; Ascorbic Acid; Biological Availability; Capsules; Cote d'Ivoire; Edible Grain; Ferric Compounds; Ferrous Compounds; Food, Fortified; Ghana; Humans; Iodine; Iron Compounds; Liposomes; Morocco; Quaternary Ammonium Compounds; Rats; Sodium Chloride, Dietary; Taste

Fatale haemoptysis occurred as a result of circumferential caustic erosion to the right intermediate bronchus caused by a tablet of ferrous sulphate which remained in contact for 4 days. The necrotic process continued, after removal of the foreign body, in the bronchial wall and its vessels. We suggest local bronchial lavage with 1% bicarbonate saline during extraction of the tablet and subsequent follow-up fibroscopies. The discovery of a necrotic ulceration of the bronchus requires strict medico-surgical surveillance in order to rapidly intervene under cover of selective intubation when necessary.

Topics: Accidents, Home; Ascorbic Acid; Burns, Inhalation; Caustics; Female; Ferrous Compounds; Hemoptysis; Humans; Lung; Middle Aged; Necrosis; Tablets

Iron-deficiency anaemia (IDA) is a common nutritional deficiency among pregnant women in India. It has a significant impact on the health of the mother as well as that of the foetus. IDA generally responds well to treatment with oral iron supplementation. However, oral iron supplements are toxic to the gastrointestinal mucosa and intolerance is common, resulting in poor compliance and failure of treatment. The iron salts such as iron hydroxide polymaltose complex (IPC) and ferrous ascorbate (FeA) are claimed to have low gastrointestinal intolerance, therefore better patient compliance than the conventionally used ferrous sulphate (FS). These preparations also claim to increase haemoglobin level faster as well as improve the iron storage better than FS. This study was done to compare the efficacy and safety of FS with IPC and FeA.. It was a randomized, parallel, open label, study among pregnant women of gestational age between 12 to 26 wk with moderate anaemia. Patients were randomly allocated to receive either FS, IPC or FeA. They were then followed up for 90 days to observe for improvement in the haemoglobin levels and other haematological parameters or any adverse drug reaction.. The haemoglobin levels were comparable in the three groups except at day 90 when FeA group had significantly higher haemoglobin level as compared to FS group (P<0.05). The overall adverse effect profiles were also comparable among the study groups except epigastric pain which was more commonly reported in the FS group.. The results of the study showed that FS, IPC and FeA have comparable efficacy and safety profile in the treatment of IDA of pregnancy.

Topics: Adolescent; Adult; Anemia, Iron-Deficiency; Ascorbic Acid; Child; Female; Ferric Compounds; Ferrous Compounds; Humans; Pregnancy; Pregnant Women; Young Adult

The objective of the study is to determine the effect of copper (Cu) plus the reducing agent ascorbic acid (AA) on the absorption of non-heme iron (Fe). Experimental study with block design in which each subject was his own control. After signing an informed consent, 14 adult women using an effective method of contraception and negative pregnancy test received 0.5 mg Fe, as ferrous sulfate, alone or with Cu, as copper sulfate, plus ascorbic acid (AA/Cu 2/1 molar ratio) at 4/1; 6/1 and 8/1 Cu/Fe molar ratios as an aqueous solution on days 1, 2, 14, and 15 of the study. Fe absorption was assessed by erythrocyte incorporation of iron radioisotopes (55)Fe and (59)Fe. Geometric mean (range ± SD) absorption of Fe at 4/1 and 6/1 Cu/Fe molar ratios (and AA/Cu 2/1 molar ratio) and Fe alone was 57.4 % (35.7-92.1 %), 64.2 % (45.8-89.9 %), and 38.8 % (20.4-73.8 %), respectively (ANOVA for repeated measures p < 0.001; post hoc test Scheffé, p < 0.05). This is attributable to the enhancing effect of AA on non-heme Fe absorption; however, Fe absorption at Cu/Fe 8/1 molar ratio was 47.3 % (27.7-80.8) (p = NS compared with Fe alone). It was expected that Fe absorption would have been equal or greater than at 4/1 and 6/1 molar ratios. Copper in the presence of ascorbic acid inhibits non-heme Fe absorption at Cu/Fe 8/1 molar ratio.

Topics: Absorption, Physiological; Adult; Ascorbic Acid; Copper; Dietary Supplements; Female; Ferrous Compounds; Humans; Middle Aged

Home fortification with lipid-based nutrient supplements (LNSs) is a promising approach to improve bioavailable iron and energy intake of young children in developing countries. To optimize iron bioavailability from an LNS named complementary food fortificant (CFF), 3 stable isotope studies were conducted in 52 young Beninese children. Test meals consisted of millet porridge mixed with CFF and ascorbic acid (AA). Study 1 compared iron absorption from FeSO4-fortifed meals with meals fortified with a mixture of FeSO4 and NaFeEDTA. Study 2 compared iron absorption from FeSO4-fortifed meals without or with extra AA. Study 3 compared iron absorption from FeSO4-fortified meals with meals containing phytase added prior to consumption, once without or once with extra AA. Iron absorption was measured as erythrocyte incorporation of stable isotopes. In study 1, iron absorption from FeSO4 (8.4%) was higher than that from the mixture of NaFeEDTA and FeSO4 (5.9%; P < 0.05). In study 2, the extra AA increased absorption (11.6%) compared with the standard AA concentration (7.3%; P < 0.001). In study 3, absorption from meals containing phytase without or with extra AA (15.8 and 19.9%, respectively) increased compared with meals without phytase (8.0%; P < 0.001). The addition of extra AA to meals containing phytase increased absorption compared with the test meals containing phytase without extra AA (P < 0.05). These findings suggest that phytase and AA, and especially a combination of the two, but not a mixture of FeSO4 and NaFeEDTA would be useful strategies to increase iron bioavailability from a CFF mixed with cereal porridge.

Topics: 6-Phytase; Anthropometry; Ascorbic Acid; Biological Availability; C-Reactive Protein; Child, Preschool; Cross-Over Studies; Developing Countries; Dietary Supplements; Edetic Acid; Edible Grain; Female; Ferric Compounds; Ferritins; Ferrous Compounds; Food, Fortified; Hemoglobins; Humans; Infant; Infant Nutritional Physiological Phenomena; Intestinal Absorption; Iron, Dietary; Male; Panicum

The cofortification of milk with iron (Fe) and zinc (Zn) is a strategy used to prevent these deficiencies during childhood. Given that Zn can negatively interact with iron in aqueous solutions, the objective of the present study was to determine the effect of Zn on Fe absorption of milk fortified with Fe and Zn. Twenty-eight women between 33 and 47 years of age, with contraception and a negative pregnancy test, participated in one of two absorption studies. They received on four different days, after an overnight fast, 200 mL of milk (26 % fat) fortified with 10 mg Fe/L, as (A) ferrous sulfate, or the same milk but with graded doses of added Zn, as Zn sulfate of (B) 5, (C) 10, and (D) 20 mg/L (study 1, n = 15). In study 2 (n = 13), subjects received the same milk formulations, but these were also fortified with ascorbic acid (70 mg/L). Milk was labeled with radioisotopes ⁵⁹Fe or ⁵⁵Fe, and the absorption of iron was measured by erythrocyte incorporation of radioactive Fe. The geometric mean and range of ±1 SD of Fe absorption in study 1 were as follows: formula A = 6.0 % (2.8-13.0 %); B = 6.7 % (3.3-13.6 %); C = 5.4 % (2.2-13.2 %); and D = 5.2 % (2.8-10.0 %) (ANOVA for repeated measures, not significant). For study 2, data are as follows: 8.2 % (3.6-18.7 %); B = 6.4 % (2.5-16.4 %); C = 7.7 % (3.2-18.9 %); and D = 5.2 (1.8-14.8 %) (ANOVA for repeated measures, not significant). In conclusion, according to the results from this study, it appears that the addition of zinc up to 20 mg/L does not significantly inhibit iron absorption from milk fortified with 10 mg/L of iron.

Topics: Adult; Animals; Ascorbic Acid; Cattle; Chile; Cross-Over Studies; Erythrocytes; Female; Ferrous Compounds; Food, Fortified; Food, Preserved; Humans; Intestinal Absorption; Iron Radioisotopes; Iron, Dietary; Middle Aged; Milk; Zinc; Zinc Sulfate

Ascorbic acid, and more recently, the carotenoids lutein and zeaxanthin have been shown to enhance Fe absorption. However, it is not clear whether Fe status improves when foods high in ascorbic acid and carotenoids are consumed with Fe-fortified meals. The present study aimed to investigate whether consuming high v. low ascorbic acid-, lutein- and zeaxanthin-rich fruit (gold kiwifruit v. banana) with Fe-fortified breakfast cereal and milk improved Fe status in women with low Fe stores. Healthy women aged 18-44 years (n 89) with low Fe stores (serum ferritin ≤ 25 μg/l and Hb ≥ 115 g/l) were randomly stratified to receive Fe-fortified breakfast cereal (16 mg Fe as ferrous sulfate), milk and either two gold kiwifruit or one banana (164 mg v. not detectable ascorbic acid; 526 v. 22·90 μg lutein and zeaxanthin, respectively) at breakfast every day for 16 weeks. Biomarkers of Fe status and dietary intake were assessed at baseline and end in the final sample (n 69). Median serum ferritin increased significantly in the kiwifruit group (n 33) compared with the banana group (n 36), with 10·0 (25th, 75th percentiles 3·0, 17·5) v. 1·0 (25th, 75th percentiles - 2·8, 6·5) μg/l (P < 0·001). Median soluble transferrin receptor concentrations decreased significantly in the kiwifruit group compared with the banana group, with - 0·5 (25th, 75th percentiles - 0·7, - 0·1) v. 0·0 (25th, 75th percentiles - 0·3, 0·4) mg/l (P = 0·001). Consumption of an Fe-fortified breakfast cereal with kiwifruit compared with banana improved Fe status. Addition of an ascorbic acid-, lutein- and zeaxanthin-rich fruit to a breakfast cereal fortified with ferrous sulfate is a feasible approach to improve Fe status in women with low Fe stores.

Topics: Actinidia; Adult; Anemia, Iron-Deficiency; Antioxidants; Ascorbic Acid; Biomarkers; Carotenoids; Edible Grain; Female; Ferritins; Ferrous Compounds; Food, Fortified; Fruit; Humans; Iron, Dietary; Musa; Phytotherapy; Plant Extracts; Receptors, Transferrin; Young Adult

The absorption profile of iron fortificants may be a determinant of their ability to generate nontransferrin-bound iron (NTBI) and, thus, their potential safety. Ferrous iron may be absorbed more rapidly than chelated ferric iron, but differences at the fortification level cannot be distinguished with nonisotopically labeled serum iron curves. Using stable isotope appearance curves (SIAC) in serum, we measured iron absorption profiles from FeSO(4) with ascorbic acid (AA) and from NaFeEDTA, as well as the serum hepcidin and NTBI response following the meals. Healthy women (n = 16) were given 6 mg oral iron as labeled FeSO(4) and NaFeEDTA with a maize porridge using a crossover design. SIAC, NTBI, and serum hepcidin were measured over 8 h after the meal. Iron from FeSO(4) plus AA was more rapidly absorbed, resulting in a 35% greater relative AUC during the first 2 h than for NaFeEDTA (P < 0.001). Median (95% CI) fractional iron absorption from the FeSO(4)- and NaFeEDTA-fortified meals was 15.2% (11.0-19.5) and 6.0% (5.0-9.2), respectively (P < 0.001). In response to the FeSO(4)-fortified meal, there was an ~60% increase in median serum hepcidin (P < 0.05) but no significant change in NTBI. There was no significant change in serum hepcidin or NTBI after the NaFeEDTA-fortified meal. SIAC are a useful new tool to compare iron absorption profiles from different iron compounds in fortified foods. Even with the use of a very well absorbed ferrous iron compound, iron fortification in this population does not increase NTBI, suggesting a low risk for adverse health consequences.

Topics: Adult; Algorithms; Anemia, Iron-Deficiency; Antimicrobial Cationic Peptides; Ascorbic Acid; Cross-Over Studies; Edetic Acid; Female; Ferric Compounds; Ferrous Compounds; Food, Fortified; Hemoglobins; Hepcidins; Humans; Intestinal Absorption; Iron Chelating Agents; Iron Isotopes; Iron, Dietary; Kinetics; Oxidation-Reduction; Protein Binding

Ferrous fumarate is a common, inexpensive iron form increasingly used instead of ferrous sulfate as a food iron supplement. However, few data exist as to whether juices enhance iron absorption from ferrous fumarate.. We studied 21 children, ages 4.0 to 7.9 years using a randomized crossover design. Subjects consumed a small meal including a muffin containing 4 mg Fe as ferrous fumarate and either apple (no ascorbic acid) or orange juice (25 mg ascorbic acid). They were separately given a reference dose of Fe (ferrous sulfate) with ascorbic acid.. Iron absorption increased from 5.5% +/- 0.7% to 8.2% +/- 1.2%, P < 0.001 from the muffins given with orange juice compared with muffins given with apple juice. The absorption of ferrous fumarate given with orange juice and enhancement of absorption by the presence of juice were significantly positively related to height, weight, and age (P < 0.01 for each). Although iron absorption from ferrous fumarate given with apple juice was significantly inversely associated with the (log transformed) serum ferritin, the difference in absorption between juice types was not (P > 0.9).. These data demonstrate an overall benefit to iron absorption from ferrous fumarate provided with orange juice. The effect was age related such that in children older than 6 years of age, there was a nearly 2-fold increase in iron absorption from ferrous fumarate given with orange juice.

Topics: Ascorbic Acid; Beverages; Child; Child, Preschool; Citrus sinensis; Cross-Over Studies; Female; Ferritins; Ferrous Compounds; Fruit; Humans; Intestinal Absorption; Iron; Male; Malus; Plant Preparations

Non-water-soluble iron compounds have been reported to be less well absorbed than ferrous sulfate in young children, and concern has been raised about their usefulness as food fortificants.. The objective was to evaluate the usefulness of ferrous fumarate and ferric pyrophosphate, compared with ferrous sulfate, in maintaining hemoglobin concentrations >105 g/L in Bangladeshi children.. Two hundred thirty-five children aged 7-24 mo (hemoglobin >105 g/L) were randomly assigned in a double-blind study to receive an infant cereal fortified with ferrous fumarate, ferric pyrophosphate, or ferrous sulfate. One serving of cereal (9.3 mg Fe; molar ratio of ascorbic acid to iron of 3:1) was consumed per day, 6 d/wk, for 9 mo. Blood samples were drawn at 4.5 and 9 mo.. Raw data were reformatted, and a "time to event" was calculated that corresponded to reaching the following thresholds: hemoglobin <105 g/L, plasma ferritin <12 microg/L, or plasma C-reactive protein >10 mg/L at baseline, 4.5 mo, or 9 mo. Data were censored when children did not reach the threshold or were lost to follow-up. A Kaplan-Meier approach was used to compare the 3 groups. No statistically significant differences were observed for hemoglobin <105 g/L (P = 0.943), plasma ferritin <12 microg/L (P = 0.601), or plasma C-reactive protein >10 mg/L (P = 0.508).. Contrary to earlier concerns, these results do not indicate differences in usefulness between water-soluble and non-water-soluble iron compounds in maintaining hemoglobin concentrations and preventing iron deficiency. These data will be important in the development of food-fortification strategies to combat anemia and iron deficiency in highly vulnerable population groups.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Bangladesh; C-Reactive Protein; Child, Preschool; Diphosphates; Female; Ferritins; Ferrous Compounds; Food, Fortified; Hemoglobins; Humans; Infant; Iron; Iron, Dietary; Male; Trace Elements

We measured iron bioavailability of meals based on wheat flour consumed by a vulnerable population in Latin America.. Bioavailability of iron (ferrous sulfate) from fortified noodles, noodle soup, noodle soup eaten with lemonade sweetened with panela (unrefined whole cane sugar), bread alone, and bread consumed with a chamomile infusion sweetened with panela was studied using the double isotopic method in 13 women.. Iron bioavailabilities from bread, noodles, and noodle soup were not significantly different (7.4%, 6.3%, and 6.0%, respectively). Iron absorption from noodle soup was significantly higher when given with lemonade (11.0%) compared with absorption of the same meal without lemonade (P < 0.02) or with the absorption of noodles (P < 0.04). Iron absorption of bread given alone or with chamomile infusion sweetened with panela (8%) was not significantly different.. Iron bioavailability of meals based on wheat flour, fortified with ferrous sulfate, is improved when given with lemonade. The consumption of this beverage may be an alternative to further increase the effectiveness of wheat flour fortification in preventing iron deficiency in low-income Latin American populations.

Topics: Acetic Acid; Adult; Anemia, Iron-Deficiency; Ascorbic Acid; Beverages; Biological Availability; Chamomile; Cross-Over Studies; Female; Ferrous Compounds; Flour; Food, Fortified; Humans; Intestinal Absorption; Iron Radioisotopes; Iron, Dietary; Middle Aged; Plant Extracts; Triticum

Unilateral total knee replacement (TKR) can result in a substantial blood loss and 30-50% of these patients receive allogeneic blood transfusion (ABT), this transfusion rate may be even higher among anaemic patients.. We assessed the requirements for ABT in 156 consecutive patients undergoing surgery for primary TKR, who received iron ferrous sulphate (256 mg/day; 80 mg of Fe(2+)), vitamin C (1000 mg/day) and folic acid (5mg/day) during the 30-45 days preceding surgery, and who were transfused if Hb <80 g/L and/or clinical signs/symptoms of acute anaemia/hypoxemia (Group 2). A previous series of 156 TKR patients serves as a control group (Group 1).. Compared to those in Group 1, patients in Group 2 presented a lower transfusion rate (5.8% vs. 32%, for Group 2 and Group 1, respectively; p<0.01), and a lower transfusion index (1.78+/-0.44 vs. 2.22+/-0.65 units per transfused patient, respectively; p<0.05). After patient's stratification according to a preoperative Hb above or below 130 g/L, the differences in transfusion rate remained significant, although 19% of patients from Group 2 still needed ABT if their preoperative Hb <130 g/L.. This protocol seems to be effective for avoiding ABT in non-anaemic TKR patients, whereas for anaemic patients another blood saving strategy, such us preoperative erythropoietin administration or postoperative blood salvage, should be added to further increase its effectiveness.

Topics: Aged; Arthroplasty, Replacement, Knee; Ascorbic Acid; Blood Transfusion; Drug Administration Schedule; Female; Ferrous Compounds; Folic Acid; Follow-Up Studies; Hematinics; Hemoglobins; Humans; Male; Prospective Studies; Treatment Outcome; Vitamins

Bioavailability data in humans of elemental iron powders is limited although elemental iron is a common form of iron when used as a fortificant.. The relative bioavailability (RBV) of seven elemental iron powders, five commercially available and two developmental are evaluated. In addition, one commercial electrolytic iron powder given with ascorbic acid (AA) was examined.. Based on a validated method this double-blinded randomized crossover study included three groups of male blood donors (n = 3*16) who were served rolls fortified with different elemental iron powders or ferrous sulfate (FeSO(4)) nine weeks apart. Blood samples were drawn every hour for six hours. RBV was obtained by comparing the increase in serum iron concentration induced by the elemental iron with the increase induced by FeSO(4).. All elemental iron powders studied were significantly less well absorbed compared to FeSO(4). The electrolytic iron given with 50-mg AA was as well absorbed as FeSO(4) (molar ratio = 1:6, AA:Fe). The mean RBVs of the iron powders were: electrolytic (A-131, RBV = 0.65); electrolytic (Electrolytic, RBV = 0.59); carbonyl (Ferronyl, RBV = 0.58); H-reduced (AC- 325, RBV = 0.56); H-reduced (Hi-Sol, RBV = 0.50); carbonyl (CF, RBV = 0.37); reduced (Atomet 95SP, RBV = 0.36). The reduced iron was distinguished by having significantly lower RBV (0.36) although no significant overall ranking was possible.. Based on a validated method this doubleblinded cross-over study in humans showed that the evaluated elemental iron powders currently available for commercial use are significantly less well absorbed compared to FeSO(4). The results indicate that the reduced iron powder was absorbed to a lower extent compared to the other iron powders and only 36% compared to FeSO(4). Ascorbic acid seems to improve the bioavailability of elemental iron even though a rather low molar ratio is used. Thus, if confirmed, this enhancing effect of ascorbic acid on elemental iron when used as a fortificant could be used by co-fortifying them.

Topics: Adult; Antioxidants; Area Under Curve; Ascorbic Acid; Biological Availability; Cross-Over Studies; Double-Blind Method; Ferrous Compounds; Food, Fortified; Humans; Iron, Dietary; Male; Middle Aged

Although ferric pyrophosphate is a promising compound for iron fortification of foods, few data are available on the effect of food matrices, processing, and ascorbic acid on its bioavailability.. We compared the relative bioavailability (RBV) of ferrous sulfate in an experimental form of micronized dispersible ferric pyrophosphate (MDFP) in a wheat-milk infant cereal given with and without ascorbic acid with the RBV of MDFP from a processed and unprocessed rice meal.. A crossover design was used to measure iron absorption in young women (n = 26) from test meals fortified with isotopically labeled [57Fe]-MDFP and [58Fe]-ferrous sulfate, based on erythrocyte incorporation of stable isotope labels 14 d later.. Geometric mean iron absorption from the wheat-based meal fortified with MDFP was 2.0% and that from the meal fortified with ferrous sulfate was 3.2% (RBV = 62). The addition of ascorbic acid at a molar ratio of 4:1 to iron increased iron absorption from MDFP to 5.8% and that from ferrous sulfate to 14.8% (RBV = 39). In the rice meals, mean iron absorption from MDFP added to the rice at the time of feeding was 1.7%, and that from ferrous sulfate was 11.6% (RBV = 15). The mean iron absorption from MDFP extruded into artificial rice grains was 3.0% and that from ferrous sulfate in unprocessed rice was 12.6% (RBV = 24). Sixteen of 26 subjects were iron deficient. Iron status was a highly significant predictor of the RBV of MDFP (P < 0.001).. RBV of the experimental MDFP varied markedly with food matrix and iron status. Assigning a single RBV value to poorly soluble compounds may be of limited value in evaluating their suitability for food fortification.

Topics: Absorption; Adult; Antioxidants; Ascorbic Acid; Biological Availability; Cross-Over Studies; Diphosphates; Female; Ferritins; Ferrous Compounds; Food; Food Handling; Food, Fortified; Humans; Intestinal Absorption; Iron; Iron Isotopes; Nutritional Status; Oryza; Triticum

Despite extensive use, information on the bioavailability of elemental iron powders to humans, as influenced by dose and other dietary constituents, is limited. Three experiments were conducted to assess the absorption of electrolytic iron powder relative to FeSO4, as affected by iron dose and by ascorbic or phytic acid. Iron absorption by 56 volunteers was measured from a farina cereal breakfast radiolabeled with 59FeSO4 or an electrolytic 55Fe powder irradiated by neutron activation. Absorption was determined from whole-body counting (59Fe) and blood isotope incorporation 2 wk later. Absorption of iron from the irradiated electrolytic powder was 5-15% that of FeSO4. Ascorbic acid (approximately 160 mg) enhanced iron absorption from FeSO4 by almost 4-fold but only doubled absorption from electrolytic iron (P for interaction < 0.01). Phytic acid from wheat bran inhibited iron absorption from FeSO4 and electrolytic iron by 73 and 50%, respectively (P for interaction, NS). Compared with 3 mg, a 20-mg dose reduced fractional absorption from FeSO4, but not electrolytic iron (P for interaction < 0.0001). Despite a much higher bioavailability (50% relative to FeSO4) of this same electrolytic iron when tested previously in a pig model, the bioavailability of the irradiated electrolytic iron was poor in humans. The diminished influence of ascorbic acid on the absorption of less soluble iron sources such as elemental iron powders may be an important consideration when choosing iron fortificants.

Topics: Adult; Antioxidants; Ascorbic Acid; Biological Availability; Drug Interactions; Female; Ferritins; Ferrous Compounds; Food, Fortified; Humans; Intestinal Absorption; Iron, Dietary; Male; Middle Aged; Phytic Acid

To study the effect of different therapeutical regimens of Ferro-Folgamma, in pregnant patients with iron deficiency anemia.. 22 pregnant patients between 20 and 35 week of gestation (mean 29 gestational week) with hemoglobin levels between 83.1-106 g/l were included. They were divided in two groups: group 1 included patients with hemoglobin levels up to 100g/l and group 2--with hemoglobin levels between 100 and 110. The dosage of the preparation in group 1 was 1 tablet Ferro-Folgamma tid for 40 days, and 1 tablet Ferro-Folgamma bid for the same period. Blood samples were taken four times during the study on day 0, 10th day, 20th day and in the week after the 40th completed day of therapy. The samples were tested for CBC, iron, transferine, feritine, folic acid. All patients were given complete information about the possible risks of iron deficiency anemia during pregnancy and parturition.. The mean hemoglobin level at initiation of treatment was 91.22 g/l (day 0). After initiation of treatment the the following rise in hemoglobin levels was detected 10th day - 103.8 g/l, 20th day - 112.6 g/l, after the 40th completed day - 136.0 g/l. The mean levels of the rest of hematological parameters were, day 0 - Er - 3.25 mln/microl, Fe - 7.53 micromol/l, transferine - 3.65 gr/l, feritine - 15.02 ngr/ml, folic acid - 14.08 ng/ml, vit. B12 - 219.68 pg/ml; 10th day - Er- 3.5 mln/microl, Fe - 14. 12 micromol/l; 20th day - Er - 4.10 mln/microl, Fe - 20.46 micromol/l; 40th completed day - Er- 4.69 mln/microl, Fe - 13.12 micromol/l, transferine - 3.82 gr/l, feritine - 27.42 ngr/ml, folic acid - 15.67 ng/ml, vit. B12 - 484.52 pg/ml respectively.. Oral treatment with Ferro-Folgamma, according the described dosage regimen, demonstrates its fast and stable effect in treatment of moderate iron deficiency and recovery of depleted iron pool in pregnant patients as well. It could be administered as a prophylactic preparation for borderline anemic states.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Drug Combinations; Female; Ferrous Compounds; Folic Acid; Gestational Age; Hemoglobins; Humans; Iron Metabolism Disorders; Pregnancy; Pregnancy Complications, Hematologic; Treatment Outcome

The effects of added ascorbic acid and particle size on iron absorption from ferric pyrophosphate were evaluated in adult women (9-10 women/study) based on erythrocyte incorporation of iron stable isotopes (57Fe or 58Fe) 14 days after administration. Three separate studies were made with test meals of iron-fortified infant cereal (5 mg iron/meal) and the results are presented as geometric means and relative bioavailability values (RBV, FeSO4 = 100%). The results of study 1 showed that iron absorption was significantly lower from ferric pyrophosphate (mean particle size 8.5 microm) than from FeSO4 in meals without ascorbic acid (0.9 vs. 2.6%, p < 0.0001, RBV 36%) and in the same meals with ascorbic acid added at a 4:1 molar ratio relative to fortification iron (2.3 vs. 9.7%, p < 0.0001, RBV 23%). Ascorbic acid increased iron absorption from ferric pyrophosphate slightly less (2.6-fold) than from FeSO4 (3.7-fold) (p < 0.05). In studies 2 and 3, RBV of ferric pyrophosphate with an average particle size of 6.7 microm and 12.5 pm was not significantly different at 52 and 42% (p > 0.05), respectively. In conclusion, the addition of ascorbic acid increased fractional iron absorption from ferric pyrophosphate significantly, but to a lesser extent than from FeSO4. Decreasing the mean particle size to 6.7 microm did not significantly increase iron absorption from ferric pyrophosphate.

Topics: Adult; Ascorbic Acid; Biological Availability; Diphosphates; Erythrocytes; Female; Ferrous Compounds; Humans; Iron; Iron Isotopes; Iron, Dietary; Particle Size; Time Factors

Iron deficiency and iron-deficiency anemia are common in the developing world. We evaluated the feasibility of iron fortification of domestic drinking water to prevent and control iron deficiency and iron-deficiency anemia. Twenty-one families representing 88 persons, including children, were selected to participate in this study. Twelve families added an iron solution plus ascorbic acid to their domestic drinking water over a four months period and nine families added a placebo. Blood samples were collected, before and after the four months, for hemoglobin and serum ferritin measurements. Iron-fortified drinking water increased hemoglobin (children 10.9 +/- 1.1 g/dl to 11.7 +/- 1.1 g/dl p < .01, adults 12.9 +/- 1.7 g/dl to 13.7 +/- 1.7 g/dl p < .01) and ferritin (children 27.6 +/- 21.6 ng/dl to 33.8 +/- 22.1 ng/dl, adults 74.8 +/- 41.3 ng/dl to 106.2 +/- 93.9 ng/dl p < .05). No significant changes in hemoglobin and ferritin were found in the placebo group after 4 months. Preparation, distribution, and consumption of the solutions were successful. Iron fortification of household drinking water can be a simple and effective alternative to deal with iron deficiency and iron-deficiency anemia in less developed areas.

Topics: Adult; Anemia, Iron-Deficiency; Ascorbic Acid; Brazil; Child; Child, Preschool; Drinking; Ferritins; Ferrous Compounds; Hemoglobins; Humans; Infant; Iron; Iron Deficiencies; Poverty; Single-Blind Method; Socioeconomic Factors; Water

The purpose of the present study was to evaluate the efficacy of low dose iron supplementation with and without a heme component, prescribed for women in the second half of pregnancy.. A randomized, double-blind, placebo controlled trial. Thirty-one women received a daily dose of 27 mg elemental iron in a product containing both heme iron and non-heme iron (Hemofer), 30 women received the same dose as pure non-heme iron with vitamin C (Collets jern med vitamin C), and 29 women received placebo. A double dummy technique was used to mask tablets. The women were tested for red cell indices and iron status markers (s-ferritin, s-iron, Total Iron Binding Capacity and erythrocyte protoporphyrin) throughout pregnancy and 8 and 24 weeks postpartum. The results were analyzed according to the 'intention to treat' principle.. The hematological effects were equal in the two treatment groups. 25% of the supplemented women fell below 110 g/l in Hb vs 52% in the placebo group (p < 0.05); none fell below 100 g/l in the supplemented groups, 14% in the placebo group. Iron status was significantly better for all measured parameters in the heme iron group compared to placebo at the end of pregnancy. Differences between the other groups were only shown for some parameters, probably due to the small sample size. In the heme iron group there were fewer women with empty iron stores postpartum than at the start of pregnancy (from 14% to 8%), in the non-heme iron group there was a significant increase (from 3% to 27%), and in the placebo group the percentage of women with empty iron stores was more than doubled (from 21% to 52%).. A daily dose of 27 mg elemental iron, containing a heme component, given in the second half of pregnancy, prevents depletion of iron stores after birth in most women. An equivalent dose of pure inorganic iron seems less effective, but the sample size in this study was too small to demonstrate significant differences between the two treatment groups.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Dose-Response Relationship, Drug; Double-Blind Method; Female; Ferritins; Ferrous Compounds; Humans; Iron; Placebos; Pregnancy; Pregnancy Complications, Hematologic; Pregnancy Trimester, Second

Efficacies of ferroplex, conferon, and feramide in the treatment of pregnant patients with iron-deficiency anemia were compared. Ferroplex proved to be the most effective. Therapy with this drug brought about the best correction of iron metabolism parameters. Feramide was the least effective agent. The efficacy of iron preparations depends on the ionic form of this metal and the combination of iron with the agents conducive to its better absorption in the gastrointestinal tract.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Delayed-Action Preparations; Drug Combinations; Female; Ferrous Compounds; Humans; Iron; Pregnancy; Pregnancy Complications, Hematologic; Reactive Oxygen Species

The purpose of this investigation was to examine the effects of oral iron supplementation on endurance performance in initially iron-depleted, nonanemic female distance runners. Eighteen iron-depleted (serum ferritin less than 20 ng.ml-1, hemoglobin greater than or equal to 12 g.dl-1) women (22-39 yr) performed a VO2max test and an endurance run to exhaustion. Subjects were pair-matched on the basis of endurance time and then randomly assigned to an iron supplement or a placebo group. Following supplementation, the iron group had a significantly higher (P = 0.03) mean serum ferritin concentration (23.4 vs 15.7 ng.ml-1) and lower (P = 0.04) mean total iron-binding capacity than the placebo group. Both groups increased their time to exhaustion (25.5% and 22.2% for the iron and placebo groups, respectively) but were not significantly different (P = 0.72) from each other. There were also no differences (P greater than 0.05) between the groups with respect to lactate concentrations and physiological measures taken during the two exercise tests. The results of this study suggest that 8 wk of oral iron supplementation improves iron status in iron-depleted female distance runners, but does not enhance endurance capacity.

Topics: Adult; Ascorbic Acid; Female; Ferrous Compounds; Humans; Iron; Iron Deficiencies; Lactates; Oxygen Consumption; Physical Endurance; Running

An evaluation was made into the usefulness of ferrous fumarate as an iron fortificant for an experimental chocolate drink powder targetted to children and adolescents. Organoleptically ferrous furmarate was acceptable when the chocolate drink powder was reconstituted in milk or water that was heated to less than 80 degrees. Unacceptable colour changes occurred, however, when boiling milk or water were used. In human Fe absorption studies when the Fe compounds were added to the chocolate drink immediately before consumption, ferrous fumarate was 3.31% absorbed compared with 2.82% for ferrous sulphate and 2.11% for ferric pyrophosphate. When the Fe compounds were processed during the manufacture of the chocolate drink powder, the absorption of ferrous furmarate was 5.27%, ferrous sulphate 2.62% and ferric pyrophosphate 0.55%. Ascorbic acid had little or no effect on the absorption of ferrous furmarate. It is concluded that food processing can influence the relative absorption of fortification Fe and that, if not reconstituted with boiling milk or water, ferrous fumarate could be a useful compound for the fortification of chocolate drink powders.

Topics: Adolescent; Ascorbic Acid; Beverages; Biological Availability; Cacao; Child; Diphosphates; Ferrous Compounds; Food Handling; Food, Fortified; Humans; Intestinal Absorption; Iron; Iron Radioisotopes

The bioavailability of iron on Fe(III)-hydroxide-polymaltose complex was compared intraindividually with that of Fe (II)-ascorbate (iron absorption) and a Fe (II)-sulphate quick release preparation (haemoglobin regeneration test). The study was carried out in a population of 16 healthy male volunteers, phlebotomized in weekly intervals until development of an iron deficiency anaemia in order to establish a test population with only small variations of their individual body iron status. Intestinal iron absorption in fasting state as measured by 59Fe whole body retention and simultaneous estimation from plasma iron tolerance curves was low for the 59Fe (III)-complex (1.2 +/- 0.1% (means +/- SD] as compared to the 59Fe (II)-ascorbate (43.7 +/- 7.1% (means +/- SD]. Iron administration together with a test meal did not affect the absorption from the 59Fe (II)-ascorbate, whereas the 59Fe (III)-complex showed a significant increase in absorption (8.8 +/- 4.7% (means +/- SD]. Haemoglobin (Hb) regeneration after 100 mg of iron as Fe (III)-complex and Fe (II)-sulphate administered during 28 days with meals amounted to a mean of 0.68 +/- 0.2 g/l and 1.1 +/- 0.3 g/l (means +/- SD) of total daily Hb-increase and a net-Hb-increase of 0.31 +/- 0.37 g/l and 0.79 +/- 0.36 g/l (means +/- SD), respectively. There was also a small but significant rise in serum ferritin during the oral treatment in both treatment groups. The results of Hb-regeneration after treatment with the Fe (III)-complex were in the range which could be expected from the absorption measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Anemia, Hypochromic; Ascorbic Acid; Biological Availability; Ferric Compounds; Ferrous Compounds; Food; Humans; Intestinal Absorption; Iron; Iron Radioisotopes; Male

The effect of a combined supplement of iron, thiamine, riboflavin and vitamin C on malarial incidence in 5 to 14-year-old children was tested in a malnourished rural community in a region of The Gambia noted for high prevalence of malaria during the rainy season. 190 children, divided into 2 matched groups, received either the supplement or a matching placebo for 3 months. No significant difference in malarial incidence was observed between the 2 groups, despite a major improvement in biochemical indices of nutrient status in the supplemented group, especially for riboflavin and vitamin C. Severity of episodes was also similar between groups, but in subjects who developed parasitaemias there was a trend towards higher parasite counts in those receiving the active supplement. Nutritional interventions in malarious areas may have adverse effects on malaria, and the increase in parasitaemia was compatible with the hypothesis that a small but significant reduction in defences had occurred. However, the absence of increases in the incidence of proven malaria cases and their severity must also be taken into account, in order to make a balanced assessment of the possible increase in risk. Further investigations are needed to measure the risk in benefit rates, and to consider the effects of individual nutrients in isolation.

Topics: Adolescent; Ascorbic Acid; Child; Child, Preschool; Erythrocyte Indices; Female; Ferrous Compounds; Gambia; Humans; Malaria; Male; Nutritional Status; Riboflavin; Rural Population; Thiamine

The effect of a 6-week combined treatment with ferrous sulfate (80 mg Fe++ three times daily) and ascorbic acid (75 mg three times daily) on the empty iron stores in 20 patients after gastrointestinal surgery was examined from changes of serum ferritin. One group of 20 patients with similar clinical characteristics served as controls. The treatment replaced the empty iron stores. Since mean serum ferritin concentrations increased from 9 +/- 8 to 29 +/- 11 micrograms/l (P less than 0.001) in males and from 8 +/- 8 to 26 +/- 10 micrograms/l (P less than 0.001) in the females. Also blood hemoglobin and serum iron concentrations increased significantly (P less than 0.01). Among the controls there were no marked changes in serum ferritin, blood hemoglobin or serum iron concentrations. However, the increase of serum ferritin caused by this combined treatment was similar with that caused previously by pure ferrous sulfate treatment. Thus, it is considered that the combined treatment with ferrous sulfate (80 mg Fe++ three times daily) and ascorbic acid (75 mg three times daily) restores the empty iron stores in patients after gastrointestinal surgery, but that the increase is not augmented by the ascorbic acid. Thus, a pure iron therapy is recommended to fill up the empty iron stores in these patients.

Topics: Adult; Aged; Ascorbic Acid; Clinical Trials as Topic; Drug Synergism; Drug Therapy, Combination; Female; Ferritins; Ferrous Compounds; Gastrointestinal Diseases; Humans; Iron; Iron Deficiencies; Male; Middle Aged; Random Allocation

Topics: Adolescent; Anemia, Hypochromic; Ascorbic Acid; Clinical Trials as Topic; Diet; Drug Combinations; Female; Ferritins; Ferrous Compounds; Hemoglobins; Humans; Iron; Iron Deficiencies; Physical Education and Training; Random Allocation; Running

A study in 49 subjects compared different methods for increasing the absorption of iron from a simple Latin American-type meal composed of maize, rice, and black beans. The addition of meat (75 g) increased the nonheme iron absorption from 0.17 to 0.45 mg; soy protein in an amount corresponding to the protein content of the meat increased the absorption to 0.51 mg (due to the high iron content of soy flour); cauliflower as a source of ascorbic acid (65 mg) increased the absorption to 0.58 mg, pure ascorbic acid (50 mg) to 0.41 mg, and ferrous sulphate mixed into the meal in an amount (6 mg) corresponding to the iron content of the soy flour increased the absorption to 0.64 mg. The addition of citric acid (1 g) reduced the absorption to 0.06 mg (to about one-third). We conclude that several methods are available for increasing iron absorption from a Latin American meal and that the choice of method depends on several factors, particularly cost.

Topics: Adult; Ascorbic Acid; Citrates; Citric Acid; Developing Countries; Diet; Female; Ferrous Compounds; Food, Fortified; Glycine max; Humans; Intestinal Absorption; Iron; Latin America; Male; Meat; Middle Aged; Nutritive Value; Plant Proteins, Dietary

The present study demonstrates the efficacies of synthetic 1,8-cineole and an 1,8-cineole-rich supercritical carbon dioxide (SC-CO

Topics: Alzheimer Disease; Amyloid beta-Peptides; Ascorbic Acid; Cell Line, Tumor; Drug Evaluation, Preclinical; Drug Synergism; Elettaria; Eucalyptol; Ferroptosis; Ferrous Compounds; Gas Chromatography-Mass Spectrometry; Humans; Hydroxyl Radical; Neuroblastoma; Peptide Fragments; Phytotherapy; Plant Extracts; Reactive Oxygen Species; Seeds; Spices

A new iron-casein complex (ICC) has been developed for iron (Fe) fortification of dairy matrices. The objective was to assess the impact of ascorbic acid (AA) on its in vitro bioavailability in comparison with ferrous sulfate (FeSO

Topics: Ascorbic Acid; Biological Availability; Caco-2 Cells; Caseins; Cells, Cultured; Diphosphates; Ferrous Compounds; Food, Fortified; Humans; In Vitro Techniques; Iron

Iron deficiency is the most common form of malnutrition. Factors responsible for this so-called "hidden hunger" include poor diet, increased micronutrient needs and health problems such as diseases and infections. Body iron status can be increased by the intake of dietary supplements and fortified food. The aim of the present study was to compare iron bioaccessibility from commercial nutritional supplements and iron microcapsules. A comparison study was performed under conditions mimicking gastric and gastrointestinal digestion. A preparation of encapsulated ferrous sulphate or lactate and vitamin C, in a formula, showed bioaccessibility factors of up to 100% when digested individually, and around 60% in the presence of a food matrix. The degree of oxidation of the ferrous ions differed, depending on the type of preparation, the presence of vitamin C and the food matrix. The highest percentage content of ferrous ion, in the soluble fractions after gastrointestinal digestion, was shown by the preparation containing microencapsulated ferrous lactate or ferrous sulphate and vitamin C. Encapsulation seems to limit the interaction of iron with the food matrix and protect it against oxidation, thus making it more accessible for intestinal uptake.

Topics: Adult; Ascorbic Acid; Biological Availability; Dietary Supplements; Digestion; Drug Compounding; Ferrous Compounds; Food Analysis; Food, Fortified; Humans; Iron; Models, Biological

Iron deficiency is a major public health concern and nutritional approaches are required to reduce its prevalence. The aim of this study was to examine the iron bioavailability of a novel home fortificant, the "Lucky Iron Fish™" (LIF) (www.luckyironfish.com/shop, Guelph, Canada) and the impact of dietary factors and a food matrix on iron uptake from LIF in Caco-2 cells. LIF released a substantial quantity of iron (about 1.2 mM) at pH 2 but this iron was only slightly soluble at pH 7 and not taken up by cells. The addition of ascorbic acid (AA) maintained the solubility of iron released from LIF (LIF-iron) at pH 7 and facilitated iron uptake by the cells in a concentration-dependent manner. In vitro digestion of LIF-iron in the presence of peas increased iron uptake 10-fold. However, the addition of tannic acid to the digestion reduced the cellular iron uptake 7.5-fold. Additionally, LIF-iron induced an overproduction of reactive oxygen species (ROS), similar to ferrous sulfate, but this effect was counteracted by the addition of AA. Overall, our data illustrate the major influence of dietary factors on iron solubility and bioavailability from LIF, and demonstrate that the addition of AA enhances iron uptake and reduces ROS in the intestinal lumen.

Topics: Anemia, Iron-Deficiency; Ascorbic Acid; Biological Availability; Biological Transport; Caco-2 Cells; Canada; Cell Survival; Ferritins; Ferrous Compounds; Humans; Hydrogen-Ion Concentration; Iron; Reactive Oxygen Species; Solubility; Tannins

4-nitroquinoline-1-oxide (4-NQO) is a pro-oxidant carcinogen bioactivated by xenobiotic metabolism (XM). We investigated if antioxidants lycopene [0.45, 0.9, 1.8 μM], resveratrol [11, 43, 172 μM], and vitamin C [5.6 mM] added or not with FeSO

Topics: 4-Nitroquinoline-1-oxide; Animals; Antioxidants; Ascorbic Acid; Carcinogens; Carotenoids; Cytochrome P-450 Enzyme System; Drosophila melanogaster; Female; Ferrous Compounds; Larva; Lycopene; Male; Resveratrol; Stilbenes; Toxicity Tests; Wings, Animal; Xenobiotics

In this study, the effect of food additives such as iron sulfate, magnesium sulfate, zinc sulfate, citric acid, gallic acid, and ascorbic acid on the reduction of 4(5)-methylimidazole (4(5)-MI) was investigated using a soy sauce model system. The concentration of 4(5)-MI in the soy sauce model system with 5% (v/v) caramel colorant III was 1404.13 μg/L. The reduction rate of 4(5)-MI level with the addition of 0.1M additives followed in order: iron sulfate (81%) > zinc sulfate (61%) > citric acid (40%) > gallic acid (38%) > ascorbic acid (24%) > magnesium sulfate (13%). Correlations between 4(5)-MI levels and the physicochemical properties of soy sauce, including the amount of caramel colorant, pH value, and color differences, were determined. The highest correlations were found between 4(5)-MI levels and the amount of caramel colorant and pH values (r(2) = 0.9712, r(2) = 0.9378). The concentration of caramel colorants in 8 commercial soy sauces were estimated, and ranged from 0.01 to 1.34% (v/v).

Topics: Ascorbic Acid; Carbohydrates; Carcinogens; Citric Acid; Color; Ferrous Compounds; Food Additives; Food Handling; Gallic Acid; Glycine max; Hydrogen-Ion Concentration; Imidazoles; Maillard Reaction; Models, Biological; Soy Foods; Zinc Sulfate

The formation and reduction of furan using a soy sauce model system were investigated in the present study. The concentration of furan fermented up to 30 days increased by 211% after sterilization compared to without sterilization. Regarding fermentation temperature, furan level after 30 days' fermentation was the highest at 30°C (86.21 ng/mL). The furan levels in the soy sauce fermentation at 20°C and 40°C were reduced by 45% and 88%, respectively compared to 30°C fermentation. Five metal ions (iron sulfate, zinc sulfate, manganese sulfate, magnesium sulfate, and calcium sulfate), sodium sulfite, ascorbic acid, dibutyl hydroxyl toluene (BHT), and butylated hydroxyanisole (BHA) were added in a soy sauce model system. The addition of metal ions such as magnesium sulfate and calcium sulfate reduced the furan concentration significantly by 36-90% and 27-91%, respectively in comparison to furan level in the control sample (p<0.05). Iron sulfate and ascorbic acid increased the furan level at 30 days' fermentation in the soy sauce model system by 278% and 87%, respectively. In the case of the BHT and BHA, furan formation generally was reduced in the soy sauce model system by 84%, 56%, respectively.

Topics: Ascorbic Acid; Butylated Hydroxyanisole; Calcium Sulfate; Fermentation; Ferrous Compounds; Food Handling; Furans; Gas Chromatography-Mass Spectrometry; Magnesium Sulfate; Manganese Compounds; Reproducibility of Results; Soy Foods; Sterilization; Sulfates; Sulfites; Temperature; Zinc Sulfate

We studied the spontaneous and metal induced oxidation of lipids and proteins in in vitro modeling ways of lipid peroxidation and blood proteins in the formation of malondialdehyde (MDA) and protein carbonyl groups (PCG) in 86 patients with chronic pyelonephritis (cPN) and 64 patients chronic glomerulonephritis(cGN) without prejudice excretory function of the kidneys. Installed the increase in the blood of patients with cPN MDAs 2 times, MDAe--14%, PCG 1.5 times; and cGN--MDAs 2.3 times, MDAe--29%, PCG--2 times. Found increased MDA content and PCG in the blood of patients with cPN and more expressive when cGN. Stimulation of in vitro peroxidation processes contributed significantly increased of production of MDA comparedwith baseline. In the modeling in vitro ascorbate-dependent and NADPH-dependent lipid peroxidation ways and the increase in protein production of MDA and PCG in both groups of patients, especially in the NADPH-dependent way, which must be considered in the correction of oxidative processes and antioxidant therapy appointment.

Topics: Ascorbic Acid; Case-Control Studies; Chronic Disease; Erythrocytes; Ferrous Compounds; Glomerulonephritis; Humans; Lipid Peroxidation; Malondialdehyde; Primary Cell Culture; Protein Carbonylation; Pyelonephritis

In order to explore the interaction of mefloquine with hemin against adult Schistosoma japonicum in vitro, the 50% and 95% lethal concentration (LC50 and LC95) of mefloquine and hemin against schistosomes, some factors, such as other iron providing agents, iron chelaters, zinc protoporphyrin-IX, and biological relevant reductants, that might impact on antischistosomal activity induced by interaction of mefloquine with hemin, and preliminary analysis of chemical interaction of both compounds were undertaken. The LC50 and LC95 of mefloquine and hemin alone against schistosomes were determined to be 6.5μg/ml and 7.8μg/ml as well as 232μg/ml and 355μg/ml, respectively. The LC50 and LC95 of mefloquine in the presence of hemin 100μg/ml was 0.24μg/ml and 0.59μg/ml, respectively. On the other hand the LC50 and LC95 of hemin in the presence of mefloquine 1μg/ml was 23.2μg/ml and 77.2μg/ml, respectively. Meanwhile, mefloquine/hemin combinations showed potential synergistic effects against adult S. japonicum, with combination index (CI) values <1. Apart from hemin, zinc protoporphyrin-IX, and other iron providing agents such as ferrous sulfate and ferriammonium sulfate combined with mefloquine exhibited no toxic effect against schistosomes. On the other hand, addition of iron chelators (deferiprone, desferrioxamine mesylate, or 2,2'-bipyridine) to the medium containing mefloquine-hemin resulted in no protective effect on the worms. Furthermore, biological reductants like glutathione, vitamine C or cysteine showed no apparent worm protection effect from toxic mefloquine-hemin even at higher concentrations (242.3-614.6μg/ml, i.e., 6.4-17.8-fold higher than the concentration of hemin). Chemical interaction of mefloquine with hemin was studied in 40% DMSO-Tris buffer solution. Both UV-Vis spectrum and mass spectrum demonstrated the strong interaction of mefloquine with hemin, which resulted in a reduction of hemin color and emergence of an adduct formed by mefloquine and hemin. The results confirm that mefloquine combined with hemin exhibits potential synergistic effect against adult S. japonicum in vitro.

Topics: 2,2'-Dipyridyl; Animals; Anthelmintics; Ascorbic Acid; Cysteine; Deferiprone; Deferoxamine; Drug Synergism; Drug Therapy, Combination; Ferric Compounds; Ferrous Compounds; Glutathione; Hemin; Inhibitory Concentration 50; Iron Chelating Agents; Mefloquine; Protoporphyrins; Pyridones; Schistosoma japonicum

Lead poisoning is a global environmental disease that induces lifelong adverse health effects. The effect of a milk formula consisting of antioxidant of bamboo leaves (AOB), vitamin C (Vc), calcium lactate (CaLac), ferrous sulfate (FeSO₄) and zinc sulfate (ZnSO₄) on the reduction of lead and lead-induced oxidative damage in lead-exposed mice was studied. The lead-reducing effect of milk formula was investigated via a 7-week toxicokinetics study and a tissue distribution level examination. The ameliorating effect of milk formula on lead-induced oxidative damage was investigated. Results demonstrated current milk formula could effectively reduce blood lead levels (BLLs) and lead distribution levels of liver, kidneys, thighbones and brain in mice based on metal ion-mediated antagonism and chelation mechanisms. This milk formula could not only protect lead-susceptible tissues against lead poisoning, but also maintain normal absorption and distribution of essential elements in vivo. Meanwhile, current milk formula could prevent the reduction of δ-aminolevulinic acid dehydratase (δ-ALAD) activity and enhancement of free erythrocyte protoporphyrins (FEP) levels in blood erythrocytes of mice. Also, this formula could indirectly protect blood cell membranes against lead-induced lipid peroxidation. We conclude that current optimized milk formula effectively reduces lead poisoning and lead-induced in vivo oxidative damage in lead-exposed mice.

Topics: Animals; Antioxidants; Ascorbic Acid; Calcium Compounds; Ferrous Compounds; Food, Formulated; Lactates; Lead; Lead Poisoning; Male; Mice; Mice, Inbred ICR; Micronutrients; Milk; Oxidative Stress; Porphobilinogen Synthase; Reproducibility of Results; Sasa; Spectrophotometry, Atomic; Tissue Distribution; Zinc Sulfate

Neurodegerative diseases have been linked to oxidative stress arising from peroxidation of membrane biomolecules and high levels of Fe have been reported to play an important role in neurodegenerative diseases and other brain disorder. Malondialdehyde (MDA) is the end-product of lipid peroxidation and the production of this aldehyde is used as a biomarker to measure the level of oxidative stress in an organism. The present study compares the protective properties of two varieties of ginger [red ginger (Zingiber officinale var. Rubra) and white ginger (Zingiber officinale Roscoe)] on Fe(2+) induced lipid peroxidation in rat brain in vitro. Incubation of the brain tissue homogenate in the presence of Fe caused a significant increase in the malondialdehyde (MDA) contents of the brain. However, the aqueous extract from both varieties of ginger caused a significant decrease in the MDA contents of the brain in a dose-dependent manner. However, the aqueous extract of red ginger had a significantly higher inhibitory effect on both Fe(2+)-induced lipid peroxidation in the rat brain homogenates than that of white ginger. This higher inhibitory effect of red ginger could be attributed to its significantly higher phytochemical content, Fe(2+) chelating ability, OH scavenging ability and reducing power. However, part of the mechanisms through which the extractable phytochemicals in ginger (red and white) protect the brain may be through their antioxidant activity, Fe(2+) chelating and OH scavenging ability. Therefore, oxidative stress in the brain could be potentially managed/prevented by dietary intake of ginger varieties (red ginger and white ginger rhizomes).

Topics: Animals; Antioxidants; Ascorbic Acid; Brain; Chlorides; Ferric Compounds; Ferrous Compounds; Flavonoids; In Vitro Techniques; Iron Chelating Agents; Lipid Peroxidation; Male; Oxidation-Reduction; Phenol; Plant Extracts; Rats; Rats, Wistar; Rhizome; Zingiber officinale

The aim of this study was to investigate the in vitro antioxidant activity of 2,2'-dipyridyl diselenide (e) by comparing this effect with m-trifluoromethyl-diphenyl diselenide (a), p-fluor-diphenyl diselenide (b), p-chloro-diphenyl diselenide (c), and p-methoxyl-diphenyl diselenide (d) in rat liver homogenate. We also investigated if the mechanisms involved in the antioxidant property of 2,2'-dipyridyl diselenide are the same that of other diselenides. Thiobarbituric acid reactive substances (TBARS) and protein carbonyl (PC) levels were determined in rat liver homogenate, as indicators of antioxidant activity. Dehydroascorbate (DHA) reductase- and glutathione S-transferase (GST)-like activities, 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical-scavenging activities and the protection against the oxidation of Fe(2+) were determined to better understand the antioxidant property of compounds. δ-Aminolevulinic dehydratase (δ-ALA-D) activity was also carried out in rat liver homogenates, as a toxicological parameter. Compound e showed the highest potency in reducing TBARS (order of IC(50) values: e < b ≤ a < d ≤ c) and PC (order of IC(50) values: e < c ≤ b ≤ a < d) levels and lower potency in inhibiting δ-ALA-D activity than other diselenides. Compound e at all concentrations tested had no enzyme-mimetic property, but had radical-scavenging activity (≥5 μM) and protected against the oxidation of Fe(2+) (50 μM); while compounds a-d showed GST and DHA-mimetic activities and protected against the oxidation of Fe(2+), but had not radical-scavenging activities. This study indicates that (i) 2,2'-dipyridyl diselenide (e) had better in vitro antioxidant effect than other diselenides and lower inhibitory effect on δ-ALA-D activity, (ii) the presence of pyridine ring is responsible for the best antioxidant effect of this compound, and (iii) 2,2'-dipyridyl diselenide acts by different mechanisms of other diselenides.

Topics: 2,2'-Dipyridyl; Animals; Antioxidants; Ascorbic Acid; Benzene Derivatives; Dehydroascorbic Acid; Ferrous Compounds; Glutathione; Glutathione Transferase; Lipid Peroxidation; Liver; Male; Organoselenium Compounds; Organosilicon Compounds; Oxidation-Reduction; Oxidoreductases; Porphobilinogen Synthase; Protein Carbonylation; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances; Tissue Extracts

Few attempts have been made to improve the activity of plant compounds with low antimicrobial efficacy. (+)-Catechin, a weak antimicrobial tea flavanol, was combined with putative adjuncts and tested against different species of bacteria. Copper(II) sulphate enhanced (+)-catechin activity against Pseudomonas aeruginosa but not Staphylococcus aureus, Proteus mirabilis or Escherichia coli. Attempts to raise the activity of (+)-catechin against two unresponsive species, S. aureus and E. coli, with iron(II) sulphate, iron(III) chloride, and vitamin C, showed that iron(II) enhanced (+)-catechin against S. aureus, but not E. coli; neither iron(III) nor combined iron(II) and copper(II), enhanced (+)-catechin activity against either species. Vitamin C enhanced copper(II) containing combinations against both species in the absence of iron(II). Catalase or EDTA added to active samples removed viability effects suggesting that active mixtures had produced H(2)O(2)via the action of added metal(II) ions. H(2)O(2) generation by (+)-catechin plus copper(II) mixtures and copper(II) alone could account for the principal effect of bacterial growth inhibition following 30 minute exposures as well as the antimicrobial effect of (+)-catechin-iron(II) against S. aureus. These novel findings about a weak antimicrobial flavanol contrast with previous knowledge of more active flavanols with transition metal combinations. Weak antimicrobial compounds like (+)-catechin within enhancement mixtures may therefore be used as efficacious agents. (+)-Catechin may provide a means of lowering copper(II) or iron(II) contents in certain crop protection and other products.

Topics: Anti-Bacterial Agents; Antioxidants; Ascorbic Acid; Camellia sinensis; Catechin; Copper Sulfate; Drug Synergism; Escherichia coli; Ferrous Compounds; Proteus mirabilis; Pseudomonas aeruginosa; Staphylococcus aureus

Home-made diets are the most frequently used complementary foods. In the present work we evaluated iron and zinc availability in a usually consumed infant diet containing either iron-fortified bread with different iron sources: ferrous sulfate, ferrous bisglycinate, NaFeEDTA. We also used non-fortified bread with absorption promoters: ascorbic acid, sodium citrate, Na2EDTA, combined with different beverages. The diet (potato, pumpkin, grits, bread, and apple) was combined with water, milk, tea, a soft drink and an orange-based artificial drink. Mineral dialyzability (D) as an indicator of potential availability was determined using an in vitro method. Statistical analysis was performed by ANOVA, and a posteriori Tukey test. There were no significant differences in FeD between diets with ferrous sulfate or ferrous bisglycinate fortified bread; in NaFeEDTA fortified bread it increased significantly (p<0.05). Iron D increase was greater in diets with bread containing absorption promoters than in those with fortified bread. The orange-based artificial drink increased FeD, while tea and milk decreased it significantly (p < 0.05). Zinc D increased significantly when the bread was fortified either with ferrous sulfate or NaFeEDTA, but remained unchanged in diets with ferrous bisglycinate fortified bread. The addition of tea or milk decreased ZnD while the orange-based artificial drink increased it significantly (p < 0.05). Regarding absorption promoters, the greater values both in FeD and ZnD were observed in diets with iron nonfortified bread containing Na2EDTA.

Topics: Ascorbic Acid; Beverages; Bread; Citrates; Dialysis; Edetic Acid; Ferric Compounds; Ferrous Compounds; Food, Fortified; Glycine; Humans; Infant; Iron; Sodium Citrate; Zinc

In the present work, a rapid and high-throughput Folin-Ciocalteu (F-C) reducing capacity assay adapted to routine/screening analysis was developed. In order to attain a fast F-C reducing kinetic reaction, the reaction conditions of the classical time-consuming F-C assay were modified and the influence of alkali and F-C reagent concentration was evaluated using gallic acid as standard. The proposed method was performed in a 96-well microplate format and it was applied to several phenolic compounds and food products (wines, beers, infusions and juices) providing F-C reducing capacity results after 3 min of reaction similar to those obtained by the time-consuming (120 min) conventional method. The additive and synergistic effect of reducing nonphenolic compounds usually found in food samples was also investigated. Ascorbic acid and ferrous sulfate provided an additive effect, while for fructose, glucose and sodium sulfite a synergistic effect was obtained. The detection limit was 0.25 mg L(-1) (as gallic acid) and the repeatability was <1.6% (n=12).

Topics: Ascorbic Acid; Beer; Beverages; Calibration; Chemistry Techniques, Analytical; Ferrous Compounds; Food; Food Analysis; Food Contamination; Fructose; Gallic Acid; Glucose; Sulfites; Time Factors; Wine

The effects of ascorbic acid (AA), phytate and tannic acid (TA) on Fe bioavailability from Fe supplied as reconstituted ferritin were compared with FeSO4 using an in vitro digestion-Caco-2 cell model. Horse spleen apoferritin was chemically reconstituted into an animal-type ferritin (HSF) and a plant-type ferritin (P-HSF) according to the typical ratios of Fe:P found in these molecules. In the presence of AA (Fe:AA molar ratio of 1:20), significantly more Fe was absorbed from FeSO4 (about 303 %), HSF (about 454 %) and P-HSF (about 371 %) when compared with ferrous sulfate or ferritin without AA. Phytic acid (PA; Fe:PA molar ratio of 1:20) significantly reduced Fe bioavailability from FeSO4 (about 86 %), HSF (about 82 %) and P-HSF (about 93 %) relative to FeSO4 and the ferritin controls. Treatment with TA (Fe:TA molar ratio of 1:1) significantly decreased Fe bioavailability (about 97 %) from both FeSO4 and the ferritin samples. AA was able to partially reverse the negative effect of PA (Fe:PA:AA molar ratio of 1:20:20) on Fe bioavailability but did not reverse the inhibiting effect of TA (Fe:TA:AA molar ratio of 1:1:20) on Fe bioavailability from ferritin and FeSO4. Overall, there were no significant differences in bioavailable Fe between P-HSF, HSF or FeSO4. Furthermore, the addition of AA (a known promoter) or the inhibitors, PA and TA, or both, did not result in significant differences in bioavailable Fe from ferritin relative to FeSO4. The results suggest that Fe in the reconstituted ferritin molecule is easily released during in vitro digestion and interacts with known promoters and inhibitors.

Topics: Absorption; Analysis of Variance; Animals; Ascorbic Acid; Biological Availability; Caco-2 Cells; Chromatography, Gel; Digestion; Electrophoresis, Polyacrylamide Gel; Ferritins; Ferrous Compounds; Fishes; Food; Humans; Hydrogen-Ion Concentration; Iron Chelating Agents; Iron, Dietary; Phytic Acid; Tannins

We previously showed that sphingomyelin (SM) inhibits peroxidation of phosphatidylcholine (PC) and cholesterol. Since SM uniquely has a trans unsaturation in its sphingosine base, we investigated whether this feature is important for its antioxidant function. Substitution of the natural trans Delta(4)-double bond with a cis double bond (cis-SM), however, increased SM's ability to inhibit Cu(2+)-mediated 16:0-18:2 PC oxidation by up to eightfold. Dihydro-SM, which lacks the double bond, was equally effective as trans-SM. In contrast to its effect in the sphingosine base, the presence of a cis double bond in the N-acyl group of trans-SM was not protective. cis-SM also inhibited the oxidation of cholesterol by FeSO_(4)/ascorbate more efficiently than the trans isomer. The enhanced protective effect of cis-SM is selective for metal ion-promoted oxidation, and appears to arise from a decrease in the effective concentration of metal ions. These studies show that the trans double bond of SM is not essential for its antioxidant effects.

Topics: Antioxidants; Ascorbic Acid; Cations, Divalent; Cholesterol; Copper; Ferrous Compounds; Lipid Peroxidation; Oxidation-Reduction; Phosphatidylcholines; Sphingomyelins; Sphingosine; Stereoisomerism

Sulfamethoxazole is metabolized by microsomal CYP2C9 to a hydroxylamine that is thought to be responsible for the relatively high incidence of hypersensitivity reactions associated with the drug. Accurate quantification of the hydroxylamine requires the loss of metabolite through autoxidation to be blocked with ascorbate. In this study, a partly nonenzymatically generated arylhydroxylated derivative of sulfamethoxazole was identified by liquid chromatography/mass spectrometry in incubations of human liver microsomes, and it was found to coelute with the isomeric hydroxylamine under the conditions of three published high-performance liquid chromatography (HPLC) assays. Partial inhibition of the aryl hydroxylation by 1-aminobenzotriazole suggested some involvement of cytochrome P450. However, the formation of this compound was ascorbate-dependent, and it was enhanced by the addition of Fe2+/EDTA and inhibited by desferrioxamine but not by mannitol. These findings are consistent with the phenol being generated via an Fe2+/ascorbate/O2-oxygenating system that does not involve hydroxyl radicals. It was also produced by H2O2/ascorbate. Because the compound shares close chromatographic similarities with the hydroxylamine metabolite, it is possible that previous studies may have inaccurately characterized or quantified sulfamethoxazole metabolism.

Topics: Ascorbic Acid; Chromatography, High Pressure Liquid; Deferoxamine; Edetic Acid; Enzyme Inhibitors; Ferrous Compounds; Humans; Hydrogen Peroxide; Hydroxylation; Kinetics; Microsomes, Liver; Molecular Structure; NADP; Sulfamethoxazole; Tandem Mass Spectrometry; Triazoles

To study the effects of ascorbic acid and citric acid on iron bioavailability using an in vitro digestion/Caco-2 cell culture model and evaluate the validity of this cell model.. This model combined in vitro digestion technique with Fe uptake by Caco-2 cells by utilizing an inserted ring attached to a dialysis membrane to simulate the gastrointestinal environment to allow simultaneous food digestion and uptake processes. Ferritin formation in the Caco-2 cells was measured as the indicator of Fe uptake by exposing Caco-2 cells to the digests containing Fe plus ascorbic acid or citric acid.. When Fe concentration in the digest was below 100 micromol/L, ferritin formation increased with the Fe concentration in the digest. The iron digest containing ascorbic acid exhibited a significant increase in ferritin formation relative to the iron digest containing citric acid. The model was more sensitive to lower iron concentrations when ascorbic acid was present in the digest, while wider range of iron concentration could be assessed by addition of citric acid.. The in vitro digestion/ Caco-2 cell culture model is a valuable tool for iron bioavailability assessment. Ascorbic acid has a stronger effect than citric acid in promoting iron bioavailability.

Topics: Ascorbic Acid; Biological Availability; Caco-2 Cells; Citric Acid; Ferritins; Ferrous Compounds; Humans; Iron; Models, Biological

It is known that an addition of FeSO4 in the presence of ascorbic acid to cells or mitochondria can injure energy coupling and some other functions in mitochondria. The present study demonstrates that decrease in ascorbate concentration from 4 to 0.2 mM in the presence of the same low concentrations of FeSO4 accelerates the nonspecific pore opening, while cyclosporin A prevents and under some conditions reverses the pore opening. Hydrophobic cations SkQ1 and MitoQ (structural analogs of plastoquinone and coenzyme Q(10), respectively) delay pore opening, SkQ1 being more efficient. It is known that an increase in matrix ADP concentration delays pore opening, while an addition of carboxyatractylate to mitochondria accelerates the beginning of pore opening. Preliminary addition of SkQ1 into a mitochondrial suspension increased the effect of ADP and decreased the effect of carboxyatractylate. These results suggest that under the conditions used SkQ1 protects mitochondria from oxidative damage as an antioxidant when added at extremely low concentrations.

Topics: Animals; Antioxidants; Ascorbic Acid; Cyclosporine; Ferrous Compounds; Mitochondria; Mitochondrial Membranes; Organophosphorus Compounds; Oxidation-Reduction; Oxidative Stress; Permeability; Plastoquinone; Rats; Time Factors; Ubiquinone

Biofortification of staple foods with iron (Fe) in the form of ferritin (Ft) is now possible, both by conventional plant breeding methods and transgenic approaches. Ft-Fe from plants and animals is absorbed well (25-30%) by human subjects, but little is known about dietary factors affecting its absorption. We used human intestinal Caco-2 cells and compared Fe absorption from animal Ft and FeSO4 to determine the effects of inhibitors and enhancers, such as phytic acid, ascorbic acid, tannic acid, calcium and heme. When postconfluent cells were coincubated with 59Fe-labeled (1 microM) FeSO4 and dietary factors, at different molar ratios of dietary factor to Fe (phytic acid:Fe, 10:1; ascorbic acid:Fe, 50:1; tannic acid:Fe, 50:1; calcium:Fe, 10:1 and hemin:Fe, 10:1), all inhibited uptake from FeSO4, except ascorbate, confirming earlier studies. In contrast, these dietary factors had little or no effect on Fe uptake from undigested Ft or Ft digested in vitro at pH 4, except tannins. However, results after in vitro digestion of Ft at pH 2 were similar to those obtained for FeSO4. These results suggest that Fe uptake occurs from both undigested as well as digested Ft but, possibly, via different mechanisms. The Fe-Ft stability shown here could minimize Fe-induced oxidation of Fe-supplemented food products.

Topics: Animals; Ascorbic Acid; Blotting, Western; Caco-2 Cells; Calcium; Diet; Digestion; Ferritins; Ferrous Compounds; Hemin; Humans; Intestinal Absorption; Iron; Phytic Acid; Tannins

Oxidative stress, inflammation and apoptosis play a critical role in the onset and progression of cellular damage. It was previously reported that hyaluronan (HA) and chondroitin-4-sulphate (C4S) were able to protect human skin fibroblasts from oxidative stress. This antioxidant activity is due to the chelation of transition metal ions. Nuclear factor kB (NF-kB), complexed with the inhibitory protein IkB alpha, is an ubiquitous response transcription factor involved in inflammatory reactions and acts by inducing cytokine expression, chemokines and cell adhesion molecules. Caspases are specific proteases responsible for the regulation and the execution of apoptotic cell death. The damage caused by free radicals may be amplified greatly by the activation of these factors. The study investigated whether the ability of these glycosaminoglycans (GAGs) to reduce oxidative damage in fibroblast cultures involves NF-kB and caspases modulation. The treatment of fibroblasts with both HA and C4S limited the cell damage induced by FeSO(4) plus ascorbate. An interesting aspect of this treatment was that these GAGs significantly inhibited NF-kB DNA binding, as confirmed by the normalization of IkB alpha protein, and reduced caspase activation at both mRNA and protein level. A possible explanation for these results, since lipid peroxidation intermediates may induce NF-kB and caspase activation, is that HA and C4S indirectly blocked NF-kB DNA binding and apoptosis by inhibiting reactive oxygen species (ROS) production. These data suggest that, during oxidative stress, HA and C4S may reduce cell damage by inhibiting NF-kB and apoptosis activation as well as protecting cells from free radical attack. According to these finding the use of HA and C4S could be positive both as tool to clarify the exact mechanism of GAGs/ROS interaction, and also as drug therapy to reduce oxidative stress during inflammation.

Topics: Antioxidants; Ascorbic Acid; Caspases; Cell Survival; Cells, Cultured; Chondroitin Sulfates; DNA; Ferrous Compounds; Fibroblasts; Humans; Hyaluronic Acid; I-kappa B Proteins; Lipid Peroxidation; NF-kappa B; NF-KappaB Inhibitor alpha; Oxidants; Oxidative Stress; Protein Binding; Reactive Oxygen Species; RNA, Messenger

Iron, zinc, and calcium dialyzability and ascorbic acid (AA) concentrations were evaluated in milk and yogurt fortified with FeNaEDTA (FE) or ferrous sulfate (FS) as a control, with or without AA addition. The values obtained for FE iron dialyzability in milk were much higher than those obtained for FS. The addition of AA to milk improved Fe dialyzability when using FS and slightly decreased Fe dialyzability in the FE-fortified nonfermented samples. Milk fermentation increased iron availability from both iron sources. Zinc and calcium dialyzability in products containing any of the two iron sources was increased in fermented milks. EDTA improved Zn dialyzability from intrinsic zinc in every manufactured dairy product. Whereas for milks fortified with FS and stored at 4 degrees C for 24 h, the AA content remained close to the original concentration, a higher AA degradation was observed when milks were fortified with FE.

Topics: Animals; Ascorbic Acid; Biological Availability; Calcium; Dairy Products; Dialysis; Edetic Acid; Fermentation; Ferric Compounds; Ferrous Compounds; Food, Fortified; Milk; Minerals; Zinc

The reduced iron powder has considerable potential for use as an iron fortificant because it does not change organoleptically during storage or food preparation for cereal flour, and its bioavailability is scarcely influenced by iron absorption inhibitors in foods. The objective of this article is to study the effects of ascorbic acid, phytic acid, and pH on iron uptake from reduced iron powder (43 microm) and FeSO 4, and to compare iron bioavailability of reduced iron powders among four selected granularity levels. The cell ferritin formation is used as a marker of iron uptake. Obviously, iron uptake of reduced iron powder is increased with decreasing of powder granularity and is much lower than FeSO 4 when the size is above 43 microm, but significantly higher at 40-60 nm. In the presence of ascorbic acid or phytic acid, Caco-2 cell iron absorption from reduced iron powder (43 microm) is significantly higher than that from FeSO 4. And iron uptake of Caco-2 cells is decreased with increasing of pH from 5.5 to 7.5. Moreover, the decrease trend is more obvious for reduced iron powder than for FeSO 4. Our results indicated that iron bioavailability of reduced iron powder by intestinal enterocytes is similar to that of iron salts, and reduced iron powder is more excellent than FeSO 4 as food fortificant, especially at ultramicroscopic granularity.

Topics: Ascorbic Acid; Biological Availability; Caco-2 Cells; Ferritins; Ferrous Compounds; Humans; Hydrogen-Ion Concentration; Iron; Oxidation-Reduction; Phytic Acid; Powders

The present study describes the effects of exposure of bovine sperm to mild and more intense ROS generating conditions. The membrane integrity of the incubated sperm was assessed and the incubated sperm were used for IVF after which the percentages of cleavage and blastocyst formation were determined for a period up to 9 days. The incubated sperm samples showed increased levels of molecular oxidation in the plasma membrane, the mitochondria, the cytosol and to a lesser extent in the sperm's DNA. The sperm membrane integrity as well as the first cleavage rates obtained with sperm from mild ROS generating conditions (100 microM H2O2) were not different from sperm incubated without pro-oxidants. However, exposure of sperm to more severe oxidative stress (500 mM H2O2 or a combination of 100 microM ascorbic acid, 20 microM FeSO4 and 500 microM H2O2) led to plasma membrane oxidation, reduced percentages of cleaved embryos and a reduction in the percentages of cleaved embryos that developed to the blastocyst stage. From these results, we conclude that the impact of oxidative stress to sperm becomes primarily manifest after the first cleavage of the formed zygote. Importantly, the level of lipid peroxidation in the sperm plasma membrane significantly correlates with blastocyst formation when the corresponding sperm is used for in vitro fertilization of oocytes.

Topics: Animals; Antioxidants; Ascorbic Acid; Cattle; Cell Membrane; DNA; Embryo, Mammalian; Ferrous Compounds; Hydrogen Peroxide; Lipid Peroxidation; Male; Mitochondria; Oxidants; Oxidation-Reduction; Spermatozoa; Statistics as Topic; Zygote

Lipid peroxidation is known to be a major factor in the aetiology of defective sperm function. Although biochemical assays for this process exist, they are relatively insensitive and require large numbers of spermatozoa; a condition that cannot be met with many infertility specimens. Recently, a new approach for monitoring peroxidative damage has been introduced, involving the probe BODIPY (581/591) C(11), which readily incorporates into cells and undergoes a spectral emission shift when attacked by reactive oxygen metabolites. We have examined the applicability of this probe as an indicator of oxidative stress in human sperm populations using flow cytometry as an end point. The measurement of peroxidation with BODIPY C(11) demonstrated significant dependence on the presence of a ferrous ion promoter (P < 0.001), which was significantly enhanced in sperm recovered from low-density Percoll fractions (P < 0.05) and was particularly damaging to the sperm midpiece. Iron-induced radical formation was suppressed by ascorbate in a dose-dependent manner (P < 0.001) and could only be promoted by Fe(II) and Cu(II); nickel, zinc and Fe(III) were ineffective. The Fe(II)-promoted BODIPY C(11) signal was significantly correlated with the measurement of reactive oxygen species generation with dihydroethidium. We conclude that BODIPY C(11) is an extremely useful probe for indexing peroxidative damage in human spermatozoa.

Topics: Antioxidants; Ascorbic Acid; Aza Compounds; Centrifugation; Copper; Fatty Acids; Ferrous Compounds; Flow Cytometry; Humans; In Vitro Techniques; Lipid Peroxidation; Male; Models, Chemical; Molecular Probes; Nitrates; Oxidative Stress; Povidone; Reactive Oxygen Species; Silicon Dioxide; Spermatozoa; Time Factors

Clusterin/apolipoprotein J is a multifunctional protein up-regulated during various pathophysiological states. Since oxidative stress plays an important role in brain aging, and in many neurodegenerative disorders, to further understand the mechanistic underpinnings of clusterin expression, in this study, we examined clusterin expression in human neuroblastoma cells under conditions of increased production of reactive oxygen species and lipid peroxidation. Specifically, we analyzed clusterin mRNA and protein levels in human neuroblastoma IMR-32 and SH-SY5Y cells following exposure to sub-lethal amounts of iron-ascorbate to induce an increase in reactive oxygen species generation and lipid peroxidation. Under such conditions, we observed a time-dependent up-regulation of clusterin protein and mRNA levels, detected by immunoblot analysis and RT-PCR, respectively. Given the known roles of clusterin, the results of the present study support the notion that an increase in clusterin expression may be a physiological defence mounted to reduce cell damage and maintain cell viability during periods of increased oxidative stress.

Topics: Alzheimer Disease; Ascorbic Acid; Blotting, Western; Cell Line, Tumor; Cell Survival; Clusterin; Ferrous Compounds; Humans; Hydrogen Peroxide; Lipid Peroxidation; Neurons; Oxidants; Oxidative Stress; Reactive Oxygen Species; Reverse Transcriptase Polymerase Chain Reaction; Up-Regulation

Several reports have shown that a number of cytokines such as tumor necrosis-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin-beta (IL-1beta) are capable to induce hyaluronan sinthases (HASs) mRNA expression in different cell culture types. The obvious consequence of this stimulation is a marked increment in hyaluronan (HA) production. It has been also reported that oxidative stress, by itself, may increase HA levels. The aim of this study was to evaluate how TNF-alpha, IFN-gamma,IL-1beta, and exposition to oxidative stress may modulate HAS activities in normal human skin fibroblasts. Moreover, the effects on HAS mRNA expression of the concomitant treatment with cytokines and oxidants, and the HA concentrations after treatments, were studied. TNF-alpha, IFN-gamma, and IL-1beta were added to normal or/and exposed to FeSO(4) plus ascorbate fibroblast cultures and HAS1, HAS2 and HAS3 mRNA content, by PCR-real time, was assayed 3,h later. HA levels were also evaluated after 24,h incubation. The treatment of fibroblasts with cytokines up-regulated HASs gene expression and increased HA production. IL-1beta induced HAS mRNA expression and HA production more efficiently than TNF-alpha and IFN-gamma. The exposition of the fibroblasts with the oxidant system markedly increased HAS activities while slightly HA production. The concomitant treatment of cells with the cytokines and the oxidant was able to further enhance, in a dose dependent way, with synergistic effect on HAS mRNA expression. On the contrary HA levels resulted unaffected by the concomitant treatment, and resemble those obtained with the exposure to FeSO(4) plus ascorbate only. This lack in HA production could be due to the deleterious action of free radicals on the HA synthesis.

Topics: Ascorbic Acid; Ferrous Compounds; Fibroblasts; Gene Expression Regulation, Enzymologic; Glucuronosyltransferase; Glycosyltransferases; Humans; Hyaluronan Synthases; Hyaluronic Acid; Interferon-gamma; Interleukin-1; RNA, Messenger; Skin; Tumor Necrosis Factor-alpha

Glossogyne tenuifolia (Labill) Cass. (Compositae) is a special medicinal plant in the Pescadores Islands. Ethanolic, cold and hot water extracts were prepared from the dried herb and their antioxidant properties and components were studied. Ascorbic acid, alpha-tocopherol, butylated hydroxyanisole, citric and ethylenediaminetetraacetic acids were used in assays for comparison. With regard to EC(50) values in antioxidant activity, ethanolic and hot water extracts (0.08 and 0.09 mg/ml) were much more effective than the cold water extract (0.76 mg/ml). At 1.0 mg/ml, reducing capacities were 1.57, 0.31 and 1.04 for ethanolic, cold water and hot water extracts, respectively. Scavenging abilities on 1,1-diphenyl-2-picrylhydrazyl radicals were in descending order: ethanolic > cold water > hot water extracts. At 20 mg/ml, the hot water extract chelated all hydroxyl ions (100%) whereas the scavenging ability of the cold water extract was 68.86%. Chelating abilities on ferrous ions were in descending order: cold water > hot water > ethanolic extracts. Phenols were found to be the major antioxidant components. All EC(50) values were below 20 mg/ml, and some even below 0.1 mg/ml, indicating that all three extracts from G. tenuifolia were rich in antioxidant properties.

Topics: Antioxidants; Ascorbic Acid; Asteraceae; beta Carotene; Biphenyl Compounds; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Ferrous Compounds; Free Radical Scavengers; Hydrazines; Hydroxyl Radical; Iron Chelating Agents; Oxidation-Reduction; Picrates; Plant Extracts; Tocopherols

Sodium iron(III) ethylenediaminetetraacetate (NaFeEDTA) has considerable promise as an iron fortificant because of its high bioavailability in foods containing iron absorption inhibitors. In this study, uptakes of iron from NaFeEDTA, FeSO4, and FeCl3 by Caco-2 cells were compared in the absence or presence of ascorbic acid (AA), an iron absorption enhancer; at selected pH levels; and in the absence or presence of an iron absorption inhibitor, bathophenanthroline disulfonic acid (BPDS). Ferritin formation in the cells was used as the indicator of iron uptake. Uptake from all three Fe sources was similar in the absence of AA. Adding AA at a 5:1 molar excess as compared to Fe increased uptake by 5.4-, 5.1-, and 2.8-fold for FeSO4, FeCl3, and NaFeEDTA, respectively. The smaller effect of AA on uptake from NaFeEDTA may be related to the higher solubility of NaFeEDTA and/or the strong binding affinity of EDTA for Fe3+, which may prevent AA and duodenal cytochrome b from effectively reducing EDTA-bound Fe. Uptake was inversely related to the pH of the media over a range of 5.8-7.2. Because uptake by DMT-1 is proton-coupled, the inverse relationship between pH and Fe uptake in all three iron sources suggests that they all follow the DMT-1 pathway into the cell. Adding BPDS to the media inhibited uptake from all three iron compounds equally. Because BPDS binds Fe2+ but not Fe3+ and because only Fe2+ is transported by DMT-1, the finding that BPDS inhibited uptake from NaFeEDTA suggests that at least some iron dissociates from EDTA and is reduced just as simple inorganic iron at the brush border membrane of the enterocyte. Taken together, these results suggest that uptake of iron from NaFeEDTA by intestinal enterocytes is regulated similarly to uptake from iron salts.

Topics: Ascorbic Acid; Biological Availability; Caco-2 Cells; Edetic Acid; Ferric Compounds; Ferritins; Ferrous Compounds; Humans; Hydrogen-Ion Concentration; Iron; Iron Chelating Agents

Carnosine has antioxidant properties and is efficient in the treatment of chemically-induced inflammatory lesions in animals. However, some studies question its biological significance as antioxidant and show lack of protection and even pro-oxidant effect of carnosine in systems containing nickel and iron ions. The ability of carnosine to: (1) reduce Fe(3+) into Fe(2+) ions; (2) protect deoxyribose from oxidation by Fe(2+)-, Fe(3+)-, and Cu(2+)-H(2)O(2)-EDTA systems; (3) protect DNA from damage caused by Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems; (4) inhibit HClO- and H(2)O(2)-peroxidase-induced luminol dependent chemiluminescence was tested in vitro. At concentration 10 mM carnosine reduced 16.6+/-0.5 nmoles of Fe(3+) into Fe(2+) ions during 20 min. incubation and added to plasma significantly increased its ferric reducing ability. Inhibition of deoxyribose oxidation by 10 mM carnosine reached 56+/-5, 40+/-11 and 30+/-11% for systems containing Fe(2+), Fe(3+) and Cu(2+) ions, respectively. The damage to DNA was decreased by 84+/-9 and 61+/-14% when Cu(2+)-, and Fe(2+)-H(2)O(2)-ascorbate systems were applied. Combination of 10 mM histidine with alanine or histidine alone (but not alanine) enhanced 1.3 and 2.3 times (P<0.05) the DNA damage induced by Fe(2+)-H(2)O(2)-ascorbate. These amino acids added to 10 mM carnosine decreased 3.1-fold (P<0.05) its protective effect on DNA. Carnosine at 10 and 20 mM decreased by more than 90% light emission from both chemiluminescent systems. It is concluded that carnosine has significant antioxidant activity especially in the presence of transition metal ions. However, hydrolysis of carnosine with subsequent histidine release may be responsible for some pro-oxidant effects.

Topics: Animals; Antioxidants; Ascorbic Acid; Carnosine; Cattle; Chlorides; Copper Sulfate; DNA; DNA Damage; Ferric Compounds; Ferrous Compounds; Humans; Hydrogen Peroxide; Hydrolysis; In Vitro Techniques; Iron Compounds; Male; Oxidation-Reduction; Oxidative Stress; Plasma

This study is the continuation of our research into vitamin C and its possible effects on human skin after topical administration. The effects of ascorbic acid, iron ions and UV irradiation on stratum corneum lipid models were investigated. The lipid models used were: a simple system (linolenic acid dispersion), a complex system (liposomes consisting of dipalmitoylphosphatidylcholine, cholesterol and linolenic acid) and complex systems with additionally incorporated ceramides (types III and IV). The lipid peroxidation was quantified by the thiobarbituric acid assay. A human adult low-calcium high-temperature (HaCaT) keratinocytes cell culture was used as a second in-vitro model. The amount of intracellular peroxides was determined by measuring the fluorescence intensity using the dihydrorhodamine 123 assay. Electron paramagnetic resonance spectroscopy was used to study the influence of ascorbic acid and iron ions on the signal intensity of 5-doxylstearic acid during UV exposure. Ascorbic acid showed prooxidative properties in the thiobarbituric acid assay whereas cell protection was measured in the HaCaT keratinocytes experiments. Electron paramagnetic resonance investigations revealed different extents of free radical production generated by iron ions, ascorbic acid and UV irradiation. In evaluating the results from this study new aspects of the mechanism of lipid damage caused by these three factors were suggested, transcending the simple redox behaviour of ascorbic acid.

Topics: Ascorbic Acid; Cell Line; Ceramides; Cholesterol; Electron Spin Resonance Spectroscopy; Ferrous Compounds; Humans; Keratinocytes; Linoleic Acid; Lipid Peroxidation; Liposomes; Membrane Lipids; Reactive Oxygen Species; Rhodamines; Skin; Ultraviolet Rays

In this study we investigated the effect of insulin on neuronal viability and antioxidant defense mechanisms upon ascorbate/Fe2+-induced oxidative stress, using cultured cortical neurons. Insulin (0.1 and 10 microM) prevented the decrease in neuronal viability mediated by oxidative stress, decreasing both necrotic and apoptotic cell death. Moreover, insulin inhibited ascorbate/Fe2+-mediated lipid and protein oxidation, thus decreasing neuronal oxidative stress. Increased 4-hydroxynonenal (4-HNE) adducts on GLUT3 glucose transporters upon exposure to ascorbate/Fe2+ were also prevented by insulin, suggesting that this peptide can interfere with glucose metabolism. We further analyzed the influence of insulin on antioxidant defense mechanisms in the cortical neurons. Oxidative stress-induced decreases in intracellular uric acid and GSH/GSSG levels were largely prevented upon treatment with insulin. Inhibition of phosphatidylinositol-3-kinase (PI-3K) or mitogen-induced extracellular kinase (MEK) reversed the effect of insulin on uric acid and GSH/GSSG, suggesting the activation of insulin-mediated signaling pathways. Moreover, insulin stimulated glutathione reductase (GRed) and inhibited glutathione peroxidase (GPx) activities under oxidative stress conditions, further supporting that insulin neuroprotection was related to the modulation of the glutathione redox cycle. Thus, insulin may be useful in preventing oxidative stress-mediated injury that occurs in several neurodegenerative disorders.

Topics: Aldehydes; Animals; Apoptosis; Ascorbic Acid; Cell Survival; Cells, Cultured; Cerebral Cortex; Female; Ferrous Compounds; Glucose Transporter Type 3; Glutathione; Insulin; Lipid Peroxidation; Necrosis; Neurons; Oxidative Stress; Rats; Rats, Wistar; Stimulation, Chemical; Uric Acid

Fenton's destruction of benzene, toluene, ethylbenzene, and xylene (BTEX) was investigated in soil slurry batch reactors. The purpose of the investigation was to quantify the enhancement of oxidation rates and efficiency by varying process conditions such as iron catalyst (Fe(II) or Fe(III); 2, 5, and 10mM), hydrogen peroxide (H2O2; 30, 150, 300 mM), and metal chelating agents (l-ascorbic acid, gallic acid, or N-(2-hydroxyethyl)iminodiacetic acid). Rapid contaminant mass destruction (97% after 3h) occurred in the presence of 300 mM H2O2 and 10 mM Fe(III). An enhanced removal rate (>90% removal after 15 min and 95% removal after 3h) was also observed by combining Fe(III), N-(2-hydroxyethyl)iminodiacetic acid and 300 mM H2O2. The observed BTEX mass removal rate constants (3.6-7.8 x 10(-4)s(-1)) were compared to the estimated rate constants (4.1-10.1 x 10(-3)s(-1)). The influence of non-specific oxidants loss (by reaction with iron hydroxides and soil organic matter) was also explored.

Topics: Ascorbic Acid; Catalysis; Chelating Agents; Ferric Compounds; Ferrous Compounds; Gallic Acid; Hydrocarbons, Aromatic; Hydrogen Peroxide; Imino Acids; Kinetics; Models, Chemical; Oxidation-Reduction; Soil Pollutants; Waste Management

Hinokitiol (alpha-thujaplicin, 2-hydroxy-4-isopropyl-2,4,6-cycloheptatrien-1-one), one of the tropolone compounds purified from the woods of Chamaecyparis and Thujopsis (hinoki and hiba), produced reactive oxygen species as a complex with transition metals. Hinokitiol/iron complex inactivated aconitase, the most sensitive enzyme to reactive oxygen, whereas it did not affect aldolase and glyceraldehyde 3-phosphate dehydrogenase. The inactivation of aconitase was iron-dependent, and prevented by TEMPOL, a scavenger of reactive oxygen species and superoxide dismutase, suggesting that the hinokitiol/iron-mediated generation of superoxide anion is responsible for the inactivation of aconitase. Addition of hinokitiol effectively enhanced the ascorbate/copper-mediated formation of 8-hydroxy-2'-deoxyguanosine in DNA. Cytotoxic effect of hinokitiol can be explained by its prooxidant properties: hinokitiol/transition metal complex generates reactive oxygen species causing inactivation of aconitase and production of hydroxyl radical resulting in the formation of DNA base adduct.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aconitate Hydratase; Anti-Infective Agents; Antineoplastic Agents, Phytogenic; Ascorbic Acid; Copper Sulfate; Deoxyguanosine; DNA; Ferrous Compounds; Fructose-Bisphosphate Aldolase; Glyceraldehyde-3-Phosphate Dehydrogenases; Monoterpenes; Oxidants; Reactive Oxygen Species; Tropolone; Yeasts

Topics: Abdominal Pain; Adolescent; Ascorbic Acid; Diet; Exercise; Female; Ferritins; Ferrous Compounds; Humans; Iron, Dietary; Meat; Running

Glycosaminoglycans (GAGs), components of extracellular matrix, are thought to play important roles in cell proliferation and differentiation in the repair process of injured tissue. Oxidative stress is one of the most frequent causes of tissue and cell injury and the consequent lipid peroxidation is the main manifestation of free radical damage. It has been found to play an important role in the evolution of cell death. Since several reports have shown that hyaluronic acid (HYA) and chondroitin-4-sulphate (C4S) are able to inhibit lipid peroxidation during oxidative stress, We investigated the antioxidant capacity of these GAGs in reducing oxidative damage in fibroblast cultures. Free radicals production was induced by the oxidizing system employing iron (Fe2+) plus ascorbate. We evaluated cell death, membrane lipid peroxidation, DNA damage, protein oxidation, hydroxyl radical (OH*) generation and endogenous antioxidant depletion in human skin fibroblast cultures. The exposition of fibroblasts to FeSO4 and ascorbate caused inhibition of cell growth and cell death, increased OH* production determined by the aromatic trap method; furthermore it caused DNA strand breaks and protein oxidation as shown by the DNA fragments analysis and protein carbonyl content, respectively. Moreover, it enhanced lipid peroxidation evaluated by the analysis of conjugated dienes (CD) and decreased antioxidant defenses assayed by means of measurement of superoxide dismutase (SOD) and catalase (CAT) activities. When fibroblasts were treated with two different doses of HYA or C4S a protective effect, following oxidative stress induction, was shown. In fact these GAGs were able to limit cell death, reduced DNA fragmentation and protein oxidation, decreased OH* generation, inhibited lipid peroxidation and improved antioxidant defenses. Our results confirm the antioxidant activity of HYA and C4S and this could represent a useful step in the understanding of the exact role played by GAGs in living organisms.

Topics: Alkadienes; Antioxidants; Ascorbic Acid; Catalase; Cell Survival; Cells, Cultured; Chondroitin Sulfates; DNA Damage; DNA Fragmentation; Ferrous Compounds; Fibroblasts; Glycosaminoglycans; Humans; Hyaluronic Acid; Hydroxyl Radical; Lipid Peroxidation; Oxidative Stress; Superoxide Dismutase

This paper reports the effect of various concentrations of ascorbic acid on the availability of Fe, Zn, Ca and Mg in two popular plant foods--cowpea and amaranthus vegetable--in Nigeria. Ascorbic acid enhancement of iron availability was over 300 % and zinc by 200 % from 0-100 mg concentration. Availability of iron was further increased by 200 mg ascorbic acid in amaranthus but showed a 50 % decrease in the legume. Availability of zinc was decreased by 200 mg ascorbic acid but to different levels in both plant foods. In the legume, maximum enhancement of Ca and Mg availability was exhibited at 100 mg ascorbic acid level but suppressed at higher concentrations. In amaranthus, maximum Ca enhancement was exerted by 200 mg ascorbic acid and 50 mg for Mg. Enhancement of Cu in the legume was marginally affected by ascorbic acid concentrations while inhibition of Cu was observed in amaranthus between 50-300 mg ascorbic acid concentrations. The effect of ascorbic acid on the availability of minerals seems to be concentration dependent and varies with theplant food.

Topics: Amaranthus; Ascorbic Acid; Calcium; Copper; Fabaceae; Ferrous Compounds; Magnesium; Nigeria; Zinc

Treatment of coenzyme Q with ozone, permanganate, and ferrous sulfate in presence of ascorbate or hydrogen peroxide yielded water-soluble degradation products, possibly having truncated side-chain and modified ring.These derivatives, but not the intact lipid-quinone, showed relaxation of phenylephrine-contracted rat arterial rings. Representative samples of these also decreased blood pressure when injected into the femoral vein in the rat.These effects offer an explanation for the hypotensive action of exogenous coenzyme Q regardless of its side-chain length.

Topics: Animals; Arteries; Ascorbic Acid; Blood Pressure; Ferrous Compounds; Hydrogen Peroxide; In Vitro Techniques; Male; Manganese Compounds; Muscle Relaxation; Muscle, Smooth, Vascular; Oxides; Ozone; Rats; Rats, Wistar; Solubility; Structure-Activity Relationship; Ubiquinone; Vasodilation; Water

The study investigates the effect of aqueous extract of fenugreek seeds (Trigonella foenum graecum) on lipid peroxidation and antioxidant status in experimental ethanol toxicity in rats. The ability of the seed extract to prevent iron-induced lipid peroxidation in vitro was also investigated. Ethanol feeding for 60 days resulted in significant increases in the activities of serum aspartate transaminase, alanine transaminase and alkaline phosphatase. The levels of serum lipid hydroperoxides and thiobarbituric acid reactive substances in liver and brain were also significantly elevated. Significantly lower activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and glutathione reductase were observed in liver and brain accompanied by depletion in glutathione, ascorbic acid and alpha-tocopherol concentrations. Activity of Ca(2+) ATPase in brain was significantly lowered. Simultaneous administration of aqueous extract of fenugreek seeds with ethanol prevented the enzymatic leakage and the rise in lipid peroxidation and enhanced the antioxidant potential. The seeds exhibited appreciable antioxidant property in vitro which was comparable with that of reduced glutathione and alpha-tocopherol. Further, histopathological examination of liver and brain revealed that, aqueous extract of fenugreek seeds could offer a significant protection against ethanol toxicity.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Antioxidants; Ascorbic Acid; Aspartate Aminotransferases; Brain; Chemical and Drug Induced Liver Injury; Ethanol; Ferrous Compounds; Humans; Lipid Peroxidation; Liver; Male; Phytotherapy; Plant Extracts; Protective Agents; Rats; Rats, Wistar; Seeds; Thiobarbituric Acid Reactive Substances; Trigonella

Topics: Ascorbic Acid; Dietary Supplements; Female; Ferrous Compounds; Humans; Iron Overload; Middle Aged; Self Medication

Iron is a potent oxidant that can lead to the formation of genotoxic lipid peroxides. Ascorbic acid, which enhances dietary iron absorption, has been suggested to enhance the oxidant effects of iron and to directly lead to the formation of lipid peroxides. The combined effects of dietary iron and ascorbic acid on genotoxicity were investigated by measuring the frequency of micronuclei in the bone marrow cells of C3H/He mice. In addition, liver iron concentration was measured in all treated groups. Three weeks old mice were fed diets for 3 weeks containing iron at 100 or 300 mg/kg diet in the form of FeSO(4) that were supplemented either with or without ascorbic acid (15 g/kg diet). The results of the bone marrow micronucleus test revealed that the high iron diet resulted in an increased frequency of micronucleated polychromatic erythrocytes (MnPCEs) as compared to low iron. Ascorbic acid supplementation in the low iron diet did not show any effect on incidence of MnPCEs and protected against the increased frequency of MnPCEs induced by the high iron diet. However, liver iron concentration was significantly increased only in the high iron treated and ascorbic acid supplemented group as compared to all other groups. These results demonstrate that ascorbic acid protects against the clastogenic effects of iron.

Topics: Administration, Oral; Animals; Antioxidants; Ascorbic Acid; Bone Marrow Cells; Cyclophosphamide; Dose-Response Relationship, Drug; Drug Interactions; Ferrous Compounds; Liver; Mice; Mice, Inbred C3H; Micronuclei, Chromosome-Defective; Micronucleus Tests; Mutagens

The aim of the paper was to study the effect of ascorbic acid (vitamin C) and ethanol on the level of thiobarbituric acid reactive substances (TBARS) in the brain, liver, lungs and blood serum of inbred albino BALB/c mice. Sixty male mice divided into 4 groups were used for the study; the mice in each group were injected intraperitoneally (i.p.): Group 1--control, saline; Group 2--H2O2 and FeSO4; Group 3--ascorbic acid (AA); Group 4--AA and ethanol. The level of TBARS in the investigated tissues of the mice in all of the groups was statistically significant higher than in the control group. The highest content of TBARS in blood serum, brain, liver and lung tissue was observed in mice which were given ascorbic acid and ethanol.

Topics: Animals; Ascorbic Acid; Ethanol; Ferrous Compounds; Hydrogen Peroxide; Male; Mice; Mice, Inbred BALB C; Organ Specificity; Thiobarbituric Acid Reactive Substances

Although potassium sorbate (PS), ascorbic acid and ferric or ferrous salts (Fe-salts) are used widely in combination as food additives, the strong reactivity of PS and oxidative potency of ascorbic acid in the presence of Fe-salts might form toxic compounds in food during its deposit and distribution. In the present paper, the reaction mixture of PS, ascorbic acid and Fe-salts was evaluated for mutagenicity and DNA-damaging activity by means of the Ames test and rec-assay. Effective lethality was observed in the rec-assay. No mutagenicity was induced in either Salmonella typhimurium strains TA98 (with or without S-9 mix) or TA100 (with S-9 mix). In contrast, a dose-dependent mutagenic effect was obtained when applied to strain TA100 without S-9 mix. The mutagenic activity became stronger increasing with the reaction period. Furthermore, the reaction products obtained in a nitrogen atmosphere did not show any mutagenic and DNA-damaging activity. PS, ascorbic acid and Fe-salts were inactive when they were used separately. Omission of one component from the mixture of PS, ascorbic acid and Fe-salt turned the reaction system inactive. These results demonstrate that ascorbic acid and Fe-salt oxidized PS and the oxidative products caused mutagenicity and DNA-damaging activity.

Topics: Ascorbic Acid; Diphosphates; DNA Damage; Edetic Acid; Ferric Compounds; Ferrous Compounds; Food Preservatives; Iron; Mutagenicity Tests; Ribosomal Proteins; Salmonella typhimurium; Sorbic Acid

Many diseases are associated with the overproduction of hydroperoxides that inflict cell damage. A novel cyclodextrin derivative, 6A,6B-diseleninic acid-6A',6B'-selenium bridged beta-cyclodextrin (6-diSeCD), was synthesized to be a functional mimic of glutathione peroxidase (GPX) that normally removes these hydroperoxides. The mimic had high catalytic GPX activity of 13.5 U/micromol, which is 13.6-fold higher than ebselen (PZ51), and was chemically and biologically stable in vitro. Antioxidant activity was studied by ferrous sulfate/ascorbate-induced mitochondria damage model system. These data show that the mimic has great antioxidant activity. Such mimics may result in better clinical therapies for diseases mediated by hydroperoxides.

Topics: Animals; Antioxidants; Ascorbic Acid; beta-Cyclodextrins; Cattle; Cyclodextrins; Ferrous Compounds; Glutathione; Mitochondria; Models, Biological; Organoselenium Compounds; Oxidation-Reduction; Reactive Oxygen Species; Selenium Compounds

Oxidative stress is one of the most frequent causes of tissue and cell injury in various pathologies. The molecular mechanism of mitochondrial damage under conditions of oxidative stress induced in vitro with low concentrations of FeSO4 and ascorbate (vitamin C) was studied. FeSO4 (1-4 microM) added to rat liver mitochondria that were incubated in the presence of 2.3 mM ascorbate induced (with a certain delay) a decrease in membrane potential and high-amplitude swelling. It also significantly decreased the ability of mitochondria to accumulate exogenous Ca2+. All the effects of FeSO4 + ascorbate were essentially prevented by cyclosporin A, a specific inhibitor of the mitochondrial Ca2+-dependent pore (also known as the mitochondrial permeability transition). EGTA restored the membrane potential of mitochondria de-energized with FeSO4 + ascorbate. We hypothesize that oxidative stress induced in vitro with FeSO4 and millimolar concentrations of ascorbate damages mitochondria by inducing the cyclosporin A-sensitive Ca2+-dependent pore in the inner mitochondrial membrane.

Topics: Animals; Ascorbic Acid; Calcium Channels; Cyclosporine; Egtazic Acid; Ferrous Compounds; Membrane Potentials; Mitochondria, Liver; Mitochondrial Swelling; Oxidative Stress; Permeability; Rats

To investigate the inhibitory effects of tea polyphenols (TP) and Vitamin C (Vit C) on FeSO4-cysteine induced lipid peroxidation in isolated human plasma and carbon tetrachloride (CCl4) induced liver free radical injury in mice.. The experiment included two parts: (1) In FeSO4-cysteine induced lipid peroxidation system of isolated human plasma, malondialdehyde (MDA) content was detected after administration of different concentrations of TP (0.3 ~ 8.1 mg/L, as C ~ F group) and Vit C (3 ~ 81 mg/L, as G ~ J group) respectively; (2) Thirty-six male Kunming mice were randomly divided into four groups: control group (A), CCl4 damage group (B), TP protection group (C) and Vit C protection group (D). TP or Vit C (100 mg/kg) was given orally to group C and D respectively, while the same volume of distilled water was given to the other two groups one time every day, continued for three days. Twelve hours after the final treatment, CCl4 (230 mg/kg) was given orally to group B ~ D. Thirty six hours later, all the mice were decapitated and liver homogenate were prepared for measuring MDA content.. In FeSO4-cysteine induced lipid peroxidation in isolated human plasma, the inhibitory rate of TP (0.3 ~ 8.1 mg/L) was 30.7%, 32.0%, 46.9% and 59.7 %, and the inhibitory rate of Vit C (3 ~ 8.1 mg/L) was 8.3%, 41.4%, 47.7% and 52.7% for various dosages. In the CCl4 induced liver free radical injury system, the inhibitory rate of the same dosage of TP and Vit C was 45.2%, 42.8% respectively.. TP (0.3 ~ 8.1 mg/L) and Vit C (9 ~ 81 mg/L) had inhibited lipid peroxidation induced by FeSO4-cysteine in isolated human plasma significantly, and the inhibitory effects of TP was superior to that of Vit C at the same dosages. The same dosage of TP and Vit C had remarkable inhibitory effects on the CCl4 induced liver free radical injury, but there was no significant difference between the two groups.

Topics: Animals; Ascorbic Acid; Carbon Tetrachloride; Cysteine; Dose-Response Relationship, Drug; Ferrous Compounds; Flavonoids; Free Radicals; Humans; Lipid Peroxidation; Liver; Male; Malondialdehyde; Mice; Phenols; Plasma; Polymers; Polyphenols; Tea

The study was undertaken to evaluate the effect of prior treatment of rats with the antimalarial drugs amodiaquine (AQ) mefloquine (MQ) and halofantrine (HF) on rat liver microsomal lipid peroxidation in the presence of 1 mM FeSO4, 1 mM ascorbate and 0.2 mM H2O2 (oxidants). Ingestion of alpha-tocopherol, a radical chain-breaking antioxidant was also included to assess the role of antioxidants in the drug treatment. In the presence of oxidants AQ, MQ and HF elicited 288%, 175% and 225% increases in malondialdehyde (MDA) formation while the drugs induced 125%, 63% and 31% increases in the absence of oxidants respectively. Similarly, AQ, MQ and HF induced lipid hydroperoxide formation by 380%, 256%, 360% respectively in the presence of oxidants and 172%, 136% and 92% in the absence of exogenously added oxidants respectively. a-tocopherol reduced AQ, MQ and HF-induced MDA formation by 40%, 55% and 52% respectively and lipid hydroperoxide formation by 53%, 59% and 54% respectively. Similarly, alpha-tocopherol attenuated the AQ, MQ and HF-induced MDA formation by 49%, 51% and 51% in the presence of oxidants and lipid hydroperoxide formation by 61%, 62% and 47% respectively. The results indicate that rat liver microsomal lipid peroxidation could be enhanced by antimalarial drugs in the presence of reactive oxygen species and this effect could be ameliorated by treatment with antioxidants.

Topics: alpha-Tocopherol; Amodiaquine; Animals; Antimalarials; Antioxidants; Ascorbic Acid; Ferrous Compounds; Hydrogen Peroxide; Lipid Peroxidation; Lipid Peroxides; Liver; Male; Malondialdehyde; Mefloquine; Microsomes, Liver; Oxidants; Phenanthrenes; Rats; Reactive Oxygen Species; Up-Regulation

To investigate whether the preincubation of brain homogenates with L-phenylalanine (Phe) could reverse the free radical effects on brain acetylcholinesterase (AChE) activity, since it has been reported that Phe binds hydroxyl radicals ((*)OH).. Two well established systems were used for production of free radicals: (a) FeSO(4) (84 microM) plus ascorbic acid (400 microM), and (b) FeSO(4), ascorbic acid and H(2)O(2) (1 mM) at 37 degrees C in homogenates of adult rat whole brain. Changes in brain AChE activity were studied in the presence of each system separately.. AChE was inhibited (18-28%) by both systems of free radicals. This inhibition was reversed when the brain homogenate was preincubated with Phe 1.8 mM.. In accordance with our previous reports, Phe could protect against the direct action of (*)OH radicals on brain AChE and in this way it might be useful in the prevention of certain cholinergic neural dysfunctions.

Topics: Acetylcholinesterase; Aging; Animals; Ascorbic Acid; Brain; Cholinesterase Inhibitors; Female; Ferric Compounds; Ferrous Compounds; Free Radicals; Frontal Lobe; Hippocampus; Hydrogen Peroxide; Hypothalamus; Kinetics; Male; Phenylalanine; Pituitary Gland; Rats; Rats, Wistar

Dietary iron absorption from a meal is determined by iron status, heme- and nonheme-iron contents, and amounts of various dietary factors that influence iron absorption. Limited information is available about the net effect of these factors.. The objective was to develop an algorithm for predicting the effects of factors known to influence heme- and nonheme-iron absorption from meals and diets.. The basis for the algorithm was the absorption of iron from a wheat roll (22.1 +/- 0.18%) containing no known inhibitors or enhancers of iron absorption and adjusted to a reference dose absorption of 40%. This basal absorption was multiplied by the expected effect of different amounts of dietary factors known to influence iron absorption: phytate, polyphenols, ascorbic acid, meat, fish and seafood, calcium, egg, soy protein, and alcohol. For each factor, an equation describing the dose-effect relation was developed. Special considerations were made for interactions between individual factors.. Good agreement was seen when measurements of iron absorption from 24 complete meals were compared with results from use of the algorithm (r(2) = 0.987) and when mean iron absorption in 31 subjects served a varied whole diet labeled with heme- and nonheme-iron tracers over a period of 5 d was compared with the mean total iron absorption calculated by using the algorithm (P = 0.958).. This algorithm has several applications. It can be used to predict iron absorption from various diets, to estimate the effects expected by dietary modification, and to translate physiologic into dietary iron requirements from different types of diets.

Topics: Alcohol Drinking; Algorithms; Animals; Ascorbic Acid; Biological Availability; Calcium; Coffee; Eggs; Female; Ferrous Compounds; Flavonoids; Humans; Intestinal Absorption; Iron, Dietary; Male; Meat; Phenols; Polymers; Polyphenols; Poultry; Seafood; Soybean Proteins; Tea; Triticum

The absorption of ciprofloxacin has been reported to be impaired by concomitant administration of ferrous sulphate. The effects of sodium ferrous citrate and ferric pyrophosphate, which have been used as extensively as ferrous sulphate, on the absorption of ciprofloxacin were compared with that of ferrous sulphate. The effects of ascorbic acid on the interactions between ciprofloxacin and each iron compound were studied in mice. Mice were treated orally with ciprofloxacin (50 mg kg(-1)) alone, the iron compound (ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate; 50 mg elemental iron kg(-1)) alone, ciprofloxacin with each iron compound or ciprofloxacin in combination with each iron compound and ascorbic acid (250 mg kg(-1)). The maximum serum concentration of ciprofloxacin was significantly (P < 0.01) reduced from 1.15+/-0.11 microg mL(-1) (ciprofloxacin alone) to 0.17+/-0.01, 0.27+/-0.01 or 0.28+/-0.02 microg mL(-1), respectively, when ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate was administered along with ciprofloxacin. The addition of ascorbic acid did not affect the inhibitory effects of each iron compound on the absorption of ciprofloxacin. Ciprofloxacin did not affect the variation of serum iron levels after administration of each iron compound. The addition of ascorbic acid significantly (P < 0.01) enhanced the increase in serum iron concentration after administration of sodium ferrous citrate, showing an increase from 270+/-6 microg dL(-1) to 463+/-11 microg dL(-1) compared with an increase from 248+/-8 microg dL(-1) to 394+/-18 microg dL(-1) after administration of sodium ferrous citrate alone. Ascorbic acid also caused a significant (P < 0.01) increase in serum iron concentration from 261+/-16 microg dL(-1) to 360+/-12 microg dL(-1) after administration of ferric pyrophosphate, although it did not affect the levels after ferrous sulphate administration. The results suggest that sodium ferrous citrate and ferric pyrophosphate should not be administered with ciprofloxacin (as for ferrous sulphate) and that sodium ferrous citrate is converted to the ferric form more easily than ferrous sulphate. This difference in convertibility might contribute to a clinical difference between sodium ferrous citrate and ferrous sulphate.

Topics: Absorption; Administration, Oral; Animals; Anti-Infective Agents; Ascorbic Acid; Ciprofloxacin; Citric Acid; Diphosphates; Drug Interactions; Ferrous Compounds; Iron; Iron Compounds; Male; Mice

We have tested undifferentiated NT2 cells as well as differentiated NT2 neurons (NT2N) for vulnerability to oxidative stress, lipid composition and antioxidant pattern. NT2N, but not NT2 cells, are highly susceptible to oxidative stress elicited by different classic pro-oxidant stimuli. In particular, NT2N cells undergo a high level of oxidative decomposition of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) of membrane phospholipids, as evaluated by monitoring generation of thiobarbituric reactive substances, 4-hydroxynonenal (HNE) and chromolipid fluorescent adducts. NT2N cells exhibit low levels of natural antioxidants such as glutathione (GSH) and alpha-tocopherol and of antioxidant enzymatic activities such as Se-dependent GSH peroxidase and catalase. Accordingly, a direct correlation between lipid peroxidation and irreversible cell damage is suggested by prevention of NT2N cell death by alpha-tocopherol.

Topics: Alzheimer Disease; Ascorbic Acid; Cell Death; Cell Differentiation; Drug Combinations; Fatty Acids; Ferrous Compounds; Humans; Hydrogen Peroxide; L-Lactate Dehydrogenase; Lipid Peroxides; Neurons; Oxidants; Oxidative Stress; Thiobarbituric Acid Reactive Substances; Tumor Cells, Cultured; Vitamin E

Topics: Aldehyde Dehydrogenase; Aldehyde Dehydrogenase, Mitochondrial; Animals; Antioxidants; Arachidonic Acid; Ascorbic Acid; Carcinoma, Hepatocellular; Ferrous Compounds; Rats; Reactive Oxygen Species; Tumor Cells, Cultured

Aluminum is a recognized neurotoxin in dialysis encephalopathy and may also be implicated in the etiology of neurodegenerative disease, particularly Alzheimer's disease. Alzheimer's disease is suspected to be associated with oxidative stress, possibly due to the pro-oxidant properties of beta-amyloid present in the senile plaques. The underlying mechanism by which this occurs is not well understood although interactions between amyloid and iron have been proposed. The presence of low molecular weight iron compounds can stimulate free radical production in the brain. This study provides a possible explanation whereby both aluminum and beta-amyloid can potentiate free radical formation by stabilizing iron in its more damaging ferrous (Fe2+) form which can promote the Fenton reaction. The velocity, at which Fe2+ is spontaneously oxidized to Fe3+ at 37 degrees C in 20 mM Bis-Tris buffer at pH 5.8, was significantly slowed in the presence of aluminum salts. A parallel effect of prolongation of stability of soluble ferrous ion, was found in the presence of beta-amyloid fragment (25-35). Ascorbic acid, known to potentiate the pro-oxidant properties of iron, was also capable of markedly stabilizing ferrous ions.

Topics: Alum Compounds; Alzheimer Disease; Amyloid beta-Peptides; Animals; Antioxidants; Ascorbic Acid; Brain Chemistry; Ferrous Compounds; Humans; Peptide Fragments

Four food grade additives-sodium ascorbate, sodium bicarbonate, sodium carbonate-10-hydrate, and ferrous sulfate-7-hydrate-were selected as the basic ingredients to formulate the controlled atmosphere agents which could effectively remove oxygen and release carbon dioxide. The mathematical models giving the relationships between the formulations and the responses (oxygen and carbon dioxide contents) were developed using response surface methodology (RSM). Within 8-24 h, the oxygen and carbon dioxide contents of all tested formulations could reach constant levels, in the ranges of 2-9% and 0-41%, respectively. These formulations were considered to be effective, safe, and easy to prepare and could be applied to wide varieties of food products.

Topics: Ascorbic Acid; Carbon Dioxide; Carbonates; Ferrous Compounds; Food Additives; Food Analysis; Food Packaging; Oxygen; Pressure; Sodium Bicarbonate

Using resting cells and extracts of Streptomyces clavuligerus NP1, we have been able to convert penicillin G (benzylpenicillin) to deacetoxycephalosporin G. Conversion was achieved by increasing by 45x the concentration of FeSO4 (1.8 mM) and doubling the concentration of alpha-ketoglutarate (1.28 mM) as compared with standard conditions used for the normal cell-free conversion of penicillin N to deacetoxycephalosporin C. ATP, MgSO4, KCl, and DTT, important in cell-free expansion of penicillin N, did not play a significant role in the ring expansion of penicillin G by resting cells or cell-free extracts. When these conditions were used with 14 other penicillins, ring expansion was achieved in all cases.

Topics: Adenosine Triphosphate; Ascorbic Acid; Cephalosporins; Colony Count, Microbial; Dithiothreitol; Ferrous Compounds; Interphase; Intramolecular Transferases; Ketoglutaric Acids; Kinetics; Magnesium Sulfate; Penicillin G; Penicillin-Binding Proteins; Penicillins; Potassium Chloride; Streptomyces

Nutritional iron deficiency in infants over 4 months of age is one of the most common deficiency disorders. Dietary iron is comprised of non-haem and haem iron, the latter being absorbed by a separate pathway and more efficiently than non-haem iron. Fortification of infant weaning foods is one of the strategies adopted for preventing iron deficiency and the aim of this project was to examine the potential use of haem iron concentrate as a fortificant.. Sixteen non-anaemic 6-month old infants were recruited and allocated to two groups of 8. Each infant consumed 2 meals/day of a commercial weaning food (100 g) for 7 consecutive days containing 40 mg ascorbic acid and 2.5 mg haem iron/100 g (Group 1) or the same quantity of iron as ferrous sulphate plus 40 mg ascorbic acid (Group 2). Bioavailability was assessed by chemical balance using carmine to mark the beginning and end of the faecal collection. The effect of haem iron concentrate (as a candidate for the factor in meat that enhances iron absorption) was examined by measuring its effect on 57Fe-labelled non-haem iron absorption.. There was no difference in iron balance between the two groups. Mean iron retention was 3.5 (SD 2.1) mg/day in Group 1 (haem iron) and 3.0 (SD 2.4) mg/day in Group 2 (ferrous sulphate). Haem concentrate did not enhance the absorption of 57Fe-labelled non-haem iron, Group 1: 1710 (SD 11.1)%, Group 2: 28.4 (SD 17.7)%.. Haem iron concentrate appears to be a highly bioavailable form of iron when added to infant weaning foods. This protein is not, however, responsible for the enhancing effect of animal protein on non-haem iron absorption.

Topics: Absorption; Ascorbic Acid; Biological Availability; Female; Ferrous Compounds; Food, Fortified; Heme; Humans; Infant; Infant Food; Iron; Iron Isotopes; Male; Milk, Human; Weaning

Photofrin, a photosensitizer used in the photodynamic therapy of cancer, selectively localizes in cellular membranes. Upon exposure to visible light, Photofrin produces singlet oxygen (1O2), which reacts with membrane polyunsaturated fatty acids forming lipid hydroperoxides. Transition metals, such as Fe2+, catalyze the production of cytotoxic free radicals from lipid hydroperoxides. Ascorbate reduces ferric to ferrous iron, further augmenting lipid peroxidation. Therefore, to increase the efficacy of Photofrin photosensitization, we added 20 microM ferrous sulfate and 100 microM ascorbic acid, in an aqueous layer over SCC-25 oral squamous cell carcinoma cells during in vitro illumination. In electron paramagnetic resonance spin trapping experiments, using POBN (alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone), we observed that the presence of this pro-oxidant combination greatly increases the production of membrane-derived lipid free radicals. The effect was time dependent but only partially concentration dependent. Trypan blue dye exclusion demonstrated that this increase in lipid radical formation correlated with cytotoxicity. These observations support the hypothesis that Photofrin photosensitization leads to lipid hydroperoxide formation, which increases the cell's susceptibility to iron-induced Fenton chemistry. The resulting free radical-mediated lipid peroxidation results in cell death. From these data we hypothesize that the efficacy of photodynamic therapy of superficial cancer might be increased by the topical application of the pro-oxidant combination of iron and ascorbate. Furthermore, their use will probably allow lower doses of Photofrin without compromising antitumor effect.

Topics: Antineoplastic Agents; Ascorbic Acid; Dihematoporphyrin Ether; Drug Interactions; Ferrous Compounds; Free Radicals; Humans; Mouth Neoplasms; Neoplasms, Squamous Cell; Photosensitizing Agents; Tumor Cells, Cultured

1. The acute effect of hexachlorocyclohexane (HCH) administration (i.p.) on testicular antioxidant system and lipid peroxidation (LPX) in immature and mature rats (15- and 90-day-old, respectively) were compared. 2. In both the age groups, the level of LPX in crude homogenate of testis (endogenous, as well as FeSO4, and ascorbic acid-stimulated) was increased after 6 hr of HCH treatment and remained high till 24 hr. However, FeSO4 and ascorbic acid-stimulated LPX was higher in 90-day-old rats in comparison to 15-day-old rats. HCH treatment also resulted in elevation of LPX level in testicular subcellular (nuclear, mitochondrial and microsomal) fractions by 6 hr of treatment. However, the magnitude of increase was greater in case of 90-day-old rats. 3. Activities of testicular cytosolic superoxide dismutases (total and CN(-)-resistant) of rats of 15- and 90-day-old age groups decreased significantly after 6 hr of HCH treatment, and remained decreased till 24 hr of the pesticide treatment. The percentage of decrease was higher in 15-day-old rats than 90-day-old rats. CN(-)-sensitive SOD activity of testis was found to decrease by 12 and 24 hr after the pesticide treatment in 15- and 90-day-old rats, respectively. The activity of catalase decreased 6 hr after the pesticide treatment in both the age groups. However, the magnitude of decrease was similar for both age groups of rats. 4. Testicular glutathione content, as well as levels of glutathione metabolizing enzymes (glutathione peroxidase and glutathione reductase), did not change in response to HCH treatment, whereas ascorbic acid content decreased by 12 and 6 hr after HCH treatment in 15- and 90-day-old rats, respectively. The level of H2O2 was found to be elevated after 6 hr of the pesticide treatment in both age groups. 5. Total epididymal sperm number was comparable in all experimental groups. However, the percentage of dead and damaged spermatozoa was significantly enhanced in HCH treated rats. 6. Acute HCH administration to rats results in induction of oxidative stress in the testis which depends upon the age of the animal.

Topics: Age Factors; Animals; Ascorbic Acid; Carcinogens; Catalase; Ferrous Compounds; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Hexachlorocyclohexane; Hydrogen Peroxide; Insecticides; Lipid Peroxidation; Male; Oxidative Stress; Rats; Sperm Count; Superoxide Dismutase; Testis; Time Factors

The presumptive coronal sutures of rat fetuses at gestation days 19 and 20 have been shown to fuse prematurely when grown in the absence of dura mater in culture. In the present study, the representative enzymes of glucose metabolism and the antioxidative pathway were assayed during the process of suture fusion. The coronal sutures of fetal day 19.5 (F19) and neonatal day 1 rats were grown in the presence or absence of dura mater in serum-free culture. The enzymes assayed were hexokinase (HK) and pyruvate kinase (PK) of glycolysis, and glucose 6-phosphate dehydrogenase (G6PD) and glutathione reductase (GR) of the antioxidative pathway. F19 sutures cultured without dura mater, which fused, showed significant increases in enzyme activities over the preculture levels. HK increased by 200% to 300% of the preculture levels, G6PD by 400% to 500%, GR by 200%, and PK by 400% to 500%. The fetal sutures cultured with dura mater, which did not fuse, showed little alterations of HK, G6PD, and GR activities, but showed a significant 200% to 400% increase in PK activity. Neonatal sutures showed significant increases in enzyme activities during culture, but the presence of dura mater did not significantly affect enzyme activities. High activity levels of enzymes of the antioxidative pathway in F19 sutures coincided with the period of premature suture fusion. Treatment of fetal calvaria with prooxidant (induced by ferrous iron and ascorbic acid) produced suture fusion even in the presence of dura mater. Treatment with deferoxamine (an iron chelator and antioxidant) during the culture prevented suture fusion. The results suggest that fusing sutures experience increased biosynthetic demands and are placed under oxidative stress. When oxidative stress overwhelms the dural influence, the sutures undergo premature fusion.

Topics: Animals; Animals, Newborn; Ascorbic Acid; Cranial Sutures; Craniosynostoses; Culture Media; Culture Techniques; Dura Mater; Female; Ferrous Compounds; Iron; Male; Oxidation-Reduction; Oxidative Stress; Rats; Rats, Sprague-Dawley

The effects of supplemental fatty acids, vitamin E (VIT E), and iron-induced oxidative stress on collagen synthesis, cellular injury, and lipid peroxidation were evaluated in primary cultures of avian epiphyseal chondrocytes. The treatments included oleic and linoleic acids (O or 50 microM) complexed with BSA and dl-alpha-tocopheryl acetate (VIT E at 0 or 100 microM). After 14 days of preculture, the chondrocytes were enriched with fatty acids for 8 days then cultured with VIT E for 2 days. The chondrocytes were then treated with ferrous sulfate (O or 20 microM) for 24 hr to induce oxidative stress. Collagen synthesis was the lowest and the activity of lactate dehydrogenase (LDH) was the highest in chondrocyte cultures treated with 50 microM linoleic acid and 0 VIT E. In contrast, VIT E supplemented at 100 microM partially restored collagen synthesis in the chondrocytes enriched with linoleic acid and lowered LDH activity in the media. The iron oxidative inducer significantly increased the values of thiobarbituric acid-reactive substances (TBARS) in the culture medium. The data showed that linoleic acid impaired chondrocyte cell function and caused cellular injury but that VIT E reversed these effects. Results from a previous study demonstrated that VIT E stimulated bone formation in chicks fed unsaturated fat, and the present findings in cultures of epiphyseal chondrocytes suggest that VIT E is important for chondrocyte function in the presence of polyunsaturated fatty acids. VIT E appears to be beneficial for growth cartilage biology and in optimizing bone growth.

Topics: Animals; Ascorbic Acid; Cattle; Cells, Cultured; Chickens; Collagen; Culture Media, Conditioned; DNA; Fatty Acids; Ferrous Compounds; Growth Plate; L-Lactate Dehydrogenase; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Oleic Acid; Oleic Acids; Oxidative Stress; Serum Albumin, Bovine; Thiobarbituric Acid Reactive Substances; Vitamin E

LDL can be oxidized by a variety of agents to form a modified lipoprotein which is capable of being avidly metabolized by macrophages. While previous in vitro studies have focused exclusively on the oxidation of LDL, other lipids found in the atheroma are also subject to oxidation and its lipoperoxide byproducts may contribute to the process of LDL modification. To examine the relationship between the oxidation of phospholipids and the subsequent modification of LDL, we incubated 250 microM phosphatidylcholine with 10 microM ferrous sulfate and 50 microM ascorbic acid in 10 mM Tris (pH 7.0). After 18 h at 37 degrees C, significant amounts of thiobarbituric acid reactive substances (TBARS) were formed. The inclusion of LDL (100 micrograms protein/ml) elevated the TBARS and increased the electrophoretic mobility of the lipoprotein. LDL treated with iron and ascorbate in the absence of phosphatidylcholine did not result in the modification of this lipoprotein. LDL that was incubated with phosphatidylcholine, iron and ascorbate was found to be metabolized by macrophages to a far greater extent than native LDL or LDL treated with phosphatidylcholine alone. Probucol (10 microM) inhibited the LDL modification process. These results demonstrate that while iron and ascorbate cannot oxidize LDL directly, the addition of phosphatidylcholine to these initiators of lipid peroxidation can mediate and lead to the modification of LDL.

Topics: Animals; Ascorbic Acid; Female; Ferrous Compounds; Lipid Peroxidation; Lipoproteins, LDL; Liposomes; Macrophages, Peritoneal; Mice; Mice, Inbred ICR; Phosphatidylcholines; Thiobarbituric Acid Reactive Substances

We investigated the effect of Fe deficiency on the nutritive utilization of Fe, Ca, P and Mg in rats. Aside from the well known depletion of Fe in liver, femur and sternum with low values of Hb, Fe deficiency impaired Ca, P and Mg metabolism at different degrees. Iron deficiency altered Mg absorption, lowered the concentration of Ca in the liver, femur and sternum, raised the concentration of P and Mg in the liver, and decreased P in the femur. The altered status was not completely rectified by iron supplementation as the animals were still slightly anemic at the end of the study. The second purpose of the study was to evaluate the ability of three iron compounds (ferric citrate, ferrous sulfate and ferrous ascorbate) to correct the undesirable effects of Fe deficiency. Ten days after treatment with these diets, Fe-deficient rats still had reduced Mg absorption, especially those fed ferric citrate. The concentrations of hemoglobin approached normal values in all groups; however, serum Fe remained low, indicating that Fe reserves were still depleted. Hepatic and femoral Fe concentrations were also lower in all Fe-deficient groups regardless of the diet given, compared with their respective controls, whereas Fe concentrations in the sternum increased significantly with all three diets, suggesting an increase in erythropoiesis. The concentration of Ca, P and Mg in liver approached normal values, and appeared to normalize in the femur, except that Ca and P concentrations remained low with the citrate diet. In the sternum, a site assumed to have higher requirements for these minerals, the concentrations of Ca, P and Mg also increased. These findings indicate that Fe is involved in the bone mineralization, and that in physiological terms, Fe interacts favorably with Ca, P and Mg metabolism, since Fe deficiency altered the status of these metals. These findings also suggest that ferrous ascorbate and ferrous sulfate were more effectively absorbed than was ferric citrate.

Topics: Analysis of Variance; Anemia, Iron-Deficiency; Animal Feed; Animals; Ascorbic Acid; Body Weight; Calcium; Eating; Ferric Compounds; Ferrous Compounds; Food, Fortified; Hemoglobins; Iron; Iron Deficiencies; Magnesium; Male; Phosphorus; Random Allocation; Rats; Rats, Wistar; Tissue Distribution

Iron deficiency is the most important nutritional problem all over the world. Fluid milk is an attractive vehicle for iron fortification, since it is a food with a high nutritional value, accessible to the whole population and easy to be given to children. Fortification of this food with iron has the disadvantage of the interaction of the iron with the constitutive elements of milk, diminishing its bioavailability and changing its sensorial properties, making it unacceptable. Nowadays, this problem can be overcome by the implementation of a new technological procedure, which consists in the microencapsulation of the ferrous sulfate with lecithin, thus avoiding the interaction of iron with the food. The absorption obtained in mice for milk-ferrous sulfate was 7.9 +/- 3.2%, while for microencapsulated ferrous sulfate-milk the result was 11.6 +/- 4.5%. Comparing these data with those obtained with the ferrous ascorbate in water 13.1 +/- 4.9% and ferrous sulfate in water 13.2 +/- 4.3%, both of them considered as reference standards, no statistically significant difference between them and the microencapsulated ferrous sulfate in milk can be observed. However, this difference becomes significant (p < 0.01) when these products are compared to the non-encapsulated ferrous sulfate in milk. On the other hand, we demonstrated that this product is stable to heat-processing (100 degrees C, 30 min) and storage at a room temperature up to 6 months that lacteous products are usually submitted to.

Topics: Absorption; Animals; Ascorbic Acid; Biological Availability; Drug Compounding; Drug Stability; Female; Ferrous Compounds; Hot Temperature; Mice; Milk; Phosphatidylcholines; Time Factors

Two isoforms of NAD(P)(+)-dependent malic enzyme (EC 1.1.1.39) were isolated from hydrogenosomes of Trichomonas vaginalis. A positively charged isoform at pH 7 was obtained in a single purification step using cation-exchange chromatography. The second isoform, negatively charged at pH 7.5, was partially purified using a combination of anion-exchange and affinity chromatography. Both isoforms displayed similar physical and kinetic properties. Molecular weight determination of the native enzyme suggested a homotetrameric arrangement of the 60 kDa subunits. The enzyme utilized NAD+ (Km, 6-6.3 microM) preferentially to NADP+ (Km, 125-145 microM). The NAD(+)-dependent activity showed a broad pH optimum with maximum under alkaline conditions (pH 9) likely to be present inside hydrogenosomes. Immunocytochemical studies using a polyclonal rabbit antibody raised against purified T. vaginalis malic enzyme proved hydrogenosomal localization of the enzyme. Subfractionation of hydrogenosomes suggested an association of the malic enzyme with the hydrogenosomal membranes. The 60 kDa malic enzyme subunit was highly sensitive to non-enzymatic cleavage by an iron-ascorbate system resulting in two enzymatically inactive fragments of about 31 kDa. Microsequencing of the fragments revealed that the 60 kDa subunit was cleaved at the metal-binding site between Asp279-Ile280. The enzyme inactivation was inhibited by an excess of manganese. Iron-dependent posttranslational modification might contribute to the regulation of malic enzyme activity in vivo.

Topics: Amino Acid Sequence; Animals; Ascorbic Acid; Cell Fractionation; Chlorides; Ferrous Compounds; Hydrogen-Ion Concentration; Intracellular Membranes; Isoenzymes; Kinetics; Malate Dehydrogenase; Manganese Compounds; Molecular Sequence Data; Molecular Weight; NAD; Organelles; Sequence Analysis; Trichomonas vaginalis

Commonly used spectrophotometric methods for determining the extent of lipid peroxidation in animal tissue extracts, such as measurements of diene conjugation and thiobarbituric acid reactive substances (TBARS), have been criticized for their lack of specificity. This study shows that lipid hydroperoxides can be effectively quantified in animal tissue extracts using an assay based on the formation of a Fe(III)xylenol orange complex. Addition of H2O2, cumene hydroperoxides, or methanolic tissue extracts to an acidic reaction mixture containing 0.25 mM Fe(II) and 0.1 mM xylenol orange caused the formation of a broad Fe(III)xylenol orange complex absorbance peak at 560-580 nm with a corresponding decrease in the xylenol orange peak at 440 nm. Complex formation measured at 580 nm was saturable with both xylenol orange and Fe (II) concentration. Addition of ascorbic acid, GSH, and cysteine (0.3-5 mM) caused a saturable reduction of the Fe(III)xylenol orange complex. Formation of the Fe(III)xylenol orange complex was linear with the amount of tissue extract added. A significant correlation (r = 0.88, p < 0.005) existed between the xylenol orange method of estimating lipid peroxidation and the conventional TBARS assay in a series of animal tissues tested. The time course of increase in A580nm in tests using tissue extracts was typical of a free radical reaction; a lag phase was followed by a log phase. No increase in A580nm was observed up to 24 h when highly peroxidizable arachidonic acid was assayed. These results indicate that the formation of the Fe(III)xylenol orange complex reflects a chemical amplification of the original level of lipid hydroperoxides present in tissue extracts and that peroxidizable lipids do not influence the assay. The potential usefulness of the xylenol orange assay for comparative biochemical and toxicological studies of oxidative stress is discussed.

Topics: Animals; Ascorbic Acid; Chromatography, High Pressure Liquid; Cysteine; Ferric Compounds; Ferrous Compounds; Fluorescent Dyes; Glutathione; Indicators and Reagents; Kinetics; Lipid Peroxidation; Liver; Mice; Mice, Inbred Strains; Muscle, Skeletal; Phenols; Rats; Rats, Wistar; Sciuridae; Spectrophotometry; Sulfoxides; Thiobarbituric Acid Reactive Substances; Turtles; Xylenes

In primary cultures of rat hepatocytes, the effects of extracellular Mg2+ and Fe on lipid peroxidation (LPO) as measured by means of malondialdehyde (MDA) formation were investigated. Incubation of hepatocytes at decreasing extracellular Mg2+ concentration enhanced LPO, depending on extracellular Fe. About 96% of MDA accumulated in the culture medium. Addition of desferrioxamine prevented LPO. Additionally, the formation of oxygen free radicals was determined by fluorescence reduction of cis-parinaric acid. With this method, an immediate decay of fluorescence was found after addition of Fe2+. Fluorescence reduction was completely prevented by desferrioxamine, indicating the function of extracellular Fe. This mechanism may operate additionally to the increase in intracellular Fe and intracellular formation of oxygen free radicals during Mg deficiency in vivo.

Topics: Animals; Ascorbic Acid; Cells, Cultured; Culture Media; Deferoxamine; Dose-Response Relationship, Drug; Fatty Acids, Unsaturated; Ferrous Compounds; Free Radicals; Lipid Peroxidation; Liver; Magnesium; Malondialdehyde; Rats; Reactive Oxygen Species; Time Factors

The effect of lipid peroxidation, induced by ascorbic acid and ferrous sulfate (Fe2+) at pH 7.4 or pH 6.5, on the membrane order of retinal cells in culture was examined. Membrane order was measured by fluorescence anisotropy using 1-[4-(trimethylammonium)-phenyl]-6-phenylhexa-1,3,5-triene as a fluorescent probe. Alterations of cellular membrane order were correlated with the susceptibility to peroxidation and viability of these cells. At pH 7.4, 1.5 mM ascorbate/7.5 microM Fe2+ induced a low production of thiobarbituric acid-reactive substances (3.47 +/- 0.26 nmol TBARS/mg protein), while 5 mM ascorbate/100 microM Fe2+ significantly increased TBARS production to 11.17 +/- 1.43 nmol/mg protein. At pH 6.5, in the presence of 5 mM ascorbate/100 microM Fe2+, cellular oxidation was mostly increased following 15 min incubation (19.33 +/- 1.66 nmol TBARS/mg protein) and decreased thereafter as a result of a prolonged exposure to the oxidizing agents to levels of 11.02 +/- 0.66 nmol TBARS/mg protein, after 180 min peroxidation. The membrane order of control retinal cells treated at pH 6.5 was not changed compared to controls at pH 7.4. Moreover, the membrane order of retinal cells peroxidized at pH 7.4 was not significantly different compared to controls, in the absence of ascorbate/Fe2+. However, significant time-dependent alterations were found in the membrane order of cells peroxidized with 5 mM ascorbate/100 microM Fe2+, at pH 6.5: cellular membrane order decreased after 15 min peroxidation, while longer peroxidative incubation periods, from 60 and up to 180 min, induced an increase in the membrane order. The dual effect of lipid peroxidation, under moderately acidic conditions (pH 6.5), on the membrane order of retinal cells was shown to be prevented upon cellular pretreatment with vitamin E, supplemented to the culture medium. Moreover, vitamin E pretreatment increased the viability of control retinal cells and reduced the production of TBARS after 15 min peroxidation with 5 mM ascorbate/100 microM Fe2+, at pH 6.5. Vitamin E was also shown to reduce conjugated dienes formation after 15 or 60 min peroxidation at pH 6.5.(ABSTRACT TRUNCATED AT 400 WORDS)

Topics: Animals; Ascorbic Acid; Cell Membrane; Cell Survival; Cells, Cultured; Chick Embryo; Ferrous Compounds; Hydrogen-Ion Concentration; Kinetics; L-Lactate Dehydrogenase; Lipid Peroxidation; Retina; Thiobarbituric Acid Reactive Substances; Vitamin E

Hepatoma cells are, at most, moderately sensitive to oxidative stress. An important cause of this lack of sensitivity is the decreased content of polyunsaturated fatty acids in comparison with normal cells. These fatty acids are one cellular target of oxygen radicals, by which they are broken down into several toxic carbonyl compounds. If the membrane phospholipids of tumor cells are enriched with polyunsaturated fatty acids, such as arachidonic acid, they become able to undergo lipid peroxidation in the presence of prooxidants. This effect is studied in the highly deviated Yoshida AH-130 ascites hepatoma and in two rat hepatoma cell lines. In parallel to their increased lipid peroxidation, cells enriched with arachidonic acid and exposed to ascorbic acid/FeSO4 showed lower viability and growth than unenriched ones.

Topics: Aldehydes; Animals; Arachidonic Acid; Ascorbic Acid; Cell Death; Ferrous Compounds; Lipid Peroxidation; Liver Neoplasms, Experimental; Malondialdehyde; Oxidative Stress; Rats; Tumor Cells, Cultured

The objective of this study was to assess the therapeutic advantage of glutathione ester along with cisplatin. Comparisons were made with renal reduced glutathione, enzymatic antioxidants, and lipid peroxidation levels. Cisplatin caused differential toxic effects on renal antioxidants and lipid peroxidation. However administration of glutathione ester modulates the toxic effects of cisplatin observed in renal antioxidants and lipid peroxidation. The finding that glutathione ester co-administration along with cisplatin is more effective and advantageous in protecting against the nephrotoxicity of cisplatin when it was given alone.

Topics: Animals; Antioxidants; Ascorbic Acid; Cisplatin; Ferrous Compounds; Free Radical Scavengers; Free Radicals; Glutathione; Glutathione Peroxidase; Kidney; Lipid Peroxidation; Rats; Rats, Wistar; Reactive Oxygen Species; Superoxide Dismutase

To determine the ability of the Hemoccult and Gastroccult tests (SmithKline Diagnostics) to detect blood in vitro in whole-bowel irrigation (WBI) solution.. One tablet of ferrous gluconate 324 mg, ferrous sulfate 325 mg, or ascorbic acid 500 mg; or one Materna prenatal vitamin tablet (Lederle Laboratories) was dissolved in 30 mL of Colyte. Colyte alone and each test solution were tested with Hemoccult and Gastroccult slides, then retested at pH values of 3 and 8. Fresh solutions were then spiked with blood and tested with Gastroccult slides. Materna and ascorbic acid solutions were spiked with blood, then tested with Hemoccult slides.. Positive results were difficult to detect on Gastroccult slides. Hemoccult slides were falsely positive for solutions containing only iron and falsely negative for blood-spiked samples containing ascorbic acid.. Both the Hemoccult and Gastroccult tests may be unreliable in detecting GI bleeding in cases of iron overdose treated with WBI.

Topics: Ascorbic Acid; Delayed-Action Preparations; Drug Overdose; False Negative Reactions; False Positive Reactions; Ferrous Compounds; Gastrointestinal Hemorrhage; Humans; Iron; Occult Blood

We developed a new gastric ulcer model in which the ulcers are induced by the local injection of a ferrous iron and ascorbic acid (Fe/ASA) solution into the gastric wall. These ulcers resemble human gastric ulcers that penetrate the muscularis mucosa. The involvement of oxygen radical-mediated lipid peroxidation as the cause of these ulcers was investigated. With ferrous iron or ascorbic acid alone, gastric ulcers did not form, whereas penetrating ulcers were produced by the simultaneous injection of the Fe/ASA solution in a dose-dependent manner. Lipid peroxides significantly accumulated in the gastric mucosa from 1 to 24 h after the injection of the Fe/ASA solution. This increase in lipid peroxides preceded grossly evident gastric ulcer. Treatment with superoxide dismutase (SOD, recombinant human CuZnSOD) significantly reduced the size of the ulcers and inhibited the accumulation in lipid peroxides in the gastric mucosa, while treatment with apo-SOD or heat-inactivated SOD did not. These results suggest that lipid peroxidation mediated by oxygen radicals plays a crucial role in the pathogenesis of the gastric ulceration induced by the Fe/ASA solution.

Topics: Animals; Ascorbic Acid; Disease Models, Animal; Dose-Response Relationship, Drug; Ferrous Compounds; Gastric Mucosa; Injections; Lipid Peroxides; Male; Rats; Rats, Sprague-Dawley; Stomach Ulcer; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Incubation of MC-1010 cells with the spin-trapping agent 5,5-dimethyl-1-pyrroline 1-oxide (DMPO) followed by brief treatment with the solid oxidant lead dioxide (PbO2) yielded, after filtration, a cell-free solution that contained two nitroxyl adducts. The first was the hydroxyl radical adduct, 5,5-dimethyl-2-hydroxypyrrolidine-1-oxyl (DMPO-OH), which formed immediately upon PbO2 oxidation. The second had a 6-line EPR spectrum typical of a carbon-centered radical (AN = 15.9 G; AH = 22.4 G) and formed more slowly. No radical signals were detected in the absence of either cells or PbO2 treatment. The 6-line spectrum could be duplicated in model systems that contained ascorbate, DMPO and DMPO-OH, where the latter was formed from hydroxyl radicals generated by sonolysis or the cleavage of hydrogen peroxide with Fe2+ (Fenton reaction). In addition, enrichment of MC-1010 cells with ascorbate prior to spin trapping yielded the 6-line EPR spectrum as the principal adduct following PbO2 oxidation and filtration. These results suggest that ascorbate reacted with DMPO-OH to form a carbon-centered ascorbyl radical that was subsequently trapped by DMPO. The requirement for mild oxidation to detect the hydroxyl radical adduct suggests that DMPO-OH formed in the cells was reduced to an EPR-silent form (i.e., the hydroxylamine derivative). Alternatively, the hydroxylamine derivative was the species initially formed. The evidence for endogenous hydroxyl radical formation in unstimulated leukocytes may be relevant to the leukemic nature of the MC-1010 cell line. The spin trapping of the ascorbyl radical is the first report of formation of the carbon-centered ascorbyl radical by means other than pulse radiolysis. Unless it is spin trapped, the carbon-centered ascorbyl radical immediately rearranges to the more stable oxygen-centered species that is passive to spin trapping and characterized by the well-known EPR doublet of AH4 = 1.8 G.

Topics: Ascorbic Acid; Carbon; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Ferrous Compounds; Free Radicals; Humans; Hydrogen Peroxide; Hydroxyl Radical; Leukemia, Monocytic, Acute; Oxidants; Oxidative Stress; Oxygen; Sonication; Spin Labels; Spin Trapping; Tumor Cells, Cultured

1. Rat liver microsomal suspension containing NADPH and MgCl2 was incubated at 37 degrees C with naproxen, a non-steroidal anti-inflammatory drug. Thiobarbituric acid reactive substances (TBA-RS), high molecular weight protein aggregates and fluorescent substances were formed in the microsomal suspension. 2. Chemiluminescence was produced from the microsomal suspension. This chemiluminescence production was well correlated to the TBA-RS formation, indicating that the chemiluminescence production was closely associated with the lipid peroxidation. 3. The addition of SKF-525A to the microsomal suspension inhibited the production of TBA-RS, chemiluminescence and 6-demethylnaproxen (6-DMN), the oxidative product of naproxen. Further, the antioxidant, alpha-tocopherol and singlet oxygen quenchers like histidine, dimethylfuran and 1,4-diazabicyclo[2,2,2]octane strikingly inhibited the productions of chemiluminescence and TBA-RS. 4. Neither naproxen nor 6-DMN caused lipid peroxidation in the absence of NADPH. Thus, lipid peroxidation and chemiluminescence during the oxidation of naproxen in liver microsomes was suggested to be provoked by reactive oxygen species and an origin of chemiluminescence was shown to be singlet oxygen.

Topics: Animals; Antimutagenic Agents; Antioxidants; Ascorbic Acid; Cobalt; Electrophoresis, Polyacrylamide Gel; Ferrous Compounds; Histidine; Lipid Peroxidation; Luminescent Measurements; Magnesium Chloride; Male; Microsomes, Liver; Molecular Weight; NADP; Naproxen; Piperonyl Butoxide; Proadifen; Rats; Rats, Wistar; Reactive Oxygen Species; Thiobarbituric Acid Reactive Substances; Vitamin E

Inhibitory effects of calcium antagonists, efonidipine (NZ-105), nicardipine, nifedipine, nimodipine and flunarizine, on mitochondrial swelling induced by lipid peroxidation or arachidonic acid in the rat brain in vitro were investigated. Mitochondrial swelling and lipid peroxidation induced by FeSO4 and ascorbic acid system showed a close and significant relationship. Mitochondrial swelling and lipid peroxidation induced by FeSO4 and ascorbic acid were inhibited by all of calcium antagonists tested. The order of inhibition was: flunarizine > nicardipine > efonidipine > nimodipine > nifedipine. This result suggests that calcium antagonists tested have anti-peroxidant activities resulting in protection of mitochondrial membrane damage and that each moiety of these structures would play an important role in appearance of anti-peroxidant activities. Furthermore, flunarizine and efonidipine inhibited mitochondrial swelling induced by arachidonic acid, which is not associated with lipid peroxidation. In contrast, nicardipine, nifedipine, and nimodipine did not inhibited this swelling. It is possible that flunarizine and efonidipine could directly interact with mitochondrial membrane. In conclusion, it is capable that calcium antagonists tested may protect from the membrane damage induced by lipid peroxidation and that flunarizine and efonidipine could stabilize the membrane, which is attributed to a direct interaction with the membrane.

Topics: Animals; Arachidonic Acid; Ascorbic Acid; Brain; Calcium Channel Blockers; Ferrous Compounds; In Vitro Techniques; Lipid Peroxidation; Male; Mitochondrial Swelling; Rats; Rats, Wistar

Effects of oxidative stress on isolated rat ventricular myocytes were studied. Myocyte viability was determined by the ability of these cells to retain rod-shaped morphology and to exclude trypan blue. The mean life time of myocytes was quantitated using the Weibull distribution function. Superfusion with 200 microM tert-butyl hydroperoxide (t-BHP) led to a time-dependent loss of cell viability, generation of the products of lipid peroxidation, oxidation of protein and non-protein thiols, a decrease in [ATP]i and in the cellular energy charge. Dithiothreitol (DTT, 5 mM) prolonged survival of myocytes exposed to t-BHP, attenuated oxidation of protein and non-protein thiols, and preserved the energy charge. Exposure to DTT did not affect the concentration of t-BHP-generated lipid peroxidation products. Promethazine (1 microM) prevented t-BHP-induced increase in the concentration of lipid peroxidation products, but did not prevent either loss of thiols or loss of cell viability. Superfusion with N-ethylmaleimide (NEM, 5 microM) also led to loss of cell viability, with accompanying decreases in protein and non-protein thiols, ATP and energy charge without the accumulation of the products of lipid peroxidation. Superfusion with FeSO4 (400 microM) and ascorbate (1 mM), (Fe-Asc) did not result in loss of cell viability or a decrease protein thiols or the energy charge. Superfusion with Fe-Asc, did, however, lead to a slight decrease in the concentration of non-protein thiols and ATP and a large increase in the concentration of lipid peroxidation products. Accumulation of lipid peroxidation products induced by Fe-Asc was prevented by promethazine.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Ascorbic Acid; Cell Survival; Ethylmaleimide; Ferrous Compounds; Free Radicals; Lipid Peroxidation; Male; Myocardium; Oxidative Stress; Peroxides; Promethazine; Proteins; Rats; Rats, Sprague-Dawley; tert-Butylhydroperoxide; Thiobarbituric Acid Reactive Substances

Catechol 2,3-dioxygenase encoded by TOL plasmid pWW0 of Pseudomonas putida consists of four identical subunits, each containing one ferrous ion. The enzyme catalyzes ring cleavage of catechol, 3-methylcatechol, and 4-methylcatechol but shows only weak activity toward 4-ethylcatechol. Two mutants of catechol 2,3-dioxygenases (4ECR1 and 4ECR6) able to oxidize 4-ethylcatechol, one mutant (3MCS) which exhibits only weak activity toward 3-methylcatechol but retained the ability to cleave catechol and 4-methylcatechol, and one phenotypic revertant of 3MCS (3MCR) which had regained the ability to oxidize 3-methylcatechol were characterized by determining their Km and partition ratio (the ratio of productive catalysis to suicide catalysis). The amino acid substitutions in the four mutant enzymes were also identified by sequencing their structural genes. Wild-type catechol 2,3-dioxygenase was inactivated during the catalysis of 4-ethylcatechol and thus had a low partition ratio for this substrate, whereas the two mutant enzymes, 4ECR1 and 4ECR6, had higher partition ratios for it. Similarly, mutant enzyme 3MCS had a lower partition ratio for 3-methylcatechol than that of 3MCR. Molecular oxygen was required for the inactivation of the wild-type enzyme by 4-ethylcatechol and of 3MCS by 3-methylcatechol, and the inactivated enzymes could be reactivated by incubation with FeSO4 plus ascorbic acid. The enzyme inactivation is thus most likely mechanism based and occurred principally by oxidation and/or removal of the ferrous ion in the catalytic center. In general, partition ratios for catechols lower than 18,000 did not support bacterial growth. A possible meaning of the critical value of the partition ratio is discussed.

Topics: Ascorbic Acid; Catechol 2,3-Dioxygenase; Catechols; Cell Division; Dioxygenases; Enzyme Reactivators; Ferrous Compounds; Iron; Kinetics; Mutation; Oxygen; Oxygenases; Plasmids; Pseudomonas putida; Substrate Specificity

Artemisinin is an effective antimalarial agent, and its action on the malarial parasite is suggested to be mediated by oxidative processes. Since malarial parasites contain a high concentration of hemin, and hemin may induce the formation of reactive oxygen species, we investigated the interaction of artemisinin, iron and hemin. We used erythrocyte membrane-bound Ca2+ pump ATPase (basal) and calmodulin (CaM)-activated Ca2+ pump ATPase as our model. Membranes were incubated with artemisinin in the presence or absence of iron-ascorbate or hemin at 37 degrees for 1 hr. Following incubation, ATPase activity was measured. Our results showed that artemisinin (500 microM) had no effect on ATPase activities. However, artemisinin enhanced the inhibitory effect of iron (50 microM)-ascorbate (500 microM) on ATPase activity (46.3 +/- 3.9 vs 63 +/- 2.1% for basal; 57.2 +/- 2.5 vs 74.8 +/- 2.1% for CaM-activated). Desferrioxamine (DFO, 200 microM) blocked significantly the effect of iron-ascorbate-artemisinin on ATPases (P < 0.01). Hemin inhibited ATPase activity in a concentration-dependent fashion. Artemisinin enhanced hemin (10 microM)-induced inhibition of basal (36.0 +/- 6.0 vs 73.7 +/- 3.0%) and CaM-activated Ca2+ pump ATPase (31.6 +/- 2.8 vs 70.0 +/- 1.5%). Iron chelators (DFO, ferene, 8-hydroxyquinoline, 1,10-phenanthroline, and 1,2-dimethyl-3-hydroxypyrid-4-one) had no effect on artemisinin plus hemin-induced enzyme inhibition. Catalase (2000 U/mL) had a minor effect on the artemisinin-hemin or hemin-mediated effect. Thiourea (1 mM) had no effect. However, superoxide dismutase (500 U/mL) and dithiothreitol blocked artemisinin-hemin or hemin-mediated ATPase inhibition significantly (P < 0.001). In conclusion, these results suggest that, in our model, artemisinin enhances the damage of hemin-induced ATPases via oxidation of thiol groups on the enzymes. Free iron or hydroxyl radical does not seem to be involved. This interaction between artemisinin and hemin may contribute to the antimalarial action of artemisinin against malarial parasites.

Topics: Antimalarials; Artemisinins; Ascorbic Acid; Calcium; Calcium-Transporting ATPases; Calmodulin; Enzyme Activation; Erythrocyte Membrane; Ferrous Compounds; Hemin; Humans; Iron Chelating Agents; Sesquiterpenes

The effects of the Parkinsonism induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were evaluated in four different monkey brain areas (frontal and occipital cortex, caudate putamen, substantia nigra). The basal and stimulated lipid peroxidation and the reduced glutathione (GSH) concentration were evaluated in three groups of male Macaca fascicularis monkeys (6 animals/group): (a) controls; (b) MPTP-treated animals; (c) animals treated with MPTP and alpha-dihydroergocryptine (DEK; ergot alkaloid characterized by a dopaminergic agonist action). In MPTP-treated animals the GSH concentration was unchanged or decreased in a non-significant way in the frontal and occipital cortex, and in substantia nigra. The basal thiobabituric acid reactive substance (TBARS) concentrations were significantly higher in the caudate putamen and substantia nigra of MPTP-treated animals. In the MPTP-treated monkeys the DEK administration induced a restoration of basal TBARS values to nearly normal ones. By incubating tissue from different brain areas with FeSO4 plus ascorbic acid, the stimulation of lipid peroxidation decreased the TBARS production in the substantia nigra of the MPTP-treated animals. These results, taken together, may indicate that an increased lipid peroxidation could possibly play a role in producing the Parkinson-like syndrome by MPTP and that a free radical excess could be responsible for the degeneration of the substantia nigra. The treatment with an ergot alkaloid (i.e., alpha-dihydroergocryptine) partially antagonizes the MPTP-induced increase in basal TBARS concentration in caudate putamen.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Ascorbic Acid; Brain; Caudate Nucleus; Dihydroergotoxine; Ferrous Compounds; Frontal Lobe; Glutathione; Lipid Peroxidation; Macaca fascicularis; Male; Occipital Lobe; Oxidation-Reduction; Parkinson Disease, Secondary; Putamen; Substantia Nigra; Thiobarbituric Acid Reactive Substances

This study was conducted to determine whether the tolerance of embryos to the stress of freezing and thawing can be modified by including in the incubation medium stimulators or inhibitors of membrane lipid peroxidation. Mouse zygotes were cultured in medium M16, supplemented or not with FeSO4, apotransferrin, and/or ascorbate. In each culture supplement, 8-cell embryos were randomly allocated to an untreated (nonfrozen) control group, or treatment by freezing using slow or ultra-rapid cooling. In the slow-frozen group, FeSO4 (49.3%, 66 of 134), decreased embryo survival, whereas apotransferrin (82.7%, 110 of 133) and ascorbate (86.4%, 114 of 132), increased significantly the percentage of intact embryos recovered after thawing compared to those cultured in the basic medium M16 (66.9%, 99 of 148). Apotransferrin and ascorbate also increased significantly the percentage of blastocysts on Day 5 (79.7%, 106 of 133, and 89.4%, 118 of 132 vs. 62.2%, 92 of 148, respectively). Ascorbate, in addition, increased significantly the percentage of implantations compared to those in the basic medium M16 (84.5%, 60 of 71 vs. 61.1%, 37 of 56). Changes in the ultra-rapidly frozen group were not so evident. However, a significant fetal wastage after implantation was observed when embryos were cultured without additives and then ultra-rapidly frozen (31.7%, 13 of 41 vs. 7.0%, 3 of 43, in the nonfrozen control group). Fetal weight was similar between culture conditions, but it was significantly lower in slow-frozen and ultra-rapidly frozen embryos than in the nonfrozen control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Apoproteins; Ascorbic Acid; Blastocyst; Culture Techniques; Embryonic and Fetal Development; Female; Ferrous Compounds; Fetal Viability; Freezing; Hot Temperature; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Mice, Inbred CBA; Time Factors; Transferrin; Zygote

A pot-culture experiment was conducted to assess the bioavailability of iron from spinach cultivated in soil fortified with graded levels of iron and zinc (FeSO4 x 7H2(0) and ZnSO4 x 7H2(0), respectively). Applications of varying levels of iron to soil increased the total iron and phosphorus contents and decreased the zinc content (P < 0.05). The effect of applying varying levels of zinc was the opposite of on the minerals in spinach. The ascorbic acid content was remarkably reduced with varying levels of iron and zinc. Higher levels of zinc and lower levels of iron in the soil increased the bioavailability of iron from spinach (P < 0.05). In conclusion, the interactions of 15 ppm zinc with 30 ppm iron significantly enhanced the bioavailability of iron, total iron and zinc contents.

Topics: Ascorbic Acid; Biological Availability; Ferrous Compounds; In Vitro Techniques; Iron; Phosphorus; Soil; Sulfates; Vegetables; Zinc Compounds; Zinc Sulfate

Hepatic fat-storing cells (FSC) play a key role in the development of fibrosis as a major source of collagen and other extracellular matrix (ECM) proteins in the injured liver. Both experimental and clinical studies have shown that lipid peroxidation is often associated with the development of liver fibrosis. Here we report that exposure of cultured human liver FSC to the pro-oxidant system ascorbate/iron results in an early induction of lipid peroxidation, as monitored in terms of MDA and fluorescent aldehyde/protein adducts production, and in a significant increase of the constitutive expression of procollagen type I mRNA paralleled by the accumulation of the protein in cell culture media. This fibrogenic effect is almost completely abolished by pretreatment of FSC cultures with the antioxidants alpha-tocopherol (Vitamin E) or diphenylphenylendiamine (DPPD). Moreover, treatment of FSC with 1.0 microM 4-hydroxynonenal (HNE), a highly reactive aldehydic end-product of lipid peroxidation, results in a significant stimulation of procollagen type I gene expression and synthesis, suggesting that this aldehyde also exerts profibrogenic activity. These findings indicate that oxidative reactions can directly influence procollagen I gene expression and synthesis in FSC, thus contributing to the development of liver fibrosis.

Topics: Adipose Tissue; Aldehydes; Antioxidants; Ascorbic Acid; Cells, Cultured; Ferrous Compounds; Gene Expression Regulation; Humans; Lipid Peroxidation; Liver; Malondialdehyde; Phenylenediamines; Procollagen; RNA, Messenger; Vitamin E

We investigated the effect of lipid peroxidation, in vitro induced by H2O2 or FeSO4 and ascorbic acid, on binding properties of muscarinic receptors in rat cerebral cortex membranes. Simultaneously the concentrations of thiobarbituric acid reactive substances (TBARS) were measured to assess the extent of lipid peroxidation. In conditions of increased TBARS levels the density of (3H)N-methylscopolamine [(3H)NMS] binding sites in rat cerebral cortex membranes was not affected. Decreased numbers of (3H)NMS binding sites observed in the presence of high concentrations of H2O2 (100 and 1000 mmol.l-1) accompanied by a decrease of TBARS levels might be related to a nonspecific effect of H2O2 on cellular proteins.

Topics: Animals; Ascorbic Acid; Cell Membrane; Cerebral Cortex; Ferrous Compounds; Hydrogen Peroxide; In Vitro Techniques; Lipid Peroxidation; Male; N-Methylscopolamine; Oxidation-Reduction; Rats; Rats, Wistar; Receptors, Muscarinic; Scopolamine Derivatives; Stress, Physiological; Thiobarbituric Acid Reactive Substances

Activities of superoxide dismutase (SOD) and lipid peroxide (LPO) were studied in corpora lutea of pregnant rats. SOD activities, both Mn-SOD and Cu,Zn-SOD, gradually increased in the corpora lutea until day 15 of pregnancy and decreased thereafter until day 21 of pregnancy, in a similar manner to serum progesterone concentration. LPO activities remained low until day 15 of pregnancy, but increased rapidly after day 15 to day 21 of pregnancy. Incubation of the dispersed luteal cells from day 15 of pregnancy in vitro showed that FeSO4 and ascorbic acid, which induce lipid peroxidation, significantly inhibited progesterone secretion. The inhibitory effects of FeSO4 and ascorbic acid were blocked by the simultaneous addition of alpha-tocopherol. These results suggest important roles for SOD and LPO in regulating luteal function during pregnancy.

Topics: Animals; Ascorbic Acid; Corpus Luteum; Female; Ferrous Compounds; Lipid Peroxides; Pregnancy; Pregnancy, Animal; Progesterone; Rats; Rats, Sprague-Dawley; Superoxide Dismutase; Vitamin E

The irreversible loss of activity of the sarcolemma-localized beta-receptor-adenylyl cyclase system (beta-RAS) in myocardial ischemia is a well documented phenomenon. Alterations in the sarcolemma (SL) induced by reactive O2 species could be responsible for this loss. Therefore the influence of oxidation of SH-groups and lipid peroxidation induced by Fe2+/Vit. C on the beta-RAS activity was studied. During incubation of SL with Fe2+/Vit. C a transient enhancement followed by a continuous loss of the beta-RAS activity (isoprenaline-, NaF-, Gpp(NH)p-, forskolin-stimulated and basal activity) was observed. In contrast there occurred a continuous loss of SH-groups and lipid peroxidation, beginning immediately after the start of incubation. Loss of SH-groups and lipid peroxidation as well as changes in the beta-RAS did not take place in the presence of the antioxidant t-Butyl-4-hydroxyanisole (BHA) or the Fe(2+)-chelator EGTA. In view of the known ischemia-induced formation of reactive O2 species our results show that these powerful oxidants could contribute to the modulation of the beta-RAS during myocardial ischemia.

Topics: Adenylyl Cyclases; Animals; Ascorbic Acid; Ferrous Compounds; In Vitro Techniques; Lipid Peroxidation; Oxidation-Reduction; Oxygen; Receptors, Adrenergic, beta; Sarcolemma; Sulfhydryl Compounds; Swine; Thiobarbiturates

Pyrogallol (a generator of superoxide anions) caused 50% increase in platelet aggregation induced by 400 microM of arachidonic acid. Dipyridamole did not produce a statistically significant inhibition of arachidonic-acid induced platelet aggregation, but it caused 100% inhibition of pyrogallol-stimulated platelet aggregation. Ferrous salts (Fe2+) induced 34% platelet aggregation which was inhibited (79.6%) by a concentration of dipyridamole of 10 microM. Dipyridamole inhibited ferrous-induced lipid peroxidation with IC-50 values of 17.5 microM. When arachidonic acid was used as aggregating agent, the corresponding IC-50 value was 140.5 microM. These results indicate that dipyridamole prevented platelet activation induced by oxygen-derived free radicals.

Topics: Adult; Arachidonic Acid; Ascorbic Acid; Dipyridamole; Ferrous Compounds; Free Radicals; Humans; Lipid Peroxidation; Male; Platelet Aggregation; Pyrogallol; Superoxides

Human spermatozoa contain appreciable amounts of intracellular glutathione, which has a protective function against peroxidative degradation of spermatozoal polyunsaturated fatty acids by the NADPH-dependent glutathione peroxidase/reductase enzymatic system. The glutathione system provides a basic defense against peroxidative damage, without which the superoxide dismutase system would dominate. Since oxidative damage is said to include enzyme leakage and changes in metabolism, cytochrome oxidase and lactate dehydrogenase activities were used as indicators of the energy metabolism in unwashed and washed human spermatozoa during lipid peroxidation. Lipid peroxidation was induced by aerobic incubation of sperms in the presence of sodium ascorbate and ferrous sulphate. In addition, since NADPH concentrations influence the concentration of reduced glutathione, we studied glucose-6-phosphate dehydrogenase activity as an indicator of pentose phosphate shunt activity, the main source of NADPH. Microdensitometric measurements of the three enzymes were made by a Vickers M85a scanning microdensitometer. We found that the lipid peroxidation process greatly affects the 3 enzymatic activities examined and that seminal plasma protects against the extensive deleterious effects of lipid peroxidation.

Topics: Ascorbic Acid; Electron Transport Complex IV; Ferrous Compounds; Glucosephosphate Dehydrogenase; Humans; L-Lactate Dehydrogenase; Lipid Peroxidation; Male; Pentose Phosphate Pathway; Semen Preservation; Spermatozoa

A commercially available enzyme immunoassay was used to determine ferritin content and subsequently the loading and release of iron from ferritin in neuroblastoma cells. LS cells were incubated with 59Fe for 24 h, lysed, and the cytoplasmic ferritin was bound to monoclonal antibodies coupled to globules. After determination of the ferritin content the same globules with bound radioactive ferritin were measured in a gamma-counter. To illustrate the applicability of this test system, increased iron loading of cellular ferritin could be demonstrated in cycloheximide-treated cells; furthermore, release of iron was documented after incubation of LS cells with a combination of 6-hydroxydopamine and ascorbate. The assay turned out to be a simple method for determination of changes in 59Fe content of ferritin in neuroblastoma cells.

Topics: Ascorbic Acid; Cycloheximide; Ferritins; Ferrous Compounds; Humans; Immunoenzyme Techniques; Iron; Iron Radioisotopes; Neuroblastoma; Oxidopamine; Tumor Cells, Cultured

The effects of pyrimido-pyrimidine derivatives (dipyridamole, RA-642, and RA-233) on lipid peroxidation, using d-alpha-tocopherol as standard, were studied in enriched membrane fractions from human and rat hepatocytes. Equimolar concentrations of ferrous sulfate and ascorbic acid were used to induce lipid peroxidation. The amount of peroxidized lipids observed in membrane fractions from human liver was smaller than in those from rat liver. In both species, however, pyrimido-pyrimidine derivatives, except for RA-233 in rat liver, inhibited lipid peroxidation dose-dependently in the following sequence: RA-642 greater than dipyridamole greater than d-alpha-tocopherol RA-233.

Topics: Animals; Ascorbic Acid; Cardiotonic Agents; Cell Membrane; Dipyridamole; Ferrous Compounds; Humans; Kinetics; Lipid Peroxidation; Liver; Malondialdehyde; Mopidamol; Pyrimidines; Rats; Species Specificity; Vitamin E

Cortical homogenates were prepared from rat brain in Krebs-Ringer phosphate media adjusted to pH 7, 6 or 5 and incubated for 1 hr under aerotic or anaerobic conditions in the presence of dipyridyl, an iron chelator. Low molecular weight species (LMWS) iron was measured spectrophotometrically after passing of the homogenates through a 10,000-Mr ultrafiltration membrane. Following aerobic incubation, LMWS iron reached 1.24 micrograms/g tissue at pH 7, and increased 1.7-fold at pH 6 and 3.1-fold at pH 5. Anoxia enhanced significantly the amount of ultrafiltrable iron at the three pH values, the LMWS iron level being increased by 190% at pH 7, by 113% at pH 6, and by 77% at pH 5. Addition of the ultrafiltrates to brain membranes caused significant rises in the production of lipid peroxides assessed by the thiobarbituric acid test, indicating that LMWS iron was in a form capable for catalysing oxygen-derived free radical-mediated lipid peroxidation. It was concluded that decompartmentalization of intracellular iron may be an important factor in the initiation of peroxidative damage to ischemic cells.

Topics: 2,2'-Dipyridyl; Acidosis; Animals; Ascorbic Acid; Brain Chemistry; Ferrous Compounds; Hydrogen-Ion Concentration; Hypoxia, Brain; Iron; Lipid Peroxidation; Lipid Peroxides; Male; Oxygen; Rats; Rats, Inbred Strains

The effect of Fe2+ and Cu2+ on the intact calf vitreous in the presence or absence of exogenous ascorbic acid was investigated in vitro. Liquefaction of vitreous gel was evident in the presence of either ion. The loss of gel structure was greater in the presence of exogenous ascorbic acid than in its absence. As shown by high-performance liquid chromatography, liquefaction was accompanied by depolymerization of vitreous hyaluronic acid which is degraded by .OH, generated by the metal ion catalyzed oxidation-reduction system. The involvement of .OH in this process was also evident from the significant reduction in liquefaction in the presence of the .OH-specific scavenger mannitol.

Topics: Animals; Ascorbic Acid; Cattle; Chromatography, High Pressure Liquid; Copper; Copper Sulfate; Ferrous Compounds; Free Radicals; Hyaluronic Acid; Polymers; Vitreous Body

Topics: Animals; Ascorbic Acid; Cell Membrane; Dihydroalprenolol; Ferrous Compounds; Lipid Peroxidation; Myocardium; Receptors, Adrenergic, beta; Sarcolemma; Swine; Thiobarbiturates

Benzoate monohydroxy compounds, and in particular salicylate, were produced during interaction of ferrous complexes with hydrogen peroxide (Fenton reaction) in a N2 environment. These reactions were inhibited when Fe complexes were flushed, prior to the addition in the model system, by nitric oxide. Methionine oxidation to ethylene by Fenton reagents was also inhibited by nitric oxide. Myoglobin in several forms such as metmyoglobin, oxymyoglobin, and nitric oxide-myoglobin were interacted with an equimolar concentration of hydrogen peroxide. Spectra changes in the visible region and the changes in membrane (microsomes) lipid peroxidation by the accumulation of thiobarbituric acid-reactive substances (TBA-RS) were determined. The results showed that metmyoglobin and oxymyoglobin were activated by H2O2 to ferryl myoglobin, which initiates membrane lipid peroxidation; but not nitric oxide-myoglobin, which, during interaction with H2O2, did not form ferryl but metmyoglobin which only poorly affected lipid peroxidation. It is assumed that nitric oxide, liganded to ferrous complexes, acts to prevent the prooxidative reaction of these complexes with H2O2.

Topics: Antioxidants; Ascorbic Acid; Benzoates; Benzoic Acid; Ferrous Compounds; Hydrogen Peroxide; Hydroxides; Hydroxyl Radical; Hydroxylation; Methionine; Metmyoglobin; Myoglobin; Nitric Oxide; Salicylates; Salicylic Acid; Ultraviolet Rays

Rabbit red blood cells (RBC) were exposed in vitro to an oxygen-radical-generating system represented by iron and ascorbic acid. Under these experimental conditions we have investigated the effect of this system on some intracellular rabbit reticulocyte and erythrocyte enzymes. The results obtained have shown a pronounced decay of hexokinase activity both in the erythrocytes and reticulocytes when exposed to these radical species. We have found that the amount of hexokinase inactivated is at least three times higher in a blood sample with a percentage of reticulocytes of 50-60%. This different behaviour of the hexokinase decay in the erythrocytes and reticulocytes could be due to its different intracellular distribution related to the two distinct cells. In addition we have evaluated some important intracellular compounds involved in maintaining the redox and the energetic state of the cell such as the reduced glutathione and the adenine nucleotides and their degradation products, in order to understand if there is any correlation between the hexokinase decay and a change concerning the metabolic conditions of the rabbit reticulocytes and erythrocytes exposed to free radicals.

Topics: Animals; Ascorbic Acid; Enzyme Activation; Erythrocytes; Ferrous Compounds; Free Radicals; Glutathione; Glycolysis; Hexokinase; Humans; Isoenzymes; Oxidation-Reduction; Oxygen; Rabbits; Reticulocytes

The effects of alpha-tocopherol (C16) and its homologues with different chain length (6-hydroxychromanes-C1, C6, C11) on lipid peroxidation induced luminol-dependent chemiluminescence in rat liver microsomal suspensions were studied. It was shown that C1, C6 and C11 inhibited the (Fe(2+) + ascorbate)-and (Fe(2+) + NADP.H)-induced chemiluminescence. The inhibitory effect was decreased in the order: C1 C6 C11, C16 was not influenced chemiluminescence. The possible reason underlying these differences was discussed: different efficiency of interaction of C16 and its homologues with hydroxyl and superoxide radicals, which initiate the luminol-dependent chemiluminescence. It was concluded that C16 (in concentration below 0.5 mM) was not interacted with hydroxyl and superoxide free radicals, generated in microsomal suspensions under (Fe(2+) + ascorbate)- and (Fe(2+) + NADP.H)-dependent lipid peroxidation.

Topics: Animals; Antioxidants; Ascorbic Acid; Chromans; Depression, Chemical; Ferrous Compounds; Lipid Peroxidation; Luminescent Measurements; Luminol; Male; Microsomes, Liver; NADP; Rats; Rats, Inbred Strains; Vitamin E

Tumor cells generally display low lipid peroxidation. A low content of polyunsaturated fatty acids in membrane phospholipids is a possible cause of their decreased susceptibility to lipid peroxidation. To investigate the importance of substrate availability in eliciting lipid peroxidation and to study cell viability in conditions of stimulated lipid peroxidation, AH-130 hepatoma cells were enriched with arachidonic acid. The enriched hepatoma cells showed increased mortality correlated with the increased incorporation of arachidonic acid in membrane phospholipids. When 0.5 mM arachidonic acid was added to hepatoma cells, this fatty acid reached a percentage content similar to that found in hepatocytes. Hepatoma cells enriched with this concentration were further incubated to determine their susceptibility to lipid peroxidation; mortality increased in parallel with increased thiobarbituric acid-reactive substance production. The highest mortality was in hepatoma cells treated with ascorbate/FeSO4. Mortality in normal cells was low, although they had a high production of thiobarbituric acid-reactive substances. The high capability of normal cells to metabolize the products of lipid peroxidation might explain the different viabilities of normal cells and hepatoma cells. It may therefore be possible to modify the composition of fatty acids of hepatoma cells in order to sensitize them to the toxic effect of prooxidant agents.

Topics: Animals; Arachidonic Acids; Ascorbic Acid; Cell Survival; Culture Media; Ferrous Compounds; Lipid Peroxidation; Liver Neoplasms, Experimental; Male; Membrane Lipids; Microsomes, Liver; Rats

In a study of absorption of iron from meals by preadolescent children (Tanner stage 1), we had noted that erythrocyte incorporation of the extrinsic iron label was somewhat greater by girls than by boys. Although the difference was not significant, the observation seemed to warrant further study. Study A: A precisely determined quantity of ferrous sulfate enriched with the stable isotope 58Fe was given without food to 15 boys and 15 girls (Tanner stage 1) after an overnight fast and was immediately followed by a dose of 70 mg of ascorbic acid. 58Fe enrichment of the erythrocytes was determined by inductively coupled plasma mass spectrometry at baseline and 14 and 42 d after administration of the 58Fe dose. Geometric mean erythrocyte incorporation of the 58Fe label was 35.2% of intake by boys and 45.0% of intake by girls. The difference was significant (analysis of covariance with serum ferritin as covariate, p = 0.035). Study B: Fifteen boys and 15 girls (Tanner stage 1) were fed a breakfast labeled with 58Fe. Geometric mean erythrocyte incorporation of the 58Fe label was 14.8% of intake by boys and 24.7% of intake by girls. The difference was significant (analysis of covariance with serum ferritin as covariate, p = 0.004). Because serum ferritin concentrations were similar in boys and girls, the gender-related difference in iron absorption (as reflected by erythrocyte incorporation of the label) does not appear to be explained by a difference in body stores of iron. We hypothesize that hormonal differences between boys and girls in Tanner stage 1 favor iron absorption by girls.

Topics: Ascorbic Acid; Body Height; Body Weight; Chelating Agents; Child; Female; Ferritins; Ferrous Compounds; Humans; Intestinal Absorption; Male; Sex Characteristics; Sexual Maturation

Fe2+/ascorbate-induced peroxidation of isolated rat liver mitochondria leads to initial volume changes and, ultimately, to severe damage characterized by gross swelling and loss of cristae and matrix material. Only the last phase is associated with significant production of malondialdehyde. The shrinkage of mitochondria during the onset of peroxidation matches changes observed in mitochondria of aging animals. Thioctacid (alpha-lipoic acid) prevents this initial shrinkage. However, its main effect in the system studied here is inhibition of active respiration.

Topics: Animals; Ascorbic Acid; Ferrous Compounds; In Vitro Techniques; Lipid Peroxidation; Malondialdehyde; Mitochondria, Liver; Rats; Thioctic Acid

Lipid peroxidation effects of ferric maltol have been compared with those of ferrous sulphate both in lecithin liposomes and in brush border and mitochondrial membranes prepared from rat small intestine. Ferrous sulphate, but not ferric maltol, initiated peroxidation in liposomes as measured by conjugated diene production, but, with 500 microM ascorbic acid present, both caused intense peroxidation which was inhibitable by N2, tocopherol, maltol and ferrous chelators, but not by OH or H2O2 scavengers. The rate of peroxidation increased with ferrous sulphate concentration up to 100 microM but was independent of ferric maltol concentration between 5-500 microM. Material eluted from rat small intestine contained a reducing factor, similar in size to ascorbic acid, capable of generating ferrous ions from ferric maltol and initiating peroxidation. Peroxidation in mitochondrial membranes appeared unaffected by addition of iron whilst that in brush border membranes was detectable only in the presence of iron. At iron concentrations of 100 microM and above ferric maltol produced less liposomal peroxidation than ferrous sulphate. Maltol itself may delay recycling of Fe3+ to Fe2+. Thus ferric maltol could provide a less toxic alternative to ferrous salts in the oral treatment of iron-deficiency.

Topics: Animals; Ascorbic Acid; Chromatography, Gel; Ferric Compounds; Ferrous Compounds; In Vitro Techniques; Lipid Peroxidation; Liposomes; Male; Microvilli; Mitochondria; NAD; Pyrans; Pyrones; Rats; Spectrophotometry, Ultraviolet

The effect of iron and iron chelators on the development of the mouse embryo in vitro from the 1-cell stage to the blastocyst has been investigated. An adverse effect of iron was found. The high affinity iron chelator, desferal, also blocked development, whilst transferrin (whether as apoprotein or saturated with iron), DETAPAC and EDTA promoted development. The addition of transferrin permitted development to the blastocyst stage of embryos from stains normally exhibiting the 2-cell block. Under such circumstances both the rate of embryonic development and the proportion of embryos reaching the blastocyst stage approached levels found in vivo. Based on these results, a new medium, BAT6, is described for the optimal in-vitro culture of mouse embryos.

Topics: Animals; Apoproteins; Ascorbic Acid; Cell Division; Culture Media; Culture Techniques; Deferoxamine; Dose-Response Relationship, Drug; Edetic Acid; Embryo, Mammalian; Embryonic Development; Female; Ferrous Compounds; Iron; Iron Chelating Agents; Mice; Pentetic Acid; Pregnancy; Transferrin

The purpose of this animal study was to investigate the histopathologic consequences of esophageal exposure to a variety of medications known to be injurious to the human esophagus. Twenty-four New Zealand white rabbits were utilized. Tablets or control plastic beads were secured to a silk suture thread and positioned in the rabbit esophagus through a proximal esophagostomy and a gastrostomy. Test medications were allowed to dissolve passively on the surface of the esophageal mucosa in the anesthetized rabbits. After 1 hr of drug exposure, the rabbits were killed and the esophagus removed and examined. No gross abnormalities were detected with the exception of a mild degree of erythema at some of the exposure sites. All medications and control beads produced microscopic mucosal changes when compared to suture controls. The beads and test medications caused thinning of the epithelium and increased subepithelial edema (P less than 0.05). Two changes, however, were unique to animals exposed to test medications: fraying and/or splitting of the epithelium and the presence of balloon cells (P less than 0.05). Balloon cells represent damaged squamous epithelial cells recognizable by their distended, globoid shape. The prevalence of balloon cells ranged from 22% to 89% of sites exposed to drug and was most commonly associated with potassium. Of all drugs reported to cause injury to the human esophagus, potassium chloride has been reported to produce the most severe lesions, including esophageal stricture and perforation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Ascorbic Acid; Aspirin; Delayed-Action Preparations; Doxycycline; Esophagus; Ferrous Compounds; Ibuprofen; Potassium Chloride; Rabbits

Accidental poisoning by oral iron preparations is a serious problem in young children. We investigated the formation of hydroxyl radicals (.OH) in rats after intragastric instillation of ferrous sulfate. .OH was detected via its reaction with intragastrically administered 2-keto-4-methylthiobutyrate to generate ethylene gas. Ascorbic acid is typically present in oral iron preparations in order to facilitate absorption by maintaining iron in the reduced state. However, ascorbate possesses two properties that can affect .OH, recycling of oxidized iron to the ferrous state augments .OH production, while ascorbate in high concentration scavenges .OH. In experiments conducted in vitro, both actions were evident, depending upon the concentration of ascorbate. In parallel experiments conducted in vivo, the scavenging action of ascorbate was more prominent. Experiments in vitro with .OH-scavengers (dimethylsulfoxide, ethanol) and with the enzyme, catalase, confirmed both the presence of .OH and its dependence upon generated hydrogen peroxide during the oxidation of ferrous salt by molecular oxygen. Hydroxyl radicals (and/or reactive higher oxidation states of iron) may play a role in tissue damage after accidental overdose of oral iron.

Topics: Administration, Oral; Animals; Ascorbic Acid; Catalase; Dimethyl Sulfoxide; Ethanol; Ethylenes; Female; Ferrous Compounds; Hydrogen Peroxide; Hydroxides; Hydroxyl Radical; In Vitro Techniques; Rats; Rats, Inbred Strains

The iron chelator desferrioxamine has been applied in many studies of pathological states by several investigators. The resulting decreases in cellular and tissue damage have been interpreted as an indication of the involvement of iron-mediated radical species. Although the nature and location of the iron species have not been identified, the assumption has often been made that desferrioxamine is able to enter cells. This paper reports investigations of the ability of desferrioxamine to cross the erythrocyte membrane in comparison with that of specific hydroxypyridone iron chelators by assessing their interaction with haemoglobin.

Topics: Ascorbic Acid; Biological Transport; Cell Membrane Permeability; Chelating Agents; Deferoxamine; Erythrocyte Membrane; Ferrous Compounds; Hemoglobins; Humans; Hydrogen Peroxide; Hydroxylation; Oxidation-Reduction; Pyridones

The levels of trimethylamine N-oxide (TMAO) in the New Zealand (Nototodarus sloani) species of squid extracts were extremely high (above 9200 ppm). When the extracts were incubated for 2 days at 25 degrees C, approximately 60% TMAO was converted to trimethylamine (TMA) and dimethylamine (DMA). This conversion was very low or negligible at 4 degrees C, but was potentiated by the presence of ferrous sulphate (0.014 M) and ascorbate (0.014 M). Citrobacter freundii and Aeromonas hydrophilia were isolated from the extracts. Cultures of these two micro-organisms and of Escherichia coli were active in catalysing the conversion of TMAO to TMA and DMA either in extract or in aqueous solution. Chloramphenicol (0.416 mg/ml) completely inhibited the growth of these micro-organisms and also effectively blocked the conversion of endogenous TMAO to TMA in the extracts. The present findings suggest that gastro-intestinal flora and dietary ferrous salts and ascorbate may play important roles in the conversion of TMAO to TMA and DMA in man following the ingestion of squid and other TMAO-containing seafoods.

Topics: Animals; Ascorbic Acid; Bacteria; Chloramphenicol; Decapodiformes; Dimethylamines; Drug Synergism; Ferrous Compounds; Methylamines

Polyunsaturated fatty acid (PUFA) levels (an index of the amount of substrate available for lipid peroxidation) were measured in several brain regions from patients who died with Parkinson's disease and age-matched control human postmortem brains. PUFA levels were reduced in parkinsonian substantia nigra compared to other brain regions and to control tissue. However, basal malondialdehyde (MDA; an intermediate in the lipid peroxidation process) levels were increased in parkinsonian nigra compared with other parkinsonian brain regions and control tissue. Expressing basal MDA levels in terms of PUFA content, the difference between parkinsonian and control substantia nigra was even more pronounced. Stimulating MDA production by incubating tissue with FeSO4 plus ascorbic acid, FeSO4 plus H2O2, or air alone produced lower MDA levels in the parkinsonian substantia nigra, probably reflecting the lower PUFA content. These results may indicate that an increased level of lipid peroxidation continues to occur in the parkinsonian nigra up to the time of death, perhaps because of continued exposure to excess free radicals derived from some endogenous or exogenous neurotoxic species.

Topics: Aged; Animals; Ascorbic Acid; Brain; Fatty Acids, Unsaturated; Female; Ferrous Compounds; Free Radicals; Humans; Hydrogen Peroxide; Lipid Peroxidation; Male; Malondialdehyde; Parkinson Disease; Postmortem Changes; Rats; Rats, Inbred Strains; Substantia Nigra; Thiobarbiturates

Vitamin A (retinol) and some of its analogs exhibited varying degrees of inhibition on induced iron and ascorbic acid lipid peroxidation of rat brain mitochondria. Malonyldialdehyde production was used as an index of the extent of in vitro lipid peroxidation. The fat-soluble vitamins retinol, retinol acetate, retinoic acid, retinol palmitate, and retinal at concentrations between 0.1 and 10.0 mmol/L inhibited brain lipid peroxidation. Retinol and retinol acetate were the most effective inhibitors. It is concluded from this study that retinol and its analogs can be considered as potential antioxidant factors, more potent than some of the well-known antioxidants such as alpha-tocopherol and butylated hydroxytoluene.

Topics: Animals; Ascorbic Acid; Brain; Diterpenes; Ferrous Compounds; Free Radicals; Lipid Peroxidation; Male; Malondialdehyde; Mitochondria; Rats; Rats, Inbred Strains; Retinaldehyde; Retinyl Esters; Tretinoin; Vitamin A

The structures of fluorescent products formed in the reaction of methyl linoleate hydroperoxides with adenine, FeSO4 and ascorbic acid were investigated to elucidate the mechanism of interaction. The fluorescent products consisted of at least four major components (I-IV), which could be separated by thin-layer chromatography and high-performance liquid chromatography. Both 2-octenal and 2,4-decadienal, degradation products of methyl linoleate hydroperoxides, reacted with adenine to produce a fluorescent product similar to one of the major compounds (II) formed in the reaction of methyl linoleate hydroperoxides. Spectroscopic data suggest that I and III are the same type of compounds, which have closed ring structures with alpha, beta-unsaturated carbonyl groups between the amino group at the 6-position and the nitrogen at the 1-position of adenine. Component II has a closed ring structure at the same site as I and III, and the presence of an ether linkage was suggested. On the basis of these structures, the involvement of 3-nonenal, methyl 12-oxo-9-dodecenoate and 2-octenal was suggested in the interaction of the methyl linoleate hydroperoxides decomposition products and adenine or DNA in the presence of FeSO4 and ascorbic acid.

Topics: Adenine; Aldehydes; Ascorbic Acid; Chemical Phenomena; Chemistry; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; DNA; Ferrous Compounds; Fluorescence; Lipid Peroxides; Magnetic Resonance Spectroscopy; Mass Spectrometry; Molecular Structure; Spectrometry, Fluorescence

The in vitro effects of several flavonoids on nonenzymatic lipid peroxidation in the rat brain mitochondria was studied. The lipid peroxidation was indexed by measuring the MDA production using the 2-thiobarbituric acid TBA test. The flavonoids, apigenin, flavone, flavanone, hesperidin, naringin, and tangeretin promoted the ascorbic acid-induced lipid peroxidation, the extent of which depended upon the concentration of the flavonoid and ascorbic acid. The other flavonoids studied, viz., quercetin, quercetrin, rutin, taxifolin, myricetin, myricetrin, phloretin, phloridzin, diosmetin, diosmin, apiin, hesperetin, naringenin, (+)-catechin, morin, fisetin, chrysin, and 3-hydroxyflavone, all showed varying extents of inhibition of the nonenzymatic lipid peroxidation, induced by either ascorbic acid or ferrous sulfate. The flavonoid aglycones were more potent in their antiperoxidative action than their corresponding glycosides. Structure-activity analysis revealed that the flavonoid molecule with polyhydroxylated substitutions on rings A and B, a 2,3-double bond, a free 3-hydroxyl substitution and a 4-keto moiety, would confer upon the compound potent antiperoxidative properties.

Topics: Animals; Ascorbic Acid; Brain; Ferrous Compounds; Flavonoids; In Vitro Techniques; Lipid Peroxides; Male; Malondialdehyde; Mitochondria; Rats; Rats, Inbred Strains; Structure-Activity Relationship

Thymine was placed in a model active oxygen-generating system containing ferrous sulfate, EDTA, and ascorbic acid. The oxidative products of thymine were separated by Sephadex LH-20 chromatography and a reversed phase high-performance liquid chromatography (HPLC) into at least five major components. One of them had a UV spectrum characteristic of 5-formyluracil and mass spectrometric analysis of this material also indicated this material to be 5-formyluracil.

Topics: Ascorbic Acid; Chromatography, High Pressure Liquid; Edetic Acid; Ferrous Compounds; Gas Chromatography-Mass Spectrometry; Oxidation-Reduction; Oxygen; Spectrophotometry, Ultraviolet; Thymine; Uracil

In both experimental animals and human subjects iron absorption over a wide dosage range was quantitatively equivalent from ferrous salts and a ferric polymaltose complex under basal conditions. The comparable bioavailability was maintained when demand was increased by iron depletion or erythroid stimulation and depressed by expansion of body stores or impaired erythropoiesis. This common pattern for iron retention from both salt and complex supports the interchangeable use of these products in therapy of absolute iron deficiency.

Topics: Animals; Ascorbic Acid; Biological Availability; Ferric Compounds; Ferrous Compounds; Humans; In Vitro Techniques; Intestinal Absorption; Iron; Iron Deficiencies; Male; Rats

The glutamine synthetase of Neurospora crassa, either purified or in cell extracts, was inactivated by ascorbate plus FeCl3 and by H2O2 plus FeSO4. The inactivation reaction was oxygen dependent, inhibited by MnCl2 and EDTA, and stimulated in cell extracts by sodium azide. This inactivation could also be brought about by adding NADPH to the cell extract. The alpha and beta polypeptides of the active glutamine synthetase were modified by these inactivating reactions, giving rise to two novel acidic polypeptides. These modifications were observed with the purified enzyme, with cell extracts, and under in vivo conditions in which glutamine synthetase is degraded. The modified glutamine synthetase was more susceptible to endogenous phenylmethylsulfonyl fluoride-insensitive proteolytic activity, which was inhibited by MnCl2 and stimulated by EDTA. The possible physiological relevance of enzyme oxidation is discussed.

Topics: Ascorbic Acid; Chlorides; Edetic Acid; Ferrous Compounds; Glutamate-Ammonia Ligase; Hydrogen Peroxide; Macromolecular Substances; Manganese; Manganese Compounds; NADP; Neurospora; Neurospora crassa; Oxidation-Reduction; Peptide Hydrolases

Topics: Administration, Oral; Animals; Ascorbic Acid; Ethylenes; Female; Ferrous Compounds; Free Radicals; Hydroxides; Hydroxyl Radical; Iron; Methionine; Oxidation-Reduction; Rats; Rats, Inbred Strains

Mitochondria are known to contain a P-450 like system similar to that found in microsomes. Since previous in vivo studies from this laboratory have suggested that renal mitochondria may metabolize salicylate (SAL) to a reactive intermediate capable of protein binding, the ability of isolated kidney and liver mitochondria to activate salicylate was investigated. Renal mitochondria were 4 times more active than liver in converting SAL to a reactive intermediate and metabolized approx. 1% of the SAL to 2,3-dihydroxybenzoic acid, the catechol analogue of SAL. The formation of 2,3-dihydroxybenzoate (2,3-DHBA) and the amount of radiolabel bound to mitochondrial protein was decreased in the presence of SKF 525-A; however, excess unlabeled metabolite had no effect on binding. These data indicate that kidney mitochondria activate SAL via a cytochrome P-450 like system, but suggest that the binding species is not 2,3-DHBA itself. Oxidation of SAL and covalent binding of radiolabel, however, were also observed after the addition of ferrous iron and ascorbic acid to a model system containing [14C]SAL and bovine serum albumin. Mannitol decreased SAL oxidation and covalent binding, suggesting radical formation may represent a non-enzymatic mechanism for SAL activation.

Topics: Animals; Ascorbic Acid; Chromatography, Thin Layer; Ferrous Compounds; Gentisates; Hydroxybenzoates; In Vitro Techniques; Kidney; Male; Mannitol; Mitochondria, Liver; Proadifen; Rats; Rats, Inbred Strains; Salicylates; Salicylic Acid

After 90 min treatment with ascorbic acid and FeSO4 at 4 degrees C, the activity of rabbit sarcoplasmic reticulum Ca-ATPase was reduced to 22% and the Arrhenius plot of enzyme activity showed an absence of a discontinuity. The presence of vitamin E restored enzyme activity (60%) and the discontinuity in the Arrhenius plot. Ca-ATPase reconstituted with delipidated protein from ascorbic acid-Fe-treated preparation and normal lipid exhibited properties similar to the intact treated enzyme, whereas that reconstituted with delipidated normal protein and lipid from treated preparation exhibited reduced activity but retained the Arrhenius discontinuity. These properties are similar to those observed for sarcoplasmic reticulum Ca-ATPase from the vitamin E-deficient muscular dystrophic rabbit.

Topics: Animals; Ascorbic Acid; Calcium-Transporting ATPases; Ferrous Compounds; Iron; Muscular Dystrophy, Animal; Rabbits; Sarcoplasmic Reticulum; Vitamin E Deficiency

The effects of phenolic anti-inflammatory drug, MK-447, on prostaglandin (PG) I2 and thromboxane (TX) A2 biosynthesis by rat dental pulp tissue were evaluated in the presence of 10 mM mannitol (MA) or 1 mM ascorbic acid with 0.3 mM Fe2+ (A + F). Although MK-447 alone at 1 and 10 microM had no significant effects, MK-447 at 100 microM stimulated both PGI2 and TXA2 biosynthesis, and suppressed the lipid peroxidation in the pulp tissue as estimated by thiobarbituric acid method. MA also reduced the lipid peroxidation, but had no effect on PG and TX production. However, in the presence of MA, the stimulatory effect of MK-447 was potentiated, and the significant effects were observed at concentrations higher than 1 microM. In contrast, A + F remarkably stimulated the lipid peroxidation, and inhibited both PG and TX biosynthesis. In the presence of A + F, MK-447 showed no stimulatory effect, and contrary, at 100 microM inhibited PG and TX production. These results suggest that the cellular levels of lipid peroxidation exert a significant influence on the effects of phenolic anti-inflammatory drugs like MK-447 on PG biosynthesis. The possible mechanism of action for such drugs has been discussed in view of the significance of lipid peroxidation in inflammatory condition.

Topics: Animals; Anti-Inflammatory Agents; Ascorbic Acid; Butylated Hydroxytoluene; Dental Pulp; Ferrous Compounds; In Vitro Techniques; Lipid Peroxides; Male; Mannitol; Prostaglandins; Rats; Rats, Inbred Strains; Thromboxane A2

In hemochromatosis and other disorders associated with iron overload, a significant fraction of the total iron in plasma circulates in the form of low molecular weight complexes not bound to transferrin. Efficient and unregulated clearance of this form of iron by the liver may account for the hepatic iron loading and toxicity that characterize these diseases. We tested this possibility by examining the hepatic removal process for representative iron complexes in the single-pass perfused rat liver. Hepatic uptake of both ferrous and ferric 55Fe from ultrafiltered human serum was found to be highly efficient and effectively irreversible (single-pass extraction of 1 microM iron, 58-75%). Similar high efficiencies were seen for iron complexed to specific physiologic and nonphysiologic coordinators, including histidine, citrate, fructose, oxalate and glutamate, and tricine. Because of lower plasma flow rates, single-pass extraction of these iron complexes in vivo should be even greater. Autoradiography confirmed that most iron had been removed by parenchymal cells. Hepatic removal from Krebs-tricine buffer was saturable with similar kinetic parameters for ferrous and ferric iron (apparent Km, 14-22 microM; V max, 24-38 nmol min-1 g liver-1). These findings suggest that high levels of non-transferrin-bound iron in plasma may be an important cause of hepatic iron loading in iron overload states.

Topics: Anaerobiosis; Animals; Ascorbic Acid; Citrates; Ferrous Compounds; Hemochromatosis; Iron; Liver; Male; Metabolic Clearance Rate; Oxidation-Reduction; Perfusion; Rats; Rats, Inbred Strains

Seminal plasma antioxidant inhibited ascorbate/iron-induced lipid peroxidation in spermatozoa, brain and liver mitochondria. The concentration required to produce inhibition in brain and liver mitochondria was high. Denaturation of spermatozoa resulted in complete loss of antioxidant action. Maintenance of native structure was essential for action of seminal plasma antioxidant in spermatozoal lipid peroxidation. The antioxidant inhibited NADPH, Fe3+-ADP induced lipid peroxidation in microsomes and consequences of lipid peroxidation such as glucose-6-phosphatase inactivation were prevented by presence of antioxidant. It did not inhibit microsomal lipid peroxidation induced by ascorbate and iron and xanthine-xanthine oxidase.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain; Cattle; Ferrous Compounds; Kinetics; Lipid Peroxides; Male; Microsomes; Mitochondria; Mitochondria, Liver; Semen; Spermatozoa

Topics: Anemia, Hypochromic; Ascorbic Acid; Drug Combinations; Ferrous Compounds; Follow-Up Studies; Humans; Iron

The effects of membrane lipid peroxidation are determined in isolated albino rat retina. Lipoperoxidation induced by addition of Fe2+ + ascorbate to the perfusion liquid leads to an irreversible decrease of amplitude in the electroretinogram. The experimental model proposed here provides the possibility to monitor the survival of the retina and demonstrates that ocular lipid peroxidation very notably shortens the survival time. The specific role of the rod membranes for the excitation mechanism in the retina as revealed by these experiments is discussed.

Topics: Animals; Ascorbic Acid; Electroretinography; Ferrous Compounds; In Vitro Techniques; Lipid Peroxides; Photic Stimulation; Rats; Retina

The first step in the proteolytic degradation of bacterial glutamine synthetase is a mixed function oxidation of one of the 16 histidine residues in the glutamine synthetase subunit (Levine, R.L. (1983) J. Biol. Chem. 258, 11823-11827). A model system, consisting of oxygen, a metal ion, and ascorbic acid, mimics the bacterial system in mediating the oxidative modification of glutamine synthetase. This model system was studied to gain an understanding of the mechanism of oxidation and of factors which control the susceptibility of the enzyme to oxidation. Availability of substrates and the extent of covalent modification of the enzyme (adenylylation) interact to modulate susceptibility of the enzyme to oxidation. This interaction provides the biochemical basis for physiologic regulation of intracellular proteolysis of glutamine synthetase. The oxidative modification requires hydrogen peroxide. While the reaction may involve Fenton chemistry, the participation of free radicals, superoxide anion, and singlet oxygen could not be demonstrated.

Topics: Amino Acids; Ascorbic Acid; Escherichia coli; Ferrous Compounds; Glutamate-Ammonia Ligase; Histidine; Hydrogen Peroxide; Kinetics; Sulfhydryl Compounds

Bovine whole semen, spermatozoa, and seminal plasma did not undergo lipid peroxidation when aerobically incubated. However, lipid peroxidation was induced in washed spermatozoa in the presence of iron or iron plus sodium ascorbate, whereas heating, sonication, or treatment with proteolytic enzymes did not have any effect. The time required for formation of optimum concentration of lipid peroxides in washed spermatozoa is very short as compared to other systems. Lipid peroxides are entirely contributed by the lipid fraction of spermatozoa. Formation of lipid peroxides is completely inhibited by the presence of seminal plasma in incubation mixture.

Topics: Animals; Ascorbic Acid; Cattle; Ferrous Compounds; Lipid Peroxides; Male; Semen; Spermatozoa

Protoporphyrinogen oxidase activity and ferrochelatase activity were measured in leucocytes from patients with porphyria variegata. The mean activity of protoporphyrinogen oxidase (PPO) in porphyria variegata (PV) was about 50% of normal (P less than 0.05). The mean activity of ferrochelatase with 59Fe2+ sulphate and protoporphyrin as substrates (in the presence of ascorbic acid) was reduced by 40% (P less than 0.009). The mean activity of ferrochelatase with 59Fe3+ chloride and protoporphyrin as substrates (in the presence of reduced glutathione) was increased by 65% (P less than 0.005). Both are statistically highly significant. The findings are interpreted as follows: (a) The occurrence of a low level of protoporphyrinogen oxidase in PV is confirmed. (b) The findings indicate a concurrent structural change in ferrochelatase (this may be structurally related to (a) but no evidence of this is at present available).

Topics: Adult; Ascorbic Acid; Chlorides; Female; Ferric Compounds; Ferrochelatase; Ferrous Compounds; Flavoproteins; Glutathione; Heme; Humans; Leukocytes; Lyases; Male; Middle Aged; Mitochondrial Proteins; Oxidoreductases; Oxidoreductases Acting on CH-CH Group Donors; Porphyrias; Protoporphyrinogen Oxidase; Protoporphyrins

Sodium ascorbate caused an increased lipid peroxidation and a large decrement in [3H]spiroperidol binding in a rat neostriatal membrane preparation (preparation C). Both effects were greater at intermediate (0.05 and 0.5 mM) than at higher or lower ascorbate concentrations. In contrast, in another neostriatal membrane preparation (preparation A), there was no loss of [3H]spiroperidol binding and only a small increase in lipid peroxidation caused by ascorbate. However, both the ascorbate-induced increase in lipid peroxidation and loss of [3H]spiroperidol binding were greatly enhanced in preparation A by the addition of iron salts. In experiments designed to explore reasons for these apparent discrepancies, we discovered that the method of tissue preparation was a critical factor. The ascorbate effects were consistently greater in a tissue preparation which was originally homogenized in an isotonic sucrose medium and centrifuged, and the cell debris discarded (as was done in preparation C), than in one in which the tissue was homogenized in a hypotonic medium and in which no low-speed centrifugation was done (as was done in preparation A). In other experiments, of several cations tested, only ferrous and ferric potentiated the above-described effects of ascorbate. Some ascorbic acid derivatives (e.g., isoascorbic acid) had properties similar to those of ascorbic acid, whereas several reducing agents could, in the presence of added iron salts, cause both a lipid peroxidation and a loss of [3H]spiroperidol binding.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Ascorbic Acid; Butyrophenones; Corpus Striatum; Ferrous Compounds; Lipid Peroxides; Male; Rats; Rats, Inbred Strains; Spiperone

Most food iron in the gut enters into two "common pools" that behave quite differently in terms of absorption. Heme iron present in hemoglobin and myoglobin, is well absorbed and is relatively unaffected by diet composition. Non-heme iron, the form of iron present in vegetables and in man's staples, generally is poorly absorbed and is greatly affected by enhancing or inhibiting substances in the diet. In experiments employing intrinsically-labeled hemoglobin as a tracer, absorption of a dry hemoglobin concentrate added to milk, a rice cereal and wheat cookies, was uniformly good, relatively constant and quite independent from the type of food. In contrast, absorption of iron salts decreases markedly when given with food. The presence or absence of inhibiting or enhancing factors of non-heme iron absorption is determinant in the possibility of obtaining required iron for most people in the world whose diet contains little heme iron. Meat and ascorbic acid are the main enhancers of non-heme food iron absorption. Common inhibitors include carbonates, oxalates, phytate, bran, tea and egg yolk. The enhancing effect of ascorbic acid on the absorption of fortification iron in milk and the effect of tea, eggs or meat on the absorption of bread iron from common Chilean meals are discussed as examples of interactions of food components with non-heme iron.

Topics: Ascorbic Acid; Diet; Ferrous Compounds; Food Analysis; Heme; Humans; Intestinal Absorption; Iron

Biological availability of egg yolk iron and effect of egg yolk on absorption of iron from the reference salt, ferrous sulfate, were evaluated in hemoglobin repletion assays with anemic rats. Three measures of response, hemoglobin concentration, gain in hemoglobin iron content, and gain in carcass iron content were related to total dietary iron intake by regression analyses. Relative biological value (RBV) of yolk iron, in diets without ascorbic acid, compared to that of the reference salt was 85%. RBV of egg iron was equivalent to ferrous sulfate iron in diets containing 1 g ascorbic acid per kilogram of diet. Increasing increments of egg yolk in diets containing ascorbic acid had no significant effect on utilization of iron from the reference salt as measured by gain in hemoglobin or carcass iron content during the regeneration period. Stimulation of iron utilization from egg yolk by ascorbic acid was mild in these studies and was less in diets containing 32 mg/kg of egg yolk iron than in those containing 15 mg/kg of iron from egg.

Topics: Absorption; Anemia, Hypochromic; Animals; Ascorbic Acid; Biological Availability; Diet; Egg Yolk; Female; Ferrous Compounds; Hemoglobins; Iron; Male; Rats; Rats, Inbred Strains; Regression Analysis

The relative biological value (RBV) of iron in egg yolk was compared with that of iron in ferrous sulfate in prophylactic assays with weanling rats. Egg yolk cooked by one of three different methods was used in each experiment: (1) yolk of eggs boiled in the shell, lyophilized, and mixed with other dry diet ingredients; (2) pasteurized yolk and other diet components steamed with 8 liters of water per kilogram of diet; and (3) pasteurized yolk and other diet ingredients baked with 0.5 liters of water per kilogram of diet. Diets containing three levels of egg yolk and four levels of ferrous sulfate were fed to different groups of rats for 1, 2, and 3 weeks. Response of dietary iron was calculated as the regression of hemoglobin iron gain on iron intake and the nutritional quality of egg iron relative to that of ferrous sulfate iron was evaluated by slope-ratio analysis. RBV was 61, 64, and 90%, respectively, for iron of egg yolk cooked by the three methods. The presence of ascorbic acid during heat treatment of the diets significantly increased RBV of yolk iron from 64 to 92% in experiment 2, and increased it to a value equivalent to that of ferrous sulfate in experiment 3.

Topics: Animals; Ascorbic Acid; Cooking; Diet; Egg Yolk; Female; Ferrous Compounds; Growth; Hemoglobins; Iron; Male; Nutritive Value; Rats; Rats, Inbred Strains

The changes in lipid peroxidation of the retina have been investigated during experimental degeneration induced by monoiodoacetic acid and oxygenous intoxication. The results obtained have shown that the development of experimental degeneration of the retina is accompanied by intensification of lipid peroxidation. Injection of vitamin E both before and after monoiodoacetic acid and oxygenous intoxication leads to suppression of lipid peroxidation.

Topics: Animals; Ascorbic Acid; Electroretinography; Ferrous Compounds; Guinea Pigs; In Vitro Techniques; Iodoacetates; Iodoacetic Acid; Lipid Peroxides; Oxygen; Rabbits; Retinal Degeneration; Vitamin E

Topics: Animals; Ascorbic Acid; Electroretinography; Ferrous Compounds; Guinea Pigs; In Vitro Techniques; Lipid Peroxides; Male; Malondialdehyde; Retina; Selenium; Stimulation, Chemical

The effect of desferrioxamine on the reduction of tissue iron and the corresponding level of tissue ascorbic acid have been investigated in female guinea pigs on Vitamin C deficient diet. Plasma and liver AA concentrations were measured after stopping treatment (day 0) and on the following 24 days. Vitamin C intake with the diet enhances rapid absorption of iron into the tissue with corresponding increased catabolism of tissue ascorbic acid. Desferrioxamine reduced tissue iron concentrations without causing pronounced loss of liver ascorbic acid. It is concluded that alterations in tissue ascorbic acid are caused by iron overload in guinea pigs without the pronounced involvement of desferrioxamine.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Deferoxamine; Dose-Response Relationship, Drug; Female; Ferrous Compounds; Guinea Pigs; Iron; Liver

Siderosis of rabbit articular chondrocytes was produced in vitro as a model for the cartilage damage of hemophilic arthropathy. Both FeSO4 0.1-2.5 mM and rabbit hemoglobin (as hemolyzed serum, 14 mg/ml) caused iron storage in cell and organ culture. FeSO4 was far more effective. The fine structure of the siderosomes resulting from both iron sources was comparable to that observed in hemophilic and other forms of hemosiderosis. Particles resembling ferric oxyhydroxide were included in the FeSO4 but not the hemoglobin derived siderin. Iron storage following FeSO4 was enhanced 5-fold by culturing with rabbit rather than fetal calf serum. Despite repeated washing of the cultures and detachment with trypsin, an extracellular pool of Fe3+ persisted in the cell pellets. Cytotoxicity of Fe was manifested by formation of myelin bodies and a dose-dependent reduction of cell number. There was an inverse relationship between cytotoxicity and iron storage following administration of FeSO4 to five other cell types. Ascorbate 40 micrograms/ml stimulated DNA synthesis but had no protective effect against the cytotoxicity of FeSO4. Little erythrophagocytosis was showen by the chondrocytes. Desferrioxamine (0.01--2.5 mM) was markedly toxic for dividing but not for stationary chondrocytes. Administered after iron storage had been induced with FeSO4, 1.0--2.5 mM desferrioxamine removed stainable siderin granules over the course of 4 days.

Topics: Animals; Ascorbic Acid; Cartilage, Articular; Cattle; Cells, Cultured; Deferoxamine; Disease Models, Animal; Erythrocytes; Ferrous Compounds; Iron; Organ Culture Techniques; Phagocytes; Rabbits; Siderosis

The time course of peroxidation of rat liver microsomes by FeSO4 in the presence of ascorbate showed a delay in the onset of peroxidation compared to the time course when NADPH replaced ascorbate as the electron donor. The delay was consistent with an antioxidant function of ascorbate, possibly mediated through endogenous vitamin E. In order to further investigate the cooperation between ascorbate and vitamin E in suppressing lipid peroxidation, a liposomal system containing polyunsaturated phospholipids was used. Peroxidation was initiated by ferrous iron at pH 5, where spontaneous oxidation of Fe2+ did not occur and the antioxidant properties of ascorbic acid could be characterized independently of its pro-oxidant properties as a reducer of Fe3+. Ascorbic acid alone at concentrations of 30--100 microM delayed peroxidation by 20 min and at higher concentrations prevented peroxidation for 60 min. Physiological levels of vitamin E decreased peroxidation at early time points but the vitamin was apparently consumed during the course of the incubation. The presence of both vitamin C and vitamin E produced suppression of peroxidation at early time points (0--20 min) which was approximately the sum of the individual inhibitions. At longer time points, however, the mixture of antioxidants was much more effective than the sum of both vitamins alone. This suggests that interaction between these antioxidants yields and enhanced delivery of antioxidant protection.

Topics: Animals; Ascorbic Acid; Ferrous Compounds; Hydrogen-Ion Concentration; Kinetics; Microsomes, Liver; Oxidation-Reduction; Phospholipids; Rats; Vitamin E

Topics: Animals; Ascorbic Acid; Carbazoles; Ferrous Compounds; Kinetics; Lipid Peroxides; Microsomes, Liver; Promethazine; Rats

Ascorbic acid and ferrous sulfate were given to peptic ulcer patients (C-Fe therapy). In gastric ulcer patients, the healing index of the C-Fe therapy group was significantly higher than that of controls, but in duodenal ulcer patients, no significant difference was observed between the healing index of the C-Fe therapy group and that of controls. According to these results, it was concluded that C-Fe therapy was effective in healing gastric ulcers and that the cause of duodenal ulcers might depend more on aggressive factors than that of gastric ulcers.

Topics: Adult; Aged; Ascorbic Acid; Drug Evaluation; Drug Therapy, Combination; Duodenal Ulcer; Ferrous Compounds; Humans; Iron; Middle Aged; Stomach Ulcer

The formation of dihydrodiols from 7-hydroxymethyl-12-methylbenz[alpha]anthracene by rat-liver microsomal fractions, by mouse skin in short-term organ culture and by chemical oxidation in an ascorbic acid/ferrous sulphate/EDTA system has been studied using a combination of thin-layer chromatography and high pressure liquie chromatography. The 3,4-, 8,9- and 10,11-dihydrodiols were formed in all three systems. The 5,6-dihydrodiol was formed in rat-liver microsomal fractions and in chemical oxidation but was not detected as a metabolite of [7-3H]hydroxymethyl-12-methylbenz[alpha]anthracene when this compound was incubated with mouse skin in short-term organ culture. The possible role of hydroxymethyl dihydrodiols in the in vivo metabolic activation of 7,12-dimethylbenz[alpha]anthracene in mouse skin has been studied using Sephadex LH-20 column chromatography. The results show that the hydrocarbon-nucleic acid products formed following the treatment of mouse skin in vivo with [7,12-3H]dimethylbenz[alpha]anthracene are not the same as those that are formed following the treatment of mouse skin under the same conditions with either 7-hydroxymethyl-12-methylbenz[alpha]anthracene or 7-methyl-12-hydroxymethylbenz[alpha]anthracene.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Ascorbic Acid; Benz(a)Anthracenes; Biotransformation; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Chromatography, Thin Layer; Culture Techniques; DNA; Edetic Acid; Ferrous Compounds; Male; Mice; Microsomes, Liver; Oxidation-Reduction; Rats; Skin; Sulfates