ascorbic-acid and sodium-metabisulfite

To investigate the efficacy of various formulations of chlorhexidine 0.2% (CHX) in terms of plaque and gingival bleeding control compared to each other and to saline rinse (CTRL) over a 35-day rinsing period.. Seventy subjects were randomly allocated to one of 4 groups rinsing twice daily for 35 days. The different groups used CHX 0.2% rinse with alcohol (CHX1) and without alcohol (CHX2), with an antidiscolouration system (CHX3) or saline rinse (CTRL). Clinical examinations to evaluate full-mouth plaque scores (FMPS) and periodontal parameters were performed at baseline, 7, 21 and 35 days. Tooth discolouration (TD) was measured at each time point using digital photographs and spectrophotometric analysis.. At 35 days, CTRL showed the highest levels of plaque. The mean changes in FMPS from baseline were 69.8% ± 6.8 for CHX1, 57.5% ± 9.8 for CHX2, 43.7% ± 9.8 for CHX3 and 25.8% ± 7.7 for CTRL. Statistically significant differences were demonstrated between CHX1 and CHX3 (p = 0.02), CHX2 vs CHX3 (p ≤ 0.05) and CHX1/CHX2 vs CHX3 (p < 0.05). In contrast, CHX3 appeared more effective in reducing inflammatory indexes. TD increased over time in 60% to 70% of participants, although lighter staining was found in the CHX3 group. Greater FMPS reduction was observed in participants with staining vs without staining (26.0% ± 12.3, p = 0.04).. Conventional CHX appeared more effective in terms of plaque reduction. Interestingly, the newest formulation showed a higher control of gingival inflammation. Staining was associated with lower plaque levels.

Topics: Adult; Anti-Infective Agents, Local; Ascorbic Acid; Chemistry, Pharmaceutical; Chlorhexidine; Coffee; Dental Plaque; Dental Plaque Index; Double-Blind Method; Female; Follow-Up Studies; Gingivitis; Humans; Male; Mouthwashes; Periodontal Index; Photography, Dental; Placebos; Spectrophotometry; Sulfites; Tea; Tooth Discoloration; Treatment Outcome; Wine; Young Adult

The use of chlorhexidine (CHX) has been recommended for a number of clinical applications including plaque control in the post-operative period. However, the use of CHX is burdened by some side effects that could affect the compliance of the patient. The aim of this clinical trial was to evaluate the side effects, the staining in particular, the patient acceptance, and the efficacy of a 0.2% CHX mouthwash containing an anti discoloration system (ADS) compared with a 0.2% CHX alone, after periodontal flap surgery.. This single-centre, cross-over, triple-blind randomized clinical trial was carried out on 48 consecutive patients. After periodontal flap surgery, the patients were prescribed to rinse two times per day for 1 min for 1 week with 10 ml of test or control CHX, contained in anonymous bottles coded K or M and assigned randomly. No brushing and interdental cleaning of the surgical area was allowed. At week 1, after suture removal, patients received full-mouth prophylaxis and were given a second anonymous bottle, reversing the products, with the same instructions as at baseline. Patients resumed tooth-brushing but not interdental cleaning. At the end of week 2, prophylaxis was repeated, mouth rinsing was discontinued and patients resumed normal oral hygiene. At weeks 1 and 2, the following variables were recorded: presence of pigmentation, gingival parameters at the surgically treated sites (gingival inflammation, tissue inflammation around the sutures, gingival swelling and presence of granulation tissue), patient perception and acceptance of the 2 mouthwashes.. Forty-seven patients completed the study. The difference between treatments related to gingival variables was not statistically significant. The test CHX caused consistently less pigmentations than the control CHX in all the evaluated areas of the dental surfaces (odds ratio (OR)=0.083 p<0.0001 in the incisal area, OR=0.036 p<0.0001 in the approximal area and OR=0.065 p<0.0001 in the gingival area). The CHX ADS was found to be more tolerated by patients than the control mouthwash and to cause less food alteration, less alterations to the perception of salt and to be less irritant for the oral tissues.. (1) CHX ADS caused less pigmentation, was burdened by less side effects and was more agreeable than the control CHX; (2) CHX ADS was as effective as CHX without ADS in reducing gingival signs of inflammation in the post-surgical early healing phase; (3) the use of CHX ADS could be of value in treatment protocols in which the patient compliance with a CHX mouthwash prescription is relevant.

Topics: Adult; Aged; Anti-Infective Agents, Local; Ascorbic Acid; Chlorhexidine; Cross-Over Studies; Dental Plaque; Double-Blind Method; Female; Gingiva; Humans; Linear Models; Male; Middle Aged; Mouthwashes; Patient Compliance; Periodontitis; Sulfites; Surgical Flaps; Taste; Tooth Discoloration; Treatment Outcome; Wound Healing

Correct oral hygiene is believed to be the basis of primary and secondary prevention. Sometimes, using a toothbrush or other mechanical instruments for oral hygiene may be difficult and it may become necessary to use an antiseptic. Chlorhexidine is an essential component in many available preparations on sale, because of its marked antiseptic qualities. One of the most frequent side-effects is the appearance of stains on the teeth and mucous membranes, which particularly disturbs the patient. A new mouthwash containing chlorhexidine has recently become available, besides maintaining its antiseptic qualities, also avoids the side-effect of staining.. The aim of this study was to check the capacity of the new mouthwash, which contains chlorhexidine and Anti Discoloration System (ADS), not only to prevent plaque formation like the other mouthwashes containing chlorhexidine but also to avoid staining that is one of the most frequent side-effects.. The comparative study was carried out on a sample of 15 patients treated with two mouthwashes both containing 0.2% chlorhexidine, but different in that the first does not contain ADS, which is instead present in the second, a new product. The results obtained show that in the 15 patients treated, there is no statistically significant difference in the ability of the mouthwash to prevent bacterial plaque, however evidence of the stain was much less with the new mouthwash.

Topics: Adult; Anti-Infective Agents, Local; Ascorbic Acid; Chemistry, Pharmaceutical; Chlorhexidine; Colorimetry; Dental Plaque; Dental Plaque Index; Female; Free Radical Scavengers; Humans; Male; Middle Aged; Mouthwashes; Periodontal Index; Pharmaceutic Aids; Single-Blind Method; Sulfites; Tooth; Tooth Cervix; Tooth Discoloration

Topics: Ascorbic Acid; Catechol Oxidase; Catechols; Foeniculum; Fruit; Hydrogen-Ion Concentration; Kinetics; Molecular Weight; Oxidation-Reduction; Pyrogallol; Seeds; Substrate Specificity; Sulfites; Temperature

Drying of date helps in preserving it to be consumed outside the harvest season and removes some moisture from dates and also slows down the action of date endogenous enzymes. This study was carried out to investigate pretreatments and drying temperature on the physical and chemical properties of 2 date varieties (Siwi and Sakkoti) at the khalal stage.. The date fruits at khalal stage were dipped in ascorbic acid solution, sodium metabisulfite solution and sulfur dioxide before cut into pieces, halves and as whole. Then dates were dried at 50, 55, 60 and 65°C, respectively till ~20% moisture content and examined the physical and chemical properties of dried dates.. Moisture content of Siwi and Sakkoti at the khalal stage was 56.90 and 51.72%, respectively, while total sugars were 79.76 and 75.74%, respectively on dry weight bases. The color of dates Hunter (L and b) were the highest of treated with meta-bisulfate solution or sulfur dioxide and the lowest of color date observed (Hunter, a) comparing with control and ascorbic acid.. The pretreatments indicated that the dipping dates in sodium meta-bisulfate solution or sulfur dioxide then, dried at 60˚C produce high quality parameters of semi-dry dates comparing control and ascorbic acid.

Topics: Ascorbic Acid; Color; Desiccation; Dietary Sugars; Enzyme Stability; Food Handling; Fruit; Hot Temperature; Hydrogen-Ion Concentration; Nutritive Value; Phenols; Phoeniceae; Protein Denaturation; Sulfites; Sulfur Dioxide

The purpose of the present study was to investigate the antioxidant and antimicrobial activities of a conventional preservative system containing desferrioxamine mesylate (DFO) and optimize the composition of the system through mathematical models.. Different combinations of ethylenediaminetetraacetic acid (EDTA), sodium metabisulfite (SM), DFO and methylparaben (MP) were prepared using factorial design of experiments. The systems were added to ascorbic acid (AA) solution and the AA content over time, at room temperature and at 40 °C was determined by volumetric assay. The systems were also evaluated for antioxidant activity by a fluorescence-based assay. Antimicrobial activity was assessed by microdilution technique and photometric detection against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis. A multi-criteria decision approach was adopted to optimize all responses by desirability functions.. DFO did not extend the stability of AA over time, but displayed a better ability than EDTA to block the pro-oxidant activity of iron. DFO had a positive interaction with MP in microbial growth inhibition. The mathematical models showed adequate capacity to predict the responses. Statistical optimization aiming to meet the quality specifications of the ascorbic acid solution indicated that the presence of DFO in the composition allows to decrease the concentrations of EDTA, SM and MP.. DFO was much more effective than EDTA in preventing iron-catalyzed oxidation. In addition, DFO improved the inhibitory response of most microorganisms tested. The Quality by Design concepts aided in predicting an optimized preservative system with reduced levels of conventional antioxidants and preservatives, suggesting DFO as a candidate for multifunctional excipient.

Topics: Anti-Infective Agents; Antioxidants; Ascorbic Acid; Aspergillus; Candida albicans; Deferoxamine; Edetic Acid; Escherichia coli; Microbial Sensitivity Tests; Models, Theoretical; Parabens; Preservatives, Pharmaceutical; Pseudomonas aeruginosa; Staphylococcus aureus; Sulfites

The existing investigation was directed to consider the protective role of vitamin C and E alone and in combination on sodium metabisulphite-induced damage on testicular. Experimental animals were received sodium metabisulphite (520 mg/kg) alone and in combination with vitamin E (100 mg/kg), vitamin C (100 mg/kg) and vitamin E + C, while the control groups received 0.9% saline solution and olive oil (the solvent of the vitamin E). Finally, the changes in the testis histology were examined stereologically. Lipid peroxidation was assessed through the measurement of malondialdehyde (MDA) levels in testis tissues. Also, serum testosterone concentrations were measured. The results indicated that 80%-90% (spermatogonia A and B, spermatocyte and Leydig) and 40% of the Sertoli cells were missed in the rats that received sodium metabisulphite, respectively, compared with the controls. The co-supplementation of vitamin E with vitamin C significantly decreased MDA (p = 0.006) and increased testosterone (p = 0.001) concentrations in the rats received SMB which were as much as control and olive groups. Co-supplementation of vitamin E and vitamin C due to their synergistic effects could be an appropriate strategy in preventing testicular from sodium metabisulphite-induced damage.

Topics: Animals; Antioxidants; Ascorbic Acid; Leydig Cells; Lipid Peroxidation; Male; Malondialdehyde; Protective Agents; Rats; Rats, Wistar; Sertoli Cells; Sulfites; Testis; Testosterone; Vitamin E

In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phase-high-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (Km, Vmax), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. Km values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of Ki were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

Topics: Antioxidants; Ascorbic Acid; Biphenyl Compounds; Caffeic Acids; Catechin; Catechol Oxidase; Chlorogenic Acid; Coumaric Acids; Enzyme Inhibitors; Fruit; Kinetics; Levodopa; Malus; Oxidation-Reduction; Parabens; Phenylpropionates; Picrates; Plant Extracts; Plant Proteins; Polyphenols; Propionates; Quercetin; Sulfites

The objective of this paper is to calculate the shelf life of ascorbic acid solution under given conditions by using a mathematical model. An antioxidant, sodium metabisulfite, was added to the ascorbic acid solution. The kinetic parameters of the degradation reaction of ascorbic acid and sodium metabisulfite, were investigated, respectively, and then a mathematical model was developed. According to the mathematical model, the calculated shelf lives of ascorbic acid solution were 783, 835, 873, and 885 days for specifications 2, 5, 10, and 20 mL, respectively. The results showed that the obtained mathematical model can be used to calculate the shelf life of ascorbic acid solution under given conditions.

Topics: Antioxidants; Ascorbic Acid; Drug Stability; Drug Storage; Half-Life; Models, Theoretical; Solutions; Sulfites; Time Factors

Subjecting bruised olives to a nitrogen atmosphere during the postharvest period prevented the oxidation of phenols and subsequent browning. However, a rapid phenol oxidation and browning occurred when fruits were re-exposed to air. Based on models deduced from the effects of aqueous antioxidant solutions on changes in different color parameters in the fermented product, the treatments to prevent browning were optimized. The recommended procedure consists of placing the harvested olives in a cold (4 to 8 °C) solution of 3% sodium metabisulfite with the pH adjusted to 3.0 (by adding food grade HCl) and applying the lye treatment before 8 h from picking. The use of these conditions led to mechanically harvested Spanish style olives with hardly any visible browning.

Topics: Antioxidants; Ascorbic Acid; Color; Colorimetry; Fermentation; Food Handling; Food Preservation; Fruit; Hydrogen-Ion Concentration; Maillard Reaction; Nitrogen; Olea; Phenols; Solutions; Sulfites

While a long shelf life for fruit products is highly desired, enzymatic browning is the main cause of quality loss in fruits and is therefore a main problem for the food industry. In this study polyphenol oxidase (PPO), the main enzyme responsible for browning was isolated from mamey fruit (Pouteria sapota) and characterized biochemically. Two isoenzymes (PPO 1 and PPO 2) were obtained upon ammonium sulfate precipitation and hydrophobic and ion exchange chromatography; PPO 1 was purified up to 6.6-fold with 0.28% yield, while PPO 2 could not be characterized as enzyme activity was completely lost after 24 h of storage. PPO 1 molecular weight was estimated to be 16.1 and 18 kDa by gel filtration and SDS-PAGE, respectively, indicating that the native state of the PPO 1 is a monomer. The optimum pH for PPO 1 activity was 7. The PPO 1 was determined to be maximum thermally stable up to 35°C. Kinetic constants for PPO 1 were K(m)=44 mM and K(m)=1.3 mM using catechol and pyrogallol as substrate, respectively. The best substrates for PPO 1 were pyrogallol, 4-methylcatechol and catechol, while ascorbic acid and sodium metabisulfite were the most effective inhibitors.

Topics: Ascorbic Acid; Catechol Oxidase; Catechols; Chromatography, Ion Exchange; Electrophoresis, Polyacrylamide Gel; Fruit; Hydrogen-Ion Concentration; Isoenzymes; Mexico; Molecular Weight; Pouteria; Pyrogallol; Sulfites; Thermodynamics

The goal of this work was to apply the Quasi-chemical primary model (a system of four ordinary differential equations that derives from a hypothetical four-step chemical mechanism involving an antagonistic metabolite) in the study of the evolution of yeast and lactic acid bacteria populations during the storage of Manzanilla-Aloreña table olives subjected to different mixtures of ascorbic acid, sodium metabisulphite and NaCl. Firstly, the Quasi-chemical model was applied to microbial count data to estimate the growth-decay biological parameters. The model accurately described the evolution of both populations during storage, providing detailed information on the microbial behaviour. Secondly, these parameters were used as responses and analysed according to a mixture design experiment (secondary model). The contour lines of the corresponding response surfaces clearly disclosed the relationships between growth and environmental conditions, showing the stimulating and inhibitory effect of ascorbic acid and sodium metabisulphite, respectively, on both populations of microorganisms. This work opens new possibilities for the potential use of the Quasi-chemical primary model in the study of table olive fermentations.

Topics: Ascorbic Acid; Colony Count, Microbial; Fermentation; Food Handling; Food Microbiology; Fruit; Lactobacillaceae; Models, Biological; Olea; Sodium Chloride; Sulfites; Yeasts

In this work, we evaluated the chemical stability profiles of UC781 based solutions to identify excipients that stabilize the microbicidal agent UC781. When different antioxidants were added to UC781 in sulfobutylether-beta-cyclodextrin (SBE-beta-CD) solutions and subjected to a 50 degrees C stability study, it was observed that EDTA was a better stabilizing agent than sodium metabisulfite, glutathione or ascorbic acid. Some antioxidants accelerated the degradation of UC781, suggesting metal-catalyzed degradation of UC781. Furthermore, we observed substantial degradation of UC781 when stored in 1% Tween 80 and 1% DMSO solutions alone or in those with 10mM EDTA. On the other hand, improved stability of UC781 in the presence of 100 and 200mM of EDTA was observed in these solutions. The addition of both EDTA and citric acid in the stock solutions resulted in recovery of more than 60% of UC781 after 12 weeks. Generally, 10% SBE-beta-CD in the presence of EDTA and citric acid stabilized UC781 solutions: the amount of UC781 recovered approaching 95% after 12 weeks of storage at 40 degrees C. We also showed that the desulfuration reaction of the UC781 thioamide involves oxygen by running solution stability studies in deoxygenated media. Improved stability of UC781 in the present study indicates that the incorporation of EDTA, citric acid and SBE-beta-CD and the removal of oxygen in formulations of this drug will aid in increasing the stability of UC781 where solutions of the drug are required.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Anilides; Antioxidants; Antiviral Agents; Ascorbic Acid; beta-Cyclodextrins; Chemistry, Pharmaceutical; Dimethyl Sulfoxide; Drug Compounding; Drug Stability; Edetic Acid; Excipients; Fumarates; Furans; Glutathione; Hot Temperature; Models, Chemical; Oxidation-Reduction; Polyethylene Glycols; Polysorbates; Solubility; Sulfites; Technology, Pharmaceutical; Thioamides; Time Factors; Vitamin E

Two peroxidases, cPOD-I and rPOD-II, have been isolated and purified from cotton cell suspension and their biochemical characteristics studied. rPOD-II from R405-2000, a non-embryogenic cultivar, has higher activity than cPOD-I derived from Coker 312, which developed an embryogenic structure. The cPOD-I and rPOD-II had molecular mass of 39.1 and 64 kDa respectively, as determined by SDS-PAGE. Both enzymes showed high efficiency of interaction with the guaiacol at 25 mM. The optimal pH for cPOD-I and rPOD-II activity was 5.0 and 6.0, respectively. The enzyme had an optimum temperature of 25 degrees C and was relatively stable at 20-30 degrees C. The isoenzymes were highly inhibited by ascorbic acid, dithiothreitol, sodium metabisulfite, and beta-mercaptoethanol. Their activities were highly enhanced by Al(3+), Fe(3+), Ca(2+), and Ni(2+), but they were moderately inhibited by Mn(2+) and K(+). The enzyme lost 50% to 62% of its activity in the presence of Zn(2+) and Hg(2+).

Topics: Aluminum; Ascorbic Acid; Calcium; Cations; Dithiothreitol; Enzyme Activation; Enzyme Stability; Gossypium; Hydrogen-Ion Concentration; Iron; Isoenzymes; Mercaptoethanol; Nickel; Peroxidases; Sulfites

Polyphenol oxidases (PPOs) were isolated from cell suspensions of two cultivars of cotton (Gossypium hirsutum L.), and their biochemical characteristics were studied. PPO from Coker 312, an embryogenic cultivar, showed a highest affinity to catechol 20 mM, and PPO from R405-2000, a nonembryogenic cultivar, showed a highest affinity to 4-methylcatechol 20 mM. The optimal pH for PPO activity was 7.0 and 6.0 for Coker 312 and R405-2000, respectively. The enzyme had an optimal temperature of 25 degrees C and was relatively stable at 20-30 degrees C. Reducing sodium metabisulfite, ascorbic acid, dithiothreitol, SnCl(2), and FeCl(3) markedly inhibited PPO activity, whereas its activity was highly enhanced by Mg(2+), Ca(2+), and Mn(2+) and was moderately inhibited by Ba(2+), Cu(2+), and Zn(2+). The analysis revealed a single band on the sodium dodecyl sulfate polyacrylamide gel electrophoresis which corresponded to a molecular weight of 55 kDa for Coker 312 and 42 kDa for R405-2000.

Topics: Ascorbic Acid; Barium; Calcium; Catechol Oxidase; Catechols; Chlorides; Copper; Dithiothreitol; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Enzyme Inhibitors; Ferric Compounds; Gossypium; Hydrogen-Ion Concentration; Magnesium; Manganese; Sulfites; Temperature; Tin Compounds; Zinc

The shelf life of minimally processed potatoes (MPP) is limited by enzyme-catalyzed browning reactions, with the increase in respiration being another factor that affects quality retention of this product. Sulfites are commonly used as effective preservative agents in minimally processing potatoes, but ascorbic acid and citric acid are considered natural sulfite substitutes and more accepted by consumers. The aim of this study was to study the effect of combinations of the preservative agents cited above (sodium metabisulfite 0.1% and 0.5%; citric acid 0.1% and 0.5%; ascorbic acid 0.5%) on the respiration rate of MPP (cv. Monalisa) processed at both ambient and refrigerated temperatures. The results have revealed that there is a significant effect of dipping treatment and temperature on respiration rate of MPP. Sodium metabisulfite (SM) reduces respiratory activity up to 0.8 mL/kg/h. The addition of either citric or ascorbic acid enhanced the effect of SM on the reduction of the respiration rate of MPP. The strongest effect (up to 3.3 mL/kg/h) was observed when a combination of all 3 agents at the higher concentrations was employed at a temperature of 18 degrees C.

Topics: Ascorbic Acid; Carbon Dioxide; Citric Acid; Dose-Response Relationship, Drug; Drug Synergism; Food Handling; Food Packaging; Food Preservation; Food Preservatives; Maillard Reaction; Solanum tuberosum; Sulfites; Temperature; Time Factors

Vitamin C exerts several functions on skin as collagen synthesis, depigmentant and antioxidant activity. Vitamin C is unstable in the presence of oxygen, luminosity, humidity, high temperatures and heavy metals, which presents a significant challenge to the development of cosmetic formulations. Therefore, the utilization of an effective antioxidant system is required to maintain the vitamin C stability. The purpose of this research work was to develop prototypes of cosmetic formulations, as O/W emulsion and extemporaneous aqueous gel, containing vitamin C and to evaluate the influence of sodium metabisulfite (SMB) and glutathione (GLT), as antioxidants, on the stability of the active substance. A HPLC stability-indicating method was developed and validated for this study and stability assays were performed in 90 and 26 days and storage conditions were 5.0+/-0.5, 24+/-2 and 40.0+/-0.5 degrees C. The HPLC stability-indicating method showed linearity (r(2)>0.99), specificity, R.S.D.<1.22% and accuracy/recovery ranging from 95.46 to 101.54%. Preparations with SMB or GLT and the antioxidant-free presented results statistically distinct, demonstrating the necessity of the antioxidant system addition. O/W emulsions with SMB or GLT retained the vitamin C content >90.38% stored at 5.0+/-0.5 and 24+/-2 degrees C. For the aqueous gel with SMB or GLT, the active substance concentration was maintained >94.03%. Considering the vitamin C stability, the SMB and the GLT showed to be statistically adequate, as antioxidants, for the cosmetic formulations.

Topics: Antioxidants; Ascorbic Acid; Drug Stability; Emulsions; Gels; Glutathione; Oils; Sulfites; Water

Polyphenol oxidase (PPO) of nettle (Urtica dioica L.) was extracted and purified through (NH4)2SO4 precipitation, dialysis, and CM-Sephadex ion-exchange chromatography and was used for its characterization. The PPO showed activity to catechol, 4-methylcatechol, L-3,4-dihydroxyphenylalanine (L-DOPA), L-tyrosine, p-cresol, pyrogallol, catechin and trans-cinnamic acid. For each of these eight substrates, optimum conditions such as pH and temperature were determined and L-tyrosine was found to be one of the most suitable substrates. Optimum pH and temperature were found at pH 4.5 and 30 degrees C respectively and Km and Vmax values were 7.90 x 10(-4) M, and 11290 EU/mL for with L-tyrosine as substrate. The inhibitory effect of several inhibitors, L-cysteine chloride, sodium azide, sodium cyanide, benzoic acid, salicylic acid, L-ascorbic acid, glutathione, thiourea, sodium diethyl dithiocarbamate, beta-mercaptoethanol and sodium metabisulfite were tested. The most effective was found to be sodium diethyl dithiocarbamate which acted as a competitive inhibitor with a Ki value of 1.79 x 10(-9)M. In addition one isoenzyme of PPO was detected by native polacrylamide slab gel electrophoresis.

Topics: Ascorbic Acid; Catechol Oxidase; Dithioerythritol; Ditiocarb; Enzyme Inhibitors; Enzyme Stability; Glutathione; Hydrogen-Ion Concentration; Kinetics; Potassium Cyanide; Sodium Azide; Substrate Specificity; Sulfites; Temperature; Thiourea; Urtica dioica

This study was undertaken to determine whether pretreating inoculated Gala apple slices with metabisulfite or acidic solutions enhanced the inactivation of Salmonella during dehydration and storage. Apple slices inoculated with a five-strain mixture of Salmonella (7.6 log CFU/g) were pretreated, dried for 6 h at 60 degrees C, and stored aerobically at 25 degrees C for 28 days. Predrying treatments included (i) no treatment, (ii) 10 min of immersion in sterile water, (iii) 10 min of immersion in a 4.18% sodium metabisulfite solution, (iv) 10 min of immersion in a 3.40% ascorbic acid solution, and (v) 10 min of immersion in a 0.21% citric acid solution. Samples were plated on tryptic soy agar with 0.1% pyruvate (TSAP), brilliant green sulfa (BGS) agar, and xylose lysine tergitol 4 (XLT4) agar for the enumeration of bacteria. Populations were not significantly (P > 0.05) reduced by immersion in water but were reduced by 0.7 to 1.1 log CFU/g by immersion in acidic solutions. Immersion in the sodium metabisulfite solution reduced populations by 0.4, 1.3, and 5.4 log CFU/g on TSAP, BGS agar, and XLT4 agar, respectively. After 6 h of dehydration at 60 degrees C, populations on untreated and water-treated slices were reduced by 2.7 to 2.8, 2.7 to 2.9, and 4.0 to 4.2 log CFU/g as determined with TSAP, BGS agar, and XLT4 agar, respectively. In contrast, populations on slices treated with sodium metabisulfite, ascorbic acid, and citric acid were reduced after 6 h of dehydration by 4.3, 5.2, and 3.8 log CFU/g, respectively, as determined with TSAP; by 4.7, 5.5, and 3.9 log CFU/g, respectively, as determined with BGS agar; and by 5.5, 5.7, and 5.6 log CFU/g, respectively, as determined with XLT4 agar. Bacteria were still detectable by direct plating after 28 days except on slices treated with ascorbic acid. Immersion in metabisulfite or acidic solutions prior to dehydration should enhance the inactivation of Salmonella during the dehydration and storage of Gala apple slices.

Topics: Ascorbic Acid; Citric Acid; Colony Count, Microbial; Food Handling; Food Microbiology; Malus; Salmonella; Sulfites; Time Factors

Sodium metabisulfite is added to a commercial propofol emulsion as an antimicrobial agent. The sulfite ion (SO3(-2)) is capable of undergoing a number of reactions, including autooxidation and the promotion of lipid peroxidation. This study evaluated sulfite reactivity in propofol emulsions by determining thiobarbituric acid reacting substances (TBARS), sulfite depletion, and emulsion pH in emulsions containing sulfite or EDTA.. Commercial EDTA and sulfite propofol emulsions were compared, and 10% soybean oil emulsion containing various additives were evaluated for TBARS, sulfite, and pH. TBARS were analyzed with a modified thiobarbituric acid method. Sulfite was analyzed by the reaction of sulfite with 5,5'-dithiobis(2-nitrobenzoic acid). pH was measured by glass electrode methodology.. Thiobarbituric acid reacting substances were detectable in commercial sulfite propofol emulsions in concentrations ranging from 0.02 to 0.22 microg/ml based on malondialdehyde. No TBARS were detected in EDTA propofol emulsions. Incubation (37 degrees C, up to 6 h) of sulfite propofol emulsions in air resulted in further increases in TBARS (35-160%). No increases occurred in incubated EDTA propofol emulsions. Metabisulfite (0.25 mg/ml) alone added to 10% soybean oil resulted in large increases in TBARS that were inhibited in part by propofol (10 mg/ml) and completely by ascorbic acid (0.05 mg/ml). Soybean oil emulsion pH declined rapidly on the addition of metabisulfite (0.25 mg/ml). The addition of propofol (10 mg/ml) partially inhibited the decline in pH and ascorbic acid (0.05 mg/ml) completely inhibited it.. These results show that sulfite supports the peroxidation of lipids in soybean oil emulsions and propofol functions to partially inhibit these processes.

Topics: Ascorbic Acid; Edetic Acid; Emulsions; Fat Emulsions, Intravenous; Hydrogen-Ion Concentration; Lipid Peroxidation; Propofol; Soybean Oil; Sulfites

Genomic DNA was isolated from subcutaneous masses observed in CD-1 and p53+/- heterozygous mice during the course of carcinogenicity studies in the vehicle control groups. These masses resulted after daily subcutaneous injection of an antioxidant vehicle with a pH adjusted to 3-4. The vehicle was 1.0% ascorbic acid plus 0.05% sodium metabisulfite in 0.75% saline in a dosing volume of 10 ml/kg/day. These masses were first palpable after 13 and 37 weeks of dosing among p53+/- and CD-1 mice, respectively. By week 26, the incidence of these masses was 89% and 80% in male and female p53+/- mice, respectively (n = 15 mice/sex) and was 0% in both male and female CD-1 mice (n = 60 mice/sex). These masses originated from panniculus carnosus muscle. Histopathological examination of the p53+/- mouse masses indicated the tumors to be sarcomas of spindle-cell origin. The histopathological examination of the masses in the CD-1 mice revealed fibrosarcomas. Five mice/sex/strain were randomly selected from a pool of mice that developed these masses in the course of the two studies. Frozen tissues from these masses were used to examine the DNA for loss of the functional p53 allele in the p53+/- mice (i.e., loss of heterozygosity, or LOH) or for loss of one of the alleles in the wild type (p53+/+) CD-1 mice by the polymerase chain reaction (PCR) technique. Loss of the functional allele was observed only in the tumor from one p53+/- male mouse. These results support a nongenotoxic mechanism for these injection site masses.

Topics: Alleles; Animals; Antioxidants; Ascorbic Acid; Carcinogenicity Tests; Female; Fibrosarcoma; Heterozygote; Injections, Subcutaneous; Loss of Heterozygosity; Male; Mice; Mice, Inbred C57BL; Polymerase Chain Reaction; Rhabdomyosarcoma; Sensitivity and Specificity; Soft Tissue Neoplasms; Sulfites; Tumor Suppressor Protein p53

Objective of this research was to find alternative methods for the control of polyphenol oxidase (PPO) activity in fruits and vegetables with the purpose of reducing or eliminating the use of SO2 for this purpose. Interactions between the use of ascorbic acid, citric acid, EDTA, sodium metabisulphite and heat treatment (70 degrees C for 2 min) in the control of PPO activity were studied in avocado (var. Fortuna), banana (var. Nanica), apple (var. Ana, Fuji, Gala & Golden), pear (var. D'Agua), peach (var. Réal), potato (var. Bintje), eggplant (var. Super F100), mushroom (Agaricus bisporus) and hearts-of-palm (Euterpe edulis Mart). The results demonstrated that PPO of avocado and eggplant was most resistant to inhibition by the methods used. The least efficient method tested for the control of PPO was the addition of ascorbic acid and EDTA, while the most efficient methods investigated included the use of ascorbic acid, citric acid, sodium metabisulphite and heat treatment. The results indicated that, with the exception of PPO from avocado, the most adequate alternative method to substitute for the use of SO2 in the control of PPO was a combination of ascorbic acid, citric acid and heat treatment.

Topics: Ascorbic Acid; Catechol Oxidase; Citrates; Citric Acid; Edetic Acid; Fruit; Hot Temperature; Maillard Reaction; Sulfites; Vegetables

A novel antiasthmatic, 2-[(4-hydroxyphenyl)amino]-5-methoxybenzenemethanol (1), oxidizes to the corresponding iminoquinone in aqueous solutions. The reaction was monitored by a paired-ion reversed-phase HPLC method. The oxidation rate was highly dependent on the solution pH, with a large rate increase occurring above pH 6.1. In nonaqueous solution, the oxidation reaction was significantly slower. Ascorbic acid protects 1 from oxidation. The aqueous solution of the decomposed product is reduced to 1 in the presence of ascorbic acid.

Topics: Aminophenols; Ascorbic Acid; Asthma; Benzyl Alcohols; Chromatography, High Pressure Liquid; Hydrogen-Ion Concentration; Kinetics; Lactates; Oxidation-Reduction; Phosphates; Solutions; Spectrophotometry, Ultraviolet; Sulfites

It was shown in experiments on 186 mice that formation of tumors of the lung and fore-stomach induced by injection of sodium nitrite in combination with aminopyrine or methylurea is inhibited following treatment with ascorbic acid, hexamethylenetetramine or sodium metabisulfite.

Topics: Aminopyrine; Animals; Ascorbic Acid; Cocarcinogenesis; Female; Lung Neoplasms; Male; Methenamine; Methylurea Compounds; Mice; Mice, Inbred Strains; Nitrites; Sodium Nitrite; Stomach Neoplasms; Sulfites

Topics: Ascorbic Acid; Cysteine; Drug Stability; Pyruvaldehyde; Solutions; Sugar Acids; Sulfites

Sodium metabisulfite, commonly used to prevent the oxidation of catecholamines during extraction from plasma onto alkaline alumina, does not prevent their subsequent degradation in acetic acid eluates. However, ascorbic acid, a potent antioxidant, is extracted with the catecholamines onto the alumina and prevents such destruction. However, ascorbic acid may interfere with the electrochemical measurement of catecholamines, unless sequential oxidation and reduction are used. Other methods of minimizing catecholamine oxidation in acetic acid eluates include refrigerating at 4 degrees C and capping the sample vials to exclude atmospheric oxygen.

Topics: Aluminum Oxide; Antioxidants; Ascorbic Acid; Catecholamines; Chromatography, High Pressure Liquid; Dopamine; Electrochemistry; Epinephrine; False Negative Reactions; Humans; Norepinephrine; Solutions; Sulfites

Ascorbic acid is frequently used in in vitro studies of neurotransmitter-evoked release of luteinizing hormone-releasing hormone (LHRH) from hypothalamic fragments. Although it is assumed that ascorbate merely prevents the oxidative degradation of catecholamines, we have discovered that ascorbic acid itself produces significant increases in the release of LHRH. Our studies showed that ascorbic acid, at concentrations below 1 mM, produced a dose-dependent release of LHRH from incubated rat mediobasal hypothalamus (MBH). The magnitude of the ascorbate-induced release was in the range of 100-200% above controls; significant amounts of LHRH were released only if the MBH were incubated with ascorbate for time periods longer than 30 minutes. We also found that ascorbate-induced increases in LHRH were equivalent to those produced by another LHRH secretagogue, naloxone, and that the combined effects of the two substances were additive in nature. Although the mechanisms underlying this effect are not fully understood, nonspecific chemical reduction is probably not a factor since sodium metabisulfite did not induce the release of LHRH. It seems probable that ascorbate may enhance the activity of endogenous norepinephrine in the MBH and, thereby, lead to increased release of LHRH.

Topics: Animals; Ascorbic Acid; Calcium; Egtazic Acid; Gonadotropin-Releasing Hormone; Hypothalamus, Middle; In Vitro Techniques; Naloxone; Rats; Secretory Rate; Sulfites; Time Factors

Topics: Ascorbic Acid; Cysteine; Drug Stability; Humans; Solutions; Spectrophotometry; Sulfites