ascorbic-acid and naringin

The interaction mechanisms of nimodipine with pepsin, trypsin, α-chymotrypsin, lysozyme and human serum albumin were investigated by multispectral and molecular docking methods. Vitamin C and naringin were the main active components of grapefruit juice, and nimodipine was the typical drug that interacts with this juice. Fluorescence spectroscopy was used to study the interaction of nimodipine with five proteinases (pepsin, trypsin, α-chymotrypsin, lysozyme and human serum albumin) and the effects of vitamin C and naringin on these interactions. The fluorescence quenching results showed that nimodipine can quench the intrinsic fluorescence of these five proteinases by a static quenching procedure. Nimodipine binds to pepsin and α-chymotrypsin, through hydrogen bonding and van der Waals forces, whereas it binds to trypsin, lysozyme and human serum albumin mainly by hydrophobic interactions. The microenvironment of the five proteinases changed. The probability of nonradiative energy transfer between the five proteinases and nimodipine was high. Both vitamin C and naringin reduced the binding constant of nimodipine to the four proteinases (except α-chymotrypsin) and might increase the concentration of free nimodipine. Thus, vitamin C or naringin in fruits or foods could increase the blood concentration of free nimodipine and perhaps a reduction in nimodipine dose was needed.

Topics: Ascorbic Acid; Binding Sites; Flavanones; Humans; Molecular Docking Simulation; Nimodipine; Peptide Hydrolases; Protein Binding; Spectrometry, Fluorescence; Thermodynamics

Lovastatin is a typical drug interacting with grapefruit juice and naringin and vitamin C are main active constituents in fruit juice. It is necessary to study the interaction between lovastatin and digestive enzymes and the effect of naringin and vitamin C on the interaction. Pepsin, trypsin and α-chymotrypsin were selected as representatives of digestive tract enzymes, and fluorescence spectroscopy was employed to study the interaction of lovastatin with three digestive enzymes and the effect of naringin and vitamin C on this interaction. The mechanism of interaction between lovastatin and three digestive enzymes was static quenching. Lovastatin bound to trypsin by electrostatic interaction, while bound to pepsin or α-chymotrypsin mainly by hydrophobic interaction. The conformation of three enzymes changed and non-radiative energy transfer occurred with high probability between three digestive enzymes and lovastatin. Both naringin and vitamin C could reduce the binding stability of lovastatin to pepsin and α-chymotrypsin, increasing concentration of free lovastatin. That is, naringin or vitamin C in the fruit or food may increase the blood concentration of lovastatin; perhaps taking frequency or dosage of lovastatin may be reduced.

Topics: Ascorbic Acid; Flavanones; Lovastatin; Molecular Docking Simulation; Peptide Hydrolases; Protein Binding; Protein Conformation; Spectrum Analysis; Static Electricity

In the current study, the phytochemical contents and expression of genes involved in flavonoid biosynthesis in Rio Red grapefruit were studied at different developmental and maturity stages for the first time. Grapefruit were harvested in June, August, November, January, and April and analyzed for the levels of carotenoids, vitamin C, limonoids, flavonoids, and furocoumarins by HPLC. In addition, genes encoding for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and 1,2-rhamnosyltransferase (2RT) were isolated, and their expression in grapefruit juice vesicles was studied. Fruit maturity had significant influence on the expression of the genes, with PAL, CHS, and CHI having higher expression in immature fruits (June), whereas 2RT expression was higher in mature fruits (November and January). The levels of flavonoids (except naringin and poncirin), vitamin C, and furocoumarins gradually decreased from June to April. Furthermore, limonin levels sharply decreased in January. Lycopene decreased whereas β-carotene gradually increased with fruit maturity. Naringin did not exactly follow the pattern of 2RT or of PAL, CHS, and CHI expression, indicating that the four genes may have complementary effects on the level of naringin. Nevertheless, of the marketable fruit stages, early-season grapefruits harvested in November contained more beneficial phytochemicals as compared to mid- and late-season fruits harvested in January and April, respectively.

Topics: Acyltransferases; Ascorbic Acid; Carotenoids; Citrus paradisi; Flavanones; Flavonoids; Fruit; Fruit and Vegetable Juices; Furocoumarins; Gene Expression Regulation, Plant; Hexosyltransferases; Intramolecular Lyases; Limonins; Phenylalanine Ammonia-Lyase; Phytochemicals; Plant Proteins

Endothelial injury and damage as well as accumulated reactive oxygen species (ROS) in aging play a significant role in the development of cardiovascular disease (CVD). Recent studies show an association of high citrus fruit intake with a lower risk of CVD and stroke but the mechanisms involved are not fully understood. This study investigated the effects of pummelo (Citrus maxima Merr. var. Tubtim Siam, CM) fruit extract on human umbilical vein endothelial cell (HUVECs) migration and aging. The freeze-dried powder of fruit extract was characterized for antioxidant capacity (FRAP assay) and certain natural antioxidants, including ascorbic acid, gallic acid, hesperidin, and naringin (HPLC). Short-term (48 h) co-cultivation of HUVECs with CM enhanced cell migration as evaluated by a scratch wound assay and Boyden chamber assay. A long-term treatment with CM for 35 days significantly increased HUVEC proliferation capability as indicated by population doubling level (PDL). CM also delayed the onset of aging phenotype shown by senescence-associated β-galactosidase (SA-β-gal) staining. Furthermore, CM was able to attenuate increased ROS levels in aged cells when determined by 2',7'-dichlorodihydrofluorescein diacetate (DCDHF) while eNOS mRNA expression was increased but the eNOS protein level was not changed. Thus, further in vivo and clinical studies are warranted to support the use of pummelo as a functional fruit for endothelial health and CVD risk reduction.

Topics: Antioxidants; Ascorbic Acid; Cell Movement; Cellular Senescence; Citrus; Flavanones; Fluoresceins; Fruit; Gallic Acid; Hesperidin; Human Umbilical Vein Endothelial Cells; Humans; Nitric Oxide Synthase Type III; Plant Extracts; Reactive Oxygen Species; RNA, Messenger

Clinically, chronic nephrotoxicity may lead to renal functional impairment and progress to end stage renal failure. The renoprotective effect of a flavonoid naringin (NG) against cyclosporine A (CsA)-induced nephrotoxicitywas investigated in this study.. Nephrotoxicity was induced in male albino Wistar rats by injecting 25 mg/kg body weight of CsAfor a period of 21 days. CsA-induced rats were also cotreated with 40 mg of NG/kg body weight, orally.. After the experimental period, the levels of lipid peroxides (TBARS) and hydroxyl radical (OH·) were found to be elevated, whereas the levels of SOD, catalase, glutathione, vitamin C, E and A were decreased in CsA-induced rats. NG co-treatment significantly decreased the levels of lipid peroxides and hydroxyl radicals and restored the levels of enzymic and non-enzymic antioxidants in renal tissues. Histological analysis revealed that CsA administration caused severe and widespread necrosis with dilatation of proximal tubules, vacuolization, tubular cell desquamation and intraluminal cast formation with massive infiltration of inflammatory cells. CsA-induced histopathological renal changes were minimal in animals which received NG treatment. The western blot and confocal microscopic expression of heme oxygenase-1 was restored by NG. In CsA-induced animals the expression was reduced compared to NG treated animals.. The present study reveals that NG can act as effective renoprotective drug against CsA-induced toxicity.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Cyclosporine; Cytoprotection; Disease Models, Animal; Flavanones; Heme Oxygenase (Decyclizing); Hydroxyl Radical; Kidney; Kidney Diseases; Male; Rats; Rats, Wistar; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Time Factors; Vitamin A; Vitamin E

Grapefruits (Citrus paradisi Macfad) contain several phytochemicals known to have health maintaining properties. Due to the consumer's interest in obtaining high levels of these phytochemicals, it is important to understand the changes in their levels by common household processing techniques. Therefore, mature Texas "Rio Red" grapefruits were processed by some of the common household processing practices such as blending, juicing, and hand squeezing techniques and analyzed for their phytochemical content by high performance liquid chromatography (HPLC). Results suggest that grapefruit juice processed by blending had significantly (P < 0.05) higher levels of flavonoids (narirutin, naringin, hesperidin, neohesperidin, didymin, and poncirin) and limonin compared to juicing and hand squeezing. No significant variation in their content was noticed in the juice processed by juicing and hand squeezing. Ascorbic acid and citric acid were significantly (P < 0.05) higher in juice processed by juicing and blending, respectively. Furthermore, hand squeezed fruit juice had significantly higher contents of dihydroxybergamottin (DHB) than juice processed by juicing and blending. Bergamottin and 5-methoxy-7 gernoxycoumarin (5-M-7-GC) were significantly higher in blended juice compared to juicing and hand squeezing. Therefore, consuming grapefruit juice processed by blending may provide higher levels of health beneficial phytochemicals such as naringin, narirutin, and poncirin. In contrast, juice processed by hand squeezing and juicing provides lower levels of limonin, bergamottin, and 5-M-7-GC. These results suggest that, processing techniques significantly influence the levels of phytochemicals and blending is a better technique for obtaining higher levels of health beneficial phytochemicals from grapefruits. Practical Application:  Blending, squeezing, and juicing are common household processing techniques used for obtaining fresh grapefruit juice. Understanding the levels of health beneficial phytochemicals present in the juice processed by these techniques would enable the consumers to make a better choice to obtain high level of these compounds.

Topics: Ascorbic Acid; Beverages; Chromatography, High Pressure Liquid; Citric Acid; Citrus paradisi; Disaccharides; Flavanones; Flavonoids; Food Handling; Furocoumarins; Glycosides; Hesperidin; Limonins; Plant Extracts

Chronic exposure to oxidative stress especially to highly reactive hydroxyl radicals (HO*) could damage biomolecules, particularly DNA, that in turn would accelerate onset of degenerative diseases. In the present study a few standard phytochemicals (vitamin C, gallic acid, catechin, apigenin, naringenin and naringin) and plant extracts (Hippophae rhamnoides kernel (HRK), Syzygium cumini kernel (SCK) and Punica granatum pericarp (PGP)) were evaluated for their potential to protect/damage DNA in Fenton's system using in vitro models. The results indicated a significant DNA protective effect for naringin and PGP whereas other phytochemicals/extracts showed DNA damaging effect similar to or more than that of control value. The phytochemicals/extracts were also evaluated for their antioxidant and iron chelation properties. In general, the phytochemicals/extracts with high antioxidant activity but without iron chelation capacity failed to protect DNA in Fenton's system, suggesting that iron chelation was an essential requirement for the phytochemicals studied here to retard HO* generation by Fenton's reaction. This was demonstrated by the high iron chelation capacity of naringin and PGP (83.67% and 68.67% respectively) and their DNA protective effect. Commonly consumed phytochemicals such as vitamin C and gallic acid with their high reducing power and at higher physiological concentration, could regenerate free iron for Fenton's reaction leading to DNA damage as shown here.

Topics: Antioxidants; Apigenin; Ascorbic Acid; Bacteriophage lambda; Catechin; Cytoprotection; DNA Damage; DNA Fragmentation; Dose-Response Relationship, Drug; Flavanones; Gallic Acid; Genomic Instability; Hydrogen Peroxide; In Vitro Techniques; Iron; Models, Biological; Plant Extracts

This study was designed to evaluate the cardioprotective potential of naringin on lipid peroxides, enzymatic and nonenzymatic antioxidants and histopathological findings in isoproterenol (ISO)-induced myocardial infarction (MI) in rats. Subcutaneous injection of ISO (85 mg/kg) to male Wistar rats showed a significant increase in the levels of thiobarbituric acid reactive substances and lipid hydroperoxides in plasma and the heart and a significant decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in the heart and the levels of reduced glutathione, vitamin C and vitamin E in plasma and heart and ceruloplasmin in plasma. Oral administration of naringin (10, 20 and 40 mg/kg, respectively) to ISO-induced rats daily for a period of 56 days showed a significant decrease in the levels of lipid peroxidative products and improved the antioxidant status by increasing the activities of antioxidant enzymes and nonenzymatic antioxidants. Histopathological findings of the myocardial tissue showed the protective role of naringin in ISO-induced rats. The effect at a dose of 40 mg/kg of naringin was more pronounced than that of the other two doses, 10 and 20mg/kg. The results of our study show that naringin possess anti-lipoperoxidative and antioxidant activity in experimentally induced cardiac toxicity.

Topics: Adrenergic beta-Agonists; Animals; Antioxidants; Ascorbic Acid; Ceruloplasmin; Enzymes; Flavanones; Glutathione; Glutathione Peroxidase; Glutathione Transferase; Heart Diseases; Hydrogen Peroxide; Isoproterenol; Lipid Metabolism; Lipid Peroxides; Lipoproteins; Male; Muscle Fibers, Skeletal; Myocardial Infarction; Myocardium; Rats; Rats, Wistar; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.

Topics: Antioxidants; Ascorbic Acid; Citrus; Flavanones; Fruit; Hesperidin; Phenols

The antioxidant properties of freeze-dried citrus fruit peels (orange, lemon, grapefruit) and methanolic extracts from the peel were studied. Freeze-dried orange peel showed the highest, lemon peel somewhat less and grapefruit peel the lowest but still remarkable antioxidant activity. This could be significantly improved by preparing methanolic extracts of the peels. Comparative examinations and autoxidation studies with the flavanon glycosides hesperidin and naringin as well as with their aglycones hesperetin and naringenin showed that the former are mainly responsible for the antioxidative activity of the citrus peel and extracts. In order to compare their antioxidative activity with that of the commercially available natural antioxidants alpha-tocopherol and ascorbylpalmitate, the freeze-dried citrus peels and their methanolic extracts should be used in higher concentrations, in consideration of their peculiar properties and complex natural composition. Furthermore, aspects of the correlation between antioxidant activity and molecular structure of the flavanones were discussed.

Topics: Antioxidants; Ascorbic Acid; Citrus; Flavanones; Flavonoids; Freeze Drying; Hesperidin; Vitamin E