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Antioxidant activities of hot water extract of Syneilesis palmata root and aerial part
Abstract
This study was performed in order to investigate the antioxidant properties of hot water extract from the root and aerial part of the Syneilesis palmata in respect to its potential use as food, cosmetics material, or medicinal resource. The results showed that the S. palmata root hot water extract (RHW) possessed a higher content of total flavonoid compounds (4.58 mg/g) and total polyphenol compounds (59.11 mg/g). The SOD-like activities of the RHW and APHW were 23.74% and 21.61%, respectively, at a concentration . In the nitrite scavenging ability of a concentration, the RHW showed 63.06% (pH 1.2) and 47.16% (pH 3.0). The values of the nitrite scavenging abilities were (ascorbic acid), (RHW), and (APHW). The values of DPPH free radical scavenging abilities were (RHW) and (APHW). The inhibition values () of xanthine oxidase were (RHW) and (APHW). In all of the experiments, the S. palmata root hot water extracts have higher activities than the aerial hot water extract, except for the xanthine oxidase inhibitory activity. These results suggest that the S. palmata is a potentially useful antioxidant source for the development of functional nutraceuticals, cosmetics and medicine.
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The aerobic oxidation of xanthine by rat liver supernatant was greatly stimulated by the addition of methylene blue or of
NAD+: the latter was reduced during the reaction. Storage of the supernatant at -20° brought about an enhancement of the xanthine
oxidation rate measured without addition of cofactors. A similar "activation" was caused by prior incubation at 37° of the
unfractionated liver homogenate, or of the supernatant separated after sonic disruption of the homogenate. The same effect
was obtained by treatment with solvents, or by prior incubation at 37° of the supernatant in the presence of proteolytic enzymes
or under anaerobic conditions. The presence of xanthine accelerated the effect of proteolytic enzymes and of anaerobiosis.
Only the changes caused by anaerobiosis could be reversed by incubating the supernatant in air before the assay.
The reaction rate was apparently unaffected by these treatments if activity of the enzyme was measured in the presence of
methylene blue or of NAD+. The latter, however, was not reduced during the oxidation of xanthine by "activated" supernatants stored at -20° if the
reaction was run in the presence of oxygen. If the reaction was in anaerobiosis, uric acid and a corresponding amount of NADH
were formed by fresh, supernatant, and by supernatants activated at -20° or by prior incubation in anaerobiosis, but not by
supernatant activated by trypsin.
The hypothesis is formulated that most of the xanthine oxidase of rat liver supernatant is a dehydrogenase (Type D), and may
be converted (activated) into an oxidase (Type O).
The antioxidant activities and total phenolics of 28 plant products, including sunflower seeds, flaxseeds, wheat germ, buckwheat, and several fruits, vegetables, and medicinal plants were determined. The total phenolic content, determined according to the Folin−Ciocalteu method, varied from 169 to 10548 mg/100 g of dry product. Antioxidant activity of methanolic extract evaluated according to the β-carotene bleaching method expressed as AOX (Δ log A470/min), AA (percent inhibition relative to control), ORR (oxidation rate ratio), and AAC (antioxidant activity coefficient) ranged from 0.05, 53.7, 0.009, and 51.7 to 0.26, 99.1, 0.46, and 969.3, respectively. The correlation coefficient between total phenolics and antioxidative activities was statistically significant. Keywords: Antioxidant activity; phenolics; medicinal plants; oilseeds; buckwheat; vegetables; fruits; wheat products
Regulated production of reactive oxygen species (ROS)/reactive nitrogen species (RNS) adequately balanced by antioxidant systems is a prerequisite for the participation of these active substances in physiological processes, including insulin action. Yet, increasing evidence implicates ROS and RNS as negative regulators of insulin signaling, rendering them putative mediators in the development of insulin resistance, a common endocrine abnormality that accompanies obesity and is a risk factor of type 2 diabetes. This review deals with this dual, seemingly contradictory, function of ROS and RNS in regulating insulin action: the major processes for ROS and RNS generation and detoxification are presented, and a critical review of the evidence that they participate in the positive and negative regulation of insulin action is provided. The cellular and molecular mechanisms by which ROS and RNS are thought to participate in normal insulin action and in the induction of insulin resistance are then described. Finally, we explore the potential usefulness and the challenges in modulating the oxidant-antioxidant balance as a potentially promising, but currently disappointing, means of improving insulin action in insulin resistance-associated conditions, leading causes of human morbidity and mortality of our era.
With increasing evidence that shows the involvement of active oxygen and nitrogen species in a variety of disorders, cancer, and aging, the role of antioxidant against oxidative stress has received renewed attention. In this review article, a rationale for design of lipophilic, radical-scavenging antioxidant is presented and the potency of a novel antioxidant, 2,3-dihydro-5-hydroxy-2,2-dipentyl-4,6-di-tert-butylbenzofuran (BO-653), as an inhibitor of LDL oxidation was evaluated by considering various factors such as reactivity toward radicals, localization, and mobility in the lipoprotein, and fate of its radical. The anti-atherogenic activity of BO-653 was compared with those of α-tocopherol, probucol, and its metabolites. Furthermore, a novel function of phenolic antioxidants such as cell regulation and induction of phase II defense antioxidants are also discussed.
Phenolics were extracted from litchi fruit pericarp (LFP) tissues, purified and their antioxidant properties analyzed. LFP phenolics strongly inhibited linoleic acid oxidation and exhibited a dose-dependent free-radical scavenging activity against α,α- diphenyl-β-picrylhydrazyl (DPPH·) and hydroxyl radicals and superoxide anions. The degradation of deoxyribose by hydroxyl radicals was inhibited by phenolics acting mainly as iron ion chelators, rather than by directly scavenging the radicals. Phenolics from litchi fruit pericarp were found to display similar reducing power activity as ascorbic acid. The effect of phenolic compound treatment on pericarp browning and electrolyte leakage of litchi fruit was also evaluated and it was observed that application of exogenous litchi phenolics to harvested litchi fruit significantly prevented pericarp browning and delayed increases in electrolyte leakage. These results suggest that litchi pericarp tissue phenolics could be beneficial in scavenging free radicals, maintaining membrane integrity and, thereby inhibiting pericarp browning of litchi fruit.
The degradation of nitrite and the inhibition towards formation of carcinogenic nitrosamines by melanoidins, produced from the glucose-glycine system were investigated at various conditions. The degradation of nitrite was highest at pH 1.2 (29%), when the ratio of melanoidins to nitrite was 1: 3. The inhibition towards formation of nitrosamines by melanoidins had the same tendency as the degradation of nitrite, the inhibition also being highest at pH 1.2 (99%). In addition, melanoidins after nitrite treatment exhibited a little higher mutagenicity and much stronger desmutagenicity than those of the original melanoidins. The change of the structure of melanoidins after treating with nitrite was also investigated by HPLC and CP-MAS NMR.
We measured the levels of soluble protein, sugar, free amino acids, minerals, total polyphenols, and flavonoid compounds in Syneilesis palmata as part of a study on nutritional and functional materials for development of valuable foods. The content of soluble protein in the aerial and root portions were 210.36 mg% and 870.42 mg%, respectively. The amount of reducing sugar was 848.12 mg% (aerial parts) and 1,420.91 mg% (roots), and that of free sugar was 14.85 mg% in aerial parts and 355.00 mg% in roots. The free amino acid level in aerial parts was 1,613.10 mg% and that in roots was 3,282.96 mg%. The mineral content of aerial parts was 3,531.53 mg% and that of roots was 1,878.34 mg%. The K, Ca, and Mg levels were greater than those of other minerals, with K comprising more than 75% of the total mineral content. The levels of polyphenol and flavonoid compounds in aerial parts were 1,920.00 mg% and 843.95 mg%, respectively, and those in roots were 487.56 mg% and 91.07 mg%, respectively.
This study was carried out to analyze antioxidative effects of extracts of Korean herbal materials, Diospyros kaki, Teucerium veronicoides and Zanthoxylum schinifolium. Total phenol compound content of Diospyros kaki extacts was higher than those of other extracts. The electron donating ability was in 250 ppm of D. kaki extracts, but was in 1,000 ppm of T. veronicoides and Z. schinifolium extracts. The superoxide dismutase (SOD)-like activity of T. veronicoides and Z. schinzfolium extract was 25, in 1,000 ppm of concentration, respectively, but those of D. kaki extracts was . The nitrate scavenging ability of D. kaki extracts was in pH 1.2 and 1,000 ppm of extract solution, but those of T. veronicoides and Z. schinifolium extracts was 53, , respectively. The nitrate scavenging ability of D. kaki, Z. schinifolium and T. veronicoides extract was 93, 55, and in pH 3.0 and 1,000 ppm of extract solution, respectively. The nitrate scavenging ability of extracts were in pH 6.0. The nitrate scavenging ability of extracts was decreased according to increase of pH. The nitrate scavenging ability of D. kaki extracts was higher than those of T. veronicoides and Z. schinifolium extracts.
Fifty-one tannins and forty-one flavonoids isolated from Oriental medicinal herbs were evaluated for their antioxidant ability with a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system. The results showed that tannins and certain flavonoids are potential free-radical scavengers, and that their activity against the DPPH radical is closely associated with their chemical structure. A comparison of the two classes of compounds showed that tannins have more potential than flavonoids because almost all the tannins demonstrated significant scavenging action within a low concentration range, whereas the activity of flavonoids varied distinctively among the different compounds. An increase of galloyl groups, molecular weight, and ortho-hydroxyl structure enhanced the activity of tannins, whereas the number and position of hydroxyl groups were important features for the scavenging of free radicals by flavonoids. Moreover, it appeared that when the free hydroxyl group was methoxylated or glycosylated, the inhibitory activity was obviously decreased or even abolished.
The presence of four new sesquiterpenes, 3β-angeloyloxy-6β-(3-methylbutanoyloxy)-14-oxofuranoeremophilane (1a), 3β,6β-bis(angeloyloxy)-14-oxofuranoeremophilane (1a), 3β-angeloyloxy-6β-(3-methylpentanoyloxy)furanoeremophilan-14-oic acid (2a), and 3β-angeloyloxy-6β-(3-methylbutanoyloxy)furanoeremophilan-14-oic acid (2b) in Syneilesis palmata (THUNB.) MAXIM, is described.
This study was conducted to examine the antioxidant activities of the extracts from aerial parts and roots of Syneilesis palmata. The ethanol extract of aerial parts showed the highest content of flavonoid compounds (31.72 mg/g), and the ethanol extract of roots has the highest content of total polyphenol compounds (68.11 mg/g). The water extract of S. palmata roots showed the highest xanthine oxidase inhibition of 99.29% and the ethanol extract of aerial parts showed 98.48% at 1.0 mg/mL. The ethanol extract of roots showed the highest value of nitrite scavenging ability of 70.89% at pH 1.2, SOD-like activity of 13.06% and electron donating ability of 98.58% at 1.0 mg/mL concentration. The effect of tyrosinase inhibition was found at only the ethanol extracts of roots (9.33%). We found that root extracts contain abundance polyphenol compounds and their antioxidant activities were greater than those of the extracts of aerial part.
METHODS for measuring antioxidants and appraising antioxidant activity appear to be of two general types. If the chemical nature of the antioxidant is known, one may strive for a test specific for the compound or group of interest; for example, the nitroprusside test for sulphydryl groups. Alternatively one may observe the inhibition of some natural oxidative process such as the β-oxidation of fats, as a function of the added antioxidant.
The autoxidation of pyrogallol was investigated in the presence of EDTA in the pH range 7.9–10.6.
The rate of autoxidation increases with increasing pH. At pH 7.9 the reaction is inhibited to 99% by superoxide dismutase, indicating an almost total dependence on the participation of the superoxide anion radical, O2·−, in the reaction. Up to pH 9.1 the reaction is still inhibited to over 90% by superoxide dismutase, but at higher alkalinity, O2·− -independent mechanisms rapidly become dominant.
Catalase has no effect on the autoxidation but decreases the oxygen consumption by half, showing that H2O2 is the stable product of oxygen and that H2O2 is not involved in the autoxidation mechanism.
A simple and rapid method for the assay of superoxide dismutase is described, based on the ability of the enzyme to inhibit the autoxidation of pyrogallol.
A plausible explanation is given for the non-competitive part of the inhibition of catechol O-methyltransferase brought about by pyrogallol.
Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from different regions of Argentina were prepared. The extracts were analysed for the determination of total flavonoid content (from 13.3 to 42.6 mg/g of propolis) by using the aluminum nitrate method, UV spectrophotometry and thin layer chromatography. All of them contained high total flavonoid content. It was also observed that all samples of ethanolic extracts of propolis showed free radical-scavenging activity in terms of scavenging of the radical DPPH but the highest activities were found for samples from Tucumán and Santiago del Estero. In all cases with 20 μg/ml of soluble principles, the percentage of DPPH degradation was different (Banda Oeste: 67.5%; Verónica: 45%; Forres: 35%; Saenz Peña: 20% and Juan José Castelli: 55%). These results may justify their use as a source of natural antioxidants.
Seeds of double low oilseed rape variety Mango (Brassica napus, var. oleifera) were subjected to a 7-day germination at 25 °C and 95% moisture content in darkness in a conditioning cabinet. The effects of the germination process on the superoxide dismutase-like activity (SOD-like activity), thiamine (vitamin B1) and riboflavin (vitamin B2) and minerals, such as Ca, Mg, Cu, Fe and Mn, were studied. Correlations between individual mineral contents, vitamin B1 and B2 contents, and the ability of phosphate buffered saline (PBS) extracts from germinated rapeseed to scavenge superoxide anion radicals in vitro were also investigated. SOD-like activity showed a gradual increase after the second day of germination, reaching a maximum level on the sixth day, and remained almost constant up to the end of the germination period. During germination, thiamine underwent a progressive decrease up to the sixth day, reaching a constant level between the sixth and the seventh day. In contrast, riboflavin content increased throughout the germination period up to the fifth day, and after that a constant level was observed. Levels of Ca and Mg were almost constant up to the fourth day and after that an increase of these minerals was observed. Cu and Mn increased during the germination process, and retentions of 33% and 22%, respectively, were observed at the end of germination. Fe content dropped after 1 day of germination and from there onward it started to increase gradually and an 18% retention was observed in 7-day germinated seeds. Positive correlations between SOD-like activity and riboflavin (r = 0.87), Cu (r = 0.74) and Mn (r = 0.87) were found during rapeseed germination.
The autoxidation of linoleic acid and methyl linolenate is inhibited by flavonoids. The antioxidant efficiency of these flavonoids increases with their concentration and in the order fustin < catechin < quercetin < rutin = luteolin < kaempferol < morin for linoleic acid and rutin < catechin < morin = kaempferol for methyl linolenate. Flavonoids are more effective on linoleic acid than on methyl linolenate. The antioxidant activity offlavonoids is related to an inhibition of the formation of trans,trans hydroperoxide isomers of linoleic acid. This inhibition exhibited the great H-atom donating ability of flavonoids to peroxy radical, thus terminating the chain radical reaction.
Plant in vitro cultures are able to produce and accumulate many medicinally valuable secondary metabolites. Antioxidants are an important group of medicinal preventive compounds as well as being food additives inhibiting detrimental changes of easily oxidizable nutrients. Many different in vitro approaches have been used for increased biosynthesis and the accumulation of antioxidant compounds in plant cells. In the present review some of the most active antioxidants derived from plant tissue cultures are described; they have been divided into the main chemical groups of polyphenols and isoprenoids, and several examples also from other chemical classes are presented. The strategies used for improving the antioxidants in vitro production efficiency are also highlighted, including media optimization, biotransformation, elicitation, Agrobacterium transformation and scale-up.
This study evaluated the effect of ischemia-reperfusion (I-R) on pulmonary capillary permeability in isolated rabbit lungs and the roles of xanthine oxidase (XO), aldehyde oxidase (AO), and neutrophils (PMN) in producing this lung injury. Effects of XO and AO were studied by inactivation with a tungsten-enriched diet (0.7 g/kg) and inhibition of XO by allopurinol (100 microM) or AO by menadione (3.5 microM). PMN effects were studied by preventing endothelial adhesion with the monoclonal antibody IB4 (10 microM). Vascular permeability was evaluated by determining the capillary filtration coefficient (Kf,c) measured before and after I-R in all experimental conditions. Reperfusion after 2 h of ischemia significantly increased pulmonary capillary permeability (Kf,c changed from 0.096 +/- 0.014 to 0.213 +/- 0.025 ml.min-1. cmH2O-1.100 g-1), and this increase was blocked by the addition of catalase (50,000 U) at reperfusion (baseline Kf,c was 0.125 +/- 0.023 and 0.116 +/- 0.014 ml.min-1.cmH2O-1.100 g-1). XO inactivation with the tungsten-supplemented diet and XO inhibition with allopurinol prevented the Kf,c increase observed after I-R (0.183 +/- 0.030 to 0.185 +/- 0.033 and 0.126 +/- 0.018 to 0.103 +/- 0.005 ml.min-1.cmH2O-1.100 g-1). Inhibition of AO had no effect on I-R injury (Kf,c 0.108 +/- 0.011 to 0.167 +/- 0.014 ml.min-1.cmH2O-1.100 g-1). Preventing PMN adhesion resulted in significant attenuation of the change in Kf,c associated with I-R (0.112 +/- 0.032 to 0.090 +/- 0.065 ml.min-1.cmH2O-1.100 g-1). We conclude that XO and PMN adherence, but not AO, are involved in the increased capillary permeability associated with I-R.
The detergent-induced amplification of lucigenin-dependent chemiluminescence of O2-, generated by xanthine oxidase or microsomal NADPH oxidase was studied. An assay system is described which is at least 10 times more sensitive than normal lucigenin-dependent chemiluminescence due to the amplification by high concentrations of octylphenylpolyethylene glycol (Triton X-100). Compared to the superoxide dismutase-sensitive reduction of acetylated cytochrome c, a 3750-fold lower amount of microsomal protein was necessary to produce an O2- signal 10-fold above the background. In contrast to cytochrome c reduction, detergent-amplified chemiluminescence of lucigenin was completely inhibited by superoxide dismutase and therefore more selective for O2-. The membrane-bound and Triton X-100-solubilized NADPH oxidase from microsomes of macrophages was activated by ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid and inhibited by Ca2+ and sodium dodecyl sulfate. The membrane-bound enzyme showed a Km value of 1.35 microM, which decreased to 0.95 microM after the addition of 12% (g/g) Triton X-100. The Km and Vmax values of soluble xanthine oxidase were not influenced by Triton X-100, indicating that the enzyme activities were not impaired by the high concentrations of detergent.
The formation of carcinogenic N-nitroso compounds by the chemical reaction between nitrous acid and oxytetracycline, morpholine, piperazine, N-methylaniline, methylurea, and (in some experiments) dimethylamine was blocked by ascorbic acid. The extent of blocking depended on the compound nitrosated and on the experimental conditions. Urea and ammonium sulfamate were less effective as blocking agents. The possibility of in vivo formation of carcinogenic N-nitroso compounds from drugs could be lessened by the combination of such drugs with the ascorbic acid.
The purpose of this article is to explain what oxygen radicals are, how transition metals are involved in their formation and reactivity, and the role played by radicals and metals in some disease states.
Diploptene(1), beta-sitosterol(2), a mixture of 6'-O-(E-P-coumaroyl)-alpha-glucopyranose and 6'-O-(E-P-coumaroyl)-beta-glucopyranose(3), a mixture of 6'-O-(E-P-caffeoyl)-alpha-glucopyranose and 6'-O-(E-P-caffeoyl)-beta-glucopyranose(4), caffeic acid(5) and astragalin(6) were isolated from an ethanolic extract of the leaves of Alsophila spinulosa Hook Tryon (Cyatheaceae). The plant has been used in folk medicine for hepatitis, gout, rheumatism, and tumor and these compounds were tested for their inhibitory effect on xanthine oxidase. Caffeic acid was the most potent constituent (IC50 = 39.21 microM; Ki = 28.2 microM) and was an uncompetitive inhibitor of the enzyme with respect to the substrate xanthine.
The authors describe a case of drug-induced cytolytic hepatitis probably secondary to hypersensitivity to allopurinol which was prescribed incorrectly for secondary hyperuricaemia during treatment with pyrazinamide. The diagnosis was reviewed in view of the late occurrence of hepatitis in relation to the onset of the antituberculous treatment, the absence of a viral aetiology and the presence of clinical manifestations, biological and histological features which were compatible with hypersensitivity to allopurinol. The authors recalled that the type of uricaemia induced by pyrazinamide is most often asymptomatic and does not require any treatment with uric acid lowering drugs. Cessation of pyrazinamide is justified in cases of symptomatic hyperuricaemia but when the indications for pyrazinamide are imperative, treatment with an eliminator of uric acid is indicated. Allopurinol is contra-indicated in association with pyrazinamide on account of its inhibitory reaction to xanthine oxidase. Xanthine oxidase decreases the level pyrazinoic acid, a metabolite of pyrazinamide, which is responsible for the inhibition of the tubular secretion of uric acid.
It is becoming increasingly apparent that certain types of inflammatory tissue injury are mediated by reactive oxygen metabolites. The most likely sources of these oxidizing agents are the phagocytic leukocytes (e.g., neutrophils, monocytes, macrophages, and eosinophils) that invade the tissue. These reactive radicals and oxidants may injure cells and tissue directly via oxidative degradation of essential cellular components as well as injure cells indirectly by altering the protease/ antiprotease balance that normally exists within the tissue interstitium. It is becoming increasingly apparent that in addition to promoting cytotoxicity, reactive oxygen metabolites may also initiate and/or amplify inflammation via the upregulation of several different genes involved in the inflammatory response, such as those that code for proinflammatory cytokines and adhesion molecules. This may occur by the activation of certain transcription factors, such as nuclear transcription factor kB (NF-kB). NF-kB is a ubiquitous transcription factor and pleiotropic regulator of numerous genes involved in the immune and inflammatory response. Essential nutrients such as vitamins C and E may protect against oxidant-mediated inflammation and tissue damage by virtue of their ability to scavenge free radicals and by their ability to inhibit the activation of NF-kB (and possibly other oxidant-sensitive transcription factors). Thus, maintaining adequate antioxidant status may provide a useful approach in attenuating the cellular injury and dysfunction observed in some inflammatory disorders.
The structure-activity relationship of flavonoids as inhibitors of xanthine oxidase and as scavengers of the superoxide radical, produced by the action of the enzyme xanthine oxidase, was investigated. The hydroxyl groups at C-5 and C-7 and the double bond between C-2 and C-3 were essential for a high inhibitory activity on xanthine oxidase. Flavones showed slightly higher inhibitory activity than flavonols. All flavonoid derivatives except isorhamnetin (30) were less active than the original compounds. For a high superoxide scavenging activity on the other hand, a hydroxyl group at C-3' in ring B and at C-3 were essential. According to their effect on xanthine oxidase and as superoxide scavengers, the flavonoids could be classified into six groups: superoxide scavengers without inhibitory activity on xanthine oxidase (category A), xanthine oxidase inhibitors without any additional superoxide scavenging activity (category B), xanthine oxidase inhibitors with an additional superoxide scavenging activity (category C), xanthine oxidase inhibitors with an additional pro-oxidant effect on the production of superoxide (category D), flavonoids with a marginal effect on xanthine oxidase but with a prooxidant effect on the production of superoxide (category E), and finally, flavonoids with no effect on xanthine oxidase or superoxide (category F).
This paper assesses critically the science base that underpins the argument that oxidative damage is a significant causative factor in the development of human diseases and that antioxidants are capable of preventing or ameliorating these disease processes. The assessment has been carried out under a number of headings, and some recommendations for future research are made based on the present day knowledge base. The knowledge database (1) Consideration of the basic science that underlies understanding of the role of free radicals in causing cellular pathologies, and the role of antioxidants in preventing this, shows that an imbalance of reactive oxygen species and antioxidant defence systems may lead to chemical modifications of biologically relevant macromolecules. This imbalance provides a logical pathobiochemical mechanism for the initiation and development of several disease states. Experimental data obtained in vivo provide evidence that antioxidants function in systems that scavenge reactive oxygen species and that these are relevant to what occurs in vivo. The relevance in vivo of these observations depends inter alia on knowledge of the uptake and distribution of the antioxidant within the human body, and on what tissue levels of the antioxidant may be expected in relation to dietary levels. (2) There is some way to go until validated precise methods are available for measuring biomarkers of oxidative damage in human subjects in vivo under minimally invasive conditions. With respect to oxidative damage in DNa, HPLC and GC-mass spectrophotometry methods have both merits and limitations. Lipid oxidation products in plasma are best measured as isoprostanes or as lipid hydroperoxides using specific HPLC techniques. Development of isoprostane measurement will advance specificity and precision. The measurement of oxidative damage to proteins has some potential but such methods have not been effectively exploited. (3) Epidemiological studies support the hypothesis that the major antioxidant nutrients vitamin E and vitamin C, and beta-carotene (which may or may not be acting as an antioxidant in vivo), may play a beneficial role in prevention of several chronic disorders. More research is needed on the impact of other non-nutrient compounds, such as other carotenoids and flavonoids, on human health. In general, human intervention studies using hard end-points are the gold standard. Trials are restricted mainly to the major antioxidants and do not allow firm conclusions because of inconsistent findings, an insufficient number of studies and the use of varying doses. There is evidence that large doses of beta-carotene may be deleterious to the health of certain subgroups of the population such as heavy habitual smokers. (4) With respect to the safety of administration of supplementary vitamins, vitamin C is safe at levels of supplementation up to 600 mg/d, and higher levels, up to 2000 mg/d, are without risk. Vitamin E has a very low human toxicity and an intake of 1000 mg/d is without risk; 3200 mg/d has been shown to be without any consistent risk. Large intakes of beta-carotene must be viewed with caution because they have been shown to confer detriment to a population at high risk of lung cancer when administered after many years of high risk (smoking) behaviour. Until further work clarifies the situation in heavy smokers with respect to taking supplements, larger doses should be avoided by such individuals. There is little reliable information about the human toxicology of flavonoids and related non-nutrient antioxidant constituents of the diet. (5) The food industry has long experience in the control of oxidative damage in foods and this experience can be used to advantage for the protection of food antioxidants which are beneficial. Some of these, such as vitamins C and E and beta-carotene, are well known, and strategies for their protection in foods are already exploited by food technologies. (ABSTRACT TRUNCATED)
Recently, dietary pattern analysis has emerged as an alternative and complementary approach to examining the relationship between diet and the risk of chronic diseases. Instead of looking at individual nutrients or foods, pattern analysis examines the effects of overall diet. Conceptually, dietary patterns represent a broader picture of food and nutrient consumption, and may thus be more predictive of disease risk than individual foods or nutrients. Several studies have suggested that dietary patterns derived from factor or cluster analysis predict disease risk or mortality. In addition, there is growing interest in using dietary quality indices to evaluate whether adherence to a certain dietary pattern (e.g. Mediterranean pattern) or current dietary guidelines lowers the risk of disease. In this review, we describe the rationale for studying dietary patterns, and discuss quantitative methods for analysing dietary patterns and their reproducibility and validity, and the available evidence regarding the relationship between major dietary patterns and the risk of cardiovascular disease.
Xanthine oxidase (XO) is a highly versatile flavoprotein enzyme, ubiquitous among species (from bacteria to human) and within the various tissues of mammals. The enzyme catalyses the oxidative hydroxylation of purine substrates at the molybdenum centre (the reductive half-reaction) and subsequent reduction of O(2) at the flavin centre with generation of reactive oxygen species (ROS), either superoxide anion radical or hydrogen peroxide (the oxidative half-reaction). Many diseases, or at least symptoms of diseases, arise from a deficiency or excess of a specific metabolite in the body. For an example of an excess of a particular metabolite that produces a disease state is the excess of uric acid which can led to gout. Inhibition of XO decreases the uric acid levels, and results in an antihyperuricemic effect. Allopurinol, first synthesised as a potential anticancer agent, is nowadays a clinically useful xanthine oxidase inhibitor used in the treatment of gout. There is overwhelming acceptance that xanthine oxidase serum levels are significantly increased in various pathological states like hepatitis, inflammation, ischemia-reperfusion, carcinogenesis and aging and that ROS generated in the enzymatic process are involved in oxidative damage. Thus, it may be possible that the inhibition of this enzymatic pathway would be beneficial. In this review the State of the Art will be presented, which includes a summary of the progress made over the past years in the knowledge of the structure and mechanism of the enzyme, associated pathological states, and in the efforts made towards the development of new xanthine oxidase inhibitors.
Cancer prevention and treatment using traditional Chinese medicines have attracted increasing interest. This study characterizes antioxidant activity and phenolic compounds of traditional Chinese medicinal plants associated with anticancer, comprising 112 species from 50 plant families. The improved ABTS(*+) method was used to systematically assess the total antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC) of the medicinal extracts. The TEAC values and total phenolic content for methanolic extracts of herbs ranged from 46.7 to 17,323 micromol Trolox equivalent/100 g dry weight (DW), and from 0.22 to 50.3 g of gallic acid equivalent/100 g DW, respectively. A positive, significant linear relationship between antioxidant activity and total phenolic content (all R(2) values>/=0.95) showed that phenolic compounds were the dominant antioxidant components in the tested medicinal herbs. Major types of phenolic compounds from most of the tested herbs were preliminarily identified and analyzed, and mainly included phenolic acids, flavonoids, tannins, coumarins, lignans, quinones, stilbenes, and curcuminoids. These medicinal herbs exhibited far stronger antioxidant activity and contained significantly higher levels of phenolics than common vegetables and fruits. Traditional Chinese medicinal plants associated with anticancer might be potential sources of potent natural antioxidants and beneficial chemopreventive agents.
The chromatographic separation of the MeOH extract from the aerial parts of Syneilesis palmata led to the isolation of a new sesquiterpene glycoside 4, together with four known compounds. Their structures were characterized to be 4beta,5beta-epoxy-caryophill-8,(15)-ene (1), 3beta-hydroxy-gultin-5-ene (2), 4alpha,5beta-dihydroxy-caryophill-8,(15)-ene (3), (-)-oplopan-4-one-10-alpha-O-beta-D-glucose (4) and 3-hexenyl-1-O-beta-D-glucopyranose (5), based on spectroscopic and chemical methods. Compound 2 showed moderate cytotoxicity against five human tumor cell lines in vitro with its ED50 values ranging from 5.90 to approximately 10.83 microg/mL.
We investigated the medicinal efficacies of plants used as food in 27 Korean Buddhist temples from 1997 to 2002. We studied 161 species of plants belonging to 135 genera in 65 families. Twenty-one plant parts were utilized as food in 42 different preparations. Approximately 82% of the plants studied had medicinal effects, with a wide range of efficacies (126 types). Of the medicinal plants, 52% were used for digestive problems, circulatory illnesses, and respiratory diseases. These results demonstrate that a high proportion of the food consumed in Korean temples is medicinal, and is used for a wide variety of diseases.
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