Syed Ibrahim Rizvi

Plant Polyphenols as Dietary Antioxidants in Human Health and Disease

Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. In the last decade, there has been much interest in the potential health benefits of dietary plant polyphenols as antioxidant. Epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis and neurodegenerative diseases. Here we present knowledge about the biological effects of plant polyphenols in the context of relevance to human health.

Markers of Oxidative Stress in Erythrocytes and Plasma During Aging in Humans

Aging is an inevitable universal biological process, which can be characterized by a general decline in physiological function with the accumulation of diverse adverse changes and increased probability of death. Among several theories, oxidative stress/free radical theory offers the best mechanistic elucidation of the aging process and other age-related phenomenon. In the present paper, we discuss the aging process and have focused on the importance of some reliable markers of oxidative stress which may be used as biomarkers of the aging process.

Markers of Oxidative Stress during Diabetes Mellitus

The prevalence of diabetes mellitus is rising all over the world. Uncontrolled state of hyperglycemia due to defects in insulin secretion/action leads to a variety of complications including peripheral vascular diseases, nephropathy, neuropathy, retinopathy, morbidity, and/or mortality. Large body of evidence suggests major role of reactive oxygen species/oxidative stress in development and progression of diabetic complications. In the present paper, we have discussed the recent researches on the biomarkers of oxidative stress during type 2 diabetes mellitus.

Markers of Oxidative Stress in Erythrocytes during Aging in Humans

Abstract:  The correlation between antioxidant capacity and oxidative damage during aging has been reported in several tissues in different species; however, data on changes of oxidative stress markers in plasma and erythrocytes of healthy populations during aging are few and sometimes contradictory. Since antioxidant capacity of the plasma is related to dietary intake of antioxidants, it is important to study the correlation between antioxidant capacity of the plasma and markers of oxidative stress in different populations. In the present study we report the age‐dependent alteration in erythrocyte malondialdehyde (MDA), intracellular‐reduced glutathione (GSH), and membrane sulphydryl (SH) groups in the Indian population and also correlate these parameters with total plasma antioxidant potential. We show an age‐dependent increase in erythrocyte MDA level and a decrease in GSH and membrane −SH group concentration. The alterations in these parameters correlated significantly with total antioxidant capacity of the plasma. We observe a higher oxidative stress in the Indian population compared to values reported for European subjects emphasizing the need to establish age‐dependent reference values for oxidative stress markers in different populations and in studies involving their role in different disease conditions.

Protective role of tea catechins against oxidation‐induced damage of type 2 diabetic erythrocytes

1. Oxidative stress is recognized as a major contributing factor for the development of late complications of diabetes.

Protein oxidation biomarkers in plasma of type 2 diabetic patients

OBJECTIVES To evaluate oxidative stress and the extent of oxidation of plasma proteins in type 2 diabetic patients. DESIGN AND METHODS Study was carried out on blood from 31 diabetic patients of both sexes (mean age = 58 + or - 7; duration of diabetes 12 + or - 5 years) and healthy age and sex matched normal subjects. Biomarkers of protein oxidation; plasma protein carbonyls (PCO), advanced oxidation protein products (AOPPs) and -SH group and free radical scavenging capacity of plasma was measured. RESULTS PCO and AOPPS levels were significantly (P<0.005) higher in diabetic patients in comparison to healthy volunteers. Reduced free radical scavenging capacity (P<0.001) and -SH group (P<0.05) was observed in plasma of type 2 diabetic patients. CONCLUSIONS Our data suggest that diabetics are susceptible to protein oxidation. Oxidative modulation of proteins due to reduced radical scavenging activity of plasma patients may be one of the reasons of altered physiological processes in type 2 diabetic patients.

Protective effect of resveratrol on markers of oxidative stress in human erythrocytes subjected to in vitro oxidative insult.

Resveratrol is a natural polyphenolic compound found largely in the skin of red grapes. Growing evidence suggests that resveratrol may play an important role in the prevention of many human diseases. Many of the biological actions of this polyphenol have been attributed to its antioxidant properties. The present study was undertaken to evaluate the effect of resveratrol on intracellular reduced glutathione (GSH) and membrane sulphydryl groups in erythrocytes subjected to oxidative stress in vitro by incubating with t‐BHP (10 µm). The study was aimed to test the efficacy of the antioxidant effect of resveratrol on human erythrocytes. Subjecting erythrocytes to oxidative stress (in vitro) by incubating them with t‐BHP (10 µm) caused a significant decrease in the intracellular GSH level and membrane –SH content compared with basal values. Incubation of erythrocytes/membranes with resveratrol (1–100 µm final conc) resulted in significant protection against the t‐BHP‐induced oxidative stress as evidenced by the increase in GSH level and membrane –SH content. It was observed that the effect of resveratrol is dose/concentration and time‐dependent. Since resveratrol is naturally present in many fruits and vegetables, a diet rich in resveratrol may provide protection against degenerative diseases. Copyright

Protective role of tea catechins on erythrocytes subjected to oxidative stress during human aging

Antioxidant effect of tea catechins has been shown in many epidemiological studies. In the present study we report the protective mechanism of tea catechins (EGCG, ECG, EGC, EC) on various oxidative stress parameters, which are elevated during aging in humans. We hereby report the in vitro effect of tea catechins on erythrocyte malondialdehyde (MDA), reduced glutathione (GSH), and on membrane sulphydryl (–SH) group in humans. Results show an age-dependent increase in erythrocyte MDA level and a decrease in GSH and membrane–SH group concentration. We report that tea catechins show significant protection to erythrocyte against oxidative stress induced by tert-butyl hydroperoxide (t-BHP). The effect was more pronounced in older age group compared to lower age group. The findings suggest a possible role of tea catechins as anti-aging compounds.

Carbofuran-induced toxicity in rats: Protective role of vitamin C

Erythrocytes are prone to oxidative stress due to the presence of hemoglobin and polyunsaturated fatty acids. Oxidative stress (OS) is associated with increased osmotic fragility (OF) of erythrocytes. Organophosphate and organocarbamate pesticides are known to cause OS in erythrocytes. We have investigated the effect of a single sub-acute dose of carbofuran (CF), an organocarbamate pesticide and ameliorating role of vitamin C on OF and OS in erythrocytes of Wistar rats. OF and OS were assessed by determining membrane stability in terms of erythrocyte OF and the activities of free radicals scavenging enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST). We observed a significant alteration in the mean erythrocyte fragility (MEF) at relatively higher NaCl concentration (0.67%) as compared to MEF at 0.55%, 0.58% and 0.56% of NaCl in control, vitamin C- and vitamin C + CF-treated groups, respectively. The activities of CAT and SOD were observed to be elevated by 74.35% and 85.56%, respectively, with significance level of p < or = 0.001, whereas GST activity got significantly (p < or = 0.001) diminished by 46.30% in the erythrocytes of CF-treated rats. Vitamin C treatment exhibited marked (p < or = 0.05) prevention of carbofuran-induced oxidative stress as well as erythrocyte osmotic fragility in the Wistar rats. These results suggest that CF treatment induces OF and OS in the erythrocytes of rats, and pretreatment with vitamin C can mitigate these toxic effects.

Traditional Indian medicines used for the management of diabetes mellitus.

Plants have always been a source of drugs for humans since time immemorial. The Indian traditional system of medicine is replete with the use of plants for the management of diabetic conditions. According to the World Health Organization, up to 90% of population in developing countries use plants and its products as traditional medicine for primary health care. There are about 800 plants which have been reported to show antidiabetic potential. The present review is aimed at providing in-depth information about the antidiabetic potential and bioactive compounds present in Ficus religiosa, Pterocarpus marsupium, Gymnema sylvestre, Allium sativum, Eugenia jambolana, Momordica charantia, and Trigonella foenum-graecum. The review provides a starting point for future studies aimed at isolation, purification, and characterization of bioactive antidiabetic compounds present in these plants.