Prooxidative effects of aspartame on antioxidant defense status in erythrocytes of rats.

Since aspartame (L-aspartyl-L-phenylalanine methyl ester, ASP) is one of the most widely used artificial sweeteners, the aim of the present study was to investigate its effects on serum glucose and lipid levels as well as its effects on oxidative/antioxidative status in erythrocytes of rats. The experiment included two groups of animals: the control group was administered with water only, while the experimental group was orally administered with ASP (40 mg/kg b.w.) daily, for a period of six weeks. When compared with the control group, the group administrated with ASP indicated higher values of serum glucose, cholesterol and triglycerides. Significantly increased concentrations of superoxide anion (O2 •−), hydrogen peroxide (H2O2), peroxynitrite (ОNОО−) and lipid peroxides (LPO) were recorded in the erythrocytes of ASP treated group in comparison to the control group. In the course of chronic ASP administration, the following was observed: the concentration of reduced glutathione (GSH) and the activity of catalase (CAT) increased. Thus, these findings suggest that long-term consumption of ASP leads to hyperglycemia and hyperlipidemia, as well as to oxidative stress in erythrocytes.

Effect of ethanol extracts from red pepper seeds on antioxidative defense system and oxidative stress in rats fed high-fat, high-cholesterol diet

The purpose of the present study was to investigate the effect of ethanol extracts from red pepper seeds on the antioxidative defense system and oxidative stress in rats fed a high fat . high cholesterol diet. Rats were divided into four experimental groups which were composed of high fat . high cholesterol diet group (HF), high fat . high cholesterol diet with 0.1% ethanol extracts from red pepper seeds supplemented group (HEA), high fat . high cholesterol diet with 0.2% ethanol extracts from red pepper seeds supplemented group (HEB) and high fat.high cholesterol diet with 0.5% ethanol extracts from red pepper seeds supplemented group (HEC). Supplementation of ethanol extracts from red pepper seeds groups (HEA, HEB and HEC) resulted in significantly increased activities of hepatic glutathione peroxidase and catalase. Hepatic superoxide radical contents in microsome and mitochondria were significantly reduced in the groups supplemented with red pepper seeds ethanol extracts. Hepatic hydrogen peroxide content in the mitochondria was reduced in ethanol extracts from red pepper seeds supplemented groups. TBARS values in the liver were reduced in red pepper seeds ethanol extracts supplemented groups. Especially, HEB and HEC groups were significantly decreased compared to the HF group. Hepatic carbonyl values were significantly reduced in mitochondria in these supplemented groups. These results suggest that red pepper seeds ethanol extracts may reduce oxidative damage, by activation of antioxidative defense system in rats fed high fat . high cholesterol diets.

Effects of long-diatance running and exercise with a bicycle ergometer on the erythrocyte antioxidative defense system / 体力科学

The erythrocyte antioxidative defense system was investigated before and after a 12km run. The effect of exercise with a bicycle ergometer on this system was also examined one and seven days after the. 12km run. Five untrained healthy men, aged 18-21 years, participated in the present study. Plasma creatine kinase (CK) activity increased after running and reached a maximum on the next day (p<0.005) . Levels of the reduced form of glutathione (GSH) decreased by 24.6% after running (p<0.005), but by 7 days later the values recovered. Levels of lipid peroxides (LPO, expressed as thiobarbituric acid-reactive substances) fell slightly after running (13.4%, not significant), then showed a significant decrease on the next day (34.7%, p<0.005) and recovered by the seventh day. Neither glutathione peroxidase (GPX) nor glutathione reductase (GR) activities (with or without FAD) showed significant changes after the 12km run. Activities of catalase (CAT) were lowest after the exercise with a bicycle ergometer on the following day (p<0.05 vs. initial levels) . Levels of GSH, GPX, GR and LPO did not change after this exercise. The decreased level of GSH after the 12km run indicates the presence of oxidative stress, while moderate exercise with a bicycle ergometer does not affect the erythrocyte glutathione metabolism in untrained men. It is also suggested that catalase activity decreases after the repeated exercise.