EFFETS OF GINSENG FEEDING ON OXIDANT GENERATION AND ANTIOXIDANT CAPACITY IN YOUNG AND OLD RATS





Y. Fu*, L. L. Ji

Dept. Kinesiology, University of Wisconsin, Madison, 53706




Rationale: Ginseng is a highly valued herbal plant cultivated in Asia and North America. The extensive literature reported that ginseng and its constituents are able to target multiple tissues and possess antiaging, antineoplastic and antistress effects. Recent studies showed that ginseng also has antioxidant properties, which may partly contribute its wide rage of pharmacological actions. The purpose of this study is to investigate effects of long-term ginseng feeding on endogenous oxidant production rate and antioxidant capacities in young and old rats. Methods: Female Fischer 344 rats at 4 (Y, n=36) or 22 (O, n=24) month of age were randomly divided into three groups. Each group was fed either a AIN-93G formula-based control diet (C), or a diet containing 500mg/kg (low dose, L) or 2500mg/kg (high dose, H) North American ginseng (Panax Quinquefolium, Kaiser Farms, WI) for 4 months. Oxidant generation was measured in various tissue homogenates using a fluorescent 2'7'-dichlorofluorescin (DCFH) probe. Superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) activities were measured spectrophotometrically. Results: Body weights of both Y (p<0.001) and O (p<0.05) rats in H group were significantly lower than their counterparts in C and L groups in the end of the experiment. DCFH oxidation rate was lower in O vs. Y rats in the heart (p<0.05), liver (p<0.05) and soleus muscle (p<0.001). Ginseng feeding significantly lowered oxidant generation in the heart (25%, p<0.05) and soleus (33%, p<0.05, H dose). O rats had significantly higher GPX activity than Y rats in the heart (p<0.01), kidney (p<0.05) and superficial vastus lateralis (SVL) muscle (p<0.05). Ginseng feeding increased GPX activity by 23% in the liver (p<0.01, Y) and by 15% in the deep VL muscle (p<0.01, H dose). SOD activities in the heart (p<0.001), liver (p<0.001), DVL (p<0.01), and SVL muscle (p<0.01) were increased with age, whereas ginseng feeding increased only heart SOD activity (11%, p<0.05). CAT activity was increased with age only in SVL (p<0.05) and soleus muscles (p<0.001), and was not affected with ginseng feeding. Conclusion: Four-month feeding of a ginseng fortified-diet in rats reduced free radical generation in selective tissues. Ginseng feeding also enhances GPX activity in the liver and DVL muscle, and SOD activity in the heart. These antioxidant effects of ginseng appear to be dose-dependent.
(Supported by a University of Wisconsin UIR grant and Kaiser Farms, Inc.)




Key words: Ginseng, Rats, Aging, Antioxidants, Free Radicals







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