Vitamin E but not Hippophea rhamnoides L. prevented nicotine-induced oxidative stress in rat brain

Oxidant effects of nicotine in the central nervous system is not clear. The aim of this study was to investigate whether nicotine induces oxidative stress in rat brain, and if it does, to test the effects of Hippophea rhamnoides L. extract (HRe-1) and also vitamin E as a positive control. The groups were: nicotine [0.5 mg/kg/day, intraperitoneal (i.p.)]; nicotine+vitamin E [75 mg/kg/day, intragastric (i.g.)]; nicotine+HRe-1 (250 mg/kg/day, i.g.); and control group (receiving only vehicles). There were eight rats per group and supplementation period was 3 weeks. Malondialdehyde (MDA) level was increased by nicotine in brain tissue, which was prevented by vitamin E whereas not affected by HRe-1. Brain tissue glutathione S-transferase activities of nicotine administered and HRe-1 supplemented groups were lower than control and vitamin E supplemented groups, while glutathione peroxidase (GSH-Px) activities of vitamin E and HRe-1 supplemented groups were lower than the nicotine administered group. Superoxide dismutase activity was not affected by any of the treatments. Total glutathione level was higher in the vitamin E supplemented group compared with control and nicotine administered groups. Vitamin E might have easily diffused to rat brain as a lipid soluble antioxidant, however, the plant extract, HRe-1, would not have sufficiently diffused to the brain to exert its antioxidant effect.