Antioxidant effect of onion oil (Allium cepa. Linn) on the damages induced by nicotine in rats as compared to alpha-tocopherol.

The beneficial effects of onion oil as an antioxidant has been assessed in nicotine administered rats by studying whether the peroxidative damage caused by nicotine can be effectively combated with the onion oil and the effects compared to vitamin E, a highly efficient antioxidant. Lipid peroxidation products and antioxidant defence system have been studied in liver, lungs, and heart. The rats were injected with nicotine (0.6 mg/kg body wt.) and simultaneously given onion oil (100 mg/kg body wt.) or vitamin E (100 mg/kg body wt.) for 21 days. Concentration of free fatty acids, TBA reactive substances (TBARS), conjugated dienes and hydroperoxides were significantly increased in the tissues of nicotine treated rats as compared to normal rats. Onion oil supplemented to nicotine treated rats showed increased resistance to lipid peroxidation and the effect was near to that of vitamin E fed rats. The activity of catalase and superoxide dismutase decreased in nicotine treated rats. Antioxidants-glutathione content, vitamin C and retinol showed no significant difference but liver vitamin E content significantly decreased in nicotine treated rats. On onion oil or vitamin E supplementation, the concentration of antioxidants were significantly raised in all the tissues studied, however, a significantly increased concentration of glutathione, vitamin E and retinol was noticed in vitamin E+nicotine treated rats. Thus, these results indicate that onion oil is an effective antioxidant against the oxidative damage caused by nicotine as compared to vitamin E.