Effects of Tocotrienol and Tocopherol Supplementation on Liver Oxidative Status and Antioxidant Enzymes Activity in Stress-Induced Rats

This study was designed to investigate the effects of tocotrienol (TT) and tocopherol (TF) supplementation on oxidative status and antioxidant enzymes activity in stress-induced rats. Twenty-four male Sprague-Dawley rats were randomly assigned into four groups, consisted of two control groups (C and CS) which were fed with a commercially prepared normal rat diet while two treatment groups (TTS and TFS) were given tocotrienol or tocopherol orally in the dose of 60 mg/kg body weight. After 28 days of treatment, the CS, TTS and TFS rats were subjected to restraint stress, two hours daily for four consecutive days. The rats were killed and their blood was taken to determine the antioxidant enzymes activity; superoxide dismutase (SOD) and glutathione peroxidase (GPx). The liver was taken to determine malondialdehyde (MDA) and glutathione levels. The findings showed that CS rats after being stressed had significantly higher levels of MDA and lower levels of glutathione in the liver. Tocotrienol and tocopherol were proved to significantly reduce the MDA and increased the glutathione content in tissues after exposure to stress compared to control groups. The findings also showed that the activity of GPx in plasma increased significantly in the CS group. However, rats fed with tocotrienol showed reduced GPx activity compared to the CS group. In conclusion, tocotrienol and tocopherol are capable of reducing the oxidative stress by reducing MDA tissue level, increasing glutathione tissue level and reducing GPx plasma activity in stress-induced rats.