Ameliorative Effect of Silymarin Against Radiation- Induced Oxidative Stress in the Liver of Male Rats

Administration of dietary antioxidants has been suggested to protect against liver tissue damage induced by radiation exposure. Silymarin is a polyphenolic plant flavonoid derived from Silymarin marianum that has hepatoprotective and anticarcinogenic effects. Therefore, the present study was carried out to investigate the radioprotective activity of Silymarin against radiation-induced liver damage. In this work, the total phenol content of silymarin was 0.527±0.016 mg GAE/ mg, total antioxidant capacity was 139±10.5 μmol/l and the DPPH radical scavenging activity was 1.52±0.12 mg/ml. The results showed that γrays (6 Gy) caused a significant increase in serum level of alanine and aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase and the level of hepatic malondialdehyde and xanthine oxidase activity. Also, a significant decrease in hepatic glutathione level and xanthine dehydrogenase, superoxide dismutase and catalase activities was observed, compared with control group. Oral administration of silymarin extract prior radiation exposure was found to offer protection against all the radiation-induced biochemical alterations. These findings showed that silymarin is a powerful antioxidant herbal drug which can protect biological systems against the oxidative stress and tissue damage induced by radiation exposure.