Effect of some natural antioxidants on aflatoxin B1-induced hepatic toxicity

Aflatoxins are potent hepatotoxic and hepatocarcinogenic agents. This hepatotoxicity is thought to be mediated by their ability to generate reactive oxygen species and cause peroxidative damage. In the present investigation we assessed the ability of some natural antioxidants namely, vitamin E and Se, beta-carotene, silymarin and coenzyme Q(10) on aflatoxin B-1 (AFB(1))-induced hepatotoxicity in a rat model. Alanine and aspartate aminotransferases and alkaline phosphatase (ALP) were found to be significantly increased in the serum of AFB(1) administered (250 mu g/kg body weight/day for 2 weeks) rats, suggesting hepatic damage. There was a marked increase in the lipid peroxide levels and a concomitant decrease in the hepatic reduced glutathione (GSH) and serum protein thiol (PrSHs) along with a nearly twofold increase in hepatic glutathione-S-transferase (GST) activity. The significant increase in GST may be attributed to its being a phase II enzyme that predominately participates in the detoxification of the ultimate electrophilic metabolite AFB(1)-8, 9 epoxide. On the other hand, no significant change was detected in the activities of glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PDH), cytochrome c-reductase and levels of DNA and RNA in the hepatic tissue of AFB(1) administered rats. Results also revealed that cotreatment with studied antioxidants offered substantial hepatoprotective effects in the AFB(1) administered rats. Moreover, results revealed that vitamin E and selenium combination and beta-carotene are more efficient than coenzyme Q(10) and silymarin in modulating the liver antioxidant enzymatic system.