ABSTRACT
Exposure to dietary aflatoxin B1 [AFB1] is considered to be an important risk factor for the development of hepatocellular carcinoma in the developing world. The mechanism of AFB1 -induced cellular damage has not been well characterized, however previous in vitro studies suggested that AFB1 was capable of inducing oxidative damages through the release of reactive oxygen species. Onions as one of the important Allium species commonly used in our daily diet are proved recently to have an antioxidant properties. Hence, the present study was conducted to investigate the role of AFB1 in induction of lipid peroxidation in liver tissue and blood samples of albino rats and to evaluate the potential benefits of onion juice pretreatment on the antioxidant defense system in comparison with vitamin C as a standard antioxidant. Results from this study showed that antioxidant defence system which plays a critical role in carcinogenesis is severely altered after AFP1 administration. The evidence comprises significant enhancement of malondialdehyde production [the most relevant lipid peroxidation product] and decreased activities of scavenging antioxidant enzymes [glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase] that scavenge superoxide, hydrogen peroxide and lipid peroxide. Also, non-enzymic antioxidant levels as glutathione, antioxidant vitamins A, F, C were significantly decreased. These deleterious effects were controlled by pretreatment with onion juice and vitamin C, however the effects of onion juice was more pronounced than that of vitamin C in AFP1 -treated animals indicating its capacity to induce effectively the in vivo antioxidant defense system. These observations indicate that with regard to human population at high risk to AFB1 exposure, ingestion of onions may be protective and therapeutic owing to issues of their efficiency, potency and absent toxicity besides their easy availability as food stuffs