Abstract

Butylated hydroxytoluene (BHT) is a synthetic phenolic antioxidant widely used as a food additive and preservative, but at high doses it exerts a pro-oxidant effect causing oxidative stress in rats, leading to hepatic and renal damage. Stachytarpheta angustifolia is reported to possess a potent in vitro antioxidant activity and several ethnomedicinal functions hence, could lessen the toxic effect of BHT by various antioxidant mechanisms. To test whether a methanol extract of S. angustifolia (MESA) protects against BHT-induced oxidative stress, male albino rats were fed different concentrations of MESA on a daily basis for a period of two weeks. BHT (1000 mg/kg) was then administered to the rats on the 14^th day by gavage. Rats in the BHT-only group had significant elevations (p<0.05) in serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) compared to those pre-treated with 250 and 500 mg/kg MESA groups. Significantly, low activity (p<0.05) of catalase (CAT) and superoxide dismutase (SOD) were observed in the BHT-only group, compared to the MESA + BHT groups. Urea, creatinine, cholesterol and triglyceride levels were significantly maintained to normal levels in the MESA + BHT rats compared to the BHT-only group. Pre-treatment with 250 and 500 mg/kg MESA also significantly lowered the level of lipid peroxidation and protein carbonyls while ascorbate was elevated compared to BHT-only group. These results indicate that in vivo, MESA counteracts many of the deleterious effects caused by BHT and that the antioxidant components in the plant extract may be viable agents for the reduction of oxidative damage and treatment of disease associated with oxidative stress.

Key words: Stachytarpheta angustifolia, butylated hydroxytoluene, antioxidant activity.