Abstract

The antioxidant activities of fermented soybean meal (FSM) extract were evaluated by various methods in vitro and in vivo. The antioxidant tests in vitro, included the total phenolic and flavonoid content, reducing activity, 1,1-diphenyl-2-picryl-hy-drazyl (DPPH·) and superoxide anion radical scavenging activity, inhibition of lipid peroxidation in rat liver homogenate and erythrocyte haemolysis in rat blood. For in vivo test, mice were subcutaneously injected with D-galactose (D-gal) for 6 weeks and intragastric administration of fermented soy milk (FSM)extract simultaneously (500, 250 and 125 mg/kg body weight per day, respectively), and then the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-px), total antioxidant capacity (T-AOC) and MDA were determined. In antioxidant assays in vitro, FSM extract was found to have Fe³⁺ reducing activity, moderate 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, superoxide anion radical scavenging activity, lipid peroxidation and erythrocyte haemolysis inhibition effect, of which IC₅₀ values were found to be 3.168, 0.321, 7.404, 0.737 and 4.599 mg/ml, respectively. For the antioxidant assays in vivo, administration of FSM extract significantly enhanced the activities of antioxidant enzymes and total antioxidant capacity and decreased the levels of malondialdehyde in both serums and livers of aging mice.

Key words: Antioxidant activities, fermented soybean meal (FSM) extract, Bacillus natto.