Abstract

IN VITRO AND IN VIVO ANTIOXIDANT ACTIVITY OF SAPONIN EXTRACTED FROM THE ROOT OF GARCINIA KOLA (BITTER KOLA) ON ALLOXAN-INDUCED DIABETIC RATS

Alli Smith, Y. R*; Adanlawo, I.G

ABSTRACT

At the present time, much attention is being paid to antioxidant substances because many pathological conditions are associated with oxidative stress. The antioxidant activities of saponin extracted from the root of Garcinia kola was investigated by in vitro and in vivo assays. The in vitro investigations includes the ability of the extract to scavenge free radicals such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH•), hydrogen peroxide (H2O2) and nitric oxide (NO), superoxide anion (O2.-), hydroxyl radical (•OH) and its ferric reducing power was also investigated. The effect of saponin from the root of bitter kola in reducing oxidative stress was evaluated in diabetic Wistar albino rat’s tissues. Diabetes was induced in rats by single intraperitonial injection of alloxan (150mg/kg body weight). Three days after alloxan induction, the hyperglycemic rats were treated with 200mg/kg of metformin, a standard antidiabetic drug and saponin from the root of Garcinia kola orally at the dose of 100, 200 and 400 mg/kg body weight daily for 7 days. The result of the in vitro assay showed that the extract scavenge these free radicals in a concentration dependent manner. The in vivo antioxidant assay results showed that saponin at different concentrations significantly decrease the MDA level compared to metformin and the control group (p < 0.05), the activities of antioxidant enzymes; Superoxide dismutase (SOD) and Catalase of albino rats given saponin increases compared with the control group. These in vitro and in vivo studies demonstrated that the saponin extract from the root of Garcinia kola have significant antioxidant and free radical scavenging activities. In other words, it could be potentially used as a rich source of natural antioxidant.

Keywords: Antioxidant, Saponin, Garcinia kola, Free radicals, Enzymes.