ABSTRACT

This study was conducted to evaluate the antioxidant and the anti-diabetic property of ethanolic extract of G. kola seed (bitter kola) extract on alloxan induced diabetic wistar rats. Thirty female wistar rats were fasted for 16-18hours and thereafter induced per 150mg/ kg b.w. of alloxan monohydrate via intraperitoneal injection. The animals were divided into seven groups of three rats each. Group A(positive control), Group B(negative control) and groups C-G (250mg/kg-31.25mg/kg oftest extract) respectively. After five days of induction, twenty-one out of the thirty wistar rats became diabetic with their mean blood glucose level ranging from 262.00 ± 25.23 -294.33 ± 7.31 mg/dL (above 240 mg/dL), and were randomly separated into seven groups A-G with three rats each. At seventh day oftreatment, excluding the 31.25 mg/kg extract group, every other treatment groups recorded > 40% reduction in the mean blood glucose concentration compared with the standard drug (51.96 %), restoring to near normal the blood glucose level. On the basis of DPPH assay system, 2,2-diphenyl-l-purythydrazine (DPPH) scavenging activity was quantified in the presence of stable DPPH, at absorbance of 517nm. The determination of anti-lipid peroxidation activity was done by using the ethanol extract of G.kola at -different concentrations (12.5mg, 25mg, 50mg, lOOmg) individually. The nitric oxide scavenging activity was conducted based on the Greiss assay method which involves generating oxide from nitroprusside. There is a significant increase (p<0.05) between the positive control (vit. C lOOmg) and the test groups that received 100-12.5mg ofthe extract. The present study indicates that the extract of G.kola of possess antioxidant properties and could serve as free radical scavengers, or act as primary antioxidants. Therefore, it can be concluded that G. kola seed extract has a potent anti-diabetic activity which is comparable to the standard drug, Gilbenclamide in alloxan - induced diabetic rats and hence maybe a good alternative in the treatment of type 2 diabetes.