RESUMO
Aims: To investigate the scientific basis for the anti-diabetic and antioxidant activity of Mucuna pruriens (Fabaceae) leaf ethanolic extract using alloxan-induced diabetic rats, DPPH and ABTS assay. Place and Duration of Study: Department of Chemistry/Biochemistry Federal University Ndufu Alike, Ebonyi State, Nigeria between October 2013 and May 2014. Methodology: The polyphenol content was determined using Folin-Ciocaltu method and their linear relationship with antioxidant activity was evaluated using linear regression analysis. The antioxidant activity was determined using 1, 1-Diphenyl, 2-picrylhydrazyl (DPPH) and (2, 2-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radical assay. The active ingredients in the ethanolic extract were isolated using HPLC method. Also the ant-diabetic activity was determined in vivo using alloxan-induced diabetic wister rats. Results: Ethanol extract showed the highest phenolic content as well as highest antioxidant activity. A strong relationship was found between phenolic contents and antioxidant activity. The HPLC analysis indicates the presence of gallic acid, caffeic acid, p-coumaric acid, quercetin and (+)-catechin. The ethanolic extract at the concentration of 400 mg/kg significantly (P<0.001) increased the intracellular antioxidant enzymes and reduced the elavated serum lipids and showed more active than the reference drug (metformin). Conclusion: Based on the obtained result, the antioxidant and anti-diabetic activity demonstrated by Mucuna pruriens leaf extracts provide good evidence to support the traditional use of this plant in treatment of diabetics.