In vitro studies on α-glucosidase inhibition, antioxidant and free radical scavenging activities of Hedyotis biflora L.

Aim of this study was to evaluate the in vitro alpha-glucosidase inhibition and antioxidant activity of hexane, ethyl acetate and methanol extracts of Hedyotis biflora L. (Rubiaceae). In in vitro alpha-glucosidase inhibition and antioxidant activity, the methanol extract showed potent effect compared to hexane and ethyl acetate extracts. The methanol extract of H. biflora (HBMe) showed 50% alpha-glucosidase inhibition at the concentration of 480.20 +/- 2.37 mu g/ml. The total phenolic content of HBMe was 206.81 +/- 1.11 mg of catechol equivalents/g extract. HBMe showed great scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC50 520.21 +/- 1.02 mu g/ml), hydroxyl (IC50 510.21 +/- 1.51 mu g/ml), nitric oxide (IC50 690.20 +/- 2.13 mu g/ml) and superoxide (IC50 510.31 +/- 1.45 mu g/ml) radicals, as well as high reducing power. HBMe also showed a strong suppressive effect on lipid peroxidation. Using the beta-carotene method, the scavenging values of HBMe was significantly lower than BHT, and metal chelating ability of HBMe also showed a strong inhibition effect when compared to the reference standard. The active compound ursolic acid from HBMe was identified using various spectroscopical studies. The results obtained in this study clearly indicate that HBMe has a significant potential to use as a natural alpha-glucosidase inhibition, antioxidant agent. (C) 2012 Elsevier Ltd. All rights reserved.