IN-VITRO EVALUATION OF ANTIOXIDANT ACTIVITIES OF OLDENLANDIA CORYMBOSA L. (SYN. HEDYOTIS CORYMBOSA) FRACTIONATED EXTRACTS IN VARIOUS SOLVENTSAbstract
Antioxidants are the substance having the potential to quench free radicals and significantly delay or inhibit oxidation of the substrate, thus protect biological systems against potentially harmful effects of free radicals; in low concentrations. The present study was aimed to evaluate the in-vitro antioxidant activity of Oldenlandia corymbosa L., a locally available medicinal plant of Assam, used as vegetable in diet and traditional medicine for liver disease and jaundice. The dried powdered plant material was extracted with 80% ethanol by Soxhlet extraction and was used for the fractionation in different solvents (methanol, petroleum ether, and ethyl acetate). The fractionated extracts were subjected to the analysis of in-vitro antioxidant activity with DPPH (2,2, Diphenyl-2-picryl hydrazyl), hydroxyl radical, nitric oxide, reducing power, and phosphomolybdenum assays for total antioxidant capacity. Ascorbic acid was used as standard at concentrations (20 μg/ml, 40 μg/ml, 60 μg/ml, 80 μg/ml and 100 μg/ml) dissolved in ethanol. Samples were prepared in the same manner. Results from in-vitro experiments revealed the significantly (p<0.05) high antioxidant activity in hydro-ethanolic extract than methanol, petroleum ether, and ethyl acetate extracts when compared with a standard antioxidant, ascorbic acid. O. corymbosa contains some important groups of phytochemicals having exogenous antioxidant properties. Our findings provide scientific support for ethnomedicinal uses of O. corymbosa to cure jaundice and liver-related ailments and indicate a promising antioxidant potential of this plant for the development of herbal therapy against various oxidative stress-related diseases.