Abstract

To evaluate the in vitro free radical (FR) scavenging activity of leaves Jatropha gossypifoliaLinn. petroleum ether, ethanol, aqueous extracts of J. gossypifolia were prepared, with successive extraction in Soxhlet apparatus. Each extract was selected to study the FR scavenging activity by superoxide scavenging assay and 2, 2-diphenyl-1 picrylhydrazyl hydrate (DPPH) radical scavenging assay method. It was found that aqueous extract contained carbohydrates, glycosides amino acids flavonoids, tannins, alkaloids and steroids; ethanolic extract contained glycosides amino acids flavonoids, tannins, alkaloids and steroids. Radical scavenging activity of plant extracts against stable DPPH was determined spectrophotometrically. Extract solutions were prepared by dissolving 0.025 g of dry extract in 10 ml of methanol. The solution of DPPH in methanol was prepared daily. The samples were kept in the dark for 15 min at room temperature and then the decrease in absorption was measured. Ethanolic extract of J. gossypifolia showed 58.7 ± 0.62% inhibition in superoxide scavenging model. Aqueous extract also showed almost similar activity (54.9 ± 0.53% compared to ethanolic extract), while petroleum ether extract showed poor inhibition of superoxide scavenging activity. All extracts showed dose and time dependent inhibition of superoxide scavenging activity. J. gossypifolia had the highest total phenolic content (42.60 mg tannic acid equivalent (TAE) /100 g fresh weight). Total phenolic content had positive correlation with antioxidant capacity. This shows that the plants, especially J. gossypifolia, may be potent source of natural antioxidants.

Key words: Jatropha gossypifolia, 2, 2-diphenyl-1 picrylhydrazyl hydrate (DPPH), phenolic content, superoxide scavenging, antioxidant activity.