Free Radical Scavenging Activity of Ipomoea obscura (L.) Ker-Gawl

Abstract

Objective: To evaluate the free radical scavenging activity of Ipomoea obscura (L.) whole plant belonging to the family Convolvulaceae. Methods: Three successive whole plant extracts (petroleum ether, methanol and water) of Ipomoea obscura were prepared and the total phenolic content was estimated. The extract were screened for their in vitro antioxidant activity using 2,2'-diphenyl-2-picryl hydrazyl (DPPH), 2,2'-azino-bis (3-ethyl-benzo-thiazoline- 6-sulfonic acid) diammonium salt (ABTS), hydrogen peroxide, nitric oxide, superoxide and hydroxyl radicals by p-nitroso dimethyl aniline (p-NDA) and deoxyribose assays and the IC₅₀ values were calculated. Results: The total phenol content in methanol and water extracts was found to be 18.15 mg/g and 9.12 mg/g, respectively. Among the three extracts tested, the methanol extract showed maximum activity with IC₅₀ values 53.12 ± 0.33, 108.40 ± 2.15, 107.90 ± 1.20 and 424.00 ± 2.90 μg/ml, for ABTS, DPPH, hydrogen peroxide and nitric oxide radical inhibition assays, respectively. The water and petroleum ether extracts showed moderate to low activity compared to methanol extract when tested for ABTS, DPPH, hydrogen peroxide and nitric oxide radical inhibition assays. All the three extracts showed less activity at high concentrations when tested against superoxide and hydroxyl radical inhibition assays. Conclusion: The successive methanol extract exhibited significant antioxidant activity and merits further investigations in animal models and isolation of its active constituents.