Determination of antioxidant activity of Oroxylum indicum leaves extracts

Abstract

Oroxylum indicum (L.) Kurz is popularly known to have various bioactive compounds such as flavonoids, glycosides, alkaloids, tannins and terpenoids etc. In this study, we investigated the antioxidant activity of 4 crude extracts of O. indicum leaves, obtained using the solvents hexane, ethyl acetate, ethanol and methanol. Antioxidant activities of the extracts were investigated by DPPH and FRAP assays. Total phenolic and flavonoid content were determined by Folin - Ciocalteu and Aluminum chloride colorimetric assays, respectively. The results indicated that the ethanolic extract of O. indicum leaves had the highest antioxidant activities in both DPPH (IC₅₀ 0.92±0.2 mg/ml) and FRAP assays (111.91±3.02 Fe²⁺ mg/g extract), and had the highest total phenolic (121.90±1.70 GAE mg/g extract) and flavonoid content (298.73±14.46 RE mg/g extract). In conclusion, ethanol extract was found to be a good solvent for extraction and having good antioxidant activity in all assays. O. indicum leaves ethanolic extract contains bioactive compounds and have good antioxidant activities that could be studied in other biological activities and may be useful for pharmaceutical products.