Phytochemical and antioxidant potential of Indigofera colutea (Burm.f.) Merr. (Fabaceae)

The total phenolic content, flavonoid content and antioxidant activity of Indigofera colutea were evaluated using three assays: ferric reducing antioxidant power (FRAP), phosphomolybdenum reducing power and hydrogen peroxide scavenging activity. Among the tested extracts, the ethanolic extract exhibited the highest total phenolic content (0.45 mg TAE/g dw) and total flavonoid content (1.527 mg QE/g dw), while the petroleum ether extract showed the lowest levels (0.039 mg TAE/g dw and 0.204 mg QE/g dw, respectively). In the antioxidant assays, the methanolic extract demonstrated the strongest ferric reducing power, whereas the ethanolic extract exhibited the highest activity in the phosphomolybdenum reducing power assay. The hydrogen peroxide scavenging activity was most effective in the ethanolic extract, followed by methanol, aqueous and acetone extracts, with petroleum ether and chloroform extracts showing the weakest activity. These findings suggest that I. colutea, particularly its ethanolic and methanolic extracts, is a promising source of natural antioxidants for potential therapeutic applications.