antioxidant activity of otostegia persica (labiatae) and its constituents

the antioxidant activity of the different extracts and fractions of aerial parts of otostegia persica (burm.) boiss. were evaluated using beta-carotene bleaching and lipid peroxidation methods. the inhibitory activity of the plant extracts on the peroxidation of linoleic acid were measured by ferric thiocyanate method in comparison to methanolic extracts of green tee, ginkgo biloba, vit.e and bha as positive controls. methanolic extract of the plant exhibited strong antioxidant activity .two compounds of methanolic extract which were separated by column and paper chromatography showed significant antioxidant activity comparable to butylated hydroxy anisole (bha) and alpha tocopherol. these active compounds were identified as morin and quercetin by using uv, ir, ms, ¹h and ¹³c nmr.