Antioxidant activity of Convolvulus hystrix Vahl and its chemical constituents.

Total alcohol and successive extracts (diethyl ether, chloroform, ethyl acetate and n-butanol) of Covolvulus hystrix Vahl were screened for their antioxidant activity using free radical 2-2-diphenyl-1-picrylhydrazyl (DPPH) and Trolox as reference substance. The tested extracts showed variable antioxidant activities. The highest antioxidant activity was achieved in total alcohol (48.32%) followed by ethyl acetate (37.8%) and n-butanol (32.96%) extracts. From the ethyl acetate extract four compounds were isolated and identified as quercetin, quercetin 3-0-rutinoside and quercetin-7-O-rhamnoside in addition to ferulic acid using different spectroscopic analysis such as, 1HNMR, 13CNMR, COSY, HMBC and HMQC.