The chemical components ofCoreopsis tinctoriaNutt. and their antioxidant, antidiabetic and antibacterial activities

Seventeen compounds were isolated from the capitula ofCoreopsis tinctoriaNutt. with various column chromatographic methods and semi-preparative HPLC. Their structures were identified by the spectroscopic data and comparison with literatures as 2 '-hydroxy-4,4 '-dimethoxy-chalcone; (1), isoliquiritigenin (2), eriodictyol (3), naringenin (4), maritimetin (5), butin (6), taxifolin (7), luteolin (8), 7,3 ',4 '-trihydroxyflavone (9), 8,3 ',4 '-trihydroxyflavone-7-O-beta-d-glucoside (10), quercetin (11), quercetagitin-7-O-beta-d-glucoside (12), quercetin-7-O-beta-d-glucoside (13), 3,4-dihydroxybenzoic acid (14), caffeic acid (15), coreoside B (16), andmyo-inositol (17). Compounds1,4,9,10and17were isolated fromC. tinctoriaNutt. for the first time. Compounds7and12possessed the highest antioxidant activity (IC50 = 64.37 and 32.86 mu g/ml, respectively) among the tested compounds (IC(50)value of positive control was 5.34 mu g/ml). Compound7exhibited potent PTP1B enzymatic inhibition with an IC(50)value of 7.73 mu g/ml (IC(50)value of positive control is 1.46 mu g/ml). Furthermore, compound5showed strong antibacterial activity against the Gram-positive bacterium,S. aureus.