The chemical components of <i>Coreopsis tinctoria</i> Nutt. and their antioxidant, antidiabetic and antibacterial activities
Abstract
Seventeen compounds were isolated from the capitula of Coreopsis tinctoria Nutt. 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-β-d-glucoside (10), quercetin (11), quercetagitin-7-O-β-d-glucoside (12), quercetin-7-O-β-d-glucoside (13), 3,4-dihydroxybenzoic acid (14), caffeic acid (15), coreoside B (16), and myo-inositol (17). Compounds 1, 4, 9, 10 and 17 were isolated from C. tinctoria Nutt. for the first time. Compounds 7 and 12 possessed the highest antioxidant activity (IC50 = 64.37 and 32.86 µg/ml, respectively) among the tested compounds (IC50 value of positive control was 5.34 µg/ml). Compound 7 exhibited potent PTP1B enzymatic inhibition with an IC50 value of 7.73 μg/ml (IC50 value of positive control is 1.46 µg/ml). Furthermore, compound 5 showed strong antibacterial activity against the Gram-positive bacterium, S. aureus.