A new sulfonyl flavonol glucoside, 5,7,4',5'-tetrahydoxyflavonol 2'-[propanoic acid-(2″'-acetoxy-1″'-sulfonyl)]-5'-O-β-d-glucopyranoside (1) was isolated from the aerial parts of Cotula anthemoides L. in addition to 15 known compounds (2-16). The structure elucidation of these compounds was based on analyses of spectroscopic data including 1D-, 2D-NMR and HR-ESI-MS techniques and by comparing their NMR data with those reported in the literature. These compounds were evaluated for their DPPH radical scavenging and tyrosinase inhibitory activity. Compound 6 showed a high DPPH radical scavenging with EC50 value of 9.1 ± 0.4 μM. Compound 11, 9 and 1 exhibited a mild tyrosinase inhibitory activity with IC50 values of 85 ± 0.8, 95 ± 1.5 and 100 ± 0.5 μM, respectively.
Keywords: Asteraceae; Cotula anthemoides; antioxidant activity; tyrosinase inhibitory activity.