Anti-oxidant constituents from Sedum takesimense.

As part of an ongoing search for antioxidants from medicinal plants, 14 phenolic constitutents were isolated from the Korean endemic species Sedum takesimense Nakai. Their structures were determined as 1-(4-hydroxyphenyl)-2-(3,5-dihydroxyphenyl)-2-hydroxyethanone (5), gossypetin-8-O-beta-d-xylopyranoside (10), and 2,6-di-O-galloylarbutin (13) on the basis of spectroscopic analyses (IR, UV, 1D and 2D NMR, HR-MS) and chemical degradation, together with 11 previously known phenolics. Two of those (10 and 13) exhibited strong scavenging activities against DPPH and superoxide radicals as well as significant inhibitory effects on lipid peroxidation (IC(50) 14.0 and 10.8 microM, respectively) and LDL oxidation induced by a metal ion Cu(2+) (IC(50) 5.7 and 3.3 microM, respectively).