Antioxidative phenylethanoid and phenolic glycosides from Picrorhiza scrophulariiflora

One new phenylenthanoid glycoside, scroside D (2), was isolated from the roots of Picrorhiza scrophulariiflora (Scrophulariaceae), together with nine known phenylethanoid and phenolic glycosides: 2-(3,4-dihydroxyphenyl)-ethyl-O-beta-D-glucopyranoside (1), 2-(3-hydroxy-4-methoxyphenyl)-ethyl-O-beta-D-glucopyranosyl (1-->3)-beta-D-glucopyranoside (3), scroside B (4), hemiphroside A (5), plantainoside D (6), scroside A (7), androsin (8), piceoside (9), and 6-O-feruloyl-beta-D-glucopyranoside (10). The structures of these compounds were elucidated using spectroscopic methods. The antioxidative activities of these isolated compounds were evaluated based on their scavenging effects on hydroxyl radicals and superoxide anion radicals, respectively. Compounds 1, 2, and 6 showed potent antioxidative effects as those of ascorbic acid and the structure-activity relationship is discussed.