Antioxidative phenols and phenolic glycosides from Curculigo orchioides

A new orcinol glucoside, orcinol-1-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (3), was isolated from the rhizomes of Curculigo orchioides GAERTN., together with seven known compounds: orcinol glucoside (1), orcinol-1-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (2), curculigoside (4), curculigoside B (5), curculigoside C (6), 2,6-dimethoxyl benzoic acid (7), and syringic acid (8). The structures of these compounds were elucidated using spectroscopic methods. The antioxidant activities of these isolated compounds were evaluated by colorimetric methods based on their scavenging effects on hydroxyl radicals and superoxide anion radicals, respectively. All the compounds showed potent antioxidative activities and the structure-activity relationship is discussed.