Isolation and structural elucidation of some glycosides from the rhizomes of smaller galanga (Alpinia officinarum Hance)

Glycosidically bound compounds were isolated from the methanol extract of fresh rhizomes of smaller galanga (Alpinia officinarum Hance). Nine glycosides (1-9) were finally obtained by reversed-phase HPLC and their structures were elucidated by MS and NMR analyses. They were the three known glycosides, (1R,3S,4S)-trans-3-hydroxy-1,8-cineole beta-D-glucopyranoside (1), benzyl beta-D-glucopyranoside (3), and 1-O-beta-D-glucopyranosyl-4-allylbenzene (chavicol beta-D-glucopyranoside, 4); and the six novel glycosides, 3-methyl-but-2-en-1-yl beta-D-glucopyranoside (2), 1-hydroxy-2-O-beta-D-glucopyranosyl-4-allylbenzene (5), 1-O-beta-D-glucopyranosyl-2-hydroxy-4-allylbenzene (demethyleugenol beta-D-glucopyranoside, 6), 1-O-(6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl)-2-hydroxy-4-allylbenzene (demethyleugenol beta-rutinoside, 7), 1-O-(6-O-alpha-L-rhamnopyranosyl-beta-D-glucopyranosyl)-4-allylbenzene (chavicol beta-rutinoside, 8), and 1,2-di-O-beta-D-glucopyranosyl-4-allylbenzene (9). Compounds 2-9 were detected for the first time as constituents of galanga rhizomes.