Flavonoids from the seeds of Alpinia galanga Willd.

Ten flavonoids were isolated from the 95% ethanol extract of the seeds of Alpinia galanga Willd. with a combination of various chromatographic techniques, including silica gel, Sephadex LH-20 and preparative HPLC. On the basis of spectroscopic data analysis, they were elucidated as (2R, 3S)-pinobaksin-3-cinnamate (1), (2R, 3R)-pinobaksin-3-cinnamate (2), pinocembrin (3), pinobaksin (4), 3-O-acetylpinobaksin (5), galangin (6), galangin-3-methylether (7), kumatakenin (8), 3-methylkaempferol (9) and (2R, 3R)-3, 5-dihydroxy- 7-methoxyflavanone (10). Among them, compound 1 is a new compound, compounds 2, 5 and 10 were isolated from the genus Alpinia for the first time, and others were isolated from this plant for the first time.