New Flavonoids from the leaves and stems of Sedum formosanum (Crassulaceae)

As a series of the phytochemical research of the family Crassulaceae, the flavonoids of Sedum formosanum from two Taiwanese and one Japanese sites were isolated and characterized by UV spectra, HR-MS, LC-MS, acid hydrolysis, NMR, and HPLC and TLC comparisons with authentic samples. Eight new flavonoids (21, 22, 24-26 and 28-30) including two flavones and six isoflavones were isolated from the leaves and stems, together with 24 known compounds (1-20, 23, 27, 31 and 32), and identified as chrysoeriol 7-O-[6´´-(3-hydroxy-3-methylglutaroyl)glucoside] (21), chrysoeriol 7-O-[6´´-(5´´´-methoxy-3-hydroxy-3-methyglutaroyl)glucoside] (22), 3´-O-methylorobol 7-O-rutinoside (24), 3´-O-methylorobol 7-O-arabinosyl-(1→2)-glucoside (25), 3´-O-methylorobol 7-O-arabinosyl-(1→6)-glucoside (26), orobol 3´,4´-dimethyl ether 7-O-rutinoside (28), orobol 3´,4´-dimethyl ether 7-O-sophoroside (29) and orobol 3´,4´-dimethyl ether 7-O-arabinosyl-(1→6)-glucoside (30). The samples were collected in three sites of Taiwan and Japan, and geographic chemical variation was observed among their sites.