Two new acetylated flavan glycosides from rhizomes of the fern Abacopteris penangiana

Two new acetylated flavan glycosides (2S,4R)-4,5,7-trihydroxy-4'-methoxy-6,8-dimethylflavan-5-O--D-6-acetylglucopyranoside-7-O--D-glucopyranoside (1) and (2S,4R)-5,7-dihydroxy-4,4'-dimethoxy-6,8-dimethylflavan-5-O--D-6-acetylglucopyranoside-7-O--D-glucopyranoside (2) were isolated from the rhizomes of Abacopteris penangiana. Their structures were elucidated on the basis of spectroscopic methods including IR, HR-ESI-MS, 1D and 2D NMR, and chemical evidences.