Calyxin H, Epicalyxin H, and Blepharocalyxins A and B, Novel Diarylheptanoids from the Seeds of Alpinia blepharocalyx

Four unprecedented diarylheptanoids-calyxin H (1) and epicalyxin H (2), possessing a diarylheptanoid unit and a chalcone moiety, and blepharocalyxins A (3) and B (4), possessing two diarylheptanoid units and a chalcone moiety-were isolated from the seeds of Alpiniablepharocalyx. The structures of 1-4, including absolute stereochemistry, were elucidated by spectroscopic means and after a consideration of their biogenesis.