Procyanidins from the seeds of Vitis amurensis

Three procyanidins, procyanidin B-5 3'-O-gallate, vitisinol, and amurensisin, were isolated from the seeds of Vitis amurensis, whose structures were elucidated on the basis of spectral and chemical evidence. Vitisinol and amurensisin contain a spiro-type biflavanyl linkage and a biphenyl-lactone partial structure, respectively.