Oligostilbenes from the roots of Vitis amurensis

Two new oligostilbenes, amurensin A (1) and amurensin B (2), were isolated from the roots of Vitis amurensis Rupr. together with five known oligostilbenes. Their structures were elucidated by means of spectroscopic evidence, and amurensin B was the first naturally occurring stilbene trimer with a cis dihydrobenzofuran moiety.