Ambiguanine A-G, hexahydrobenzophenanthridine alkaloids from Corydalis ambigua var. amurensis.

Abstract Seven hexahydrobenzophenanthridine-type alkaloids, Ambiguanine A–G, along with eight known alkaloids, were isolated from tubers of Corydalis ambigua var. amurensis . Their structures were elucidated based on extensive spectroscopic analyses, with absolute configurations determined by CD experiments.