Two new hexahydrobenzo[c] phenanthridine alkaloids, ambiguanine H (1) and ambiguanine I (2) together with six known hexahydrobenzo[c] phenanthridine alkaloids (3–8), were isolated and purified from the Corydais ambigua var. amurensis leaves. Their structures were elucidated by extensive spectroscopic methods and all the compounds except comp. 6 showed the remarkable protective effect on myocardium ischemia-hypoxia cells and comp. 4 was the most active compound with cell viability of 49.4, 53.3, 68.2 and 84.5% in the range of at 0.01–10μmol/L which were stronger than that of salvia acid B. © 2016 Phytochemical Society of Europe