New bufadienolides and C23 steroids from the venom of Bufo bufo gargarizans

Six new bufadienolides (1–6) and two new C23 steroids (7 and 8), together with three known compounds (9–11) were isolated from the venom of Bufo bufo gargarizans. Their structures were elucidated by spectroscopic analysis and single-crystal X-ray diffraction. In vitro cytotoxicities of all compounds were evaluated in A549 cancer cell line. Compounds 2, 3 and 10 showed significant cytotoxic activities.