New aporphine alkaloids with antitumor activities from the roots of Thalictrum omeiense

Two new aporphine alkaloids, 6aR-2'-(3-oxobutenyl)-thaliadin (1) and N-methylthalisopynine (2), along with ten known analogs (3–12), were isolated from the roots of Thalictrum omeiense W. T. Wang et S. H. Wang. Their structures were determined by extensive spectroscopic and X-ray crystallographic analyses. Compounds 1–7 and 9–12 were tested for their antiproliferative effects in vitro against two human cancer cell lines (A549 and MCF-7). Among them, compounds 1, 3, and 7 exhibited moderate inhibitory activity against the tested cell lines with IC50 values ranging from 23.73 to 34.97 μM.