Two new oleanane derivatives from the fruits of Leonurus japonicus and their cytotoxic activities.

Two new oleanane derivatives, leonuronins A and B (1 and 2), along with three known oleanane triterpenes (3-5) were isolated from the fruits of Leonurus japonicus. Their structures were elucidated on the basis of NMR, MS, IR and UV spectroscopic data. The new compounds were tested for cytotoxic activities against A549 and Hela cancer cell lines. Compounds 1 and 2 exhibited weak cytotoxicity with IC50 values ranging from 6.97 to 18.13 µM.