Two new seco-lanostane-type triterpenes, named mayomlactones A (1) and B (2) were isolated from the fruits of Leplaea mayombensis together with 10 known compounds (3-12). Structures of the new compounds were elucidated by extensive spectroscopic studies. Except compounds 11 and 12, all the other chemical compounds are newly reported from Leplaea genus. From the results of this investigation, compounds 1-10 were examined for antiproliferative activity against HeLa cells as well as cytotoxicity against 3T3 cell line. Compounds 3 and 4 showed moderate antiproliferative activity with IC50 values of 10.4 ± 0.1 and 18.6 ± 0.2 μM, respectively. On the other hand, compounds 1, 4 and 9 showed weak cytotoxicity with IC50 values 44.1 ± 0.5, 55.8 ± 0.7 and 55.1 ± 0.5 μM. Overall, none of the tested compounds showed good selectivity (SI ranging from 0.51 to 3.06) but high toxicity against the 3T3 cell line.
Keywords: antiproliferative activity; cytotoxicity; s-lanostane-type triterpene.