One new cycloartane triterpenoid, named markhacanasin C (1), together with three known triterpenoids, oleanolic acid (2), ursolic acid (3) and 6β,19α-dihydroxyursolic acid (4) were isolated by various chromatographic methods from the most cytotoxic fraction of the ethyl acetate extract of Markhamia stipulata var. canaense V.S. Dang leaves. Among them, 4 was reported for the first time from the genus Markhamia, while 2 and 3 were found for the first time from this species. Their structures were elucidated by IR, UV, HR-ESI-MS and NMR experiments. The cytotoxicity of isolated compounds (3 and 4) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated. At the concentration of 100 μg/mL, 3 exhibited significant cytotoxic activity (86.36 ± 3.69%).
Keywords: Bignoniaceae; cytotoxic activity; markhacanasin C.