Cytotoxic Activities of 9,10-seco-Cycloartane-Type Triterpenoids from the Chinese Liverwort Lepidozia reptans

Ten new triterpenoids, including nine 9,10-seco-cycloartanes (1–9) and one 9,19-cyclolanostane (10), as well as one sesquiterpenoid (11) and four known compounds (12–15), were extracted and purified from the whole plant of the Chinese liverwort Lepidozia reptans. Multiple techniques (NMR, HRESIMS, IR, and X-ray crystallographic analysis) were applied to determine the structures of the isolated compounds. Bioassay determinations showed that compound 7, which contains an α,β-unsaturated carbonyl moiety in its structure, inhibited the growth of a panel of cancer cell lines with IC50 values ranging from 4.2 ± 0.2 to 5.7 ± 0.5 μM. Further investigation revealed that compound 7 induces PC-3 cell death via mitochondrial-related apoptosis.