Structurally diverse triterpenoids with cytotoxicity from Euphorbia hypericifolia

Extensive phytochemical investigation on the whole herbs of Euphorbia hypericifolia led to the isolation of 18 structurally diverse tetracyclic and pentacyclic triterpenoids, including four 4α,14α-dimethyl-5α-ergostanes (1-4), two seco-adiananes (5 and 6), three dammaranes (7-9), four cycloartanes (10-13), one tirucallane (14), two fernanes (15 and 16), one ursane (17), and one oleanane (18). Among them, euphypenoids A (1) and B (5) were new triterpenoids. Their structures were elucidated on the basis of extensive spectroscopic analysis, single-crystal X-ray diffraction, and chemical transformation. All isolates were screened for their cytotoxic activities against the colorectal cancer cell line HCT-116, and compounds 1, 12, and 15 showed remarkable activities with IC₅₀ values of 12.8 ± 1.6, 7.4 ± 0.2, and 10.6 ± 1.2 μM, respectively.