Cycloartane-type triterpenoids and steroids from Trichilia connaroides and their multidrug resistance reversal activities

Four undescribed cycloartane-type triterpenoids (1−4) and seven undescribed steroids (6−12), along with five known analogues (5 and 13−16), were isolated from the leaves of Trichilia connaroides. Their structures were identified based on the NMR data and HRESIMS, and the absolute configurations were determined through single-crystal X-ray diffraction analysis, Mosher's method, and ECD calculations. The multidrug resistance (MDR) reversal activities of all the isolates were assessed, and compounds 10 and 11 showed significant activities to reverse the MDR of MCF-7/DOX cells with IC₅₀ values of 2.90 and 3.76 μM, respectively. These bioactive compounds may bring fresh insights into the research and development of MDR reversal agents.