Unusual triterpenoids and steroids from Cipadessa baccifera and their biological activities

Five undescribed triterpenoids and steroids (1-5), as well as ten known compounds, were purified from the branches and leaves of Cipadessa baccifera. Notably, 1 and 2 are rare cipadesin-type limonoids with an unusual 8,30-epoxide ring and 1,8-ether linkage, respectively. Compound 5 possessed pregnane steroid skeleton with an uncommon 5/6/6/6/5-fused ring system. Their structures were constructed by extensive spectroscopic analysis (NMR, IR, UV, and HRESIMS), and their absolute configurations were confirmed by ECD calculations and quantum chemical calculations. All the isolates were in vitro assayed for their antimicrobial potentials against 6 pathogenic microorganisms and antiproliferation activities against five human cancer cell lines. As a result, compounds 5, 12, 13, and 14 exhibited moderate antibacterial activities (MIC: 25-50 μg/mL). Moreover, 5 showed cytotoxicity against five cancer cell lines with IC₅₀ values ranging from 8.0 to 19.9 μM.