Rearranged 6/6/5/6-Fused Triterpenoid Acids from the Stems of Kadsura coccinea.

Fourteen new rearranged 6/6/5/6-fused triterpenoid acids, namely, kadcoccine acids A-N (1-14), were isolated from an EtOAc-soluble extract of the stems of Kadsura coccinea. Their structures were characterized mainly by analyzing 1D and 2D NMR and HRESIMS data and were shown to feature a rare 14(13→12)-abeo-lanostane skeleton. Compounds 7 and 8 represented the first examples of a 5-substituted 2(5H)-furanone motif on the C-17 side chain of this skeleton. The absolute configurations of C-23 for compounds 1, 7, and 8 were determined by comparison of their experimental electronic circular dichroism spectra. All the isolates were screened for their in vitro cytotoxicity against six human tumor cell lines (HL-60, SMMC-7721, A-549, MCF-7, SW-480, and HeLa), and compounds 2 and 8 exhibited weak inhibitory effects with IC50 values ranging from 3.11 to 7.77 μM.