Cytotoxic sesquiterpenes from Magnolia kachirachirai

Bioassay-guided fractionation of the root wood of Magnolia kachirachirai (Kanehira & Yamamoto) Dandy (Magnoliaceae) led to the isolation of three new compounds, kachiraterpenol (1), (E)-2,3-bis(4-hydroxy-3-methoxyphenyl)prop-2-enal (15), and kachiranol (19), together with 27 known compounds, of which 4,4'-dihydroxy-3,3'-dimethoxybenzophenone (16) was isolated for the first time from a natural source. Their structures were elucidated by spectroscopic analysis. Two of these isolates, costunolide (2) and dehydrosaussurea lactone (4), showed cytotoxic properties against MCF-7, NCI-H460, and SF-268 cancer cell lines in vitro.