Taccachatrones A–G, Highly Oxidized Steroids from the Rhizomes of Tacca chantrierii and Their Cytotoxicity Assessment

Seven highly oxidized steroids, taccachatrones A–G (1–7), together with four known taccalonolides (8–11), were characterized from the rhizomes of Tacca chantrieri. The structures of 1–7 were established on the basis of spectroscopic data analysis, while the absolute configurations were determined by single-crystal X-ray diffraction. Compounds 1–4 may be derived from taccalonolide derivatives by the degradation of three carbon atoms. Compounds 7, 8, 10, and 11 exhibited cytotoxicity to human cancer cell lines, indicating that the presence of a lactone moiety, as well as a double bond between C-22 and C-23, might play key roles in mediating their cytotoxicity.