Taccachatrones H‒L, cytotoxic taccalonolides from rhizomes of Tacca chantrieri.

Five highly oxidized taccalonolides, namely taccachatrones H‒L, together with nineteen reported analogues, were characterized from the rhizomes of Tacca chantrieri André. Their structures were established on the basis of extensive spectroscopic analysis and comparison with the spectral data reported in the literature. Taccachatrones H‒L were evaluated for their cytotoxic activities against five human cancer cell lines, including HL-60, A549, SMMC-7721, MCF-7, and SW480. Taccachatrone I exhibited the strongest cytotoxic activity across all tested cell lines, with IC50 values ranging from 8.34 to 13.19 μM. The preliminary structure-activity analysis suggested that substitutions at C-1, C-11, and C-15 may play important roles in the cytotoxic activity of taccalonolides. Molecular docking suggested a possible interaction between taccachatrone I (2) and β-tubulin, providing a hypothesis for further experimental validation.