A new antibacterial tirucallane from roots.

Phytochemical investigation of the roots of a Thai medicinal plant, provided a new tirucallane, 3-epimesendanin S 12-acetate (), together with four known compounds, 3-epimesendanin S (), meliasenin G (), -sitosterol () and -sitosterol glucoside (). Their structures were characterized by intensive spectroscopy including 1 D and 2 D NMR, UV, IR and MS spectrometric analysis. The isolated compounds were evaluated for antibacterial and acetylcholinesterase inhibitory activities. Compounds - showed antibacterial activity against and with MIC values ranging from 16-128 μg/mL. In addition, compound was active against and with MIC values of 64 and 128 μg/mL, respectively.