Two new rearranged clerodane diterpenes from Thai Tinospora baenzigeri

A new rearranged clerodane-type diterpene (1), tinobaenzigeride, and a new rearranged clerodane glucoside (2) were isolated from the stems of Tinospora baenzigeri, along with four known compounds (3‒6). Their structures were elucidated by spectroscopic data analysis. In addition, the structure and configuration of 1 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 are a rare example of rearranged clerodanes, since it contains a fully oxygenated tetrahydrofuran moiety. The isolated compounds were evaluated for their cytotoxicity against Hep-G2 and MCF-7 cancer cells, none of them did show any significant activity at 25 μM.