Clerodane-type diterpenoids from tuberous roots of Tinospora sagittata (Oliv.) Gagnep.

Three new clerodane type diterpenoids (2-4), together with one known analogues (1), were isolated from the tuberous roots of Tinospora sagittata (Oliv.) Gagnep. Compound 3 is an unusual clerodane diterpenoid with the carbonyl functionality at C-3, which represents the first example from this diterpenoid compounds class. The structures were established on the basis of spectroscopic data interpretation. The absolute configuration of 1 was determined for the first time by single-crystal X-ray diffraction analysis with CuKα irradiation. These isolates were evaluated for their cytotoxic activities against five human cancer cell lines and inhibitory activities on LPS-induced NO production in RAW264.7 cells.