2014 Volume 62 Issue 7 Pages 719-724
Phytochemical investigations of the tubers of Dioscorea bulbifera L. resulted in the isolation of nine norclerodane diterpenoids, including two new compounds, diosbulbins N (1) and P (3), a new naturally occurring compound, diosbulbin O (2), and six known ones, diosbulbins A–D, F and G (4–9). Their structures were established by spectroscopic and chemical methods. The absolute stereochemistry of 1 was determined by a modified Mosher’s method, and the absolute configuration of 2 was determined by a single-crystal X-ray diffraction analysis with CuKα irradiation. Compounds 1–3 were evaluated for in vitro cytotoxicity against five human cancer cell lines.