LAUSR

Abstract Phytochemical investigation of the hexane extract of the roots of Mezoneuron benthamianum (Baill.) led to the isolation of two Cassane diterpenoids, taepeenin A and nortaepeenin A. Their structures were determined by extensive analysis of spectroscopic data (1D and 2D NMR, IR and MS) and by comparison with the spectroscopic data reported in the literature. In addition, they were evaluated for in-vitro cytotoxic activities against four cancer cell lines: Lung (NCI-H322), Breast (T47D), Prostate (PC-3) and Lung (A549). The two compounds taepeenin A and nortaepeenin A showed significant cytotoxic activity against the cells lines. However, nortaepeenin A showed a more significant and consistent activity than taepeenin A, as nortaepeenin A had lower IC50 values of 49.4, 42.8, 38.3 and 76.2 μM against Lung (NCI-H322), Breast (T47D), Prostate (PCI-3) and Lung (A549) respectively while taepeenin A had IC50 values of 71.8, >100, >100, and >100 μM against Lung NCI-H322, Breast (T47D), Prostate (PCI-3) and Lung (A549) cell lines respectively.