Cycloartan-24-ene-1α,2α,3β-triol, a cycloartane-type triterpenoid from the resinous exudates of Commiphora myrrha, induces apoptosis in human prostatic cancer PC-3 cells.

Plant-derived antitumor drugs are currently used in chemotherapy. Cycloartane triterpenoids have shown a cytotoxic effect on human prostate cancer cells. The aim of the present study was to isolate a cycloartane triterpenoid from Commiphora myrrha and evaluate its anticancer potential. Cycloartan-24-ene-1α,2α,3β-triol (MY-1) was isolated from Commiphora myrrha, and its structure was determined through 1H and 13C nuclear magnetic resonance spectroscopy. The cytotoxic and apoptotic effects of MY-1 on human prostatic cancer PC-3 cells were estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining assay, and the expression of apoptotic-related proteins were evaluated by western blotting. MY-1 showed cytotoxic activity on PC-3 cells in a concentration-dependent manner with an IC50 value of 9.6 µM at 24 h. MY-1 induced cell cycle arrest and apoptosis. Western blot analysis revealed that MY-1 regulated the expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), p53 and caspase-3 in the PC-3 cells. These findings indicate that MY-1 exerts significantly pro-apoptotic activity against human hormone-independent prostatic cancer and support MY-1 as a potential anticancer drug.