Lantadene A (LA) which is one of the major pentacyclic triterpenoids in Lantana camara leaves was reported to exhibit anti-cancer property. However, the detail mechanism of LA inhibition against prostate cancer cells is still remained unknown. Hence, this study aimed to extract LA which was then used to treat LNCaP cells for the prediction of its apoptotic mechanism. A serial of separation techniques including maceration, solvent partition, crystallization and column chromatography was applied to recover LA. Approximately, 0.45%w/w LA was obtained from the plant leaves with 87.16% purity. The results found that the viability of LNCaP cells decreased with the increase of LA concentration with the IC50 of 208.4 µg/mL. High content screening showed the nucleuses of intact cells were started to collapse at the LA concentration more than 12.5 µg/mL, whereas the breakage of mitochondrial membrane was observed together with the release cytochrome C into cytosols. The activities of caspases -3/7 and -9 was found to increase in a dose dependent manner. Cell cycle arrest was happened during the (G0/G1) phase at the concentration of LA more than 50 µg/mL. As a conclusion, LA was effective to inhibit the growth of LNCaP cells without any cytotoxic effects to RWPE-1 cells. The inhibitory action of LA followed the intrinsic pathway of mitochondria dependent mechanism.