Pristimerin is a naturally occurring triterpenoid that has been shown to suppress the proliferation of various cancer cell lines at the concentration (IC50) range of 0.2-4 μM, including those of breast, glioma, prostate, pancreatic, ovarian, colon. Pristimerin can inhibits monoacylglycerol lipase(MGL) with an IC50 of 93 nM through a reversible mechanism.