Description: Gambogic Acid (also called Guttatic Acid, Guttic Acid) is a naturally occurring xanthonoid isolated from the brownish or orange resin from Garcinia hanburyi. It has potential antitumor activity and is currently undergoing clinical trials in China. The mechanism of action for Gambogic Acid is to activate caspases with EC50 of 0.78-1.64 μM and competitively inhibit Bcl-XL, Bcl-2, Bcl-W, Bcl-B, Bfl-1 and Mcl-1 with IC50 of 1.47, 1.21, 2.02, 0.66, 1.06 and 0.79 μM, respectively. The cytotoxic natural product GA competes for BH3 peptide binding sites on several antiapoptotic members of the Bcl-2 family and neutralizes the ability of these proteins to suppress release of apoptogenic proteins from mitochondria. In vitro, it was demonstrated that GA inhibited the proliferation of human gastric carcinoma MGC-803 cells in a dose-dependent manner. When the cells were exposed to GA 5 mg/ml for 72 h, the rate of inhibition reached 89.45%.
References: Mol Cancer Ther. 2008 Jun;7(6):1639-46; Bioorg Med Chem. 2004 Jan 15;12(2):309-17.