(2Z)-2-Methyl-4-[(1R,3aS,5S,11R,14aS)-3a,4,5,7-tetrahydro-8-hydroxy-3,3,11-trimethyl-13-(3-methyl-2-butenyl)-11-(4-methyl-3-pentenyl)-7,15-dioxo-1,5-methano-1H,3H,11H-furo[3,4-g]pyrano[3,2-b]xanthen-1-yl]-2-butenoic acid

Gambogic Acid is an apoptosis inducer in sever tumor cell lines via regulation of Bax and inhibition of Bcl-2 genes. Induces EGFR degredation through AMPK dependant-LRIG1 upregulation in glioma cells. Apoptosis inducer in several tumor cell lines including T47D cells. Activates caspases (EC50 values are 0.78 - 1.64uM) and competitively inhibits antiapoptotic Bcl-2 family proteins (IC50 values are 1.47, 1.21, 2.02, 0.66, 1.06 and 0.79uM for Bcl-XL, Bcl-2, Bcl-W, Bcl-B, Bfl-1 and Mcl-1 respectively). Reverses gefitinib-resistance in mice bearing tumors with EGFR-T790M mutation. Also blocks Kir2.1 channels (EC50 ≤100nM).