Embelin (Embelic acid), isolated from the Japanese Ardisia herb, is an inhibitor of the X-linked inhibitor of apoptosis (IC50: 4.1 uM).

X linked:4.1 μM

来自日本紫金牛草的Embelin是一种小分子抑制剂，能够结合到XIAP BIR3域，与此同时Smac和caspase-9也会与之结合。Embelin以剂量依赖的方式抑制PC-3和LNCap细胞的生长，其IC50值分别为3.7 μM和5.7 μM。而对于正常的PrEC细胞和WI-38细胞，Embelin的毒性较低，其IC50值分别为20.1 μM和19.3 μM。用25 μM和50 μM的Embelin处理PC-3细胞48小时后，分别有30%和75%的细胞发生凋亡。[1] Embelin还通过选择性抑制5-脂氧合酶（5-LO）和微粒体前列腺素E2合酶-1（mPGES-1）强效地抑制了烯酸类物质的生物合成，其IC50值分别为0.06 mM和0.2 mM。[2]

Fluorescence Polarization Competitive Binding Assay: Fluorescence polarization experiments are performed in Dynex 96-well, black, round-bottom plates. A 5 μL sample of Embelin dilutions in DMSO, and preincubated XIAP BIR3 protein (0.06 μM) and the N terminus of a Smac peptide (SM7F) (0.01 μM) in the assay buffer are added to 96-well plates to produce a final volume of 125 μL. For each assay, the bound peptide control containing XIAP BIR3 protein and SM7F (equivalent to 0% inhibition) and free peptide control containing only free SM7F (equivalent to 100% inhibition) were included. The plates were mixed and incubated at room temperature for 3 h to reach equilibrium.

Cell growth is determined by the MTT-based assay using Cell Proliferation Reagent WST-1 according to the manufacturer's instruction. Cells (5000 cells/well) are grown in medium with 10% FBS, and various concentrations of Embelin are added to the cells. Four to five days later, WST-1 is added to each well and incubated for 1-3 h at 37 °C. Absorbance is measured with a plate reader at 450 nm with correction at 650 nm.(Only for Reference)