Chemical compositions and antiproliferation activities of the chloroform fraction from Pyropolyporus fomentarius in K562 cells.

Pyropolyporus fomentarius, a fungus of the polyporaceae family, has been used in the treatment of various diseases, such as gastroenteric disorder, hepatocirrhosis, oral ulcer, inflammation, and several cancers. This study was conducted to investigate the compositions and cell growth inhibition effects of P. fomentarius chloroform (CHCl3) fraction and to clarify the possible mechanisms. Gas chromatography-mass spectrometry analysis was performed to investigate the composition of the P. fomentarius CHCl3 fraction. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell membrane damage was evaluated with a scanning electron microscope and flow cytometry following propidium iodide and bis-(1,3-dibarbituric acid)-trimethine oxanol staining. Apoptosis was analyzed using annexin V-PE/7-amino-actinomycin D (7-AAD) staining. Generation of intracellular calcium ion (Ca(2+)), reactive oxygen species (ROS), and changes of mitochondrial membrane potential (Δψ m) were detected by flow cytometry using fluo 3-acetoxymethyl ester, 2',7'-dichlorofluorescin-diacetate, and rhodamine 123. Our obtained data indicate that P. fomentarius CHCl3 fraction could inhibit proliferation of K562 cells depending on both the dosage and the incubation time, cause cell membrane damage, influence intracellular [Ca(2+)]i variation, promote the yield of ROS, decrease the level of Δψ m, and initiate the apoptotic response in K562 cells.