Aim: Cancer is one of the leading worldwide public health problems. Natural product has provided a valuable source biological active compound for maintaining humans health even after years of introduction of synthetic drugs. Fomes fomentarius (F. fomentarius), a fungus belongs to Polyporaceae family, is widely used for different medicinal purposes. Considering inadequate reports on the fungus, cytotoxic effect of its extracts on brine shrimp larvae and colon adenocarcinoma cell line (SW742) was investigated in this study.
Methods: The fruiting body of the fungus was chopped and extracted with water, ethanol, methanol, and ethanol-methanol (50-50) solvents. Regarding the results of brine shrimp lethality assay (BSLA), ethanol extract showed the highest toxicity, so subjected to fractionation with chloroform, ethyl acetate, and water. The fractions were tested for cytotoxic activity in human colon adenocarcinoma (SW742) cells by MTT assay. Ethyl acetate fraction exhibited more cytotoxic activity against SW742 cell line. Therefore, it was chosen to be purified using silica gel column chromatography. Subfractions of ethyl acetate were tested for their cytotoxicity by MTT assay. The content of these subfractions were also analyzed using gas chromatography-mass spectrometry (GC-MS).
Results: According to the results, ethanol extract had the greatest potency in BSLA, and ethyl acetate fraction showed the highest cell cytotoxicity. Based on GC-MS chromatogram, palmitic acid was the compound with the largest quantity in the three selected subfractions of ethyl acetate.
Conclusion: It was found that palmitic acid with other compounds in F. fomentarius had cytotoxic activity against colon adenocarcinoma cells. This feature may provide a biological basis for further clinical evaluation.