Screening of mushrooms bioactivity: piceatannol was identified as a bioactive ingredient in the order Cantharellales

Wild edible mushroom species are appreciated for consumption due to their high nutritional value. The aim of the present study was to examine in vitro beneficial bioactivity of mushroom extracts and to investigate the molecular identity of the active ingredients. In this regard, methanol extracts of 29 different wild edible mushroom species, that are traditionally consumed by residents in the National Park of North Pindos in North-Western Greece, were examined for antioxidant, antiproliferative, cytotoxic, and pro-apoptotic activities towards a human lung adenocarcinoma cell line A549 by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and by flow cytometry. Certain mushroom species exhibited high antioxidant activity, which was related to their high content in total phenols and flavonoids. Methanol extracts of Cantharellus cibarius, Cantharellus cinereus, Craterellus cornucopioides and Hydnum repandum , which belong to the order Cantharellales, exhibited high cytotoxicity and induced apoptosis–necrosis to A549 cells. High Performance Liquid Chromatography (HPLC) coupled with Mass Spectrometry analysis revealed as an active ingredient piceatannol ((E)-4-[2-(3,5-dihydroxyphenyl)ethenyl]1,2-benzenediol-3,3′,4,5′-tetrahydroxy- trans -stilbene). Piceatannol, according to our best knowledge, is identified for the first time in wild edible mushrooms. Experiments with authentic piceatannol confirmed the potent antiproliferative activity of this compound. Tested mushrooms are promising sources of bioactive compounds.