Bioactive Compounds and Pharmacological Properties of the Polypore Fomes fomentarius, a Medicinal Wild Mushroom Collected from Morocco

Polypore mushrooms have been widely recognized for centuries for their use in food and medicine due to their strong capacity to produce numerous biomolecules with beneficial effects on human health. <i>Fomes fomentarius</i> is one such species that remains poorly explored, particularly when growing in Morocco. Herein, this study aimed to characterize the bioactive compounds of <i>F. fomentarius</i> and evaluate its pharmacological properties. Spectrophotometric analysis showed that <i>F. fomentarius</i> revealed high levels of total phenolics (75.83 mg GAE/g dme) and flavonoids (37.62 mg CE/g dme). Gas chromatography-mass spectrometry (GC-MS) analysis identified 109 volatile and non-volatile compounds, primarily sugars (24), fatty acids (23), alcohols (10), organic acids (9), and terpenoids (6). In addition, liquid chromatography-mass spectrometry (LC-MS) analysis allowed the identification of 24 phenolic compounds, with isorhamnetin (2734.00 µg/g), <i>p</i>-hydroxybenzoic acid (409.00 µg/g), and kaempferol (351.10 µg/g) as the most abundant. Regarding pharmacological properties, <i>F. fomentarius</i> extract demonstrated strong antioxidant activity, with the DPPH radical-scavenging assay showing the highest potency, followed by <i>β</i>-carotene bleaching inhibition and ferric ion-reducing power, with EC₅₀ (half maximal effective concentration) values of 114.40, 174.50, and 250.70 µg/mL, respectively. Additionally, it exhibited broad-spectrum antimicrobial activity against all seven human pathogenic microorganisms, with <i>Epidermophyton floccosum</i> being the most susceptible ((minimum inhibitory concentration (MIC)) = 2 mg/mL and minimal fungicidal concentration (MFC) = 4 mg/mL) and <i>A. fumigatus</i> the most resistant (MIC = 26.67 mg/mL and MFC ≥ 64 mg/mL). Overall, the result indicated that Moroccan <i>F. fomentarius</i> is a rich source of diverse bioactive compounds with potent antioxidant and antimicrobial activities, supporting its potential for various applications.