Naphthalene derivatives and other constituents with immunomodulatory activities from the fruiting bodies of Fomes fomentarius (L.) Fr.

Chemical investigation of the fruiting fungus Fomes fomentarius (L.) Fr. led to the isolation of 11 compounds, among which two previously undescribed derivatives, named fominols A and B, were identified. Their structural elucidation was accomplished through comprehensive spectroscopic analysis, including NMR and HRMS, supplemented by J-based configuration analysis (JBCA) and computational methods. The structures of fominols A and B are distinguished by a rare 7,10-epoxycyclohepta[de]naphthalene subunit. Biological evaluation using CCK-8, EdU, and ELISA assays revealed that compounds 9 and 11 displayed moderate antiproliferative effects on stimulated T/B lymphocytes, accompanied by reduced secretion of the cytokines IFN-γ and IL-2. Additionally, compounds 3, 5, and 11 showed weak inhibitory activity against NO production in mouse macrophage cells.