Unusual prenylated phenols with antioxidant and immunosuppressive activities from the edible mushroom Lentinula edodes

Prenylated phenols, the primary class of mushroom-derived meroterpenoids, exhibit significant structural diversity and biological activities. Two new prenylated phenols (1 and 2), along with four aromatic derivatives, were isolated from the wild mushroom Lentinula edodes for the first time. Their structures were established based on extensive spectroscopic data (UV, IR, MS, and NMR) and further corroborated by X-ray crystallographic analysis. Compounds 1 and 2 are unusual meroterpenoids characterized by 4-prenylated benzene 1,2,3-triols or 3-prenylated benzene 1,2-diols. Compound 2 showed moderate immunosuppressive activity by inhibiting the proliferation of induced T/B cells; it also demonstrated inhibitory effects on the proliferation of the HaCaT cell line (IC₅₀ 24.5 µM) and antioxidant activity at 50 µM.