Irpexoates A–D, Four Triterpenoids with Malonyl Modifications from the Fruiting Bodies of the Medicinal Fungus Irpex lacteus

Four eburicane-type triterpenoids with malonyl modifications, namely irpexoates A–D ( 1 – 4 ), were isolated from the fruiting bodies of the medicinal fungus Irpex lacteus . The structures of the new compounds were established by extensive spectroscopic methods, including 1D and 2D NMR, HRESIMS spectroscopic analysis. Irpexoate B ( 2 ) displayed weak cytotoxicity against four human cancer cell lines (A-549, SMMC-7721, MCF-7, SW480) with IC 50 values varying from 22.9 to 34.0 μM, and irpexoate D ( 4 ) showed weak cytotoxicity against the human cancer cell line SW480 with an IC 50 value of 35.2 μM. Graphical Abstract