Cytotoxic triterpenoids and triterpene sugar esters from the medicinal mushroom Fomitopsis betulina.

Thirteen undescribed 24-methylene lanostane triterpenoids, named polyporenic acids E-M and fomitosides L-O, as well as seventeen known analogues, were isolated from the fruiting bodies of the mushroom Fomitopsis betulina. Their structures were determined using 1D, 2D NMR, IR, and HRESIMS. Fomitoside L and fomitoside N exhibited cytotoxicity against HL60 leukemia cells (IC = 15.8 and 23.7 μM, respectively). Among the known compounds, notable cytotoxicities against HL60 leukemia cells and selectivity with respect to MRC-5 healthy cells were noticed for dehydropachymic acid (IC = 10.9 μM, SI 8.6), pachymic acid (IC = 11.0 μM, SI 9.8), 3-epi-dehydrotumulosic acid (IC = 19.9 μM, SI 5.8) and 12α-hydroxy-3α-(3'-hydroxy-4'-methoxycarbonyl-3'-methylbutyryloxy)-24-methyllanosta-8,24 (31)-dien-26-oic acid (IC = 19.2 μM, SI 2.2).