Ergostane-Type Sterols from King Trumpet Mushroom (Pleurotus eryngii) and Their Inhibitory Effects on Aromatase

Two new ergostane-type sterols; (22E)-5α,6α-epoxyergosta-8,14,22-triene-3β,7β-diol (1) and 5α,6α-epoxyergost-8(14)-ene-3β,7α-diol (2) were isolated from the fruiting bodies of king trumpet mushroom (Pleurotus eryngii), along with eight known compounds (3–10). All isolated compounds were evaluated for their inhibitory effects on aromatase. Among them, 4 and 6 exhibited comparable aromatase inhibitory activities to aminoglutethimide