New Triquinane-Type Sesquiterpenoids from Macrocystidia cucumis (Basidiomycetes).

Arthrosporone (1) and eight new triquinane-type sesquiterpenoids have been isolated from mycelial cultures of the agaric Macrocystidia cucumis. The cucumins A−D (2, 4−6) are highly unsaturated hirsutane derivatives, whereas the cucumins E−G (7−9) represent a new type of linear triquinanes. Cucumin H (10) is a new member of the ceratopicane group. The absolute configuration of cucumin F (8) was assigned by 1H-NMR analysis of the corresponding Mosher esters. Two further metabolites were identified as cyclo(phenylalanylprolyl) (12) and cyclo(leucylprolyl) (13). Cucumin A (2) exhibits antibacterial and cytotoxic activities.