New botrydial sesquiterpenoids from Hymenoscyphus epiphyllus.

Four new botrydial derivatives, hymendial (1), 7 alpha-hydroxydihydrobotrydial (2), 7 alpha-hydroxy-10-O-methyldihydrobotrydial (4), and 7 alpha-acetoxy-15 alpha-methoxy-10-O-methyl-dihydrobotrydial (5) were isolated together with dihydrobotrydial (3) from the culture fluid of the ascomycete Hymenoscyphus epiphyllus. In addition, cytochalasin H (6a), 18-deoxycytochalasin H (6b) and (+)-mellein (7) were produced by this fungus. Hymendial (1), possessing an alpha, beta-unsaturated dialdehyde functionality, exhibits antimicrobial and cytotoxic activities and is mutagenic in the Ames Salmonella assay.