Antibiotics from basidiomycetes. XIII. The alliacols A and B from Marasmius alliaceus (Jacq. ex Fr.) Fr.

Two antimicrobial and cytotoxic metabolites were isolated from fermentation broth of Marasmius alliaceus. The structures of the two crystalline antibiotics, alliacols A (6) and B (1) were elucidated by spectroscopic methods and chemical correlation with alliacolide (3). The alliacols show weak antibacterial and antifungal activity. Both antibiotics strongly inhibit DNA synthesis in cells of the ascitic form of Ehrlich carcinoma at concentrations of 2 approximately 5 microgram/ml. Both alliacols A and B react with cysteine to form adducts with strongly reduced biological activities.