[New antifungal antibiotics, bacillopeptins and fusaricidins]

We isolated four strains of bacteria producing antifungal antibiotics from the rhizosphere of garlic with basal rot caused by the plant pathogenic fungal strain Fusarium oxysporum. Among them, Bacillus subtilis FR-2 was found to produce new antifungal antibiotics, named bacillopeptins A, B, and C. Their structures have been determined by 1D and 2D NMR and MS experiments, and amino acid analysis coupled with chiral HPLC, to be cyclic lipopeptides each containing a long-chain beta-amino acid. Another bacterial strain, Bacillus polymyxa KT-8, was shown to produce new antifungal antibiotics named fusaricidins A, B, C, and D which are more potent than bacillopeptins in their antimicrobial activity. The structures of the fusaricidins have been elucidated similarly as bacillopeptins to be cyclic hexadepsipeptides all containing 15-guanidino-3-hydroxypentadecanoic acid as a side chain. Fusaricidins strongly inhibit the growth of various kinds of fungi and moreover surprisingly show strong inhibitory activity against Gram-positive bacteria such as Staphylococcus aureus or Micrococcus luteus.