ISOLATION, STRUCTURES, AND ANTIFUNGAL ACTIVITIES OF NEW AUREOBASIDINS

Aureobasidins are a group of cyclic depsipeptides with antifungal acti vity and are produced by Aureobasidium pullulans. Aureobasidins are co mposed of eight amino acids and one hydroxy acid such as 2-hydroxy-3-m ethylpentanoic acid (Hmp), and highly lipophilic. Five new aureobasidi ns, S1, S2a, S2b, S3 and S4, Which have higher hydrophilicity in rever sed phase HPLC than the known aureobasidins A approximately R, were di scovered in a fermentation broth of A. pullulans R106 by means of on-l ine liquid chromatography/mass spectrometry with electrospray ionizati on. We identified the structures of the compounds and studied their an tifungal activities. Three of the new aureobasidins, S2b, S3 and S4, w hich have hydroxylated Hmp as the hydroxy acid, were highly active aga inst Candida spp. and Cryptococcus neoformans.