Isolation, physico-chemical properties and structure elucidation studies on HA-2-91 , a new tetraene polyene antifungal antibiotic produced by Streptomyces arenae var ukrainiana

HA-2-9 1. a new tetraene polyene macrolide anti biotic 1 has been isolated from th e culture broth of Streptomyces are­ nae va r IIkrainiana and purified by silica gel column chromato graphy followed by preparative TLC. Its structure has been determined on the basis of spectral data (UV, IR, I Hand I3C NMR, mass), wh ich accounts for its potent antifungal activity. Polyene antibiotics a re characterized to have 26 to 38 membered macrocyclic lactone ring containing 3 to 8 conjugated double bonds t and most of them possess remarkable antifungal activity. The polyenes are grouped according to th e number of double bonds present in th e molecule and it has been rep.orted that the an tifungal activity increases s ignificantl y with th e presence of mo re conjugated double bonds. They are usually associated with the m celiu m and occur as a mixture of congene rs, which has bee n reported in lit­ erature at length 2 . 4 . In the course of our screening program for new antifu ngal antibiotics, a Streptomy­ ces sp. U K I 0 producing a novel ntifu nga l anti biotic, HA-2-91 was isolated from th e Ukrai nian soil and iater on identified as Streptomyces arenae va r ukrainiana 5 . The taxonomy of the producing strain of HA-2-91 and its antifunga l activity in detail as well as toxicity have been described in our previous paper6. In the present communication. we report the isolation, purification, physico-chemical properties of HA-2-91 and its structure elucidation on the basis of UV, IR, IH and 13C NMR and mass spectral data; as well as their comparison with the spectral data of other re­ por~ed tetraene antibiotics in order to establish it as a new antifunga l antibiotic .