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

Polyene antibiotics a re characterized to have 26 to 38 membered macrocyclic lactone ring contain ing 3 to 8 conjugated double bonds t and most of them possess remarkable antifungal activity. The polyenes are grouped according to the number of double bonds present in the molecule and it has been rep.orted that the an tifungal activity increases s ignificantl y with the presence of more conjugated double bonds . They are usually associated with the m ce liu m and occur as a mixture of congeners, which has been reported in literature at length2.4. In the course of our sc reening program for new antifunga l antibiotics, a Streptomyces sp. U K I 0 producing a novel ntifungal anti biotic, HA-2-91 was isolated from the Ukrainian soil and iater on identified as Streptomyces arenae var ukrainiana . The taxonomy of the producing strain of HA-2-91 and its antifungal 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 compari son with the spectral data of other repor~ed tetraene antibiotics in order to establish it as a new antifungal antibiotic .