PHYSICO-CHEMICAL AND MICROBIOLOGICAL COMPARISON OF NYSTATIN, AMPHOTERICIN A AND AMPHOTERICIN B, AND STRUCTURE OF AMPHOTERICIN A

Abstract

Two polyene antibiotics, nystatin and amphotericin A, were compared by physicochemical and microbiological methods. The two antibiotics were found to have the same molecular weight, 926, by plasma desorption and electron-impact MS. However, ¹³C NMR spectrometry and HPLC studies indicated that the two molecules are different. The 200 MHz NMR studies indicated a chemical environment of 24 carbons of amphotericin A identical with that of the carbons of amphotericin B and nystatin. The structure of amphotericin A is identical with that of amphotericin B, except that there is a single bond between carbons 28 and 29 instead of a double bond, as shown by two-dimensional NMR studies.