Structure and properties of major largomycin FII chromophore components

Largomycin FII, a protein antitumor antibiotic of molecular weight 29,300 daltons, contains a chromophore that is separable under mild denaturing conditions. The chromophore complex was found to be considerably less stable than the holoprotein towards light and heat, suggesting a protective effect of the protein on the chromophore. Separation of the chromophore into several components was achieved using high performance liquid chromatography, and the biological activity of the isolated components was determined. Data gathered from UV, IR, proton and carbon NMR, and fast atom bombardment mass spectrometry indicated that all the chromophore components belong to the pluramycin class of antitumor agents. Pluramycin A and deacetylpluramycin A were found to be the two major components.     

The photodeactivation of hedamycin, an antitumor antibiotic of the pluramycin type

The cytotoxicities of hedamycin and photohedamycin A as well as of kidamycin and isokidamycin were determined using HeLa cell cultures. Photohedamycin A proved to be 15 times less cytotoxic than hedamycin thus explaining the loss of biological activity observed for solutions of hedamycin left in daylight. The fact that photohedamycin A is less active than hedamycin, and isokidamycin less than kidamycin points to the important role the rings E and F play in the biological activity of hedamycin and kidamycin.     

Synerazol, a new antifungal antibiotic

Synerazol, a new antifungal antibiotic, was isolated from cultured broth of Aspergillus fumigatus SANK 10588. The structure was determined based on NMR and mass spectral evidences. Synerazol was found to be a related substance to pseurotin A. Synerazol was active against Candida albicans and other fungi, and showed marked synergistic activity with azole-type antifungal agents.