Antibiotics produced by Streptomyces olivaceus 142. II. Isolation, purification and activity spectrum of antibiotic WR 142-FPG.

A method of isolating antibiotic Wr 142-FPG from the fermentation broth and mycelium of mutant FPG of the strain Streptomyces olivaceus 142 has been developed. The method of purification of the active substance and activity spectrum agains microorganisms are described. Some of the basic properties of two preparations are given: a) the preparation designed I, partly purified, containing a peptide moetye and b) the preparation designed II, which is a homogeneous chromatographically preparation with mol. wt. about 510, obtained from preparation I by separation on silica gel. Both preparations are active against the same spectrum of microorganisms and are similarly cytotoxic for normal and neoplastic cells. They differ from each other in specific activity and toxicity. LD50 of preparation I for white mice i.p. is about 240 mg/kg and LD50 of preparation II about 5 mg/kg. Comparison of the activity of the purified preparation of WR 142-FPG with that of known anti-fungal antibiotics showed that Wr 142-FPG inhibits growth of Candida albicans and other pathogenic yeasts at concentrations 10--100 times lower than amphotericin B, antimycin A, nystatin and primaricin.