DESCRIPTIONS OF ANTIBIOTICS 



409 



Xantholhriciii 



Produced by: Streptotuyces sp. closely related to 

 S. albus. 



Method of extraction: Extraction of culture-fil- 

 trates with chloroform, counterextraction of the 

 chloroform solution with sodium acid sulfite so- 

 lution, oxidation of the NaHSOs extract with 

 h3'drogen peroxide, re-extraction with chloroform, 

 followed by crystallization of the antibiotic from 

 chloroform-ether solution. 



Chemical and physical properties: Yellow needle- 

 like crystals; m.p. 165°C. Soluble in water, chlo- 

 roform, ethyl acetate, and ethanol. C = 43.64%; 

 H = 3.82%; N = 35.21%; O = 17.34^/0- No P, S, 

 or halogens detected. Maximal light absorption 

 at 257.5 and 390 to 402 m/x in phosphate buffer at 

 pH (i.O. Inactivated by prolonged standing at low 

 or high pH values. Xanthothricin loses its color 

 at pH 10.5. 



Biological activity: Moderate activity against 

 certain gram-positive and gram-negative bacteria 

 and mycobacteria. No activity against fimgi. 



Toxicity: LD50 (mice) 1.7 mg per kg intrave- 

 nously, 8.4 mg per kg orally. 



Reference: 1. Machlowitz, R. A. et nl. Anti- 

 biotics & Chemotherapy 4: 259-201, 1954. 



Zaomycin 



Produced by: Streptomyces zaomyceticus. 

 Method of extraction: Extraction at pH 2.0 from 



broth-filtrate in n-butanol. Back-extraction into 

 water at pH 8.5. This process repeated, then the 

 aqueous solution concentrated in vacuo. The crude 

 powder dissolved in methanol and precipitated by 

 ether. Further purification carried out by chroma- 

 tography on alumina. The column is loaded with 

 ethanol and developed by aciueous ethanol and 

 water. Purified zaomycin sodium salt is obtained 

 by this method. Free zaomycin acid precipitates 

 out of water solutions at pH 3.5. Crystallization 

 obtained from an ethyl acetate-methanol mixture. 



Chemical and physical properties: Acidic sub- 

 stance, pale yellow; m.p. 242-246°C (decomposi- 

 tion). Unstable. Maximal stability in water at 

 pH 7.0 to 8.0. Slightly solul^le in water. Soluble in 

 dilute acids and alkalies and in methanol and 

 ethanol. Insoluble in most organic solvents. Nin- 

 hydrin, Millon, biuret, and FeCls (reddish brown 

 color) tests positive. Negative Fehling and Lieber- 

 mann nitroso reactions. 



Biological activity: Active against gram-positive 

 bacteria. Inactive against gram-negative bacteria 

 and fungi. Activity against mycobacteria limited 

 to certain nonpathogenic strains. Static action on 

 Trichomonas foetus, but inactive on Trichnphi/ton 

 interdigitale. 



Toxicity: Intravenous injection of 301 ^g per kg 

 of sodium zaomycin in mice is nontoxic. 



Reference: 1. Hinuma, Y. J. Antibiotics (Ja- 

 pan) 7A: 134-136, 1954. 



