ANTIBIOTICS OF ACTINOMYCETES 215 



Chem. Soc, 71, 1949, 2590; 75, 1953, 1018; Leach, B. E., and Teeters, 

 C. M., ibid., 73, 1951, 2794; Leach, B. E., and Teeters, C. M., ibid., 

 74, 1952, 3187. 



Neomycin 



Produced by: Strepto?nyces fradiae and other Streptomyces sp. 



Synonyms: Flavomycin. Streptothricin BI is a synonym of neomycin C, 

 and streptothricin BII is a synonym of neomycin B. 



Method of extraction: Adsorption on charcoal and elution with acid alcohol. 

 Adsorption on IRC 50 and elution with dilute HC1. 



Chemical and physical properties: Basic glycosidic, white, stable substance. 

 Water-soluble, insoluble in organic solvents. No typical absorption 

 spectrum in ultraviolet light. Composed of two isomers, neomycin B 

 and C, which can be separated by chromatography over alumina. 

 Neomycin B = [a]f + 54°, neomycin C = [a]™ + 80°. Proximate 

 formula C29H 6 8N 8 Oi6. 



Biological activity: Active against gram-positive and gram-negative bac- 

 teria, mycobacteria, and actinomycetes. Not active against fungi. 

 Neomycin B is more potent than neomycin C by dilution assay (290 

 units/mg against 153 units/mg) but does not diffuse in the agar so fast 

 as does neomycin C. 



Toxicity: LD 50 (mice), subcutaneous, 300-350 mg/kg (neomycin complex); 

 220 mg/kg (neomycin B); 290 mg/kg (neomycin C). 



Utilization: Treatment of bacterial infections of the skin and eyes. Sterili- 

 zation of the intestine. 



Reference: Waksman, S. A., Neomycin, Rutgers University Press, New 

 Brunswick, N. J., 1953; Hamre, D. M., Pansy, F. E., Lapedes, D. N., 

 Perlman, D., Bayan, A. P., and Donovick, R., Antibiotics & Chemo- 

 therapy, 2, 1952, 135-141; Dutcher, J. D., Hosansky, N., Donin, 

 M. N., and Wintersteiner, O., J. Am. Chem. Soc, 73, 1951, 1384. 



Neonocardin 



Produced by: Nocardia kuroishi. 



Method of extraction: Unknown. 



Chemical and physical properties: Found to be different from other known 

 antibiotics by paper chromatography. 



Biological activity: Active against Micrococcus pyogenes var. aureus, Esch- 

 erichia coli, and Bacillus anthracis. Very little activity against Bacillus 

 subtilis and Pseudomonas aeruginosa. 



Toxicity: No data. 



Utilization: No data. 



Reference: Uesaka, I., J. Antibiotics (Japan), C 3, 1950, 27-34; 5, 1952, 

 75-79; Ueda, S., and Uesaka, I., ibid, 170-171. 



