ANTIBIOTICS OF ACTINOMYCETES 205 



Exfoliatin 



Produced by: Streptomyces exfoliatus. 



Method of extraction: Broth extraction with ethyl acetate, concentration 

 to a syrup in vacuo. The syrup is washed with petroleum ether and 

 ether, leaving the crude exfoliatin. Can be crystallized from ethanol. 



Chemical and physical properties: Colorless needle crystals soluble in ethanol, 

 acetone, chloroform, and ethyl acetate. Very slightly soluble in petro- 

 leum ether, ether, and water; m.p. 172°C. C 2 7H4oOi6Cl-H 2 0. 



Biological activity: Active against gram-positive bacteria. Almost inactive 

 against gram-negative bacteria, except members of the genus Hemo- 

 philus. 



Toxicity: LD 50 (mice), subcutaneous, about 500 mg/kg. 



Utilization: Not known yet. 



Reference: Umezawa, H., Takahashi, S., Takeuchi, T., Maeda, K., and 

 Okami, Y., J. Antibiotics (Japan), 5, 1952, 466; Japan. J. Med. Sci. 

 Biol., 5, 1952, 311-316. 



Flaveolin 



Produced by: Streptomyces sp. Resembles S. flaveolus. 



Method of extraction: Adsorption from culture filtrate at neutrality on 

 charcoal. Elution with acidic acetone. Concentration in vacuo. Ex- 

 traction at pH 8.0 with butanol. Back extraction of the butanol with 

 acidic water. Further purification by countercurrent distribution 

 between butanol and phosphate buffer at pH 5.5. 



Chemical and physical properties: Yellow substance, basic. The hydrochlo- 

 ride is soluble in water, methanol, and ethanol. Slightly soluble in 

 acetone, benzene, butanol, and chloroform. Insoluble in ether, petro- 

 leum ether, and ethyl acetate. Millon, Biuret, and Sakaguchi reactions 

 negative. Maximum stability at acid reaction (pH 2.0). 



Biological activity: Active against gram-positive bacteria, gram-negative 

 bacteria, mycobacteria, and fungi. More active in acidic test media 

 than in alkaline media. 



Toxicity: LD 60 (mice), intravenous, about 30 mg/kg. 



Utilization: No data. 



Reference: Takahashi, B., J. Antibiotics (Japan), 6, 1953, 11-20. 



Flavomycin 



Produced by: Streptomyces roseoflavus. 



Synonym: Neomycin. 



Method of extraction: Same as streptothricin and streptomycin. 



