258 



DESCRIPTIONS OF AXTUilOTICS 



DON (6-Diazo-5-«>xo-L-noiieiiciiiej 



Produced by: StreptODiyces sp. similar to S. au- 

 reus and S. phaeochromogenes (4). 



Method of extraction: Broth adjusted to pH 6.8, 

 filtered, and concentrated in vacuo. Concentrate 

 diluted tenfold with 95 per cent ethanol and fil- 

 tered. Filtrate purified by (a) adsorption on alu- 

 mina at pH 5.5 to 6.5 and elution with 25 per cent 

 aqueous alcohol; (b) carbon chromatography (1 

 per cent aqueous acetone as solvent and devel- 

 oper); and (c) crystallization of best carbon frac- 

 tion from acjueous alcohol or acetone (5). 



Chemical and physical properties: Fine light 

 yellow-green needles. Decomposes at 145-155°C 

 with gas evolution. Very soluble in water, aqueous 

 methanol, ethanol, and acetone. Slightly soluble 

 in absolute alcohols. Ultraviolet absorption max- 

 ima at 274 (E'lcm 683) and 244 m^ (^'llm 376). No 

 spectral shift in alkali or acid. Loss of activity 

 against Torulopsis albida concomitant with loss 

 of ultraviolet absorption characteristics in 0.1 A' 

 alkali or 0.1 A' HCl (5). Infrared spectrum given 

 in reference 5. [a]^ = +21° (c = 5.4 per cent in 

 water). Positive ninhydrin and Tollen tests. Aque- 

 ous solution yields gas when treated with strong 

 acid. Rf values on paper chromatography given 

 in reference 5. Sensitive to extremes of pH and 

 heat. pKa' values of 2.1 and 8.95 in water. DON 

 has been synthesized and the DL- and D-isomers 

 prepared. C = 42.16%; H = 5.70%; N = 24.07%; 

 diazo N = 16.01%,. Alolecular weight, 171. CeHg- 

 N303(2,5, 14). 



Biological activity: Antitumor sul)stance. 

 Slightly active on certain bacteria, j^easts, and 

 Erro equinus in eggs. Some activity (at toxic lev- 

 els) on Plasmodium lophurae infections in chicks 

 (4). Unlike azaserine, DON does not give rise to 

 long, nonseptate filaments in E. coli (11). Crocker 

 sarcoma 180 growth is "restrained" in mice bj^ 

 oral or intraperitoneal treatment, but the tumor 

 growth potential is not affected (1). DON inhibits 

 Miyono adenocarcinoma, Ehrlich carcinoma, 

 Krebs 2 ascites carcinoma, carcinoma 1025, Ridg- 

 way osteogenic sarcoma, Mecca lymphosarcoma, 

 and leukemia L 1210. Slight inhibition of a variety 

 of other carcinomas. No effect on sarcoma T 

 241, Gardner lymphosarcoma, or Harding-Passey 

 melanoma (10, 13). Active on mast cell neoplasm 

 P 815, l)ut resistant sublines of this tumor can be 

 developed (12). DON is reportedly a better in- 

 hit)itor of mouse tumors; azaserine is superior in 

 rat tumors (15). Active on an ascitic plasma cell 

 neoplasm (70429) in mice (19). 



Toxicity: LDoo (mice) 76 ± 14 mg per kg intra- 

 venously (4) ; 250 Mg per kg intraperitoneally in a 

 single daily dose for 7 days is tolerated by mice, 



but with weight loss. Tumor-bearing mice are 

 more susceptible to DON toxicity than normal 

 mice (1). In single doses DON and azaserine have 

 similar toxicity, but DON is 50 to 100 times more 

 toxic in chronic toxicity tests with mice, rats, and 

 dogs (9). LDso of DON in eggs is about ^^oth that 

 of azaserine. DON or azaserine toxicity to eggs 

 overcome by immediate injection of adenine or 

 hypoxanthine following injection of DON or 

 aza.serine (7). Two doses of 0.5 mg per kg given 

 to mother rats between implantation and mid- 

 term cause complete litter destruction; the fetus 

 is affected directly, not the placenta, ovaries, or 

 pituitary. This effect can be overcome by adenine. 

 No cumulative toxicity or impairment of fertility 

 was noted in mother rats having repeated complete 

 destruction of litters. Subsequent offspring were 

 normal (17). Toxic symptoms in human beings 

 include oral soreness and ulceration, diarrhea, and 

 vomiting (18). 



Utilization: Clinical trials in human beings indi- 

 cated transient or no activity on a variety of neo- 

 plastic diseases (3). Some activity has been re- 

 ported on Hodgkin's disease (16). Some evidence 

 of "temporary arrest" of neoplastic diseases in hu- 

 man beings (18, 20). 



References: 



1. Clarke, D. A. et al. Abstr. 129th Meeting 



Am. Chem. Soc. 12M, 1956. 



2. Westland, R. D. ef al. Abstr. 129th Meeting 



Am. Chem. Soc. 14M, 1956. 



3. Eidinoff, M. L. et al. Abstr. 130th Meeting 



Am. Chem. Soc. 2C, 1956. 



4. Ehrlich, J. et al. Antibiotics ct Chemo- 



therapy 6: 487-497, 1956. 



5. Dion. H. W. et al. J. Am. Chem. Soc. 78: 



3075-3077, 1956. 



6. Burchenal, J. H. and Dagg, M. K. Proc. 



Am. Assoc. Cancer Research 2: 97, 1956. 



7. Dagg, C. P. et al. Proc. Am. Assoc. Cancer 



Research 2: 101, 1956. 



8. Magi 11, G. B. et al. Proc. Am. Assoc. Can- 



cer Research 2: 130, 1956. 



9. Sternberg, S. S. ct al . Proc. Am. Assoc. 



Cancer Research 2: 150, 1956. 



10. Sugiura, K. and Sugiura-Schmid, M. Proc. 



Am. Assoc. Cancer Research 2: 151, 1956. 



11. Maxwell, R. E. and Nickel, Y. S. Antibio- 



tics & Chemotherapy 7:81-89, 1957. 



12. Potter, M. Ann. N. Y. Acad. Sci. 76: 



630-642, 1958. 



13. Burchenal, J. H. and Holmberg, E. A. D. 



Ann. N. Y. Acad. Sci. 76: 826-837, 1958. 



14. DeWald, H. A. and Moore, A. M. J. Am. 



Chem. Soc. 80: 3941-3945, 1958. 



15. Reilly, H. C. In Amino acids and peptides 



