Gramicidines antimicrobial activity

In 1939 the isolation of a mixture of microbial products named tyrotbricin from a soil bacillus was described. Further investigation showed this material to be a mixture of gramicidin and tyrocidine. In rapid succession the isolation of actinomycin (1940), streptothricin (1942), streptomycin (1943), and neomycin (1949), produced by Streptomjces were reported and in 1942 the word antibiotic was introduced. Chloramphenicol, the first of the so-called broad spectmm antibiotics having a wide range of antimicrobial activity, was discovered in 1947. Aureomycin, the first member of the commercially important tetracycline antibiotics, was discovered in 1948. 

Lee, D.L., and Hodges, R.S. (2003) Structure-activity relationships of de novo designed cyclic antimicrobial peptides based on Gramicidin S. Biopolymers 71, 28—48. 

R 492 D. L. Lee and R. S. Hodges, Structure - Activity Relationships of de Novo Designed Cyclic Antimicrobial Peptides Based on Gramicidin S , Biopolymers, 2003,71, 28... 

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