Bacteriostatic, bactericidal, and drug resistance studies of ethyl gallate on Mycobacterium tuberculosis.

Recent reports show that a compound identified as ethyl gallate (Little et al., 1953) found in Haematoxylon campechianum is specifically inhibitory to Mycobacterium tuberculosis, strain 607 (Johnstone et al., 1953). The antimicrobial activity of gallates is not new information, for several such reports and patents are known (Sabalitschka and Tietz, 1931; Bucher, 1945; and Tollenaar, 1952); but the isolation of ethyl gallate from the plant, the highly specific action against M. tuberculosis, and the demonstration of similar activity of other gallates are, as far as these authors know, the first published information. Waksman and Reilly (1944) after a comparative study of several antibiotics found that they were not only bacteriostatic but also bactericidal. Smith and Waksman (1947) in a study of streptomycin demonstrated it to be both tuberculostatic and tuberculocidal. Since ethyl gallate, as well as two other synthesized esters of gallic acid, namely propyl and butyl gallate, appeared to have similar antibiotic properties, it was felt desirable to determine to what extent this activity was bacteriostatic or bactericidal. In addition, this report contains a study of the ability for M. tuberculosis to become drug resistant and relates to what extent cross resistance occurs among other esters of gallic acid.