Synthesis and Anti-bacterial Activity of New Substituted 2-trifluoromethyl-4-quinolinylhydrazone Analogs against...

Tuberculosis (TB) is a serious disease that still affects humanity, despite being old, caused by the bacterium Mycobacterium tuberculosis (Mtb). The emergence of drug-resistant strains has alarmed governments and international organizations, such as the World Health Organization (WHO). The need for research on new drugs that are effective in a shorter treatment time and active against resistant strains still persists.

The objective of this study is to synthesize and evaluate forty-four substituted 2-trifluoromethyl-4-quinolinylhydrazone analogs, as probable inhibitors of Mycobacterium tuberculosis growth.

The anti-mycobacterial activities of all tested compounds against Mycobacterium tuberculosis strains, as well as the cytotoxicity test, were evaluated using the in vitro microplate procedure with broth microdilution assay.

Thirteen compounds exhibited some activity against sensitive strain ATCC 27294, six of which were the most active: 4a, 4c, 6a, 6b, 6c, and 6g; with MIC around 7 - 8 μM, close to that presented by ethambutol (15.9 μM), a drug used in the treatment of tuberculosis. These same compounds also were active against a resistant strain of Mtb (T113), with MIC around 7 - 8 μM. Three of these compounds 4a, 6a, and 6c were not cytotoxic against Vero cells at concentrations near the MIC.

This study indicates the importance of the hydrazone function to obtain promising anti-TB compounds and open new perspectives for drug development.