β-CA-specific inhibitor dithiocarbamate Fc14-584B: a novel antimycobacterial agent with potential to treat drug-resistant tuberculosis.

Inhibition of novel biological pathways in Mycobacterium tuberculosis (Mtb) creates the potential for alternative approaches for treating drug-resistant tuberculosis. In vitro studies have shown that dithiocarbamate- derived beta-carbonic anhydrase (beta-CA) inhibitors Fc14-594A and Fc14-584B effectively inhibit the activity of Mtb beta-CA enzymes. We screened the dithiocarbamates for toxicity, and studied the in vivo inhibitory effect of the least toxic inhibitor on M. marinum in a zebrafish model. In our toxicity screening, Fc14-584B emerged as the least toxic and showed minimal toxicity in 5-day-old larvae at 300 mu M concentration. In vitro inhibition of M. marinum showed that both compounds inhibited growth at a concentration of 75 mu M. In vivo inhibition studies using 300 mM Fc14-584B showed significant (p > .05) impairment of bacterial growth in zebrafish larvae at 6 days post infection. Our studies highlight the therapeutic potential of Fc14-584B as a beta-CA inhibitor against Mtb, and that dithiocarbamate compounds may be developed into potent anti-tuberculosis drugs.