In vitro and in vivo antimycobacterial activity of an antihypertensive agent methyl-L-DOPA

Methyl-L-DOPA, an antihypertensive agent, has significant in vitro activity against a variety of atypical mycobacteria such as the Mycobacterium avium complex, M. scrofulaceum, M. xenopi and M. marinum, and rare pathogens like M. fortuitum. In the present investigation, the screening of the in vitro activity was further extended by testing the in vitro activity against a total of 53 different strains of mycobacteria, including 34 clinical isolates of both drug-sensitive and drug-resistant Mycobacterium tuberculosis. Most of the strains were inhibited at 10-25 μg/mL concentrations of the drug. When methyl-L-DOPA was injected into male mice at a concentration of 10 μg/g body weight (20 g each), methyl-L-DOPA significantly protected them when challenged with a 50 median lethal dose of M. tuberculosis H₃₇Rv102. According to the χ² test, the in vivo data were highly significant (p<0.01).