Activity of bromhexine and ambroxol, semi-synthetic derivatives of vasicine from the Indian shrub Adhatoda vasica, against Mycobacterium tuberculosis in vitro.

The benzylamines, bromhexine and ambroxol, widely used as mucolytics, have a pH-dependent growth-inhibitory effect on Mycobacterium tuberculosis. As these compounds are concentrated in macrophages, they might exert a clinically useful effect on intracellular tubercle bacilli. This, combined with indirect effects including enhancement of lysozyme levels in bronchial secretions and levels of rifampicin in lung tissue and sputum, and possibly clearance of bacilli-laden mucus from cavities and bronchi, suggests a potentially useful adjunctive function for these agents in the therapy of tuberculosis, and adds credibility to early reports of the beneficial effect of benzylamines in this disease.