Improved in vitro potency of Clofazimine derivatives against Neisseria species

Globally, millions of infections that are resistant to antimicrobial agents are reported annually, leading to more than 700,000 fatalities. Among all, challenges arise particularly from nontuberculosis mycobacterial (NTM) and Gram-negative bacteria, as they exhibit limited treatment options in light of increasing reports of multi-drug resistant strains.

Clofazimine (CFZ) is an antimycobacterial medication used to treat leprosy, and it is also known for its side effect of inducing skin pigmentation. The use of CFZ and its analogues against a broad range of Gram-negative bacteria has not been extensively investigated. In this study, we designed, synthesized and studied 11 CFZ analogues and identified examples with comparable or improved in vitro anti-bacterial activity relative to that of CFZ itself. This is the first report demonstrating in vitro activity of CFZ and its analogues against Neisseria species. The results of these studies may facilitate the development of CFZ analogues with limited side effects in humans.