Evaluation of andrographolide from Andrographis paniculata against drug-resistant and H37Rv strains of Mycobacterium tuberculosis.

Abstract

Tuberculosis (TB) remains a major global health concern, particularly due to the emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis strains. While previous studies have suggested andrographolide as a potential antimycobacterial agent based on in silico predictions, limited empirical evidence exists on its direct efficacy against MDR-TB. This study systematically evaluates the antimycobacterial activity of andrographolide through the microbroth dilution method against M. tuberculosis H₃₇Rv and three distinct MDR strains. The minimum inhibitory concentrations (MICs) were determined using Middlebrook 7H9 medium, with rifampicin and isoniazid as positive controls. Andrographolide completely inhibited M. tuberculosis H₃₇Rv at an MIC of 125 µg/mL, while MICs for MDR strains varied (500 µg/mL, 125 µg/mL, and 250 µg/mL for MDR-Isolates 1, 2, and 3, respectively). Unlike previous studies that primarily relied on computational docking models, our findings provide direct experimental validation of andrographolide's strain-specific efficacy, demonstrating its potential as a promising lead compound for anti-tubercular drug development. These results underscore the need for further preclinical investigations to explore its therapeutic applications in combating drug-resistant TB.