Bactericidal activity of gallic acid against multidrug-resistant Mycobacterium tuberculosis.

The persistent rise of multidrug-resistant (MDR) bacteria represents a significant public health challenge, necessitating the exploration of alternative therapeutic options. The slow pace of approval for new anti-tuberculosis (TB) medications underscores the urgent need to identify potential alternative agents. Gallic acid (GA) possesses numerous biological properties, including antibacterial and antiseptic effects. In this study, both standard and MDR strains of M. tuberculosis were utilized to assess the antibacterial efficacy of GA and related mechanisms. GA achieved minimum inhibitory and minimum bactericidal concentrations comparable to those of the examined antibiotics with significantly lower cytotoxicity in the THLE-3 cell line (p-value < 0.05). Furthermore, GA displayed bactericidal properties, enhanced the effectiveness of moxifloxacin and levofloxacin against MDR M. tuberculosis, and modulated the expression of efflux pump genes, specifically Rv1410c and Rv1258c (p-value < 0.001). These results contribute to a deeper understanding of GA's antibacterial potential and suggest a novel alternative approach for managing MDR bacterial infections.