Flavonoids from Alpinia officinarum as Potential Anti-Tubercular Agents Using Molecular Docking Studies

Abstract

Bioguided isolation yielded three flavonoids galangin (1), kaempferide (2) and kaempferol (3) from methanol extract of Alpinia officinarum Hance. Galangin exhibited highest antitubercular activity, with MIC of < 4.0 μg/mL against M. bovis BCG (in vitro) and M. tuberculosis (ex vivo), than kaempferide. In vitro and ex vivo macrophage infection model assay revealed the inhibition of both active and dormant stage for M. tuberculosis H37Ra and M. bovis BCG on exposure to galangin. Molecular docking studies into the active site of DprE1 enzyme helped to understand the ligand-protein interactions and establish a structural basis for inhibition of M. tuberculosis. These flavonoids indicated their non-specificity towards M. tuberculosis by testing against Gram-positive and Gram-negative bacteria and also least cytotoxic up to 100 μg/mL on three human cancer cell lines THP-1, PANC-1 and A549, respectively. So these flavonoids are inhibitors against M. tuberculosis that can be explored further as potential antitubercular drugs.