Selective antibacterial activity of quercetin against Xanthomonas campestris

Abstract

Quercetin is a major flavonoid in onion and known to antimicrobial activity against several pathogenic bacteria. However, the antibacterial activity of quercetin had not been evaluated against plant pathogenic Xanthomonas campestris and Erwinia carotovora. In here, quercetin and the solvent extracts of onion were investigated their antibacterial activity. Quercetin showed a selective inhibitory activity against X. campestris, and the minimal inhibition concentration (MIC) and minimal bactericidal concentration of quercetin were 15.6 and 20.0 ?g mL?1 respectively. Otherwise, it showed no inhibitory activity against E. carotovora, and no the additive and the synergistic effects with streptomycin on X. campestris. And the EtOAc extract from the peel of onion that contained quercetin showed 2-fold lower MIC (500 ?g mL?1) than the EtOH extract, thus EtOAc was suggested as the extraction solvent for quercetin from onion peel. ? The Korean Society for Applied Biological Chemistry 2022.