Antibacterial properties of quercetin

Quercetin is a polyphenolic flavonoid with potential chemoprotective properties. In the present work its antibacterial properties were studied against Staphylococcus aureus, Escherichia coli, Shigella flexneri, Proteus vulgaris, Pseudomonas aeruginosa, Lactobacillus casei var shirota by broth dilution method. Quercetin inhibited S. aureus, P. aeruginosa at concentration 20 mcg/mL while P. vulgaris and E. coli were inhibited at concentration 300 mcg/mL and 400 mcg/mL respectively. Shigella flexneri and Lactobacillus casei var shirota were completely indifferent even at concentration of 500 mcg/mL.