Comparative study on the antibacterial activity of some flavonoids and their sulfonic derivatives.

The antibacterial activity of quercetin, morin, sodium salt of quercetin-5'-sulfonic acid (NaQSA) and sodium salt of morin-5'-sulfonic acid (NaMSA) were tested against six bacterial strains: Escherichia coli (ATCC 25922 and clinical isolates--ESBL), Pseudomonas aeruginosa (ATCC 27853 and clinical isolates--carbapenem resistant), Staphylococcus aureus (ATCC 29213 and clinical isolats- MRSA). The most effective inhibitors against the model strain S. aureus are NaQSA and NaMSA (MIC = 3.