Nitrogen-Containing Flavonoids-Preparation and Biological Activity

Area of Science:

• Medicinal Chemistry
• Microbiology
• Molecular Biology

Background:

• Flavonoids like quercetin and luteolin are known to modulate bacterial resistance to antibiotics.
• The precise molecular mechanisms underlying this modulation have not been fully elucidated.
• Exploring novel flavonoid derivatives can lead to new strategies against multidrug-resistant bacteria.

Purpose of the Study:

• To synthesize new quercetin and luteolin derivatives using Buchwald-Hartwig amination.
• To investigate the impact of aniline moiety incorporation on the biological activities of these flavonoids.
• To elucidate the molecular mechanisms by which these derivatives affect antibiotic resistance in Staphylococcus aureus.

Main Methods:

• Buchwald-Hartwig amination was employed to synthesize novel flavonoid derivatives.
• Biological activities including antioxidant, anti-inflammatory, and cytotoxicity were assessed.
• The modulation of antibiotic resistance mechanisms, specifically erythromycin and gentamicin resistance in Staphylococcus aureus, was investigated at the molecular level.

Main Results:

• The introduction of aniline moiety abolished anti-inflammatory activity but maintained low cytotoxicity.
• Both quercetin and luteolin derivatives were found to attenuate erythromycin resistance by suppressing the ermA gene in Staphylococcus aureus.
• 4-(trifluoromethyl)anilino quercetin demonstrated potent inhibition of ErmA, likely via interaction with its RNA-binding pocket.
• 4-fluoroanilino derivatives effectively impeded the staphylococcal efflux system.
• All synthesized derivatives showed enhanced activity in modulating gentamicin resistance compared to parent compounds.

Conclusions:

• Incorporating substituted anilines into the flavonoid core significantly enhances their ability to combat multidrug resistance in bacteria.
• The study provides the first report on the molecular mechanism of flavonoid-mediated antibiotic resistance modulation, focusing on ermA gene suppression and efflux pump inhibition.
• These novel derivatives represent promising candidates for developing new agents against multidrug-resistant bacterial infections.