Flavonoids as Antimicrobial Agents: A Comprehensive Review of Mechanisms and Therapeutic Potential

Flavonoids, plant-derived polyphenolic compounds, have garnered significant attention for their broad-spectrum antimicrobial potential, encompassing antibacterial, antifungal, and antiviral activities. These bioactive molecules exert their effects through multiple mechanisms, including disruption of microbial cell membranes, inhibition of nucleic acid synthesis, suppression of biofilm formation, and interference with key bacterial enzymes. Notable flavonoids such as quercetin, apigenin, and kaempferol exhibit potent activity against bacterial pathogens like Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, as well as fungal pathogens such as Aspergillus fumigatus and Candida albicans. Furthermore, flavonoids can potentiate the efficacy of conventional antibiotics by inhibiting bacterial efflux pumps, a critical mechanism contributing to antibiotic resistance. Recent advancements in structure-activity relationship (SAR) studies have underscored the influence of structural modifications- such as prenylation, hydroxylation, and methoxylation-on the antimicrobial potency of flavonoids. By highlighting these insights, this review provides a unique perspective on flavonoid-based antimicrobial strategies, particularly their synergistic potential with existing antibiotics. These findings position flavonoids as promising candidates for novel antimicrobial therapies, particularly in the face of increasing antibiotic-resistant pathogens. However, further research is needed to elucidate their precise mechanisms and optimize their therapeutic applications.