Antimicrobial and anti-biofilm activities of plant extracts against Pseudomonas aeruginosa – a review

Abstract

Antimicrobial resistance among bacterial pathogens, including Pseudomonas aeruginosa, is a global problem that has led to research on naturally occurring compounds as an alternative source of antibacterial and anti-biofilm agents. This review focuses on determining plant extracts' antimicrobial and anti-biofilm activities against P. aeruginosa, an opportunistic pathogen contributing to microbial and biofilm-associated infections in humans. Medicinal plants are being widely researched as they are rich sources of phytochemicals, including flavonoids, alkaloids, tannins and terpenoids. These phytochemicals have been well known for their antibacterial activity, which contributes to the effectiveness of certain plants, including Punica granatum and Triumfetta welwitschia, against P. aeruginosa. Hypericum perforatum and Berginia ciliata contains phytochemicals that directly inhibit the quorum sensing mechanism, inhibiting the direct cell-to-cell communication, thereby preventing or reducing biofilm formation by P. aeruginosa. Plant extracts also inhibit bacterial growth and should be considered an alternative to antibiotics. Furthermore, plant extracts can be used with antibiotics for better efficacy against P. aeruginosa. However, more research must be carried out to select plants with a broad spectrum of activity against not only P. aeruginosa infections but other gram-negative bacteria in general. It would be economically viable to develop as a therapeutic drug. This would align with the third United Nations sustainable development goals on good health and well-being and is a significant step forward in the battle against antibiotic resistance.