Plant-derived Bioactive Compounds and Their Mechanistic Roles in Combating Microbial Biofilms

Biofilms are a group of microorganisms that exist on living or non-living surfaces, embedded within extracellular matrices produced by microbial cells. They primarily cause antimicrobial resistance and treatment failure in clinical settings. Biofilms resist conventional antimicrobials because of their polymicrobial nature, ability to evade host immune detection, and increased tolerance to antimicrobial agents. Consequently, considerable attention is given to finding alternative anti-biofilm agents. Medicinal plants contain diverse biologically active compounds reported to possess antimicrobial and anti-biofilm activities. This review elucidates the mechanisms of action of plant-derived bioactive compounds (alkaloids, tannins, indoles, terpenes, and flavonoids) on in vitro microbial biofilms, shedding light on their ability to disrupt and prevent biofilm formation. Additionally, the review emphasizes current and future research directions for these phytochemicals, including synergism with conventional antibiotics and advanced drug delivery systems for treating and eradicating biofilm-associated infections.