Antibiofilm activity of phytochemicals against Enterococcus faecalis: A literature review

Enterococcus faecalis is a leading causative pathogen of recalcitrant infections affecting heart valves, urinary tract, surgical wounds and dental root canals. Its robust biofilm formation, production of virulence factors and antibiotic resistance contribute significantly to its pathogenicity in persistent infections. The decreased effectiveness of most of antibiotics in preventing and/or eradicating E. faecalis biofilms mandates the discovery of alternative novel antibiofilm agents. Phytochemicals are potential sources of antibiofilm agents due to their antivirulence activity, diversity of chemical structure and multiple mechanisms of action. In this review, we describe the phenotypic and genetic attributes that contribute to antimicrobial tolerance of E. faecalis biofilms. We illuminate the benefits of implementing the phytochemicals to tackle microbial pathogens. Finally, we report the antibiofilm activity of phytochemicals against E. faecalis, and explain their mechanisms of action. These compounds belong to different chemical classes such as terpenes, phenylpropenes, flavonoids, curcuminoids and alkaloids. They demonstrate the ability to inhibit the formation of and/or eradicate E. faecalis biofilms. However, the exact mechanisms of action of most of these compounds are not fully understood. Therefore, the future studies should elucidate the underlying mechanisms in detail.