Carbazole Alkaloids as Antimicrobial and Antibiofilm Agents: A Focus on Plant-Derived Natural Alkaloids.

With the increasing challenge of antimicrobial resistance (AMR) and a decline in the development of new antimicrobial drugs, there is an urgent need to discover and develop novel agents to combat antibiotic resistance and prevent a potential return to a post-antibiotic era. Various factors contribute to microbial resistance, including both inherent and acquired mechanisms. Biofilm formation stands out as a key virulence determinant in many bacterial infections, significantly enhancing bacterial resistance to antibiotics and evading host defenses. Although overcoming pathogens can be difficult, exploring compounds with diverse modes or mechanisms of action, distinct from conventional drugs, holds promise in tackling AMR. Natural products have long been recognized as a valuable source of bioactive compounds, characterized by diverse structures and functional group chirality. There is an immediate need to investigate natural products, particularly those derived from plants, as potential sources of antimicrobial agents, including antibacterial and antifungal agents. Alkaloids, known for their protective nature, can serve as powerful weapons against resistant microorganisms, either alone or in combination with synthetic antimicrobials. Our review sheds light on carbazole alkaloids and their derivatives as potential antibiotic drugs, highlighting their important mechanisms of action and their potential in eradicating biofilm formation in multidrug-resistant pathogens.