Emerging trends and future opportunities for coumarin-heterocycle conjugates as antibacterial agents

Infectious diseases resulting from various strains of pathogenic bacteria are among the leading causes of death and morbidity worldwide. The currently-available antibacterial medications developed from natural or synthetic sources are the cornerstone of bacterial infection intervention, but somehow the mounting spread and expansion of multidrug-resistant harmful bacteria has become a major concern for medical-providing communities and pharmaceutical-releasing companies. The pervasiveness of coumarin-based products in nature and the simplicity of their lab chemical synthesis, in addition to the ability of the coumarin backbone to communicate, may interact with the bacterial DNA gyrase at the B subunit and hinder DNA secondary structure by abolishing ATPase activity; thus, coumarin-based products and their conjugates may have the potential to act as antibacterial agents. It is conceivable that conjugation of the coumarin chemical nucleus with other heterocyclic-based antibacterial scaffolds may present opportunities for the creation of novel antibacterial drugs. This presentation may be based on the fact that several coumarin-heterocycle conjugates, including clorobiocin, coumermycin A1, and novobiocin, have already been used in medical methods for the treatment of various infectious bacterial diseases. This study explores, during the period of the last 5 years, the relationships between the structure and activity of coumarin-heterocycle conjugates with potential for antibacterial action. This investigation also explored the potential for developing these conjugates into antibacterial medicines.