Bioactive compounds from marine algae and fungi in down-regulating quorum sensing

Abstract

The prevalence of antibiotic resistance in a broad range of clinically significant microorganisms has been consistently increasing. This prevalent problem is one of the main challenges of the twenty-first century. Quorum sensing inhibitors (QSi) or quorum quenching render a potential substitute or potent adjuvants of conventional antibiotics for the treatment of antibiotic-resistant bacterial strains since these substances may reduce the pathogenicity of bacteria without levying the selection pressure associated with antibacterial therapies. In the marine environment, poisonous and beneficial bacteria cohabit alongside eukaryotes including algae, and fungus. Consequently, it is not surprising that eukaryotes have developed a range of defense mechanisms for interacting with bacteria, including the synthesis of secondary metabolites. The bioactive compounds derived from green, red, and brown algae and fungi like epicoccum, penicillum, furasium, and many more have demonstrated quorum inhibition properties against different microbial including pathogenic species such as Bacillus sp., Mycobacterium tuberculosis, Agrobacterium tumefaciens, Variovorax sp., Vibrio fischeri. Chromobacterium violaceum and ESKAPE pathogens. However, in gram-negative bacteria, the two proteins that compose up quorum sensing (QS) systems are the AHL synthetase, also known as the LuxI-homologue, which generates the AHL signal, and the LuxR homolog, a dual-function receptor response protein that binds and recognizes AHL molecules to facilitate interactions with quorum sensing controlled promoter sequences. This study focuses on several bioactive compounds derived from marine microorganisms, particularly fungi and algae that have been found to possess inhibitory effects on quorum sensing including the underlying mechanism of quorum sensing.