Invitro and Insilico studies on Antibiofilm and Antiquorum sensing activities of Chlorella vulgaris and Spirulina platensis

Abstract

The emergence of antimicrobial resistance (AMR) is through various newlinemechanisms. One of the mechanisms is biofilm formation. Biofilm is the heterogeneous newlinegroup of single or multispecies microbial community encased in a self-synthesized newlineExtracellular Polymeric Substances (EPS). The EPS act as a shield, which prevents the newlineentry of antibiotics into the biofilm and attenuate the bacteria. Quorum sensing newlinemechanism helps in the formation of biofilm, expression of virulence factors and the newlinedevelopment of resistance. Therefore, disrupting biofilm formation and quorum sensing newlinesignalling are considered as a favourable strategy to reduce bacterial pathogenicity. newlineHence, the present study was aimed to search for novel compounds with antibiofilm and newlineantiquorum sensing properties from microalgae Chlorella vulgaris and Spirulina platensis. newlineThe microbes selected were the clinical isolates of Pseudomonas aeruginosa and newlineStaphylococcus aureus, because they are responsible for a variety of severe nosocomial newlineinfections in human.The obtained results revealed that the methanolic extract of newlineChlorella vulgaris (CVM) and Spirulina platensis (SPM) showed potential antibiofilm newlineand antiquorum sensing activity against Pseudomonas aeruginosa and Staphylococcus newlineaureus. Among the algae studied, Spirulina platensis showed significant inhibitory newlineactivity against the gram-negative bacterium Staphylococcus aureus than the grampositive newlinebacterium Pseudomonas aeruginosa. Further, the CVM and SPM were newlinesubjected to FT-IR and GC-MS analysis to identify the functional groups and the newlinebioactive compounds. The identified compounds (12 from CVM, 17 from SPM and 5 newlinephenolic compounds from the literature) were docked against antiquorum sensing target newlineproteins LasR (PDB ID: 3UV0) and AgrA (PDB ID: 3BS1) by using GLIDE. The two newlinecompounds, gallic acid (GA) and epicatechin (EC) were selected based on the GScore newline(GScore: -0.624 and -9.002 against LasR and GScore: -6.622 and-5.849 against AgrA, newlinerespectively), the number of H-bonds and the interacting amino acids with targ