In silico anti-quorum sensing activities of phytocompounds of Psidium guajava in Salmonella enterica serovar Typhi

Biofilm contributes hugely to the persistence of typhoid fever in human population and quorum sensing (QS) is an integral mechanism involved in biofilms. Interruption of the QS network has therefore been put forward as one of the important anti-virulence strategies. Methanol extract of Psidium guajava leaves has been confirmed to possess antibacterial and anti-biofilm activities against Salmonella Typhi. This study therefore aimed at investigating the interactions of phytocompounds previously identified in the extract with selected QS proteins of S. Typhi in silico . Appropriate formats of compounds were retrieved and translated using online web servers. Quantitative estimate of drug-likeness, as well as absorption, distribution, metabolism, excretion and toxicity profiles of the compounds, were assessed on ADMETlab 2.0. Three-dimensional structures of two QS proteins of S. Typhi were obtained from Protein Data Bank while others were modelled on SWISS-MODEL. Selected compounds (ligands) were docked with the four proteins via AutoDock 1.5.6 and analyzed on Discovery studio. Eight, out of the seventy-two, phyto-compounds of methanol extract of P. guajava possess desirable drug-likeness (QED > 0.67). Three of them have toxic characteristics and thus, were removed from further consideration. Molecular docking revealed that, of the 5 ligands docked against the proteins, only Benzeneethanamine, 4-methoxy- and Cyclopentadecanone, 2-hydroxy- had affinities for the proteins of interest. The affinity of Cyclopenftadecanone,2-hydroxy- for each of the proteins is higher than that of Benzeneethanamine,4-methoxy- with hydrogen bonds contributing significantly to the interactions. Benzeneethanamine, 4-methoxy- and Cyclopentadecanone,2-hydroxy- from Psidium guajava leaves possess inhibitory properties against QS proteins of S. Typhi.