Tryptophan interferes with the quorum sensing and cell surface hydrophobicity of : a promising approach to inhibit the biofilm development.

Unlabelled: , a Gram-positive bacterium has been implicated in a plethora of human infections by virtue of its biofilm-forming ability. Inhibition in microbial biofilm formation has been found to be a promising approach towards compromising microbial pathogenesis. In this regard, various natural and synthetic molecules have been explored to attenuate microbial biofilm. In this study, the role of an amino acid, L-tryptophan was examined against the biofilm-forming ability of The compound did not execute any antimicrobial characteristics, instead, showed strong antibiofilm activity with the highest biofilm inhibition at a concentration of 50 µg/mL. Towards understanding the underlying mechanism of the same, efforts were given to examine whether tryptophan could inhibit biofilm formation by interfering with the quorum-sensing property of . A molecular docking analysis revealed an efficient binding between the quorum-sensing protein, AgrA, and tryptophan. Moreover, the expression of the quorum-sensing gene () got significantly reduced under the influence of the test compound. These results indicated that tryptophan could interfere with the quorum-sensing property of the organism thereby inhibiting its biofilm formation. Further study revealed that tryptophan could also reduce the cell surface hydrophobicity of by downregulating the expression of . Moreover, the tested concentrations of tryptophan did not show any significant cytotoxicity. Hence, tryptophan could be recommended as a potential antibiofilm agent to manage the biofilm-associated infections caused by .

Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-021-02924-3.