Computational exploration and in vitro validation of anti-quorum sensing potential of phytochemicals from Coleus amboinicus.

Development of antimicrobial resistance in bacteria is a major concern. The study of quorum sensing (QS), the bacterial communication system that coordinates important events in an infection, opens a new avenue for treating infections. QS helps in biofilm formation which acts as a physical barrier and alters the microenvironment which traps the molecules or slows down the antibiotic diffusion making them less effective. Since the standard drugs are not very effective against bacteria anymore, demand for the discovery of other alternatives arises. Phytochemicals extracted from commonly used plants like Coleus amboinicus, known to have antimicrobial properties, can be used to develop novel drugs against quorum sensing and hence suppress bacterial infection. Here, we have identified a set of phytochemicals from C. amboinicus whose drug-like properties were predicted using SwissADME and their interactions with the targets involved in QS in Pseudomonas aeruginosa, Vibrio harveyi and Chromobacterium violaceum were studied by performing molecular docking using PyRx software. Beta-amyrin, chrysoeriol and apigenin were found to be the top scored molecules with docking scores of -9.3, -11.3, and - 11.1 kcal/mol respectively, and were considered for molecular dynamics simulation using GROMACS software. This was followed by in vitro tests such as Agar well diffusion, Scanning electron microscopy, Pyocyanin assay and Crystal violet assay. Erythromycin was used as the standard drug and as a positive control to validate the results. Based on both in vitro and in silico studies, the phytochemicals from C. amboinicus have the potential to be inhibitors of quorum sensing targets. These findings are preliminary and should be interpreted as hypotheses to be tested experimentally rather than as established mechanisms.