Anti-infective potential of a quorum modulatory polyherbal extract (panchvalkal) against certain pathogenic bacteria

Background: In view of the gravity of the problem of antimicrobial resistance among pathogenic bacteria against conventional bactericidal agents, investigation on alternative approaches to combat bacterial infections is warranted. Objective: Current study aimed at investigating anti-infective potential of a polyherbal ayurvedic formulation namely panchvalkal against three different pathogenic bacteria. Materials and methods: The panchvalkal formulation available as Pentaphyte P5 (R) was tested for its possible in vitro quorum-modulatory potential against Chromobacterium violaceum, Serratia marcescens, and Staphylococcus aureus through broth dilution assay. In vivo efficacy was demonstrated employing Caenorhabditis elegans as the model host for test pathogens. Results: This formulation was found to exert quorum-modulatory effect on C. violaceum, S. marcescens, and S. aureus at 250-750 mu g/ml. Besides altering production of the quorum sensing-regulated pigments in these bacteria, the test formulation also had in vitro effect on antibiotic susceptibility, catalase activity and haemolytic potential of the pathogens. In vivo assay confirmed the protective effect of this panchvalkal formulation on C. elegans, when challenged with the pathogenic bacteria. Repeated exposure of S. aureus to panchvalkal did not induce resistance in this bacterium. Conclusion: To the best of our awareness, this the first report on quorum-modulatory potential of panchvalkal formulation, validating the anti-infective potential and moderate prebiotic property of this polyherbal preparation. (C) 2018 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Publishing Services by Elsevier B.V.