QUORUM SENSING INHIBITORY POTENTIAL OF METHANOLIC EXTRACTS OF Cuminum cyminum AND Garcinia cambogia AGAINST FOODBORNE PATHOGENS

A broad range of characteristic features are directly associated with bacterial Quorum sensing (QS) such bioluminescence, pigment production, conjugation, antibiotic production etc. Increasing amount of multi-drug resistant pathogens are the main reason for the emergence of antimicrobial compounds. Thus, the qualitative and quantitative evaluation of methanolic extracts of Cuminum cyminum (seeds) and Garcinia cambogia (dried fruit pericarp) were assessed using Chromobacterium violaceum biomonitor strains. Acyl homoserine lactones (AHLs) were identified from Thin Layer Chromatography (TLC) method. Qualitative assay for violacein inhibition of plant extracts showed potential activity. Also, Aeromonas veronii and Enterobacter cloacae indicates quorum sensing production in response with Chromobacterium violaceum, (CVO26) biosensor strain. Anti-quorum sensing activity of plant extracts showed significant decrease in violacein production with isolated AHLs (Acyl homoserine lactones). Both the extracts show lowest MIC (Minimum inhibitory concentrations) values ranging from 3.12 mg/mL-12.5 mg/mL against Aeromonas veronii and Enterobacter cloacae, and MBC (Minimum bactericidal concentrations) value 25 mg/mL against these foodborne pathogens. Quantitative estimation of violacein inhibition also determined by using extracts, indicates dose dependent increase in violacein inhibition. Methanolic extract of Cuminum cyminum resulted optimum percentage of violacein inhibition. When compared with positive control, naturally synthesized autoinducers from foodborne pathogens were detected as C4- AHL (N- butyryl-L-homoserine lactone) and C6-AHL (N-hexonyl-L-homoserine lactone). In conclusion, the methanolic extract of Cuminum cyminum resulted in optimum percentage of violacein inhibition.