Evaluating the antimicrobial potential of green cardamom essential oil focusing on quorum sensing inhibition of Chromobacterium violaceum

Spices are well known for their taste and flavor imparting properties. Green cardamom (Elletaria cardamomum), a herb spice belongs to family Zingiberaceae. In current study, GC-MS analysis of green cardamom essential oil (CEO) resulted in identification of twenty-six compounds with alpha-terpinyl acetate (38.4%), 1,8-cineole (28.71%), linalool acetate (8.42%), sabinene (5.21%), and linalool (3.97%) as major bioactive components. Present study also described the antimicrobial properties like zone of inhibition, minimum inhibitory concentration against microbial strains with special emphasis on quorum sensing inhibition. Disk diffusion assay showed that C. albicans and S. mutans were the most sensitive microorganisms followed by S. aureus, L. monocytogenes, B. cereus and S. typhimurium sensor strains, respectively. Whilst P. aeruginosa was found most resistant strain as CEO did not inhibited its growth. The minimum inhibitory concentration (MIC) values of CEO against tested strains were 10 +/- 0.00 mg/mL against S. typhimurium, S. aureus and 5 +/- 0.00 mg/mL against S. mutans, C. albicans strains, respectively. Regarding quorum sensing inhibition the tested concentrations 0.625 and 0.313 mg/mL of CEO inhibited violacein production with very little effect on growth of C. violaceum. Conclusively, study proved that quorum sensing inhibition values of CEO were much lower compared to MIC revealed values. Hence, cardamom bioactive constituents can effectively be used to develop novel antimicrobial drugs against conventional antibiotics.