Anti-quorum sensing and antimicrobial activities of some traditional Chinese medicinal plants commonly used in South-East Asia

Abstract

Aims: Traditional Chinese medicine (TCM) has been used for relief and treatment of ailments dating back thousands of years and continues to the present day, with rapidly increasing interest in evidence-based evaluation of its efficacy. Studies of TCM plants have demonstrated that several have antimicrobial properties but few have explored their antiquorum sensing potential. Quorum sensing (QS), also known as bacterial cell-to-cell communication, is used by a number of opportunistic pathogenic bacteria in the regulation of virulence expression. Compounds that interfere with QS signals and attenuate bacterial virulence without killing them may offer an alternative therapeutic solution with less pressure of antibiotic resistance developing. This study screened TCM plants for anti-quorum sensing properties and antimicrobial activities. Methodology and Results: Twenty TCM plants commonly used in South-East Asia were screened for QS inhibitors using two biomonitor strains, Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PAO1. Ten of these selected TCM plant (50%) were found to have QS inhibitory properties: Angelica sinensis (Umbelliferae), Cnidium monnieri (Umbelliferae), Astragalus membranaceus (Leguminosae), Crataegus cuneata (Rosaceae), Dioscorea nipponica (Dioscoreaceae), Lilium brownii (Liliaceae), Aloe barbadensis (Liliaceae), Magnolia officinalis (Magnoliaceae), Ephedra sinica (Ephedraceae) and Panax pseudoginseng (Araliaceae). Of these, six (30%) also showed varying antimicrobial activity against C. violaceum and P. aeruginosa. Conclusion, significance and impact of study: The results suggest that traditional Chinese medicinal plants could be a prospective source to explore for useful compounds in the fight against bacterial infections.