Quorum quenching activity of(Burm f.) Nees andrographolide compounds on metallo-β-lactamase-producing clinical isolates ofPA22 and PA247 and their effect ongene expression.
Heliyon. 2021 May ;7(5):e07002. Epub 2021 May 10. PMID: 34027192
An Margarete Tan Lim
(Burm f.) Nees is a tropical plant native to Southeast Asia that has been used as an effective remedy for a wide variety of illnesses in traditional Chinese and Ayurvedic medicine. The antimicrobial activity of its crude extract had been shown to be due to its quorum quenching activity. The study determined the effect of purified extracted compounds from the leaf of A. paniculata, namely: andrographolide, 14-deoxyandrographolide, 14-deoxy-12-hydroxyandrographolide and neoandrographolide on quorum sensing-mediated virulence mechanisms in clinical isolates of metallo-β-lactamase (MβL)-producing. Their effect on the expression of thegene, which codes for LasR, a transcription activator protein of the quorum sensing system inwas also determined using RT-qPCR. All the pure compounds significantly decreased the biofilm formation, protease production and swarming motility of theisolates compared to the untreated controls (p<0.05). Results of the RT-qPCR assay showed that all compounds significantly downregulated the expression ofcompared to the untreated control (p<0.05), supporting the position that the lower virulence activities of the treated group were due to quorum quenching activity of the pure compounds. Multiple comparisons using Tukey's HSD analysis revealed that the means of the relative expression ofof the isolates treated with the different compounds were not significantly different from each other (p>0.05), suggesting equal potencies. Results show the potential of the isolated pure compounds from A. paniculata for use as antimicrobial agents as a result of their quorum quenching activities.