Quorum quenching activity of Andrographis paniculata (Burm f.) Nees andrographolide compounds on metallo-β-lactamase-producing clinical isolates of Pseudomonas aeruginosa PA22 and PA247 and their effect on lasR gene expression
Authors
An Lim
aBiology Department, College of Science, De La Salle University, Manila, Philippines
Glenn Oyong
bMolecular Science Unit Laboratory, Center for Natural Sciences and Environmental Research (CENSER), De La Salle University, Manila, Philippines
Maria Tan
dChemistry Department, College of Science, De La Salle University, Manila, Philippines
Chien Shen
eChinese Medicinal Chemistry, National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, Taiwan
Consolacion Ragasa
dChemistry Department, College of Science, De La Salle University, Manila, Philippines
Esperanza Cabrera
aBiology Department, College of Science, De La Salle University, Manila, Philippines
Keywords:
Andrographis paniculata, Pseudomonas aeruginosa, Quorum sensing, Biofilm, Protease, Swarming, Andrographolides
Abstract
Andrographis paniculata (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 Pseudomonas aeruginosa. Their effect on the expression of the lasR gene, which codes for LasR, a transcription activator protein of the quorum sensing system in P. aeruginosa was also determined using RT-qPCR. All the pure compounds significantly decreased the biofilm formation, protease production and swarming motility of the P. aeruginosa isolates compared to the untreated controls (p < 0.05). Results of the RT-qPCR assay showed that all compounds significantly downregulated the expression of lasR compared 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 of lasR of 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.
Keywords: Andrographis paniculata, Pseudomonas aeruginosa, Quorum sensing, Biofilm, Protease, Swarming, Andrographolides
Author Biographies
An Lim, aBiology Department, College of Science, De La Salle University, Manila, Philippines
cSchool of Medical Technology, Centro Escolar University, Manila, Philippines
Esperanza Cabrera, aBiology Department, College of Science, De La Salle University, Manila, Philippines
bMolecular Science Unit Laboratory, Center for Natural Sciences and Environmental Research (CENSER), De La Salle University, Manila, Philippines
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