Inhibition of the Quorum Sensing System, Elastase Production and Biofilm Formation in Pseudomonas aeruginosa by Psammaplin A and Bisaprasin

Emmanuel T Oluwabusola, Nursheena Parveen Katermeran, Wee Han Poh, Teo Min Ben Goh, Lik Tong Tan, Oluwatofunmilayo Diyaolu, Jioji Tabudravu, Rainer Ebel, Scott A Rice, Marcel Jaspars* (Corresponding Author)

*Corresponding author for this work

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Natural products derived from marine sponges have exhibited bioactivity and, in some cases, serve as potent quorum sensing inhibitory agents that prevent biofilm formation and attenuate virulence factor expression by pathogenic microorganisms. In this study, the inhibitory activity of the psammaplin-type compounds, psammaplin A (1) and bisaprasin (2), isolated from the marine sponge, Aplysinellarhax, are evaluated in quorum sensing inhibitory assays based on the Pseudomonas aeruginosa PAO1 lasB-gfp(ASV) and rhlA-gfp(ASV) biosensor strains. The results indicate that psammaplin A (1) showed moderate inhibition on lasB-gfp expression, but significantly inhibited the QS-gene promoter, rhlA-gfp, with IC50 values at 14.02 μM and 4.99 μM, respectively. In contrast, bisaprasin (2) displayed significant florescence inhibition in both biosensors, PAO1 lasB-gfp and rhlA-gfp, with IC50 values at 3.53 μM and 2.41 μM, respectively. Preliminary analysis suggested the importance of the bromotyrosine and oxime functionalities for QSI activity in these molecules. In addition, psammaplin A and bisaprasin downregulated elastase expression as determined by the standard enzymatic elastase assay, although greater reduction in elastase production was observed with 1 at 50 μM and 100 μM. Furthermore, the study revealed that bisaprasin (2) reduced biofilm formation in P. aeruginosa.

Original languageEnglish
Article number1721
Number of pages17
Issue number5
Early online date6 Mar 2022
Publication statusPublished - 6 Mar 2022

Bibliographical note

Funding: The facilities and equipment support were provided partially by the National Institute of Education, Singapore. This research is funded by the National Research Foundation, Prime Minister’s Office, Singapore under its Marine Science Research and Development Program (Award Nos. MSRDP-P15 and MSRDP-P34). In addition, we acknowledge the E.U. Seventh Framework
Programme Project PharmaSea (grant agreement no-312184) for financial support for the collection of the marine sample.
Acknowledgments: E.T.O. and J.T. wish to thank the resource owners of the district of Wainunu, Bua, Fiji Islands, for the marine sponge used in this study. M.J. wishes to thank Russell Gray of Marine Biodiscovery Centre, Aberdeen, for running the NMR spectrometry.


  • marine sponge
  • psammaplin
  • marine natural products
  • quorum sensing inhibitor
  • Pseudomonas aeruginosa
  • inhibitor of biofilm formation
  • elastase inhibitor


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