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Quorum sensing inhibitors from Leucetta chagosensis Dendy, 1863
T Mai1,2, F Tintillier1, A Lucasson3
1IRD, UMR241-EIO, Papeete, Tahiti, French Polynesia.
Letters in Applied Microbiology
|July 4, 2015
Summary
Marine sponges yield novel compounds that inhibit bacterial communication. These quorum sensing inhibitors (QSIs) show potential for controlling marine pathogens, particularly in aquaculture.
Area of Science:
- Marine Natural Products Chemistry
- Microbiology
- Drug Discovery
Background:
- Sponges are prolific sources of bioactive small molecules, investigated for therapeutic potential.
- Marine invertebrates like sponges face microbial pathogens, necessitating defense mechanisms.
- Sponges utilize signaling molecules for self-defense, offering avenues for anti-infective research, including quorum sensing inhibitors (QSIs).
Purpose of the Study:
- To investigate the quorum sensing inhibitory (QSI) crude extract of the marine sponge Leucetta chagosensis.
- To isolate and characterize new alkaloids with potential anti-infective properties.
- To evaluate the efficacy of isolated compounds against Vibrio harveyi quorum sensing pathways.
Main Methods:
- Extraction and isolation of alkaloids from Leucetta chagosensis.
- Structural elucidation of new compounds using spectroscopic methods.
- In vitro testing of isolated compounds as inhibitors of Vibrio harveyi quorum sensing pathways (CAI-1, AI-2, harveyi auto inducer).
Main Results:
- Isolation of three new alkaloids: isonaamine D, di-isonaamidine A, and leucettamine D, along with known compounds isonaamine A and isonaamidine A.
- Isonaamidine A and isonaamine D demonstrated inhibition of all three quorum sensing pathways in Vibrio harveyi.
- Isonaamidine A exhibited particularly strong activity against the AI-2 quorum sensing pathway.
Conclusions:
- New classes of quorum sensing inhibitors (QSIs) were identified from the sponge Leucetta chagosensis.
- The strong inhibition of the AI-2 pathway by isonaamidine A is significant for controlling Vibrio harveyi, a marine pathogen relevant to aquaculture.
- Structure-activity relationships were established, aiding the future design of novel QSIs to combat marine infectious diseases.
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