An Aminopyrimidone and Aminoimidazoles Alkaloids from the Rodrigues Calcareous Marine Sponge Ernsta naturalis

International audienceA chemical study of the CH2Cl2−MeOH (1:1) extract from the sponge Ernsta naturalis collected in Rodrigues (Mauritius) based on a molecular networking dereplication strategy highlighted one novel aminopyrimidone alkaloid compound, ernstine A (1), seven new aminoimidazole alkaloid compounds, phorbatopsins D–E (2, 3), calcaridine C (4), naamines H–I (5, 7), naamidines J–K (6, 8), along with the known thymidine (9). Their structures were established by spectroscopic analysis (1D and 2D NMR spectra and HRESIMS data). To improve the investigation of this unstudied calcareous marine sponge, a metabolomic study by molecular networking was conducted. The isolated molecules are distributed in two clusters of interest. Naamine and naamidine derivatives are grouped together with ernstine in the first cluster of twenty-three molecules. Phorbatopsin derivatives and calcaridine C are grouped together in a cluster of twenty-one molecules. Interpretation of the MS/MS spectra of other compounds of these clusters with structural features close to the isolated ones allowed us to propose a structural hypothesis for 16 compounds, 5 known and 11 potentially new

Quorum Sensing Inhibitory and Antifouling Activities of New Bromotyrosine Metabolites from the Polynesian Sponge Pseudoceratina n. sp.

Four new brominated tyrosine metabolites, aplyzanzines C–F (1–4), were isolated from the French Polynesian sponge Pseudoceratina n. sp., along with the two known 2-aminoimidazolic derivatives, purealidin A (5) and 6, previously isolated, respectively, from the sponges Psammaplysilla purpurea and Verongula sp. Their structures were assigned based on the interpretation of their NMR and HRMS data. The compounds exhibited quorum sensing inhibition (QSi) and antifouling activities against several strains of bacteria and microalgae. To our knowledge, the QSi activity of this type of bromotyrosine metabolite is described here for the first time

Potential of tropical macroalgae from French Polynesia for biotechnological applications

WOS:000489922500001International audienceExtracts from 26 marine macroalgal species (11 Phaeophyceae, 7 Chlorophyta, and 8 Rhodophyta) sampled from the lagoons of Tahiti, Moorea, and Tubuai (French Polynesia) were tested for several biological activities. The red macroalga Amansia rhodantha exhibited the strongest antioxidant activities using four complementary methodologies (total phenolic content, 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power assay, and oxygen radical absorbance capacity assay). Therefore, the major metabolites of A. rhodantha were isolated and their structures identified. Some brown algae, especially species of the family Dictyotaceae like Padina boryana and Dictyota hamifera, showed cytotoxic activities against murine melanoma cells. Caulerpa chemnitzia extract demonstrated also a strong alpha-glucosidase inhibition (83.8% at 10 mu g mL(-1)) and Asparagopsis taxiformis extract a high acetylcholinesterase inhibition (71.3% at 100 mu g mL(-1)). Lastly, several Polynesian seaweeds demonstrated quorum-sensing inhibition for Vibrio harveyi. These results suggested that some seaweeds from French Polynesia have a great biotechnological potential for future applications in aquaculture, health, or cosmetic industries

Osirisynes G-I, New Long-Chain Highly Oxygenated Polyacetylenes from the Mayotte Marine Sponge Haliclona sp.

International audienceChemical study of the CH2Cl2−MeOH (1:1) extract from the sponge Haliclona sp. collected in Mayotte highlighted three new long-chain highly oxygenated polyacetylenes, osirisynes G-I (1-3) together with the known osirisynes A (4), B (5), and E (6). Their structures were elucidated by 1D and 2D NMR spectra and HRESIMS and MS/MS data. All compounds were evaluated on catalase and sirtuin 1 activation and on CDK7, proteasome, Fyn kinase, tyrosinase, and elastase inhibition. Five compounds (1; 3-6) inhibited proteasome kinase and two compounds (5-6) inhibited CDK7 and Fyn kinase. Osirisyne B (5) was the most active compound with IC 50 on FYNB kinase, CDK7 kinase, and proteasome inhibition of 18.44 µM, 9.13 µM, and 0.26 µM, respectively

A Ring-Distortion Strategy from Marine Natural Product Ilimaquinone Leads to Quorum Sensing Modulators

WOS:000434220200016International audienceWe report herein a ring-distortion strategy applied to marine natural substances ilimaquinone and 5-epi-ilimaquinone. A chemically diverse library of molecules was synthesised that included rearrangements of the sesquiterpene moiety and original reorganisations of the quinone ring. Chemoinformatic analyses evaluated the rise of structural diversity and the exploration of chemical space. Some focussed biological activities of this library were also investigated; quorum sensing activity of Vibrio harveyi was envisaged and some of the new compounds were shown to be good quorum sensing inhibitor candidates, whereas others were activators. Toxicities were also evaluated and some products showed micromolar activities against human umbilical vein endothelium, human hepatocellular carcinoma and human lung carcinoma (A549) cells