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Étude de la diversité structurale et des propriétés biologiques de diterpènes macrocycliques d’Euphorbia de Corse

Abstract : The species belonging to the Euphorbia genus are remarkable for their ability to produce a large number of secondary metabolites, especially diterpenoids with a wide variety of carbon skeletons, which possess many interesting biological properties. A previous work demonstrated the strong antiviral activity of Euphorbia extracts against the chikungunya virus replication (CHIKV).The objective of this work was to discover and study new chemical series from Euphorbia species growing spontaneously in Corsica and possessing anti-CHIKV and/or an anti-MDR properties (multi-drugs resistance). Several strategies were employed, including the chemical modifications on previously isolated compounds to create chemical diversity, and the isolation of new compounds guided by LC-MS/MS analysis. The investigation carried out on Euphorbia dendroides led to the isolation of 24 molecules, of which 15 were described for the first time. Some of isolated deoxyphorbol esters showed strong anti-CHIKV activity, while 2 jatrophane esters inhibited Candidate albicans receptors responsible for the drug resistance phenomenon. About ten compounds have been isolated from E. pithyusa anti-CHIKV extract. Only a dideoxyphorbol ester exhibited a strong anti-CHIKV activity. The interpreation of LC-MS/MS analysis of E. pithyusa fractions using molecular networks and fragmentation pathways study, allowed the targeted isolation of twenty myrsinol, premyrsinol and phorbol derivatives to be isolated in its sister species E. pithyusa subsp. cupanii. Furhtermore, molecular networks were used for chemotaxonomic comparison, to highlight chemotaxonomic differences and similarities between the two subspecies. Finally, chemical modifications were carried out on two abundant jatrophane esters isolated from E. dendroides, allowing 6 original derivatives to be synthetized.
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Submitted on : Friday, November 12, 2021 - 5:22:37 PM
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Mélissa Esposito. Étude de la diversité structurale et des propriétés biologiques de diterpènes macrocycliques d’Euphorbia de Corse. Autre. Université Pascal Paoli, 2017. Français. ⟨NNT : 2017CORT0009⟩. ⟨tel-03426945⟩

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