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Mansoura University (2019)

Bioactive natural products from family Solanaceae and endophytic fungi from desert plants

El-Bermawi, Ahmed El-Said Bedir.

Titre : Bioactive natural products from family Solanaceae and endophytic fungi from desert plants

Auteur : El-Bermawi, Ahmed El-Said Bedir.

Etablissement de soutenance : Mansoura University

Grade : Doctor of Philosophy (PhD) in Pharmaceutical Science 2019

Résumé
The aim of this work is to carry out phytochemical and biological study of secondary metabolite from the whole plant of Lycium schweinfurthii belonging to family solanaceae and from the endophyte of the leaves of some drsert collected plants in order to discover new natural products with interesting biological activities. In this study, thirty seven compounds were isolated and identified using various spectroscopic techniques from which three compounds are isolated for the first time from natural source. Also, the isolated compounds were screened for their cytotoxic and some enzymatic inhibitory activities.Part I : Phytochemical investigation of Lycium schweinfurthii Dammer One and half Kilograms of the powdered air-dried aerial and root parts of Lycium schweinfurthii were extracted by maceration in a percolator with MeOH then fractionated with pet.ether extract, DCM, EtOAc and n-butanol respectively.The isolated compounds were identified using various spectroscopic techniques including ; UV, IR, 1D- and 2D-NMR and HRMS. 28 compounds were identified of which 3 new compounds are reported in the present study for the first time from a natural source and 25 known ones. The known compounds include one sesquiterpine, 2 sterols, 2 fatty alcohols, one coumarine, 2 lignans, 3 cinnamoyl ferulate derivatives, 5 flavonoids, 2 flavonoid glycosides, 5 phenolic acids and 2 phenolic glucosides.Part II : Phytochemical investigation of Lycium schweinfurthii Dammer endophyte.The endophytic fungus Alternaria sp. was isolated from fresh leaf tissues of L. schweinfurthii, P. maritimum and C. acutum. The isolated strain gave 99% identity to Altenaria sp. Phytochemical investigation of the EtOAc extracts of solid rice culture medium of Alternaria sp. led to the isolation of 6 known compounds reported from the genus Alternaria before. They were identified adopting various spectroscopic techniques (UV, 1D- and 2D-NMR, HRESIMS) as alternariol, alternariol-5-O –methylether, altenusin, altenuene, talaroflavone and alteric acid. It is of interest to note that, the present study represents the first one investigated the secondary metabolites of the endophytic fungi of the Amaryllidaceae and for both species ; Cynanchum acutum and Lycium schweinfurthii.Part –III Biological investigation of the isolated compounds 1- Cytotoxic activities of some of the isolated compounds against several cancer and normal cell lines:Compounds 1, 14, 17 and 27 suggested to be potential candidates for skin cancer with higher selectivity index 10.2- Inhibition of α-glucosidase activity cis-docosanoyl ferulate (3), trans ferulyl tyramine (10), luteolin (13), chryseriol (14), kaempferol (17), quercetin (18) and 3-methoxy-4-O-β-D-glucopyranosyl-methyl benzoate (26) exhibited potent α-glucosidase inhibitory activity 3- Inhibition of pancreatic lipase Pinoresinol (8) showed stong inhibitory activity against pancreatic lipase enzyme 4- Inhibition of acetylcholine esterase enzymatic activity Of the tested compounds only β-sitosterol (5), pinoresinol (8) and chryseriol-7-O- β-D-glucoside (24) exhibited potent acetylcholine esterase inhibitory activities.5- Inhibition of hTERT gene expression

Présentation étendue (EULC)

Page publiée le 29 mars 2020