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Partager le résultat de cette recherche Interroger des sources externesIdentification polyphasique des souches d’actinobactéries isolées d’échantillons de sols semi-arides / Nassima Leulmi
Titre : Identification polyphasique des souches d’actinobactéries isolées d’échantillons de sols semi-arides : Caractérisation structurale des antibiotiques produits. Type de document : texte imprimé Auteurs : Nassima Leulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 174 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Actinobactéries Streptomyces sols semi-arides antibiotiques polyéthers ionophores cytotoxicité Actinobacteria Semi-arid soils Antibiotics ionophoric polyethers Cytotoxicity ??????????????? ??? ??? ???? ???????? ??????? polyéthers ionophores ?????? ?????? Index. décimale : 570 Sciences de la vie. Biologie Résumé : Actinobacteria are a group of filamentous bacteria, mainly inhabit the soil. They are known for producing a wide variety of bioactive molecules, especially antibiotics. Is in this context that our research work focused. A total of 99 isolates were recovered from a semi-arid soi,collected from; rhizospheric associated soil (Khenchela), mountain soil (Mount chélia region, khenchela) and Sebkha soil (Oum El bouaghi). Three strains (SF10, SFKH4 and SFKH10), were selected, based on preliminary screening for antimicrobial activity. The isolates were identified as belonging to the genus Streptomyces, based on phenotypic and chemotaxonomic study. Phylogenetic analysis revealed that the strains SF10, SFKH4 and SFKH10 were most closely related to Streptomyces youssoufiensis, Streptomyces spororaveus and Streptomyces coeruleorubidus with a pairwise 16S rRNA gene sequence similarity of 99, 8, 99 % and 99%. Ethyl acetate extracts provied by the culture of the strains on solid culture were tested for their antimicrobial activity against the test microorganisms. The structure elucidation of the biologically active molecules, purified by different chromatographic methods, was carried out by coupling several techniques of mass
spectrometry and Nuclear Magnetic Resonance (1H NMR, 13C NMR, MS, MS tandem, IR and UV-Visible). Streptomyces youssoufiensis SF10 strain produced several molecules belonging to ionophoric polyethers family, abierixin, nigericin, epinigericin, and the newly isolated grisorixin methyl ester. Moreover, only one molecule, belonging to macrotetrolides family (dinactin), was obtained from Streptomyces coeruleorubidus SFKH10 strain. In addition, the partial characterization of the molecules secreted by S. spororaveus SFKH4 strain has shown its capacity to produce a large variety of complexes compounds having high molecular weight. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred DFT (Density Functional Theory) computational calculations. This analysis was able to provide the relative stability of the most favored epimers. This consideration is of general interest and can be applied to the wide class of naturally occurring polycyclic polyethers. On the other hand, the study of the cytotoxicity of the purified and identified molecules revealed that both nigericin and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (IC50 values of 3.85 and 3.05 μM for VIPI and COMI humain glioblastoma stem cells, respectively). In conclusion, the present study has revealed the potential of semi-arid Algerian ecosystems as a good source for bioactives molecules-producing actinobacteria, specialy Streptomyces youssoufienisis SF10 strain whose secondary metabolites profile has not been studied so far by bioguided method. The clear antiproliferative activity of grisorixin methyl ester on glioblastoma stem cells represents a promising starting point aimed to the development of new drug candidates in the treatment of glioblastoma multiforme.
Diplôme : Doctorat en sciences Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11029 Identification polyphasique des souches d’actinobactéries isolées d’échantillons de sols semi-arides : Caractérisation structurale des antibiotiques produits. [texte imprimé] / Nassima Leulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 174 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Actinobactéries Streptomyces sols semi-arides antibiotiques polyéthers ionophores cytotoxicité Actinobacteria Semi-arid soils Antibiotics ionophoric polyethers Cytotoxicity ??????????????? ??? ??? ???? ???????? ??????? polyéthers ionophores ?????? ?????? Index. décimale : 570 Sciences de la vie. Biologie Résumé : Actinobacteria are a group of filamentous bacteria, mainly inhabit the soil. They are known for producing a wide variety of bioactive molecules, especially antibiotics. Is in this context that our research work focused. A total of 99 isolates were recovered from a semi-arid soi,collected from; rhizospheric associated soil (Khenchela), mountain soil (Mount chélia region, khenchela) and Sebkha soil (Oum El bouaghi). Three strains (SF10, SFKH4 and SFKH10), were selected, based on preliminary screening for antimicrobial activity. The isolates were identified as belonging to the genus Streptomyces, based on phenotypic and chemotaxonomic study. Phylogenetic analysis revealed that the strains SF10, SFKH4 and SFKH10 were most closely related to Streptomyces youssoufiensis, Streptomyces spororaveus and Streptomyces coeruleorubidus with a pairwise 16S rRNA gene sequence similarity of 99, 8, 99 % and 99%. Ethyl acetate extracts provied by the culture of the strains on solid culture were tested for their antimicrobial activity against the test microorganisms. The structure elucidation of the biologically active molecules, purified by different chromatographic methods, was carried out by coupling several techniques of mass
spectrometry and Nuclear Magnetic Resonance (1H NMR, 13C NMR, MS, MS tandem, IR and UV-Visible). Streptomyces youssoufiensis SF10 strain produced several molecules belonging to ionophoric polyethers family, abierixin, nigericin, epinigericin, and the newly isolated grisorixin methyl ester. Moreover, only one molecule, belonging to macrotetrolides family (dinactin), was obtained from Streptomyces coeruleorubidus SFKH10 strain. In addition, the partial characterization of the molecules secreted by S. spororaveus SFKH4 strain has shown its capacity to produce a large variety of complexes compounds having high molecular weight. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred DFT (Density Functional Theory) computational calculations. This analysis was able to provide the relative stability of the most favored epimers. This consideration is of general interest and can be applied to the wide class of naturally occurring polycyclic polyethers. On the other hand, the study of the cytotoxicity of the purified and identified molecules revealed that both nigericin and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (IC50 values of 3.85 and 3.05 μM for VIPI and COMI humain glioblastoma stem cells, respectively). In conclusion, the present study has revealed the potential of semi-arid Algerian ecosystems as a good source for bioactives molecules-producing actinobacteria, specialy Streptomyces youssoufienisis SF10 strain whose secondary metabolites profile has not been studied so far by bioguided method. The clear antiproliferative activity of grisorixin methyl ester on glioblastoma stem cells represents a promising starting point aimed to the development of new drug candidates in the treatment of glioblastoma multiforme.
Diplôme : Doctorat en sciences Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11029 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LEU/7380 LEU/7380 Thèse Bibliothèque principale Thèses Disponible
Titre : Synthèse de composés hétérocycliques à visée anticancèreuse Type de document : texte imprimé Auteurs : Nora Chouha, Auteur ; Taoues Boumoud, Auteur ; Laurent Desaubry, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 155 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Triarylimidazoles spirooxindoles acide citrique BF3.OEt2 iminobenzimidazole fluorizoline oncogène KRAS cytotoxicité leucémie citric acid KRAS oncogene cytotoxicity leukemia Index. décimale : 540 Chimie et sciences connexes Résumé : Our work focuses on the development of new synthetic approaches to anticancer compounds. This work was carried out at the University of Constantine and Strasbourg, under Prof. Taoues Boumoud and Dr. Laurent Désaubry’s supervision. Triarylimidazoles and spirooxindoles are heterocycles found among several important anti-cancer agents. In order to facilitate the pharmacochemical exploration of these compounds, improving their synthesis was aimed. Novel catalytic ways were developped for the synthesis of triarylimidazoles and spiro[chroméne-oxindoles] with good yields via multicomponent reactions in the presence of citric acid and BF3.OEt2 as catalysts respectively. Two articles demonstarting the catalytic effects of the former catalysts in the synthesis of benzimidazoles and spirooxindole derivatives were published. Original work carried out in Strasbourg has demonstrated the cytotoxic properties of an iminobenzimidazole on cancerous lines. Analogues of this compound, were prepered, to determine the structural requirements for this cytotoxicity. An article describing these works was published inThe Open Medicinal Chemistry Journal. Another cytotoxic agent “fluorizoline” and analogues thereof were also prepared. Two first articles demonstrating the inhibition of KRAS oncogene by this compound and its activity in models of chronic lymphocytic leukemia were also published.
Diplôme : Doctorat En ligne : ../theses/chimie/CHO7370.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11019 Synthèse de composés hétérocycliques à visée anticancèreuse [texte imprimé] / Nora Chouha, Auteur ; Taoues Boumoud, Auteur ; Laurent Desaubry, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 155 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Triarylimidazoles spirooxindoles acide citrique BF3.OEt2 iminobenzimidazole fluorizoline oncogène KRAS cytotoxicité leucémie citric acid KRAS oncogene cytotoxicity leukemia Index. décimale : 540 Chimie et sciences connexes Résumé : Our work focuses on the development of new synthetic approaches to anticancer compounds. This work was carried out at the University of Constantine and Strasbourg, under Prof. Taoues Boumoud and Dr. Laurent Désaubry’s supervision. Triarylimidazoles and spirooxindoles are heterocycles found among several important anti-cancer agents. In order to facilitate the pharmacochemical exploration of these compounds, improving their synthesis was aimed. Novel catalytic ways were developped for the synthesis of triarylimidazoles and spiro[chroméne-oxindoles] with good yields via multicomponent reactions in the presence of citric acid and BF3.OEt2 as catalysts respectively. Two articles demonstarting the catalytic effects of the former catalysts in the synthesis of benzimidazoles and spirooxindole derivatives were published. Original work carried out in Strasbourg has demonstrated the cytotoxic properties of an iminobenzimidazole on cancerous lines. Analogues of this compound, were prepered, to determine the structural requirements for this cytotoxicity. An article describing these works was published inThe Open Medicinal Chemistry Journal. Another cytotoxic agent “fluorizoline” and analogues thereof were also prepared. Two first articles demonstrating the inhibition of KRAS oncogene by this compound and its activity in models of chronic lymphocytic leukemia were also published.
Diplôme : Doctorat En ligne : ../theses/chimie/CHO7370.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11019 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité CHO/7370 CHO/7370 Thèse Bibliothèque principale Thèses Disponible
Titre : Étude phytochimique et biologique de trois espèces Algériennes : Calendula stellata Cav. (Asteraceae), Scabiosa stellata L. (Caprifoliaceae) et Salvia barrelieri Etl. (Lamiaceae). Type de document : texte imprimé Auteurs : Meryem Lehbili, Auteur ; Ahmed Kabouche, Directeur de thèse ; Abdulmagid Alabdul Magid, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 375 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Calendula stellata Scabiosa stellata Salvia barrelieri saponosides iridoïdes triterpenoïdes flavonoïdes activité antioxydante activité antimicrobienne cytotoxicité saponosids iridoids triterpenes flavonoids antioxidant activity antimicrobial activity cytotoxicity ???????? ?????????? ????? ??????? ????? ????????? ???? ????? Index. décimale : 540 Chimie et sciences connexes Résumé : The phytochemical study of three species: Calendula stellata, Scabiosa stellata and Salvia barrelieri led to the isolation of 55 compounds, from which 16 were new, by the use of different chromatographic methods of separation and purification on solid or liquid support.
The isolated compounds were distributed through 27 saponosids, 7 triterpenes, 11 flavonoids, 7 iridoids and 2 chlorogenic acid derivatives. Two mono-iridoids and two flavonoids showed an important antiradical activity (IC50:7-16 µM). Fourteen compounds exhibited a good antibacterial activity (MIC: 15- 125 µg/mL). The new compounds showed a low to moderate cytotoxic activity against all tested cell lines, except for the monodesmoside, obtained from Scabiosa stellata (Scabiostellatoside F) which exhibited a good antiproliferative effect against HT1080 (IC50 = 12 µM).
Diplôme : Doctorat En ligne : ../theses/chimie/LEH7306.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10921 Étude phytochimique et biologique de trois espèces Algériennes : Calendula stellata Cav. (Asteraceae), Scabiosa stellata L. (Caprifoliaceae) et Salvia barrelieri Etl. (Lamiaceae). [texte imprimé] / Meryem Lehbili, Auteur ; Ahmed Kabouche, Directeur de thèse ; Abdulmagid Alabdul Magid, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 375 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Calendula stellata Scabiosa stellata Salvia barrelieri saponosides iridoïdes triterpenoïdes flavonoïdes activité antioxydante activité antimicrobienne cytotoxicité saponosids iridoids triterpenes flavonoids antioxidant activity antimicrobial activity cytotoxicity ???????? ?????????? ????? ??????? ????? ????????? ???? ????? Index. décimale : 540 Chimie et sciences connexes Résumé : The phytochemical study of three species: Calendula stellata, Scabiosa stellata and Salvia barrelieri led to the isolation of 55 compounds, from which 16 were new, by the use of different chromatographic methods of separation and purification on solid or liquid support.
The isolated compounds were distributed through 27 saponosids, 7 triterpenes, 11 flavonoids, 7 iridoids and 2 chlorogenic acid derivatives. Two mono-iridoids and two flavonoids showed an important antiradical activity (IC50:7-16 µM). Fourteen compounds exhibited a good antibacterial activity (MIC: 15- 125 µg/mL). The new compounds showed a low to moderate cytotoxic activity against all tested cell lines, except for the monodesmoside, obtained from Scabiosa stellata (Scabiostellatoside F) which exhibited a good antiproliferative effect against HT1080 (IC50 = 12 µM).
Diplôme : Doctorat En ligne : ../theses/chimie/LEH7306.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10921 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LEH/7306 LEH/7306 Thèse Bibliothèque principale Thèses Disponible 
Titre : Étude phytochimique et évaluation des activités antioxydante, antibactérienne et cytotoxique de deux plantes du genre Phagnalon (Asteraceae) Type de document : texte imprimé Auteurs : Hanene Cherchar ép Saadi, Auteur ; Djemaa Berrehal, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 190 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Asteraceae Phagnalon saxatile Phagnalon sordidum activité antioxydante activité antibactérienne cytotoxicité antioxidant activity antibacterial activity cytotoxicity ?????? ????? ??????? ?????? ????? ????????? ?????? ??????? Index. décimale : 540 Chimie et sciences connexes Résumé : Our phytochemical and biological works concerned the aerial parts of two species belonging to Asteraeae family : Phagnalon saxatile (L) Cass. and Phagnalon sordidum L.
Several chromatographic methods allowed us to isolate ten products from the n-butanol and ethyl acetate extracts of Phagnalon saxatile from which one is new, and twenty one products from Phagnalon sordidum.
Structures were determined by different spectral methods: nuclear magnetic resonance with different applications (NMR 1H, NMR 13C, COSY, HSQC and HMBC), the mass spectrometry, UV, acid hydrolysis as well as comparison with literature data.
4 methods were used to evaluate the antioxidant activity of Phagnalon sordidum and Phagnalon saxatile. The latter showed a good activity by the use of 4 methods: DPPH, ABTS, CUPRAC and superoxide radical scavenging activity by alkaline DMSO whereas Phagnalon sordidum exhibited a moderate activity with DPPH and CUPRAC tests.
Furthermore, petroleum ether and chloroform extracts from Phagnalon saxatile showed moderate antibacterial activity against the tested strains. The isolated products (1-O- β-D-glucopyranosyl-1,4-dihydroxy-2-((E) 2-oxo-3-butenyl) benzene, 1-O-β-glucopyranosyl- 2(3’,3’-diméthylallyl) hydroquinone and Potassium 4-hydroxy-3-methoxybenzoique acide
methyl ester-5-sulfate) from Phagnalon saxatile showed a moderate cytotoxic activity by the use of MTT method.
Diplôme : Doctorat En ligne : ../theses/chimie/CHE7249.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10841 Étude phytochimique et évaluation des activités antioxydante, antibactérienne et cytotoxique de deux plantes du genre Phagnalon (Asteraceae) [texte imprimé] / Hanene Cherchar ép Saadi, Auteur ; Djemaa Berrehal, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 190 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Asteraceae Phagnalon saxatile Phagnalon sordidum activité antioxydante activité antibactérienne cytotoxicité antioxidant activity antibacterial activity cytotoxicity ?????? ????? ??????? ?????? ????? ????????? ?????? ??????? Index. décimale : 540 Chimie et sciences connexes Résumé : Our phytochemical and biological works concerned the aerial parts of two species belonging to Asteraeae family : Phagnalon saxatile (L) Cass. and Phagnalon sordidum L.
Several chromatographic methods allowed us to isolate ten products from the n-butanol and ethyl acetate extracts of Phagnalon saxatile from which one is new, and twenty one products from Phagnalon sordidum.
Structures were determined by different spectral methods: nuclear magnetic resonance with different applications (NMR 1H, NMR 13C, COSY, HSQC and HMBC), the mass spectrometry, UV, acid hydrolysis as well as comparison with literature data.
4 methods were used to evaluate the antioxidant activity of Phagnalon sordidum and Phagnalon saxatile. The latter showed a good activity by the use of 4 methods: DPPH, ABTS, CUPRAC and superoxide radical scavenging activity by alkaline DMSO whereas Phagnalon sordidum exhibited a moderate activity with DPPH and CUPRAC tests.
Furthermore, petroleum ether and chloroform extracts from Phagnalon saxatile showed moderate antibacterial activity against the tested strains. The isolated products (1-O- β-D-glucopyranosyl-1,4-dihydroxy-2-((E) 2-oxo-3-butenyl) benzene, 1-O-β-glucopyranosyl- 2(3’,3’-diméthylallyl) hydroquinone and Potassium 4-hydroxy-3-methoxybenzoique acide
methyl ester-5-sulfate) from Phagnalon saxatile showed a moderate cytotoxic activity by the use of MTT method.
Diplôme : Doctorat En ligne : ../theses/chimie/CHE7249.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10841 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité CHE/7249 CHE/7249 Thèse Bibliothèque principale Thèses Disponible
Titre : Phytochemical and biological studies of two Algerian medicinal plants : Cytisus villosus Pourr. (Fabaceae) and Hypericum afrum Lam. (Hypericaceae) Type de document : texte imprimé Auteurs : Farida Larit, Auteur ; Samira Benyahia, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 353 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Anglais (eng) Catégories : Français - Anglais
ChimieTags : Hypericum Cytisus Secondary metabolites Total phenolics Antioxidant Cytotoxicity Antifungal Antibacterial Antimalarial Antileishmanial Activity MAO-A and MAO-B Docking Simulation Métabolites secondaires Total phénoliques Cytotoxicité Antifongique Antibactérienne Antipaludique Antileishmanienne MAO-A et MAO-B "MAO-A MAO-B Cytisus Hypericum ?????? ????????? ???????? ???? ??????? ???? ????????? ???? ???????? ???? ?????????????" Index. décimale : 540 Chimie et sciences connexes Résumé : Natural products are important sources of novel therapeutic agents. Bioactive secondary metabolites
isolated from natural sources, can act as drugs or as lead compounds for synthetic drugs. In our work, two plants
have been studied; the endemic species of Hypericum afrum Lam.(Hypericaceae) and Cytisus villosus Pourr.
(Fabaceae). Fractions of the aerial parts of these two plants have been screened in vitro for several biological
assays including cannabinoid and opioid receptors agonist assays, antifungal, antibacterial, antimalarial,
antileishmanial, antiproliferative, antioxidant, anti-inflammatory and MAO inhibition.
The chloroform, ethyl acetate and n-butanol fractions of H. afrum showed significant antioxidant activity and
potent antitrypanosomal activity against T. brucei. The n-butanol fraction of C. villosus showed highly potent
antitrypanosomal activity against T. brucei. In addition, the ethyl acetate fractions of both plants showed potent
inhibition of recombinant human monoamine oxidases (MAO-A and -B).
A bioassay-guided fractionation paradigm has been used for the isolation of bioactive compounds of these plants
and hence the subfractions that showed significant activity were further purified.
This study led to the isolation and identification of 20 compounds, three of which belonging to phloroglucinols,
terpenoids and isoflavonoids are new. The structures of the isolated compounds were elucidated through various
spectroscopic methods, including high- resolution mass spectrometry, one and two-dimensional nuclear magnetic
resonance spectroscopy.
Computational study was carried out by conformational search and docking techniques to provide insight into the
binding mode of molecules on the active site of MAO’s isoenzymes.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAR7157.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10430 Phytochemical and biological studies of two Algerian medicinal plants : Cytisus villosus Pourr. (Fabaceae) and Hypericum afrum Lam. (Hypericaceae) [texte imprimé] / Farida Larit, Auteur ; Samira Benyahia, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2017 . - 353 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Anglais (eng)
Catégories : Français - Anglais
ChimieTags : Hypericum Cytisus Secondary metabolites Total phenolics Antioxidant Cytotoxicity Antifungal Antibacterial Antimalarial Antileishmanial Activity MAO-A and MAO-B Docking Simulation Métabolites secondaires Total phénoliques Cytotoxicité Antifongique Antibactérienne Antipaludique Antileishmanienne MAO-A et MAO-B "MAO-A MAO-B Cytisus Hypericum ?????? ????????? ???????? ???? ??????? ???? ????????? ???? ???????? ???? ?????????????" Index. décimale : 540 Chimie et sciences connexes Résumé : Natural products are important sources of novel therapeutic agents. Bioactive secondary metabolites
isolated from natural sources, can act as drugs or as lead compounds for synthetic drugs. In our work, two plants
have been studied; the endemic species of Hypericum afrum Lam.(Hypericaceae) and Cytisus villosus Pourr.
(Fabaceae). Fractions of the aerial parts of these two plants have been screened in vitro for several biological
assays including cannabinoid and opioid receptors agonist assays, antifungal, antibacterial, antimalarial,
antileishmanial, antiproliferative, antioxidant, anti-inflammatory and MAO inhibition.
The chloroform, ethyl acetate and n-butanol fractions of H. afrum showed significant antioxidant activity and
potent antitrypanosomal activity against T. brucei. The n-butanol fraction of C. villosus showed highly potent
antitrypanosomal activity against T. brucei. In addition, the ethyl acetate fractions of both plants showed potent
inhibition of recombinant human monoamine oxidases (MAO-A and -B).
A bioassay-guided fractionation paradigm has been used for the isolation of bioactive compounds of these plants
and hence the subfractions that showed significant activity were further purified.
This study led to the isolation and identification of 20 compounds, three of which belonging to phloroglucinols,
terpenoids and isoflavonoids are new. The structures of the isolated compounds were elucidated through various
spectroscopic methods, including high- resolution mass spectrometry, one and two-dimensional nuclear magnetic
resonance spectroscopy.
Computational study was carried out by conformational search and docking techniques to provide insight into the
binding mode of molecules on the active site of MAO’s isoenzymes.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAR7157.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10430 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LAR/7157 LAR/7157 Thèse Bibliothèque principale Thèses Disponible
