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Partager le résultat de cette recherche Interroger des sources externesIsolement et détermination structurale de métabolites secondaires d’espèces des genres Santolina et Centaurea (Asteraceae) - Activités biologiques. / Fatiha Labed
Titre : Isolement et détermination structurale de métabolites secondaires d’espèces des genres Santolina et Centaurea (Asteraceae) - Activités biologiques. Type de document : texte imprimé Auteurs : Fatiha Labed, Auteur ; Fadila Benayache, Directeur de thèse Mention d'édition : déc-19 Année de publication : 2019 Importance : 300 f. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Chimie organique : phytochimie Santolina chamaecyparissus Centaurea pungens Asteraceae Métabolites secondaires Activité antioxydante Dosage des phénols et flavonoïdes totaux Activité antimicrobienne Antimicrobial activity Secondary metabolites Antioxidant activity Determination of phenol content بنغوريات Centaurea الثانوية نشاط مضادات الأكسدة تقدير الفينولات والفلافونيدات الكلية نشاط مضادات الميكروبات Index. décimale : 540 Chimie et sciences connexes Résumé : This work is part of the research program established by our research unit which consists in the phytochemical investigation of Algerian medicinal plants belonging to families known for their richness in secondary metabolites with potential biological activities. In this context, two species were selected: Santolina chamaecyparissus and Centaurea pungens, given their belonging to the family Asteraceae whose richness in bioactive compounds is well established. Known mainly for their essential oils, the aerial parts of S. chamaecyparissus (leaves + flowers) were macerated in 70% ethanol. After filtration, concentration and dilution with distilled water, the obtained hydroalcoholic extract is subjected to successive extractions by solvents of increasing polarity (CHCl3, AcOEt and n-BuOH) to give the three corresponding derivative extracts. Our experiments concerned the CHCl3 and n-BuOH extracts and focused on the determination of the total phenols of the two extracts and then the evaluation of their antioxidant activity by the DPPH radical reduction and TEAC tests. The results showed that the n-BuOH extract is richer in phenolic compounds and is better antioxidant than the CHCl3 extract in the DPPH radical scavenging assay with vitamin C as positive control. In the TEAC test, the results were in agreement with those of the DPPH radical test, in fact the n-BuOH extract showed a significant and similar activity to that of quercetin 3-O-glucoside used as positive control.
Following these encouraging results, both extracts were subjected to chromatographic techniques
and 15 compounds were isolated. The structures of 14 of these compounds were determined.
These are 5 flavone aglycones including 4 methoxylated; 3 glycosylated flavones, 2 of which were new for Santolina genus; 2 megastigmane glucosides new for Asteraceae family; 2 phenylpropanoids new for the genus Santolina and 2 cyanogenic compounds also new for the genus Santolina. The phytochemical investigation of Centaurea pungens (Flowers) conducted by similar methods as reported for S. chamaecyparissus, allowed the isolation of 9 pure products: 3 sesquiterpene lactones, 2 of which were described for the first time in the literature, 2 methoxylated flavones, 3 glucosylated flavones and a derivative of quinic acid. In order to validate the use of C. pungens in traditional medicine, the antimicrobial activity of the 9 isolated compounds was assessed against Gram-positive strains: Bacillus cereus, Staphylococcus aureus and Listeria innocua, and Gramnegative strains: Pseudomonas aeruginosa and Pseudomonas fragi.Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAB7860.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11849 Isolement et détermination structurale de métabolites secondaires d’espèces des genres Santolina et Centaurea (Asteraceae) - Activités biologiques. [texte imprimé] / Fatiha Labed, Auteur ; Fadila Benayache, Directeur de thèse . - déc-19 . - 2019 . - 300 f.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Chimie organique : phytochimie Santolina chamaecyparissus Centaurea pungens Asteraceae Métabolites secondaires Activité antioxydante Dosage des phénols et flavonoïdes totaux Activité antimicrobienne Antimicrobial activity Secondary metabolites Antioxidant activity Determination of phenol content بنغوريات Centaurea الثانوية نشاط مضادات الأكسدة تقدير الفينولات والفلافونيدات الكلية نشاط مضادات الميكروبات Index. décimale : 540 Chimie et sciences connexes Résumé : This work is part of the research program established by our research unit which consists in the phytochemical investigation of Algerian medicinal plants belonging to families known for their richness in secondary metabolites with potential biological activities. In this context, two species were selected: Santolina chamaecyparissus and Centaurea pungens, given their belonging to the family Asteraceae whose richness in bioactive compounds is well established. Known mainly for their essential oils, the aerial parts of S. chamaecyparissus (leaves + flowers) were macerated in 70% ethanol. After filtration, concentration and dilution with distilled water, the obtained hydroalcoholic extract is subjected to successive extractions by solvents of increasing polarity (CHCl3, AcOEt and n-BuOH) to give the three corresponding derivative extracts. Our experiments concerned the CHCl3 and n-BuOH extracts and focused on the determination of the total phenols of the two extracts and then the evaluation of their antioxidant activity by the DPPH radical reduction and TEAC tests. The results showed that the n-BuOH extract is richer in phenolic compounds and is better antioxidant than the CHCl3 extract in the DPPH radical scavenging assay with vitamin C as positive control. In the TEAC test, the results were in agreement with those of the DPPH radical test, in fact the n-BuOH extract showed a significant and similar activity to that of quercetin 3-O-glucoside used as positive control.
Following these encouraging results, both extracts were subjected to chromatographic techniques
and 15 compounds were isolated. The structures of 14 of these compounds were determined.
These are 5 flavone aglycones including 4 methoxylated; 3 glycosylated flavones, 2 of which were new for Santolina genus; 2 megastigmane glucosides new for Asteraceae family; 2 phenylpropanoids new for the genus Santolina and 2 cyanogenic compounds also new for the genus Santolina. The phytochemical investigation of Centaurea pungens (Flowers) conducted by similar methods as reported for S. chamaecyparissus, allowed the isolation of 9 pure products: 3 sesquiterpene lactones, 2 of which were described for the first time in the literature, 2 methoxylated flavones, 3 glucosylated flavones and a derivative of quinic acid. In order to validate the use of C. pungens in traditional medicine, the antimicrobial activity of the 9 isolated compounds was assessed against Gram-positive strains: Bacillus cereus, Staphylococcus aureus and Listeria innocua, and Gramnegative strains: Pseudomonas aeruginosa and Pseudomonas fragi.Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/chimie/LAB7860.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11849 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LAB/7860 LAB/7860 Thèse Bibliothèque principale Thèses Disponible
Titre : Le sapin d'Algérie (Abies numidica de Lannoy ex Carrière): étude phytochimique des métabolites secondaires et évaluation in vitro, in vivo et in silico des activités biologiques de ses composés. Type de document : texte imprimé Auteurs : Djamila Benouchenne, Auteur ; Ines Bellil, Directeur de thèse ; Douadi Khelifi, Directeur de thèse Mention d'édition : 02/12/2021 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2021 Importance : 146 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie / Nutrition Abies numidica de Lannoy LC-MS/MS GC/MS cytotoxicité inhibition des enzymes activités biologiques toxicité in vivo métabolites secondaires cytotoxicity inhibition of
enzymes, biological activities in vivo toxicity secondary metabolites السمية الخلوية تثبيط الإنزيمات والأنشطة البيولوجية سمية في الجسم الحي المستقلبات الثانويةIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
This study aims to enhance the virtues of an Algerian endemic plant which is the Algerian fir ""Abies numidica de Lannoy ex Carrière"" by a phytochemical characterization and an evaluation of the biological activities of its leaves. The phytochemical study revealed the main secondary metabolites found in particular were polyphenols (phenolic acids, flavonoids and tannins). LCMS / MS Analysis of the polyphenolic in extracts revealed the richness of the leaves of the Algerian fir in phenolic compounds, 12 molecules were identified in the AE fraction and 8 compounds were determined in the n-BuOH extract. GC-MS analysis showed the presence of 29 terpene compounds. The evaluation of the antioxidant power in vitro by colorimetric methods (DPPH •, ABTS • +, reducing power, CUPRAC and phenanthroline) showed that the AE and n-BuOH extracts endowed with a high antioxidant power. The antimicrobial effect of the medicinal plant varies depending on the nature of the strain and the extract tested. The extracts exhibited a significant cytotoxicity against Artemia salina lethality. In vivo, the AE and n-BuOH extract from the leaves of A. numidca showed no mortality at the concentration of 2000 mg / kg. Furthermore, biochemical parameters confirmed the presence of liver damage, by increasing the concentration of liver transaminases. The in silico toxicity study confirmed that the extracts were not toxic. The present study confirmed the effectiveness of the plant and provided measurable biological proof of its antioxidant, enzyme inhibitory and antibacterial power.
Diplôme : Doctorat En ligne : ../theses/biologie/BEN7855.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11844 Le sapin d'Algérie (Abies numidica de Lannoy ex Carrière): étude phytochimique des métabolites secondaires et évaluation in vitro, in vivo et in silico des activités biologiques de ses composés. [texte imprimé] / Djamila Benouchenne, Auteur ; Ines Bellil, Directeur de thèse ; Douadi Khelifi, Directeur de thèse . - 02/12/2021 . - جامعة الإخوة منتوري قسنطينة, 2021 . - 146 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie / Nutrition Abies numidica de Lannoy LC-MS/MS GC/MS cytotoxicité inhibition des enzymes activités biologiques toxicité in vivo métabolites secondaires cytotoxicity inhibition of
enzymes, biological activities in vivo toxicity secondary metabolites السمية الخلوية تثبيط الإنزيمات والأنشطة البيولوجية سمية في الجسم الحي المستقلبات الثانويةIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
This study aims to enhance the virtues of an Algerian endemic plant which is the Algerian fir ""Abies numidica de Lannoy ex Carrière"" by a phytochemical characterization and an evaluation of the biological activities of its leaves. The phytochemical study revealed the main secondary metabolites found in particular were polyphenols (phenolic acids, flavonoids and tannins). LCMS / MS Analysis of the polyphenolic in extracts revealed the richness of the leaves of the Algerian fir in phenolic compounds, 12 molecules were identified in the AE fraction and 8 compounds were determined in the n-BuOH extract. GC-MS analysis showed the presence of 29 terpene compounds. The evaluation of the antioxidant power in vitro by colorimetric methods (DPPH •, ABTS • +, reducing power, CUPRAC and phenanthroline) showed that the AE and n-BuOH extracts endowed with a high antioxidant power. The antimicrobial effect of the medicinal plant varies depending on the nature of the strain and the extract tested. The extracts exhibited a significant cytotoxicity against Artemia salina lethality. In vivo, the AE and n-BuOH extract from the leaves of A. numidca showed no mortality at the concentration of 2000 mg / kg. Furthermore, biochemical parameters confirmed the presence of liver damage, by increasing the concentration of liver transaminases. The in silico toxicity study confirmed that the extracts were not toxic. The present study confirmed the effectiveness of the plant and provided measurable biological proof of its antioxidant, enzyme inhibitory and antibacterial power.
Diplôme : Doctorat En ligne : ../theses/biologie/BEN7855.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11844 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7855 BEN/7855 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 تقنیات النموذجیة الجزیئیة مضاد للاكسدة مضاد لليشمانيا مضاد الملاريا مضاد التريبانوسوما" 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 : 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 . - 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 تقنیات النموذجیة الجزیئیة مضاد للاكسدة مضاد لليشمانيا مضاد الملاريا مضاد التريبانوسوما" 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 : 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
