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Partager le résultat de cette recherche Interroger des sources externesEssais d'optimisation des conditions de cuisson et d'extraction des polyphénols de six légumes et évaluation des activités / Imène Laib
Titre : Essais d'optimisation des conditions de cuisson et d'extraction des polyphénols de six légumes et évaluation des activités : antioxydante et anticholinestérase. Type de document : texte imprimé Auteurs : Imène Laib, Auteur ; Malika Barkat, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 287 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Optimisation légume cuisson polyphénols totaux flavonoïdes activité antioxydante activité anticholinestérase Optimization vegetable cooking total polyphenolic flavonoids antioxidant activity anticholinesterase activity لتحسين الخضار الطبخ البوليفينول الكلي الفلافونويد النشاط المضاد للأكسدة نشاط مضادات
الكولينستريزIndex. décimale : 640 Industrie Alimentaire Résumé : This study focuses on the optimization of the cooking conditions and the extraction of polyphenols from six vegetables (potato, onion, spinach, aubergine carrot and pepper) and the study of the impact of the cooking method (boiling, steaming and microwaving) on these compounds and their biological activities (antioxidant activity and anticholinesterase activity).
To evaluate the quantity of phenolic compounds extracted from raw and cooked vegetables, a experiment design was realized. The factors chosen are (Temperature, time, power) for cooking and (solvent concentration, maceration time, ultrasonication and grinding) for polyphenol extraction . The study was initiated by Plackett-Burmann design to perform the screening of factors and to select the most influential on the Y response (total phenolic) and an optimization by exploiting central composite design. Determination of total polyphenols, flavonoids and LC-MS / MS analysis were performed to monitor the variation of phenolic compounds after cooking. In addition, in this work, we anlyzed antioxidant and anticholinesterase properties of the phenolic compounds of the six raw and cooked vegetables.
The results obtained for the six vegetables are different, boiling in water and steam cooking methods have reduced the levels of total polyphenols and flavonoids of the six vegetables. While microwave cooking had different effects on the six vegetables, it had a negative effect on the total polyphenol and flavonoid levels of the potato, spinach, carrot and pepper.
However, a positive effect was recorded on the total polyphenols and flavonoids of eggplant. Retention of these compounds has been observed in onions cooked by microwave. The impact of cooking on antioxidant activity varies from one vegetable to another. Cooking caused a decrease in the antioxidant activity of potatoes, onions, carrots, peppers and steamed spinach.
A positive effect of cooking was recorded on the antioxidant potential of spinach (cooked in water and by microwave) and eggplant. All three cooking methods showed negative effects on the anticholinesterase activity of potato, spinach and pepper. However, an increase in this activity was recorded for onion, eggplant and carrot. Cooking in water proved to be the worst method for preserving the polyphenols from cooked vegetables and their activities (antioxidant activity and anticholinesterase). The losses of polyphenols are due to their increased solubility in water. However, microwave cooking is suggested as the best method to preserve the polyphenol levels, the antioxidant and anticholinesterase activities of the studied vegetables.
Diplôme : Doctorat en sciences En ligne : ../theses/agronomie/LAI7279.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10894 Essais d'optimisation des conditions de cuisson et d'extraction des polyphénols de six légumes et évaluation des activités : antioxydante et anticholinestérase. [texte imprimé] / Imène Laib, Auteur ; Malika Barkat, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 287 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Optimisation légume cuisson polyphénols totaux flavonoïdes activité antioxydante activité anticholinestérase Optimization vegetable cooking total polyphenolic flavonoids antioxidant activity anticholinesterase activity لتحسين الخضار الطبخ البوليفينول الكلي الفلافونويد النشاط المضاد للأكسدة نشاط مضادات
الكولينستريزIndex. décimale : 640 Industrie Alimentaire Résumé : This study focuses on the optimization of the cooking conditions and the extraction of polyphenols from six vegetables (potato, onion, spinach, aubergine carrot and pepper) and the study of the impact of the cooking method (boiling, steaming and microwaving) on these compounds and their biological activities (antioxidant activity and anticholinesterase activity).
To evaluate the quantity of phenolic compounds extracted from raw and cooked vegetables, a experiment design was realized. The factors chosen are (Temperature, time, power) for cooking and (solvent concentration, maceration time, ultrasonication and grinding) for polyphenol extraction . The study was initiated by Plackett-Burmann design to perform the screening of factors and to select the most influential on the Y response (total phenolic) and an optimization by exploiting central composite design. Determination of total polyphenols, flavonoids and LC-MS / MS analysis were performed to monitor the variation of phenolic compounds after cooking. In addition, in this work, we anlyzed antioxidant and anticholinesterase properties of the phenolic compounds of the six raw and cooked vegetables.
The results obtained for the six vegetables are different, boiling in water and steam cooking methods have reduced the levels of total polyphenols and flavonoids of the six vegetables. While microwave cooking had different effects on the six vegetables, it had a negative effect on the total polyphenol and flavonoid levels of the potato, spinach, carrot and pepper.
However, a positive effect was recorded on the total polyphenols and flavonoids of eggplant. Retention of these compounds has been observed in onions cooked by microwave. The impact of cooking on antioxidant activity varies from one vegetable to another. Cooking caused a decrease in the antioxidant activity of potatoes, onions, carrots, peppers and steamed spinach.
A positive effect of cooking was recorded on the antioxidant potential of spinach (cooked in water and by microwave) and eggplant. All three cooking methods showed negative effects on the anticholinesterase activity of potato, spinach and pepper. However, an increase in this activity was recorded for onion, eggplant and carrot. Cooking in water proved to be the worst method for preserving the polyphenols from cooked vegetables and their activities (antioxidant activity and anticholinesterase). The losses of polyphenols are due to their increased solubility in water. However, microwave cooking is suggested as the best method to preserve the polyphenol levels, the antioxidant and anticholinesterase activities of the studied vegetables.
Diplôme : Doctorat en sciences En ligne : ../theses/agronomie/LAI7279.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10894 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LAI/7279 LAI/7279 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude de la micropropagation de Mentha x rotundifolia (L.)Huds et Mentha pulegium L. : Production des huiles essentielles et évaluation des activités biologiques. Type de document : texte imprimé Auteurs : Amira Benahmed ép Meskaldji, Auteur ; Abdelmalik Belkhiri, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 141 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : biologie et écologie végétale: Biotechnologie végétale Mentha pulegium Mentha rotundifolia micropropagation huile essentielle activité antioxydante activité antimicrobienne M. pulegium M. rotundifolia essential oil antioxidant
activity antimicrobial activity الإكثار الدقيق الزيت العطري النشاط المضاد للأكسدة النشاط المًضاد للميكروباتIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
Micropropagation of two local species M. rotundifolia and M. pulegium has been carried with two main objectives: firstly, to set up optimal conditions for culture and regeneration of the two species, then evaluate temperature and photoperiod stress conditions on the EO composition and the antioxidant and antimicrobial activities. Explant of the two species was settled on culture with MS medium, acclimated under temperature and photoperiod stress conditions. Mother plants and vitro plants EO were obtained by hydrodistillation and analyzed by GC-MS. Antioxydant and antimicrobial activities of EO were carried out with standards methods (DPPH, ABTS, and CUPRAC) and (diffusion), respectively. Cultures inductions were achieved with MS medium supplemented with 1 mg/l BAP + 1 mg/l GA3. Explants multiplications of M. rotundifolia and M. pulegium were successfully done on MS medium supplemented with 0,5 mg/l BAP +0,5 mg/l GA3 and 0,5 mg/l BAP +1 mg/l GA3, respectively. In vitro rooted plants of the two mints species were well acclimated with a total survival rate greater than 96%. Regarding EO production, photoperiod and light stress assays have shown a significant increase in EO content and selective biosynthesis orientations in relation with phyto-constituents with high value (l-menthone, oxyde de piperitenone) or with side effects (hépatotoxic pulegone).This study has shown that abiotic parameters (light and photoperiod) positively affect vitro plants EO antioxidant activities, while no obvious effect was observed for antimicrobial activities. Finally, the results of this study led to the establishment of an effective in vitro micropropagation protocol from Mentha axillary buds, with the possibility to increase yield and / or to direct the chemical profile of EO for future commercial use.Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BEN7456.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11287 Etude de la micropropagation de Mentha x rotundifolia (L.)Huds et Mentha pulegium L. : Production des huiles essentielles et évaluation des activités biologiques. [texte imprimé] / Amira Benahmed ép Meskaldji, Auteur ; Abdelmalik Belkhiri, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 141 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : biologie et écologie végétale: Biotechnologie végétale Mentha pulegium Mentha rotundifolia micropropagation huile essentielle activité antioxydante activité antimicrobienne M. pulegium M. rotundifolia essential oil antioxidant
activity antimicrobial activity الإكثار الدقيق الزيت العطري النشاط المضاد للأكسدة النشاط المًضاد للميكروباتIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
Micropropagation of two local species M. rotundifolia and M. pulegium has been carried with two main objectives: firstly, to set up optimal conditions for culture and regeneration of the two species, then evaluate temperature and photoperiod stress conditions on the EO composition and the antioxidant and antimicrobial activities. Explant of the two species was settled on culture with MS medium, acclimated under temperature and photoperiod stress conditions. Mother plants and vitro plants EO were obtained by hydrodistillation and analyzed by GC-MS. Antioxydant and antimicrobial activities of EO were carried out with standards methods (DPPH, ABTS, and CUPRAC) and (diffusion), respectively. Cultures inductions were achieved with MS medium supplemented with 1 mg/l BAP + 1 mg/l GA3. Explants multiplications of M. rotundifolia and M. pulegium were successfully done on MS medium supplemented with 0,5 mg/l BAP +0,5 mg/l GA3 and 0,5 mg/l BAP +1 mg/l GA3, respectively. In vitro rooted plants of the two mints species were well acclimated with a total survival rate greater than 96%. Regarding EO production, photoperiod and light stress assays have shown a significant increase in EO content and selective biosynthesis orientations in relation with phyto-constituents with high value (l-menthone, oxyde de piperitenone) or with side effects (hépatotoxic pulegone).This study has shown that abiotic parameters (light and photoperiod) positively affect vitro plants EO antioxidant activities, while no obvious effect was observed for antimicrobial activities. Finally, the results of this study led to the establishment of an effective in vitro micropropagation protocol from Mentha axillary buds, with the possibility to increase yield and / or to direct the chemical profile of EO for future commercial use.Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BEN7456.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11287 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7456 BEN/7456 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude des activités biologiques de l’huile essentielle extraite des graines de foeniculum vulgare Mill : en vue de son utilisation comme conservateur alimentaire. Type de document : texte imprimé Auteurs : Ali Bouguerra, Auteur ; Malika Barkat, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2012 Importance : 111 f. Format : 31 cm. Langues : Français (fre) Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie alimentaire: Sciences Alimentaires Huile essentielle activité antioxydante activité antibactérienne activité antifongique Foeniculum vulgare Mill
Essential oil antioxidant activity antibacterial activity antifungal Feoniculum vulgare
Mill الزیوت الأساسیة الفاعلیة المضادة للأكسدة الفاعلیة المضادة للبكتیریا الفاعلیة المضادة للفطریات (Foeniculum vulgare Mill.) ذرة الشمرةIndex. décimale : 640 Industrie Alimentaire Résumé :
The synthetic food conservatives are limited in several countries, because of their undesirable effects on health. Moreover, the current trend of the consumers seeks a more natural food increased during these last decades. Several research tasks have concentrated on the essential oils extracted from the aromatic plants. The various results published have indicated that they are endowed with several biological properties. In this context, we tried to evaluate antioxidant, antibacterial and
antifungal activities of essential oil extracted from Foeniculum vulgare Mill. seeds.
The extraction was carried out by water distillation Clevenger’s type apparatus, the yield was 0.79±0.02%. The evaluation of the antiradical activity of the fennel seeds essential oil was evaluated by the reduction of the DPPH• method. The EC50 (efficiencies’ concentration) obtained is 752.65±32.5µg.ml-1. The fennel seeds essential oil shows also a very interesting antioxidant activity (81.74± 3.92%) by the of β-Carotene bleaching method. Diffusion Method has demonstrated that the fennel seeds essential oil has a feeble antibacterial activity. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) are estimated by agar dilution method, the MIC obtained are included between 20 000 and 45 000 µg.ml-1, the MBC proved also raised. The antifungal activities of the essential oil against fungi were undertaken using inverted petriplate. The results obtained indicate that the fennel seeds essential oil has strong activity. Minimum fongistatic concentrations (MFCS), and minimum fungicidal concentration (MFCC) were estimated by broth dilution method, the MFCS obtained are included between 625 and 1250µg.ml-1, the MFCC obtained is 1250µg.ml-1. The antifungal index (AI50) were estimated, the Alternaria was
most sensitive where his AI50 was 26.22±0,693µg.ml-1. With the rise of this study, we can conclude that the fennel seeds essential oil could be regarded as a very promising preservative for food industry able to prevent the oxidation of food and to reduce growth in of deterioration of food and producing mycotoxins mycelial.Note de contenu :
Annexes.Diplôme : Magistère En ligne : ../theses/agronomie/BOU6092.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=5996 Etude des activités biologiques de l’huile essentielle extraite des graines de foeniculum vulgare Mill : en vue de son utilisation comme conservateur alimentaire. [texte imprimé] / Ali Bouguerra, Auteur ; Malika Barkat, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2012 . - 111 f. ; 31 cm.
Langues : Français (fre)
Catégories : Français - Anglais
Nutrition, Alimentation et Technologies Agro-AlimentairesTags : Biotechnologie alimentaire: Sciences Alimentaires Huile essentielle activité antioxydante activité antibactérienne activité antifongique Foeniculum vulgare Mill
Essential oil antioxidant activity antibacterial activity antifungal Feoniculum vulgare
Mill الزیوت الأساسیة الفاعلیة المضادة للأكسدة الفاعلیة المضادة للبكتیریا الفاعلیة المضادة للفطریات (Foeniculum vulgare Mill.) ذرة الشمرةIndex. décimale : 640 Industrie Alimentaire Résumé :
The synthetic food conservatives are limited in several countries, because of their undesirable effects on health. Moreover, the current trend of the consumers seeks a more natural food increased during these last decades. Several research tasks have concentrated on the essential oils extracted from the aromatic plants. The various results published have indicated that they are endowed with several biological properties. In this context, we tried to evaluate antioxidant, antibacterial and
antifungal activities of essential oil extracted from Foeniculum vulgare Mill. seeds.
The extraction was carried out by water distillation Clevenger’s type apparatus, the yield was 0.79±0.02%. The evaluation of the antiradical activity of the fennel seeds essential oil was evaluated by the reduction of the DPPH• method. The EC50 (efficiencies’ concentration) obtained is 752.65±32.5µg.ml-1. The fennel seeds essential oil shows also a very interesting antioxidant activity (81.74± 3.92%) by the of β-Carotene bleaching method. Diffusion Method has demonstrated that the fennel seeds essential oil has a feeble antibacterial activity. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) are estimated by agar dilution method, the MIC obtained are included between 20 000 and 45 000 µg.ml-1, the MBC proved also raised. The antifungal activities of the essential oil against fungi were undertaken using inverted petriplate. The results obtained indicate that the fennel seeds essential oil has strong activity. Minimum fongistatic concentrations (MFCS), and minimum fungicidal concentration (MFCC) were estimated by broth dilution method, the MFCS obtained are included between 625 and 1250µg.ml-1, the MFCC obtained is 1250µg.ml-1. The antifungal index (AI50) were estimated, the Alternaria was
most sensitive where his AI50 was 26.22±0,693µg.ml-1. With the rise of this study, we can conclude that the fennel seeds essential oil could be regarded as a very promising preservative for food industry able to prevent the oxidation of food and to reduce growth in of deterioration of food and producing mycotoxins mycelial.Note de contenu :
Annexes.Diplôme : Magistère En ligne : ../theses/agronomie/BOU6092.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=5996 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6092 BOU/6092 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude phytochimique et évaluation des activités biologiques de la plante Daucus muricatus (Apiaceae) Type de document : texte imprimé Auteurs : Amira Noui, Auteur ; Salah Akkal, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 85 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
ChimieTags : Apiaceae Daucus muricatus LC-ESI-MS/MS Composés phénoliques Activité antioxydante phenolic compounds antioxidant activity العائلة الخيمية البوليفينولات الفعالية المضادة للاكسدة Index. décimale : 540 Chimie et sciences connexes Résumé : This work is dedicate to the phytochemical study of Daucus muricatus species (Apiaceae), it was aimed at investigating the phytochemical components of butanolic extract using HPLC-DAD-ESI-MS/MS. The proposed method provided tentative identification of 25 phenolic compounds, including, 13 hydroxycinnamic acid derivatives, 5 hydroxybenzoïc acid derivatives,8 flavonoïds and other polar
compounds as quinic acid. Evaluation of the antioxidant activities by using four complementary tests (DPPH, ABTS, CUPRAC and carotene Bleanching) showed that both extracts exhibited importatnt antioxidant activities.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/NOU7349.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10999 Etude phytochimique et évaluation des activités biologiques de la plante Daucus muricatus (Apiaceae) [texte imprimé] / Amira Noui, Auteur ; Salah Akkal, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 85 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
ChimieTags : Apiaceae Daucus muricatus LC-ESI-MS/MS Composés phénoliques Activité antioxydante phenolic compounds antioxidant activity العائلة الخيمية البوليفينولات الفعالية المضادة للاكسدة Index. décimale : 540 Chimie et sciences connexes Résumé : This work is dedicate to the phytochemical study of Daucus muricatus species (Apiaceae), it was aimed at investigating the phytochemical components of butanolic extract using HPLC-DAD-ESI-MS/MS. The proposed method provided tentative identification of 25 phenolic compounds, including, 13 hydroxycinnamic acid derivatives, 5 hydroxybenzoïc acid derivatives,8 flavonoïds and other polar
compounds as quinic acid. Evaluation of the antioxidant activities by using four complementary tests (DPPH, ABTS, CUPRAC and carotene Bleanching) showed that both extracts exhibited importatnt antioxidant activities.
Diplôme : Doctorat en sciences En ligne : ../theses/chimie/NOU7349.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10999 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité NOU/7349 NOU/7349 Thèse Bibliothèque principale Thèses Disponible
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
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