1 |
Atividade antinociceptiva e anti-inflamatória do sesquiterpeno nerolidol em camundongos. / Antinociceptive and anti-inflammatory activities of the sesquiterpeno nerolidol in mice.Fonsêca, Diogo Vilar da 06 December 2012 (has links)
Made available in DSpace on 2015-05-14T12:59:41Z (GMT). No. of bitstreams: 1
arquivototal.pdf: 2581356 bytes, checksum: 263a53dd1bd0ffe8ccf75ad8984a3779 (MD5)
Previous issue date: 2012-12-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Nerolidol, an acyclic sesquiterpene found as the major component in several essential oils, has antineoplastic, antimicrobial and antileishmanial activities, however its action in painful processes has never been studied. This study investigated the antinociceptive and anti-inflammatory activities of nerolidol in experimental pain and inflammation models in mice. On the pharmacological behavioral screening, the different doses tested by the nerolidol had psicodepressors behavioral changes such as decreased ambulation and analgesia. The LD50 could not be determined, since there were no deaths until the maximum dose of 2000 mg/kg. Motor coordination, evaluated through the rotarod test, was not altered in animals treated with nerolidol in any of the doses used. After, methods to evaluate the antinociceptive activity were used. Nerolidol reduced the number of acetic-acid induced abdominal contractions compared to the control group in all of the three doses tested. The formalin test, inhibited licking time both in the first phase (0 5 min) and in the second phase (15 30 min). Under the hot-plate test, nerolidol did not alter latency at any of the observed time-points. The mechanism of action of the antinociceptive property of nerolidol was assessed using the formalin test. The antinociception produced by nerolidol was significantly blocked in animals pre-treated with bicuculline (1 mg/kg, i.p.), indicating the involvement of GABAergic system. However, the effect of nerolidol was not reversed by the naloxone (non selective opioid antagonist, 5 mg/kg, s.c.) and glibenclamide (K +ATP channels bloker, 10 mg/kg, i.p.), demonstrating that at least directly, the nerolidol does not act by these mechanisms. The treatment with nerolidol was able to reduce the paw edemas induced by carragenina. At the model of peritonitis induced by carraggenan, nerolidol decreased the influx of leukocytes and also the levels of TNF-α in the peritoneal fluid. Therefore, these results indicate that nerolidol has antinociceptive activity with possible participation of the GABAergic system. Besides, nerolidol has anti-inflammatory activity that may be attributed to inhibition pro-inflammatory cytokines production TNF-α. / O nerolidol, sesquiterpeno acíclico encontrado como constituinte majoritário em vários óleos essenciais, apresenta atividade antineoplásica, antimicrobiana e leishmanicida, porém sua ação em processos dolorosos nunca foi estudada. Este trabalho visa investigar a atividade antinociceptiva e anti-inflamatória do nerolidol em modelos experimentais de dor e inflamação em camundongos. Na triagem farmacológica comportamental, as diferentes doses testadas do nerolidol apresentaram alterações comportamentais psicodepressoras, tais como ambulação diminuída e analgesia. A DL50 não pôde ser determinada, uma vez que não se observaram mortes até a dose máxima de 2000 mg/kg. A coordenação motora, avaliada no teste do rota-rod, não foi alterada nos animais tratados com nerolidol em nenhuma das doses. Em seguida, metodologias foram realizadas para avaliar a atividade antinociceptiva. O nerolidol reduziu o número de contorções abdominais induzidas por ácido acético, quando comparado ao grupo controle nas três doses testadas. No teste da formalina, foi capaz de inibir o tempo de lambida tanto na primeira fase (0-5min) quanto na segunda fase (15-30 min). No teste da placa quente, o nerolidol não alterou a latência em nenhum dos tempos observados. O mecanismo de ação da propriedade antinociceptiva do nerolidol foi avaliado através do teste da formalina. A antinocicepção produzida pelo nerolidol foi significativamente bloqueada em animais pré-tratados com bicuculina (1 mg/kg, i.p.), indicando o envolvimento do sistema GABAérgico. O efeito antinociceptivo do nerolidol, contudo, não foi revertido pela naloxona (antagonista não seletivo dos receptores opioides, 5 mg/kg, s.c.) e pela glibenclamida (bloqueador dos canais de K+ATP, 10 mg/kg, i.p.), sugerindo que o nerolidol não atua por esses mecanismos. O tratamento com o nerolidol foi capaz de reduzir o edema de pata induzido por carragenina. No modelo da peritonite induzida por carragenina, o nerolidol diminuiu o influxo de leucócitos e também os níveis de TNF-α no lavado peritoneal. Sendo assim, esses resultados mostram que o nerolidol tem atividade antinociceptiva com possível participação do sistema GABAérgico Além disso, o nerolidol possui atividade anti-inflamatória que pode ser atribuída à inibição da produção da citocina pró-inflamatória TNF-α.
|
2 |
Évaluation de l’efficacité des antimicrobiens naturels libres et encapsulés contre la colonisation du jus d’orange par des bactéries lactiques : comparaison entre quatre systèmes d'encapsulation / Evaluation of the efficacy of free and encapsulated natural antimicrobials against the colonization of orange juice by lactic acid bacteria : comparison between four encapsulation systemsEphrem, Elissa 18 December 2018 (has links)
Le jus d'orange frais est largement apprécié par les consommateurs en raison de son goût agréable et sa haute valeur nutritionnelle. La qualité du jus d'orange frais est rapidement altérée, notamment par les microorganismes. L'addition des antimicrobiens d'origine végétale au jus d'orange pourrait augmenter la durée de vie de ce jus durant le stockage à 4 °C. Parmi ces antimicrobiens naturels, plusieurs sont sensibles aux facteurs environnementaux qui diminuent leur efficacité dans les produits alimentaires, ce qui nécessite leur incorporation dans des systèmes d'encapsulation. Bien que ce domaine soit promettant, l'évaluation de l'activité des molécules antimicrobiennes encapsulées dans des jus de fruits reste limitée. Nous avons recherché une molécule naturelle active contre Lactobacillus fermentum, une bactérie impliquée dans la détérioration du jus 'orange, dans le milieu de culture. Le nérolidol (Ner), un sesquiterpène alcool, a été sélectionné parmi 28 molécules naturelles (terpènes et phénols) criblées et a montré une puissante activité contre L. fermentum (concentration minimale inhibitrice (CMI) = 25 μM et concentration minimale bactéricide (CMB)= 50 μM) dans le milieu de culture à 37 °C. Dans la suite du travail, le Ner a été incorporé dans le complexe d'inclusion hydroxypropyl-β-cyclodextrin (HP-β-CD)/Ner, les liposomes conventionnels (LCs), les liposomes contenant le complexe d'inclusion (DCL) et les bicelles. Les analyses HPLC ont montré que les complexes d'inclusion, les LCs et le système DCL contenaient 40, 30 et 15 μg Ner/mg poudre, respectivement. En outre, les systèmes ont été caractérisés en termes de morphologie, de taille, d'homogénéité et de potentiel zêta. Le Ner a été incorporé dans les bicelles à un rapport molaire phospholipides:Ner de 100:1 sans altération de la structure du système (taille, homogénéité, potentiel zêta, morphologie). Cette formulation a montré une efficacité d'encapsulation du Ner et un taux d'incorporation des phospholipides élevés et un pourcentage de Ner dans les bicelles de 0,86%. A des concentrations plus élevées, le Ner a altéré les caractéristiques physiques (taille, homogénéité, morphologie) et thermodynamiques de la membrane des bicelles et a augmenté le désordre au niveau membranaire. Le complexe d'inclusion HP-β-CD/Ner (CMI = 100 μM et CMB= 200 μM) a montré une bonne efficacité contre L. fermentum dans le milieu de culture à 37 °C. L'efficacité du Ner libre et du complexe d'inclusion HP-β-CD/Ner a énormément diminué dans le jus d'orange réfrigéré, vu qu'un effet bactéricide total a été obtenu après 8 et 17 jours d'incubation, respectivement, à 2000 μM en Ner. Alors que les liposomes ont bloqué cette activité pour au moins 20 jours et ont altéré l'aspect du jus. A 4000 μM en Ner libre ou incorporé dans le complexe d'inclusion, une mort bactérienne totale a été observée après 5 et 6 jours, respectivement. En outre, la présence du complexe d'inclusion n'a pas modifié le pH et l'acidité titrable du jus, alors qu'une faible augmentation du degré de Brix a été observée. Des études ultérieures sur l'activité antibactérienne des bicelles incorporant le Ner peuvent être envisagées pour déterminer l'efficacité du système préparé. Ce système pourrait être aussi caractérisé en termes de cinétique de libération, de protection du Ner / Fresh orange juice is widely appreciated by consumers due to its pleasant taste and high nutritional value. Fresh orange juice is rapidly altered during storage, especially by microorganisms. The addition of plant-derived antimicrobials to orange juice may increase its shelf life during storage at 4 °C. Many of these natural antimicrobials are sensitive to environmental factors which reduce their effectiveness in food products. Therefore, their incorporation into encapsulation systems is required. Although this strategy is promising, the evaluation of the activity of encapsulated antimicrobials in fruit juices remains limited. In this study, we searched for a natural molecule active against Lactobacillus fermentum, a bacterium involved in the deterioration of orange juice, in the culture medium. Nerolidol (Ner), a sesquiterpene alcohol, was selected among 28 natural molecules (terpenes and phenols) and showed a potent activity against L. fermentum (minimum inhibitory concentration (MIC) = 25 μM and minimal bactericidal concentration (CMB) = 50 μM) in culture medium at 37 °C. Ner was incorporated into hydroxypropyl-β-cyclodextrin (HP-β-CD) inclusion complex, conventional liposomes (CLs), dug-in-cyclodextrin-in liposome (DCL) and bicelles. HPLC analysis showed a Ner content of 40, 30 and 15 μg per mg powder of HP-β-CD/Ner inclusion complex, LCs, and DCL system, respectively. In addition, the systems were characterized in terms of morphology, size, homogeneity, and zeta potential. Ner was incorporated in bicelles at a phospholipids to Ner molar ratio of 100:1 without altering the structural characteristics of the system (size, homogeneity, zeta potential, morphology). This formulation showed a high encapsulation efficiency of Ner, a high phospholipid incorporation rate, and a molar percentage of Ner in bicelles of 0.86%. At higher concentrations, Ner altered the physical (size, homogeneity, morphology) and the thermodynamic parameters of the bicelles membrane in addition to the increase in membrane fluidity. The HP-β-CD/Ner inclusion complex (MIC = 100 μM and CMB = 200 μM) showed good efficacy against L. fermentum in the culture medium at 37 C. The efficacy of free Ner and HP-β-CD/Ner inclusion complex was greatly reduced in refrigerated orange juice, as a total bactericidal activity was observed after 8 and 17 days of incubation, respectively, at a Ner concentration of 2000 μM. Whereas, liposomes blocked this activity for at least 20 days and altered the appearance of the juice. At 4000 μMof free Ner or Ner incorporated into the inclusion complex, a total bacterial death was observed after 5 and 6 days, respectively. In addition, the presence of the inclusion complex did not alter the pH and the titratable acidity of the juice, while a slight increase in the Brix degree value was observed. Subsequent studies on the antibacterial activity of bicelles incorporating Ner may be considered to determine the effectiveness of the prepared system. This system could also be characterized in terms of release rate and Ner stability
|
3 |
CONTRIBUIÇÃO AO CONHECIMENTO QUÍMICO DOS METABÓLITOS SECUNDÁRIOS DE TRÊS ESPÉCIES BACCHARIS DA SEÇÃO CYLINDRICAE: Baccharis pentodonta, Baccharis tridentata e Baccharis rufescensSimioni, Raquel Endler 29 August 2013 (has links)
Made available in DSpace on 2017-07-24T19:38:10Z (GMT). No. of bitstreams: 1
Raquel Simioni.pdf: 2107045 bytes, checksum: 0dadb3940e17669ea7a07463fcfe1389 (MD5)
Previous issue date: 2013-08-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research aimed to chemically study the secondary metabolites from inflorescences and leaves of male and female specimens of three species from the genus Baccharis: B. rufescens, B. pentodonta and B. tridentata. The plant materials were hydrodistilled for the collection and analysis of the obtained essential oils by GC/MS/FID, UV-Vis, IR and 1H and 13C NMR. The column chromatographic fractionation of the essential oil from male specimens of B. rufescens led to the isolation of two sesquiterpene alcohols, namely spathulenol and (E)-nerolidol, and the ketone 4,7(11)-amorphadien-8-one, which was obtained for the first time making it possible to study its structure using 2D NMR techniques. The essential oils of female specimens of B. rufescens were analyzed by 13C NMR, confirming the presence of (E)-nerolidol and the absence of the mentioned ketone. The oils of male and female specimens of B. pentodonta were very similar, presenting the major sesquiterpenes spathulenol, epiglobulol, viridiflorol, (+)-torreyol and α-cadinol. Likewise, the compositions of the essential oils from male and female specimens of B. tridentata were very similar, showing spathulenol as the major component, followed by caryophyllene oxide and (+)-torreyol. The aqueous extract remaining after the steam distillation of essential oils from B. tridentata was subjected to extraction with chloroform and then with ethyl acetate at pH 8 and pH 4. The extract obtained with ethyl acetate at pH 8 was analyzed by UV-Vis and shift reagents were added, making it possible to observe the presence of a flavanone whose 1H and 13C NMR spectra indicate that this substance is eriodictyol. The extract was chromatographed on a column of silica and structure of eriodictyol was carried out by UV-Vis, IR and 1H and 13C NMR. The ethyl acetate extract at pH 4 was analyzed by UV-Vis and 1H and 13C NMR, verifying the likely presence of 3-caffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid. / O presente estudo teve como objetivo estudar quimicamente os metabólitos secundários de inflorescências e folhas de espécimes masculinos e femininos de três espécies do gênero Baccharis: B. rufescens, B. pentodonta e B. tridentata. Os materiais vegetais foram hidrodestilados para a obtenção e análise dos óleos essenciais por técnicas de CG-EM-DIC, UV-Vis, IV e RMN de 1H e de 13C. O fracionamento em coluna cromatográfica do óleo essencial de espécimes masculinos de B. rufescens levou ao isolamento de dois álcoois sesquiterpênicos, espatulenol e (E)-nerolidol, e da cetona 4,7(11)-amorfadien-8-ona, que foi obtida pela primeira vez em quantidade suficiente para estudos detalhados sobre sua estrutura com uso de técnicas de RMN 2D. Os óleos essenciais de espécimes femininos de B. rufescens foram analisados por RMN de 13C, confirmando a presença majoritária de (E)-nerolidol e ausência da mencionada cetona. Os óleos de espécimes masculinos e femininos de B. pentodonta mostraram-se muito similares entre si, identificando-se como majoritários os sesquiterpenos espatulenol, epiglobulol, viridiflorol, (+)-torreiol e α-cadinol. Da mesma forma, as composições dos óleos essenciais de espécimes masculinos e femininos de B. tridentata mostraram-se muito similares, identificando-se o espatulenol como componente majoritário, seguido de óxido de cariofileno e (+)-torreiol. O extrato aquoso restante após a hidrodestilação dos óleos essenciais de B. tridentata foi submetido à extração com clorofórmio e em seguida com acetato de etila em pH 8 e em pH 4. O extrato obtido com acetato de etila em pH 8 foi analisado por UV-Vis com adição de reagentes de deslocamento, tornando possível observar a presença de uma flavanona cujos espectros de RMN de 1H e de 13C indicaram tratar-se de eriodictiol. O extrato foi cromatografado em coluna de sílica e a estrutura do eriodictiol foi assegurada por UV-Vis, IV e RMN de 1H e de 13C. O extrato acetato de etila em pH 4 foi analisado por UV-Vis e RMN de 1H e de 13C, verificando-se a provável presença do ácido 3-cafeoilquínico, ácido 3,5-dicafeoilquínico e ácido 4,5-dicafeoilquínico.
|
4 |
ESTUDO QUÍMICO DA PRÓPOLIS DOS CAMPOS GERAIS DO PARANÁCordeiro, Adriana Rute 30 August 2013 (has links)
Made available in DSpace on 2017-07-24T19:38:10Z (GMT). No. of bitstreams: 1
Adriana Rute Cordeiro.pdf: 1697344 bytes, checksum: c49bee8f561162a88549115390df463d (MD5)
Previous issue date: 2013-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to develop methods for obtaining extracts for the isolation and chemical analysis of propolis using two samples from the region known as “Campos Gerais do Paraná”. One of the studied propolis samples was produced in the district of Ipiranga and another in the municipality of Ponta Grossa. The utilized general fractionation method allowed obtaining from the same sample the essential oils and then the aqueous extracts and various organic fractions containing chemical components of several polarities. The analyses of the essential oils showed that both samples of propolis contain several components found in Baccharis dracunculifolia, known as vassoura or alecrim do campo, indicating that these are similar to those of green propolis produced in southeastern Brazil. The analyses also demonstrated the presence of phenol compounds such as flavonoids and caffeoylquinic acids, pointing once again that the botanical origin of both propolis includes the alecrim do campo. The analyses of essential oils originating from Ipiranga propolis sample indicated spathulenol and (E)-nerolidol as the main components, while the one acquired in Ponta Grossa showed high proportions of two substances containing aromatic rings in their structures, 2,6-di-t-butyl-p-cresol and benzyl benzoate. The two sesquiterpene alcohols spathulenol and (E)-nerolidol are commonly found in essential oils from B. dracunculifolia and appear in propolis from Ponta Grossa in low percentages, while the two mentioned aromatic compounds are not commonly found in the genus Baccharis. The various analyses of extracts and isolates showed that two aromatic acids may be considered as marker substances for both samples of propolis. The para-hydroxycinnamic acid seemed to be characteristic of propolis from Ipiranga, while the benzoic acid could be considered typical of the sample from Ponta Grossa. Atomic absorption spectrometry analyses that were conducted with both studied propolis did not indicate neither high levels of essential minerals nor the presence of heavy metals, and this fact represents a guarantee that producers have been working in clean environments. / Este estudo buscou desenvolver métodos para a obtenção de extratos destinados ao isolamento e análises químicas de própolis utilizando duas amostras provenientes da Região dos Campos Gerais do Paraná. Uma das amostras de própolis estudadas foi produzida no município de Ipiranga e a outra no município de Ponta Grossa. O método geral de fracionamento utilizado permitiu obter, de uma mesma amostra, os óleos essenciais e em seguida o extrato aquoso e diversos extratos orgânicos contendo substâncias de várias polaridades. As análises dos óleos essenciais demonstraram que ambas as amostras de própolis contém vários componentes também presentes na espécie vegetal Baccharis dracunculifolia, conhecida como vassoura ou alecrim do campo, indicando tratar-se da chamada própolis verde, similares às produzidas na região sudeste do Brasil. As análises também demonstraram a presença de substâncias fenólicas, tanto flavonoides como ácidos cafeoilquínicos, reforçando que a origem botânica das própolis analisadas inclui o alecrim dos campos. As análises de óleos essenciais da amostra de Ipiranga indicaram como componentes principais o espatulenol e o (E)-nerolidol, enquanto que as de Ponta Grossa apresentaram altas proporções de duas substâncias contendo anéis aromáticos em suas estruturas, o 2,6-di-t-butil-p-cresol e o benzilbenzoato. Os dois álcoois sesquiterpênicos espatulenol e (E)-nerolidol são encontrados comumente em óleos essenciais de B. dracunculifolia e aparecem na própolis de Ponta Grossa em baixas porcentagens, enquanto que os dois mencionados compostos aromáticos não são tão comuns em espécies do gênero Baccharis. As diversas análises de extratos e isolamentos demonstraram que dois ácidos aromáticos podem ser considerados como substâncias marcadoras das duas amostras de própolis analisadas. O ácido para-hidroxicinâmico mostrou-se característico da própolis de Ipiranga, enquanto que o ácido benzóico pode ser considerado típico da amostra de Ponta Grossa. As análises por espectrometria de absorção atômica que foram conduzidas com ambas as própolis estudadas não indicaram níveis elevados de metais e nem a presença de metais pesados inconvenientes, sendo mais uma garantia de que os produtores estão trabalhando em ambientes limpos quanto a este aspecto.
|
5 |
Amélioration des qualités nutritionnelles et organoleptiques des aliments par encapsulation de composés actifs (arômes, vitamines, antioxydants, acides gras insaturés...) / Amelioration of the organolepti and nutritional values of food by encapsulation of its bioative ingredients (aromas, vitamins, antioxidants, unsaturated fatty acids...)Azzi, Joyce 04 December 2017 (has links)
L'incorporation d'ingrédients bioactifs dans les produits alimentaires est en plein essor. Il a été démontré que ces ingrédients possèdents des propriétés biologiques importantes permettant l'amélioration de la santé et la prévention des maladies dites de civilisations. Toutefois, l'ajout de ces molécules bioactives est dans la plupart des cas impossible ou insuffisant, du fait que ces composés ne sont que peu solubles dans les systèmes aqueux et présentent i) une stabilité limitée contre les dégradations chimique ou physique, ii) une libération non contrôlée ou une faible biodisponibilité. Face à ces contraintes, les recherches actuelles visent à élaborer des systèmes d'encapsulation efficaces pour résoudre ces problèmes de formulation. Dans notre étude, deux représentants d'ingrédients alimentaires ont été choisi : le sesquiterpène nérolidol (Ner) et le flavonoïde quercétine (Quer) présentant diverses activités biologiques mais des propriétés physicochimiques problématiques. Ainsi, l'objectif de notre travail a été d'encapsuler ces composés actifs dans les cyclodextrines (CDs), les liposomes conventionnels (LCs) et le système mixte cyclodextrine-liposomes (DCLs) afin de développer des systèmes naturels et éco-compatibles ayant des applications potentielles dans les domaines alimentaires.Trois axes ont été abordés. Le premier axe a porté sur la préparation et la caractérisation des complexes d'inclusion CD/invité en solution et à l'état solide. Les techniques de spectroscopie UV-visible, Chromatographie Liquide à Haute Performance (CLHP), Carbone Organique Total (TOC), ¹H Résonance magnétique nucléaire (RMN), 2D ROESY RMN et de la modélisation moléculaire ont été utilisées comme outils pour la caractérisation des complexes obtenus. Des études de phase de solubilité ont également été réalisées. Le deuxième axe a porté sur la préparation des LCs et DCLs par la méthode d'injection éthanolique et leur caractérisation. Les préparations des LCs encapsulant la quercétine a été réalisée à partir de phospholides naturels de jaune d'oeuf (Lipoid E80) et de soja insaturés (Lipoid S100) ou saturés (Phospholipon 90H) afin d'étudier l'effet de la composition lipidique que les caractéristiques des liposomes. La formulation optimale a été par la suite appliquée pour préparer des LCs encapsulant le nérolidol et des DCLs encapsulant les deux molécules. Ce dernier est produit par l'incorporation des complexes d'inclusion HP-β-CD/Ner (à différents rapport moléculaire CD:Ner) et SBE-β-CD/Quer dans la cavité aqueuse des liposomes. Le dernier axe a été orienté vers l'évaluation de l'effet de l'encapsulation sur les propriétés physicochimiques du nérolidol et de la quercétine (libération in vitro, photostabilité, stabilité dans les milieux gastro-intestinales, stabilité de stockage) et leur activité antioxydante. Les résultats ont montré que les CSs ont été capables d'encapsuler les composés actifs étudiés, d'augmenter leur solubilité, leur photostabilité ainsi que leur activité antioxydante. En outre, les liposomes à base de Lipoid E80 ont été trouvés majoritairement de taille nanométrique et ont conféré aux molécules une efficacité d'encapsulation (EE) élevée ainsi qu'une meilleure stabilité par rapport aux deux autres types de liposomes. De plus, la taille des DCLs ains que leur EE ont été prouvées dépendante du rapport moléculaire CD:invité. Par rapport aux LCs, les DCLs ont assuré une libération prolongée du nérolidol, ont augmenté la photostabilité des composés et la stabilité de la quercétine dans les milieux biologiques. Les résultats de cette étude suggèrent que ces systèmes peuvent être considérés comme outils prometteurs pour l'optimisation des formulations alimentaires incorporant le nérolidol et/ou la quercétine. / Phytochemicals are widely distributed secondary metabolites, divided into three major classes : terpenoids, flavonoids and alkaloids. They are shown to possess important biological properties such as anti-cancer, anti-inflammatory and anti-microbial properties. Therefore, increasing the use of these bioactive molecules in food products may reduce the risk of widespread diseases referred to as "diseases of civilization". However, their low solubility, susceptibility to degradation and their rapid release reduce their bioavailability in the human body and thus their biological effect. To solve the aforementioned physicochemical drawbacks, encapsulation systems were developed to allow the incorporation of phytochemicals in food. In this study, two food ingredients : the sesquiterpene nerolidol and the flavonol quercetin were selected du to their potent biological activities but their problematic physicochemical properties.Therfore, the aim of this work was to encapsulate these molecules into cyclodextrins (CDs), conventional liposomes (CLs) and the double systeme drug-in-cyclodextrin-in-liposomes (DCLs), in order to develop nztural and biocompatible formulations that may find applications in food fields. This project was built around three main research axes. The first part dealt with the preparation and the characterization of CD/guest inclusion complexes both in solution and in solid state. Characterizations were performed with UV-visible spectroscopy, High Performance Liquid Chromatography (HPLC), Total Oragnic Carbon (TOC), ¹H NMR, 2D ROESY NMR, and molecular modeling. These investigations were complemented with phase solubility studies.The second axis addressed the preparation of CLs ans DCLs by ethanol injection method and characterization of the vesicles. CLs encapsulating quercetin were prepared from three different types of phospholipids (Lipoid E80, Lipoid S100, Phospholipon 90H) in order to study the effect of lipid composition on the characteristics of liposomes. The optimal formulation was then selected to prepare nerolidol loaded-CLs and DCLs encapsulating the two compounds. HP-β-CD/Ner (at different CD:Ner molar ratios) and SBE-β-CD/Quer inclusion complexes were used as the aqueous phase in the DCL system. The last part focused on the effect of encapsulation on the physicochemical properties of nerolidol and quercetin (in vitro release, photostability, stability in gastro-intestinal fluids, storage stability) and their antioxidant activities. Results demonstrated that CDs could successfully encapsulate bioactive compounds, enhance their solubility , photostability and antioxidant activity. Furthermore, Lipoid E80-liposomes were nanometric in size, exhibited a high entrapment efficiency and higher stability in comparison to the other formulations. Moreover, CD:guest molar ratio influenced the size of DCLs and their encapsulation efficiency. When compared to CLs, DCLs extended the release of neridol, enhanced the photostability of both compounds ans increased the stability of quercetin in biological fluids. These results could be considered as a promising tool to achieve an optimized and efficient formulation incorporating nerolidol and quercetin in food industry.
|
Page generated in 0.0493 seconds