Le diabète est reconnu comme un problème majeur de santé publique causant des conséquences humaines et économiques redoutables. La phytothérapie s’offre comme une nouvelle avenue thérapeutique pour le contrôle de la glycémie. Le grenadier, Punica granatum, a servi de remède contre le diabète dans le système Unani de la médecine pratiquée en Inde et au Moyen Orient. Des études ont démontré un effet hypoglycémiant des extraits de grenadier via divers mécanismes notamment par une amélioration de la sensibilité à l’insuline et la régénération des cellules béta-pancréatiques. Cependant, aucune étude n’a démontré à ce jour, l’effet de grenadier sur le transport de glucose dans le muscle, étape cruciale dans la régulation de l’homéostasie glucidique postprandiale. De plus, l’effet de la maturation sur le potentiel antidiabétique du fruit de grenadier n’a pas été étudié. Ainsi, le but de ce projet est d’évaluer l’effet antidiabétique des extraits de grenadier sur le transport de glucose dans les cellules musculaires C2C12 en fonction de la variété et du stade de maturation du fruit et d’élucider les mécanismes d’action. Le choix des variétés du grenadier tunisien (Espagnoule [EP] et Gabsi [GB]) a été orienté pour leur pouvoir antioxydant et leur consommation locale. Deux parties de la plante ont été utilisées, les fleurs et les fruits à 3 stades de maturation soit 2, 4 et 6 mois. Les résultats ont montré que seule la variété du grenadier Gabsi stimule significativement le transport de glucose par rapport au contrôle (DMSO), et ceci sans être toxique. Cet effet est plus prononcé au stade de fruit mûr (à 6 mois) que celui de la fleur. De plus, l’extrait de fleurs stimule la voie insulino-indépendante de l’AMPK et augmente le niveau d’expression des transporteurs spécifiques de glucose (GLUT-4). Par contre, l’extrait de fruits mûrs, en plus de ces deux mécanismes, active fortement aussi la voie insulino-dépendante de l’AKT. En conclusion, cette étude présente un nouveau mécanisme d’action antidiabétique de grenadier (plus particulièrement du fruit mûr) qui est dépendant de la variété. / Diabetes is a major public health problem worldwide with astounding human and economic consequences. The seed and the flower of pomegranate (Punica granatum), a native plant of Central Asia and the Mediterranean regions, exhibited a hypoglycaemic effect in in vivo studies. However, the underlying mechanisms have not yet been elucidated. The aim of this project was to evaluate the effect of the flower and the fruit (at 3 maturation stages) of pomegranate on glucose transport in skeletal muscle cells and to determine the molecular mechanisms involved in this effect. To accomplish this, we chose two varieties of pomegranate cultivated in Tunisia (Gabsi [GB] and Espagnoule [EP]), which have been shown to be highly consumed in that area and to possess high antioxidant activity. Differentiated C2C12 cells were treated for 18 hours with 80% ethanolic extract of the flowers and fruits (at 2, 4, and 6 months) of each variety. Our results showed that the Gabsi variety of pomegranate significantly enhances glucose uptake, without any toxicity. This effect is more pronounced in the ripe fruit (6 months) than in the flower. In parallel, the ripe fruit stimulated both the insulin-dependent pathway (Akt) and the insulin-independent pathway (AMPK), while the flower stimulated the latter only. In addition, both flower and ripe fruit treatment resulted in enhanced expression level of GLUT-4 glucose transporter in the muscle. Hence, these results suggest that regulation of glucose transport in skeletal muscle is one of the components involved in the anti-diabetic effect of Tunisian pomegranate.

A biodiversidade da flora brasileira abre a possibilidade de estudos com extratos naturais para formulações de soluções irrigantes bactericidas e biocompatíveis para uso na terapia endodontia. Este estudo teve como objetivo analisar o potencial antimicrobiano de extratos da Punica granatum L. (P. granatum) contra micro-organismos presentes nas infecções do sistema de canais radiculares. Foram preparados extratos hidroetanólicos (50% etanol e 50% água) na concentração de 100 mg/mL, a partir da liofilização da casca, folha e semente da P. granatum, contra os seguintes microrganismos: Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis e Candida albicans. Os grupos foram distribuídos de acordo com o extrato de P. granatum: G1 etanol 50% (controle positivo), G2 - hipoclorito de sódio 1% (NaOCl) (controle negativo), G3 Extrato da casca, G4 Extrato da folha, G5 Extrato da semente. A capacidade antimicrobiana dos extratos foi avaliada pelo teste de difusão em ágar, concentração inibitória mínima (CIM) e concentração bactericida/fungicida mínima (CBM/CFM). Os dados, em mm, foram analisados por Analise de Variância e teste de Tukey (p<0,05). Pelo teste de difusão em ágar, verificou-se que, independentemente do micro-organismo, o maior halo de inibição foi encontrado para o controle positivo (30,76 &plusmn; 4,73 a), seguido da casca e folha, que não apresentaram diferença significante entre si (23,32 &plusmn; 3,65 b e 21,08 &plusmn; 2,28 b, respectivamente). A semente apresentou o menor halo de inibição microbiana (17,83 &plusmn; 6,92 c) (p<0,05). Na comparação isolada para cada micro-organismo, os extratos da casca e folha apresentaram atividade antimicrobiana semelhante ao NaOCl para a bactéria S. mutans (p=0,0000), além de exercerem bom efeito antimicrobiano sobre os demais micro-organismos. Para as bactérias E. faecalis e E. coli, os extratos (casca, folha e semente) apresentaram halos de inibição semelhantes entre si (p>0,05), porém inferiores aos obtidos pelo controle positivo. Com relação a CIM e CBM/CFM, encontrou-se efeito bactericida e bacteriostático para todos os extratos. Verificou-se maior zona de inibição para o extrato da casca contra a C. albicans<i/> (CIM = 6,25 mg/mL e CFM = 12,5 mg/mL), seguido da S. aureus (CIM e CBM =12,5 mg/mL). Concluiu-se que, os extratos hidroalcoólicos de P. Granatum L. apresentaram atividade antimicrobiana contra os patógenos orais comuns nas infecções endodontias, com a maior atividade para os obtidos da casca e folha / Brazilian flora biodiversity opens possibility of studies with natural extracts for bactericidal and biocompatible solutions for use in endodontic therapy. The purpose of this study was to investigate the antimicrobial effect of Punica granatum L. (pomegranate) against pathogens of infections from root canal system. Ethanolic solutions (50% ethanol and 50% water) were prepared in 100 mg/mL of lyophilized extracts derived from the peel, seed and leaf of pomegranate, against the following oral microorganisms: Escherichia coli, Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans. The groups were distributed according to the extract tested for root canal irrigation: G1 - 50% ethanol (positive control), G2 - 1% sodium hypochlorite (NaOCl) (negative control), G3 - Solution of the peel, G4 Seed solution, G5 - Solution of the leaf. The antimicrobial capacity of the extracts was evaluated by the agar diffusion test, minimum inhibitory concentration (MIC) and minimum bactericidal / fungicidal concentration (MCB/MFC). The data were analyzed by ANOVA (extracts and microorganisms) and Tukey test (p<0.05). By the diffusion test in agar, it was verified that, independently of the microorganism, the largest inhibition zone was found for the positive control (30.76 &plusmn; 4.73 a), followed by peel and leaf, which did not presented significant difference between them (23.32 &plusmn; 3.65 and 21.08 &plusmn; 2.28 b, respectively). The seed had the lowest of microbial inhibition zone (17.83 &plusmn; 6.92 c) (p<0.05). In the isolated comparison for each microorganism, peel and leaf extracts presented antimicrobial activity similar to NaOCl for S. mutans (p = 0.0000), besides having a good antimicrobial effect on the other microorganism. For the E. faecalis and E. coli, the extracts (peel, leaf and seed) had similar inhibition zones (p>0.05), but lower than those obtained by the positive control. Regarding MIC and MBC/MFC, it was found a bactericidal and bacteriostatic effect for all extracts. The P. granatum peel extract had greater inhibition zone against C. albicans (MIC = 6.25 mg/mL and MFC = 12.5 mg/mL), followed by S. aureus (MIC and MBC = 12.5 mg/mL). It may be concluded that the hydroalcoholic extracts of P. granatum L. presented antimicrobial activity against oral pathogens common in endodontic infections, with the highest activity for those obtained from the peel and leaf

Le diabète est reconnu comme un problème majeur de santé publique causant des conséquences humaines et économiques redoutables. La phytothérapie s’offre comme une nouvelle avenue thérapeutique pour le contrôle de la glycémie. Le grenadier, Punica granatum, a servi de remède contre le diabète dans le système Unani de la médecine pratiquée en Inde et au Moyen Orient. Des études ont démontré un effet hypoglycémiant des extraits de grenadier via divers mécanismes notamment par une amélioration de la sensibilité à l’insuline et la régénération des cellules béta-pancréatiques. Cependant, aucune étude n’a démontré à ce jour, l’effet de grenadier sur le transport de glucose dans le muscle, étape cruciale dans la régulation de l’homéostasie glucidique postprandiale. De plus, l’effet de la maturation sur le potentiel antidiabétique du fruit de grenadier n’a pas été étudié. Ainsi, le but de ce projet est d’évaluer l’effet antidiabétique des extraits de grenadier sur le transport de glucose dans les cellules musculaires C2C12 en fonction de la variété et du stade de maturation du fruit et d’élucider les mécanismes d’action. Le choix des variétés du grenadier tunisien (Espagnoule [EP] et Gabsi [GB]) a été orienté pour leur pouvoir antioxydant et leur consommation locale. Deux parties de la plante ont été utilisées, les fleurs et les fruits à 3 stades de maturation soit 2, 4 et 6 mois. Les résultats ont montré que seule la variété du grenadier Gabsi stimule significativement le transport de glucose par rapport au contrôle (DMSO), et ceci sans être toxique. Cet effet est plus prononcé au stade de fruit mûr (à 6 mois) que celui de la fleur. De plus, l’extrait de fleurs stimule la voie insulino-indépendante de l’AMPK et augmente le niveau d’expression des transporteurs spécifiques de glucose (GLUT-4). Par contre, l’extrait de fruits mûrs, en plus de ces deux mécanismes, active fortement aussi la voie insulino-dépendante de l’AKT. En conclusion, cette étude présente un nouveau mécanisme d’action antidiabétique de grenadier (plus particulièrement du fruit mûr) qui est dépendant de la variété. / Diabetes is a major public health problem worldwide with astounding human and economic consequences. The seed and the flower of pomegranate (Punica granatum), a native plant of Central Asia and the Mediterranean regions, exhibited a hypoglycaemic effect in in vivo studies. However, the underlying mechanisms have not yet been elucidated. The aim of this project was to evaluate the effect of the flower and the fruit (at 3 maturation stages) of pomegranate on glucose transport in skeletal muscle cells and to determine the molecular mechanisms involved in this effect. To accomplish this, we chose two varieties of pomegranate cultivated in Tunisia (Gabsi [GB] and Espagnoule [EP]), which have been shown to be highly consumed in that area and to possess high antioxidant activity. Differentiated C2C12 cells were treated for 18 hours with 80% ethanolic extract of the flowers and fruits (at 2, 4, and 6 months) of each variety. Our results showed that the Gabsi variety of pomegranate significantly enhances glucose uptake, without any toxicity. This effect is more pronounced in the ripe fruit (6 months) than in the flower. In parallel, the ripe fruit stimulated both the insulin-dependent pathway (Akt) and the insulin-independent pathway (AMPK), while the flower stimulated the latter only. In addition, both flower and ripe fruit treatment resulted in enhanced expression level of GLUT-4 glucose transporter in the muscle. Hence, these results suggest that regulation of glucose transport in skeletal muscle is one of the components involved in the anti-diabetic effect of Tunisian pomegranate.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-10T15:32:35Z No. of bitstreams: 1 EMANOELA PEREIRA DE PAIVA - DISSERTAÇÃO PPGHT 2014..pdf: 1247989 bytes, checksum: 71e09e36ef957366d878001bfc7fb6d7 (MD5) / Made available in DSpace on 2018-05-10T15:32:35Z (GMT). No. of bitstreams: 1 EMANOELA PEREIRA DE PAIVA - DISSERTAÇÃO PPGHT 2014..pdf: 1247989 bytes, checksum: 71e09e36ef957366d878001bfc7fb6d7 (MD5) Previous issue date: 2014-02-17 / Objetivou-se neste trabalho avaliar diferentes técnicas de propagação vegetativa da romãzeira. No primeiro momento, objetivou-se testar técnicas de estaquia, com o intuito de avaliar a viabilidade de propagação das variedades ‘Molar’ e ‘Wonderful’ na estação de seca e chuvosa. Posteriormente, verificou-se a viabilidade de produção de mudas enxertadas com estas duas variedades, utilizando-se como porta-enxerto mudas da variedade ‘Molar’ propagadas por estaquia. A pesquisa foi realizada de agosto de 2012 a novembro de 2013, em casa de vegetação, no campus do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande, Pombal/PB. Objetivando estudar a propagação por estaquia da romãzeira, foram realizados dois experimentos com cada variedade (‘Molar’ e ‘Wonderful’), um no período seco, que compreendeu de agosto a dezembro de 2012 (Experimento I), e outro no período chuvoso, de janeiro a junho de 2013 (Experimento II), para as duas variedades. Utilizou-se o delineamento inteiramente casualizado, com quatro repetições e cinco mudas por repetição, adotando-se o esquema fatorial composto por dois fatores, o manejos de estacas (Estacas com folhas; Estacas sem folhas e Estacas sem folhas mais incisão na base) e épocas de avaliação (dias após o plantio das estacas), de modo a estudar o crescimento, fisiologia e acúmulo de massa seca das mudas de romãzeira. Com o intuito de estudar a propagação por enxertia, utilizou-se o delineamento inteiramente casualizado, considerando-se o esquema fatorial (4 x 4), quatro métodos de enxertia (Garfagem no topo em fenda cheia; Garfagem em fenda lateral; Borbulhia em placa e Borbulhia em T invertido) x quatro épocas de avaliação (45; 60; 75 e 90 dias após a enxertia), com quatro repetições e cinco mudas por unidade experimental, de modo a avaliar o crescimento, fisiologia e acúmulo de massa seca das mudas de romãzeira. As estacas manejadas com incisão na base proporcionaram o maior crescimento e vigor das mudas de ambas as variedades de romãzeira estudadas, e a época chuvosa do ano favorece a propagação vegetativa da romãzeira. Os métodos de enxertia por garfagem proporcionaram melhor desenvolvimento das mudas de romãzeira, sendo as mudas enxertadas por garfagem em fenda lateral as que obtiveram maior crescimento e acúmulo de matéria seca. / The objective of this study was to evaluate different techniques for the vegetative propagation of the pomegranate. In the first moment, our objective was to test techniques for cutting, in order to assess the feasibility propagation varieties 'Molar' and 'Wonderful' in the dry and rainy seasons. Subsequently, we verified the feasibility of production of grafted seedlings with these two varieties, using as rootstock seedlings of the variety 'Molar' propagated by cuttings. The survey was conducted from August 2012 to November 2013, in a greenhouse, in the Campus Center of Science and Agrifood Technology, Federal University of Campina Grande, Pombal-PB, Brazil. Aiming to study the propagation by cuttings of pomegranate, two experiments were conducted with each variety ('Molar' and 'Wonderful'), one in the dry season, which comprised August to December 2012 (Experiment I) and another in the rainy season, from January to June 2013 (Experiment II), for the two varieties. We used a completely randomized design with four replications and five plants per replication, adopting the factorial design consisting of two factors, the managements of cuttings (cuttings with leaves, cuttings without leaves and cuttings without leaves more incision at the base) and evaluation periods (days after planting the cuttings) in order to study the growth, physiology and dry mass of seedlings pomegranate. In order to study the propagation by grafting, we used the randomized design, considering the factorial (4 x 4), four methods of grafting (grafting the top cleft, cleft in lateral slit; budding plate and T budding inverted) x four times of assessment (45, 60, 75 and 90 days after grafting), with four replications and five plants per experimental unit in order to evaluate the growth, physiology and accumulated dry weight of seedlings pomegranate. Cuttings managed with incision at the base gave a higher growth and strength the seedlings of both varieties studied pomegranate and the rainy season favors the vegetative propagation of the pomegranate. The methods of grafting provided better growth of seedlings of pomegranate. Being the grafted seedlings by grafting the left side with the greatest growth and dry matter accumulation.

Dans le contexte actuel d'allongement de l'espérance de vie, la prévalence et le coût de prise en charge des maladies liées à l'âge telles que l'ostéoporose sont de plus en plus importants. Dans le cadre du développement de nouvelles stratégies de prise en charge des pathologies osseuses, la nutrition offre un potentiel évident et représente une excellente solution alternative aux traitements habituels. Bien que trop marginales, les études des activités biologiques de certains aliments ont pourtant d'ores et déjà montré des effets protecteurs sur l'acquisition du capital osseux et sa préservation par le biais de leurs propriétés anti-inflammatoires et antioxydantes. A ce titre, la consommation de grenade est envisagée car elle fait actuellement l'objet d'intérêts scientifiques croissants ayant déjà suggéré ses avantages nutritionnels et pharmacologiques pour la prévention de certaines pathologies chroniques associées au vieillissement. Dans le cadre du projet de thèse, les premiers travaux réalisés, focalisés donc sur la grenade, ont permis de dégager le concept selon lequel les propriétés biologiques de ce fruitexceptionnel seraient expliquées par la composition particulière de ses différentes parties : en polyphénols pour le jus (anthocyanines) et la peau (ellagitannins) et en acide punicique pour les pépins, et surtout au potentiel anti-oxydant et anti-inflammatoire de ces molécules. Cette hypothèse a donné lieu à une première étude à vocation phytochimique qui a permis de déterminer, de standardiser, produire et caractériser deux types d'extraits de grenade titrés en molécules d'intérêt (acide punicique et ellagitannins). Nous avons ensuite étudié l'impact de la consommation du fruit (donné dans sa totalité) ou de ses principales parties (jus et peau) ou encore d'extraits concentrés en ellagitannins et en acide punicique, sur la biologie osseuse, dans un modèle expérimental d'ostéoporose post-ménopausique bien décrit (ostéopénie consécutive à une carence oestrogénique induite par ovariectomie chez des souris C57bl6/j). Cette étude préclinique a permis de montrer que tous les régimessupplémentés en grenade (quelle que soit la partie) permettent de limiter les processus de déminéralisation et l'altération micro-architecturale de l'os, s'expliquant par une réduction des marqueurs de résorption osseuse et une amélioration de ceux de la formation ; et une diminution des paramètres inflammatoires, et oxydants. Ensuite, afin de déterminer les structures médiatrices de ces effets, une approche originale ex-vivo a permis d'étudier plus finement les mécanismes cellulaires ostéoblastiques et ostéoclastiques associés à la consommation des extraits de grenade testés. Cette analyse a été développée de façon à tenir compte du métabolisme particulier de ces micronutriments et donc des modifications systémiques engendrées suite à l'ingestion des extraits. Ce travail a permis de mettre en évidence que les effets observés in-vivo sur l'os,pouvaient être expliqués par une action directe aussi bien sur les ostéoblastes que sur les ostéoclastes, et donc une optimisation du remodelage osseux. De fait, la consommation d'ellagitannins et d'acide punicique augmente l'activité des ostéoblastes (activité alcaline phosphatase et formation de nodules de calcium) et l'expression des principaux acteurs et facteurs de transcription impliqués dans leur différenciation, tout en diminuant l'expression de ceux responsables de la différenciation ostéoclastique. Dans le même temps, l'analyse des transcrits met en évidence que les extraits de grenade favorisent l'activation d'acteurs impliqués dans les mécanismes de défenses contre le stress oxydant et l'inflammation, au niveau du microenvironnement osseux. Ces résultats révèlent pour la première fois le potentiel de la grenade au regard de la physiologie osseuse en proposant ses possibles mécanismes d'actions, via une approche nutritionnelle complète et intégrée respectant la physiologie. / In the current context of increased life expectancy, prevalence and socioeconomic consequences of age-related diseases such as osteoporosis represent a major public health problem worldwide. This is why development of new strategies of prevention is highly suitable to provide a wide array of options (alternatives to usual therapies) for health professionals. So far, studies targeting nutrient biological activities have been mainly focused on both calcium and vitamin D. Nevertheless, other nutrients have shown a protective effect on bone mass acquisition and preservation through their anti-inflammatory and antioxidant properties. In this light, pomegranate is endowed with such a potential. Indeed there is an increasing scientific interest that has already suggested its nutritional and pharmacological benefits on prevention of some chronic age-associated diseases. As part of this project, the initial work focused on pomegranate has highlighted the link between its health benefit potential and the exceptional composition of its main parts: polyphenols from the juice (anthocyanins) and the peel (ellagitannins) and punicic acid from seed, those micronutrients being able to elicit antioxidant and anti-inflammatory capacities. Our work hypothesis resulted from a first phytochemical study leading to identify, standardize, characterize and produce two types of pomegranate extracts titrated on 2 molecules of interest (punicic acid and ellagitannins). We thus investigated the outcome of consumption, first of the whole fruit or its principal parts (peel and juice) and in a second time of concentrated ellagitannins and punicic acid extracts on bone biology in a well described experimental model of postmenopausal osteoporosis (osteopenia induced by estrogen deficiency after ovariectomy in C57bl6/j mice). In this preclinical study, wedemonstrated that all the diets supplemented with pomegranate significantly prevented bone loss and micro-architecture impairment. Those findings are associated with transcriptional changes in bone tissue, suggesting involvement of both osteoclastogenesis inhibition and osteoblastogenesis improvement, and reduced inflammatory and oxidative parameters, as well. Then, to determine more accurately the molecules and the signaling pathways involved in those effects, an original ex-vivo study was set up on both osteoblasts and osteoclasts, with respect to physiological conditions (i.e., the aim being to mimic systemic changes and generation of specific circulating metabolites associated with the extractsingestion). This work allowed clarifying the bone sparing effects observed in-vivo. Indeed, pomegranate extracts had the ability to elicit a significant increase in alkaline phosphatase activity, matrix mineralization and transcriptional levels of major osteoblast lineage markersinvolving key signaling pathways, while the expression of specific osteoclast differentiation markers and RANK-RANKL downstream signaling targets were down-regulated. In addition, transcripts analysis revealed that pomegranate extracts were able to induce defense mechanisms against oxidative stress and inflammation in the bone microenvironment. Our results show for the first time the pomegranate potential regarding bone physiology, underlying its possible mechanisms on bone remodeling through a complete and integrated nutritional approach respecting the physiology.

De nos jours, on attribue une myriade d’effets bénéfiques aux polyphénols alimentaires. Ces affirmations reposent la plupart du temps sur des études in vitro, sur quelques études in vivo et presque jamais sur des essais cliniques. On se rend compte de plus en plus que l’intérêt des polyphénols ne résiderait pas uniquement dans leur pouvoir antioxydant mais également dans leur capacité à cibler de multiples cibles moléculaires comme l’inflammation. De plus, de nombreuses études commencent à prendre en compte la biodisponibilité des polyphénols dans l’organisme et leur interaction avec le microbiote intestinal. C’est pourquoi en plus de nous intéresser à deux polyphénols issus de la Pomme-grenade, nous nous sommes intéressés à deux de leurs dérivés métaboliques. Pratiquement aucune étude ne s’était penchée sur l’effet de ces molécules dans un contexte de maladies neuro-dégénératives. Pour se faire, nous avons testé la punicalagine, l’acide ellagique, l’urolithin A et l’urolithin B sur des modèles C. elegans de la SLA et de la maladie de Huntington qui présentaient des phénotypes moteurs, de la neuro-dégénérescence et de l’inflammation. Enfin, nous avons utilisé un modèle de souris ayant subi une axotomie du nerf optique pour confirmer le pouvoir neuro-protecteur de l’urolithin A. Nos résultats ont montré que ces composés dans des proportions différentes étaient en mesure de réduire la toxicité neuronale de protéines liées à la SLA et HD et ainsi diminuer les niveaux de paralysie et de neuro-dégénérescence de nos modèles C. elegans. En parallèle, nous avons observé que cette neuro-protection se faisait au travers une diminution de l’inflammation et pour l’urolithin A une amélioration de la morphologie des mitochondries via la mitophagie. En dernier, nous avons constaté que l’urolithin A était en mesure de promouvoir la survie neuronale chez la souris à la suite d’une lésion du nerf optique. Pour conclure, cette étude par son approche in vivo de multiples maladies neuro-dégénératives renforce les preuves existantes de l’effet bénéfique de la consommation de Pomme-grenade et encourage l’utilisation pharmacologique de l’urolithin A. / Nowadays, a myriad of beneficial effects is attributed to dietary polyphenols. Most of these claims are based on in vitro studies, some in vivo studies, and almost never on clinical trials. It is increasingly realized that the interest of polyphenols does not only lie in their antioxidant power but also in their ability to target multiple molecular pathways such as inflammation. In addition, many studies are beginning to take into account the bioavailability of polyphenols in the body and their interaction with the gut microbiota. That's why in addition to two polyphenols from Pomegranate, we looked at two of their metabolic derivatives. Almost no study has examined the effect of these molecules in the context of neurodegenerative diseases. To do this, we tested punicalagin, ellagic acid, urolithin A and urolithin B on C. elegans models of ALS and Huntington's disease that had motor phenotypes, neurodegeneration and inflammation. Furthermore, we used a mouse model that underwent an axotomy of the optic nerve to confirm the neuroprotective power of urolithin A. Our results showed that these compounds in different proportions were able to reduce the neuronal toxicity of proteins. related to ALS and HD and thus decrease the levels of paralysis and neuro-degeneration of our C. elegans models. In parallel, we observed that this neuroprotection was done through a reduction of the inflammation and for urolithin A an improvement of the morphology of mitochondria via mitophagy. Lastly, we found that urolithin A was able to promote neuronal survival in mice as a result of optic nerve injury. To conclude, this study by its in vivo approach to multiple neuro-degenerative diseases reinforces existing evidence of the beneficial effect of pomegranate consumption and encourages the pharmacological use of urolithin A.

The pomegranate fruit is one of the high valued crops, but there is insufficient information regarding the fruit properties in South Africa. The aim of the study was to evaluate the physico-chemical properties as well as total phenols, anthocyanin, antioxidant, organic sugars and acids of cultivar Wonderful on three locations of the Western Cape. This study was conducted on mature pomegranate fruits harvested in the 2012 and 2013 seasons. Fruit weight (g), length (mm), and width (mm), peel/aril colour and total arils weights (g) were measured. Fruits were also analysed for total soluble solids (TSS) or °Brix), titratable acidity (TA) and juice pH. Results of the study showed that there were significant differences in all measured factors with the exception of % aril yield between the three locations. Though varied per season, fruits produced at Bonnievalle had better physical and chemical properties than at the other localities. With the exception of Aril hue angle, all measured parameters had significant interaction effect regardless of locality (P<0.05). Total soluble solids content varied from 16.0–17.3 (°Brix), pH values from 2.7–3.0, titratable acid content varied from 1.3–1.7 and maturity index from 9.7–13.4. The anthocyanin, total phenols and antioxidant were in order of 772–1134; 1611–1834 and 12.57–14.84. Organic acids (Citric and Malic) showed differences while Acetic acid was not significant in all areas and organic sugar (fructose, Glucose and Sucrose) all had significant differences. It can also be concluded that changes in colour of peel and arils of pomegranate (cv. Wonderful) was mostly as a result of seasonal variation as well as growing area as evident by the interaction between both main factors. / Agriculture / M.Sc (Agriculture)

The pomegranate fruit is one of the high valued crops, but there is insufficient information regarding the fruit properties in South Africa. The aim of the study was to evaluate the physico-chemical properties as well as total phenols, anthocyanin, antioxidant, organic sugars and acids of cultivar Wonderful on three locations of the Western Cape. This study was conducted on mature pomegranate fruits harvested in the 2012 and 2013 seasons. Fruit weight (g), length (mm), and width (mm), peel/aril colour and total arils weights (g) were measured. Fruits were also analysed for total soluble solids (TSS) or °Brix), titratable acidity (TA) and juice pH. Results of the study showed that there were significant differences in all measured factors with the exception of % aril yield between the three locations. Though varied per season, fruits produced at Bonnievalle had better physical and chemical properties than at the other localities. With the exception of Aril hue angle, all measured parameters had significant interaction effect regardless of locality (P<0.05). Total soluble solids content varied from 16.0–17.3 (°Brix), pH values from 2.7–3.0, titratable acid content varied from 1.3–1.7 and maturity index from 9.7–13.4. The anthocyanin, total phenols and antioxidant were in order of 772–1134; 1611–1834 and 12.57–14.84. Organic acids (Citric and Malic) showed differences while Acetic acid was not significant in all areas and organic sugar (fructose, Glucose and Sucrose) all had significant differences. It can also be concluded that changes in colour of peel and arils of pomegranate (cv. Wonderful) was mostly as a result of seasonal variation as well as growing area as evident by the interaction between both main factors. / Agriculture / M. Sc (Agriculture)

L’intégration des fibres naturelles cellulosiques de plantes annuelles ou de résidus agricoles ou agro-industriels dans l’élaboration de matériaux de structures composites et le développement de nouveaux liants biosourcés sont aujourd’hui un domaine de recherche d’intérêt croissant. La thèse s'est déroulée dans le cadre du programme « Eco-panneaux », dont les deux objectifs principaux furent tout d'abord de valoriser les fibres végétales d’origine tunisienne comme l’alfa, le jonc et les folioles de palme et ensuite d'évaluer le potentiel d'espèces végétales tunisiennes dont les écorces sont riches en tannins (fruit de grenade, racines du sumac et tronc de pin d’Alep). Les études de caractérisation des fibres ont montré que leurs masses volumiques sont inférieures à 1. Le calcul du point de saturation des fibres (FSP) montre des valeurs majoritairement comprises entre 60 et 100 %. Nous avons également pu caractériser la cinétique d'imprégnation d'eau pour chacune des fibres. L’imprégnation se stabilise après 24 h d’immersion. Riches en minéraux (concentrations supérieures à 1 %), les fibres ont montré des teneurs en cellulose, en lignines et en hémicellulose comparables à celles généralement rencontrées avec les fibres de bois. L’analyse thermogravimétrique (ATG) a permis de constater que les matrices végétales étudiées sont thermiquement stables pour des températures inférieures à 200°C. Le dosage colorimétrique pour étudier la composition en polyphénols des matrices tannifères, l’analyse infrarouge et l’étude structurale de l’extrait des tanins, ainsi que le calcul du « Stiasny number » , montrent la forte teneur de l’écorce de grenade en tanins hydrolysables et la richesse des écorces du tronc de pin d’Alep et des racines du sumac en tanins condensés. L’étude des propriétés thermiques des extraits de tanins par ATG montre que les tanins de pin d’Alep et du sumac sont thermiquement plus stables que ceux de la grenade. La colle formulée à partir d’hexamine et de tanins de pin d’Alep présente un module d’élasticité élevé. Alors que la colle à base de tanins de grenade forme le réseau le moins dense. Ces résultats ont été confirmés par l’étude de la résistance au cisaillement. L'étude réalisée sur les composites fibres-plâtre (mise en œuvre et caractérisation physico mécanique des composites) a montré que les fibres locales pourraient constituer une alternative aux fibres d'importation utilisées actuellement. Une première caractérisation de la conductivité thermique des panneaux isolants élaborés à partir des fibres locales et de colles de tanins montre une conductivité thermique moyenne de 0,106w/K.m. / The integration of natural cellulosic fibers from annual plants and agricultural residues and agro-industrial materials in the development of composite structures and the development of new bio-based adhesives, are now a research field with growing interest. The thesis was conducted within the framework of "Eco-panels" program, which its two main objectives were firstly, to enhance plant fibers of Tunisian origin as alfa, rush and palm leaflets and then to evaluate the potential of Tunisian plant species whose bark is rich in tannins (pomegranate fruit, sumac roots and Aleppo pine trunk). The characterization studies of fibers showed that their densities are less than 1. The calculation of the fiber saturation point (FSP) shows values mostly between 60 and 100 %. We were also able to characterize the impregnation kinetics of water for each of these fibers. The impregnation stabilizes after 24 h of immersion. Rich in minerals (concentrations greater than 1 %), the fibers showed levels of cellulose, lignin and hemicellulose comparable to those generally encountered with wood fibers. The thermogravimetric analysis (TGA) shows that the plant matrices are thermally stable for temperatures below 200 ° C. The colorimetric assay of the polyphenolic composition of tanniferous matrices, the infrared analysis and the structural study of the tannins extract, as well as the calculation of "Stiasny number" show the high content in hydrolysable tannins for pomegranate barks and richness of Aleppo pine trunk barks and sumac roots barks in condensed tannins. The study by TGA of the thermal properties of tannins extracts shows that Aleppo pine and sumac tannins are thermally more stable than those of pomegranate. The formulation made from hexamine and Aleppo pine tannins has the greatest elasticity modulus. While the formulation prepared from pomegranate tannins forms the least dense network. These results were confirmed by the study of the shear strength. The study conducted on fiber-plaster composites (implementation and physico-mechanical characterization of composites) showed that local fiber could be an alternative to imported fibers used currently. A first characterization of the thermal conductivity of insulation panels made from local plant fibers and tannins adhesives shows an average conductivity of 0,106 W / Km.

Résumé : Lobjectif des travaux entrepris au cours de cette thèse visait à mettre en place un procédé global de conservation des graines de grenade (Punica granatum L.). Ce procédé se base essentiellement sur une déshydratation osmotique (DO), associée à un pré-traitement de congélation et un post-traitement de séchage par entrainement. Dans ce contexte, plusieurs paramètres d'optimisation du transfert de masse ont été étudiés, tels que la nature de la solution dimmersion (saccharose, glucose, glucose/saccharose et jus de datte « sous-produit » enrichi en saccharose), la température (30, 40, et 50°C) et létat du fruit (frais, congelé). En outre, nous avons mis en relation ces conditions avec certaines propriétés des graines : leur texture, leur structure, et leur couleur. Létude des paramètres de déshydratation (perte en eau (WL), gain en solides (SG), et réduction en poids (WR)) a montré quen utilisant des graines congelées et indépendamment de la température et de la solution utilisée, la majorité du transfert de masse seffectue pendant les vingt premières minutes de traitement. A lissue de cette période, la perte en eau est estimée à 46%, 41%, 39%, et 37% respectivement dans les solutions de saccharose, glucose/saccharose, de jus de datte et du glucose. La DO des graines fraîches est caractérisée par une cinétique plus lente, mais une perte finale en eau plus importante. Comme le montrent les analyses en microscopie électronique, cela sexplique par une déstructuration cellulaire survenant à la suite de la congélation des graines, ce qui vient conforter les résultats des observations microscopiques. Les mêmes techniques ont également indiqué une modification de texture/structure induite par le processus de DO. Dautre part, lutilisation dune solution de saccharose (55°Brix) et dune température de 50°C favorise un meilleur transfert de masse. La détermination des différentes fractions deau dans la graine par calorimétrie différentielle (DSC) a montré une augmentation dun facteur ~2,5 fois de la fraction deau non congelable (eau liée) et une réduction de ~3,5 fois de la fraction deau congelable (eau libre) favorisant ainsi une meilleure conservation du fruit. Le suivi de la qualité intrinsèque des graines au cours de la DO a montré une perte dune quantité non négligeable de certains composés (protéines, cendres) de la graine vers la solution, ce qui pourrait avoir une influence majeure sur la qualité organoleptique et nutritionnelle du fruit. La DO seule ne pourrait pas maintenir une stabilité du produit au cours de la conservation. En effet, lactivité deau du produit fini après DO est proche de 0,90. Ainsi, dans un but plus appliqué, un traitement complémentaire de séchage par entrainement (2 m/s durant 4 heures) a été mis en place, à différentes températures (40, 50, et 60°C), afin de réduire lactivité deau à une valeur inférieure à 0,65. Afin doptimiser le traitement de séchage, nous avons étudié en premier lieu leffet de la température sur lévolution de la matière sèche, de lactivité deau et du pourcentage de séchage des graines. Dautre part, plusieurs paramètres de qualité des graines de grenade (lactivité antioxydante, la teneur en composés phénoliques, les anthocyanines, la couleur, et la texture) ont été étudiés à différentes températures. Ce travail est une contribution à létude des propriétés physico-chimiques des graines de grenade (Punica granatum L.) au cours des procédés de congélation, de déshydratation et de séchage. Les caractéristiques du produit fini peuvent justifier de nouvelles voies de transformation et dexploitation des graines de grenade. Abstract: The aim of this work was to create a complete conservation process of pomegranate seeds (Punica granatum L.). This process is essentially based on osmotic dehydration (OD), which was associated to freezing and air-drying process. Several parameters were studied to optimize the process such as osmotic solution (sucrose, glucose, and sucrose/glucose and date juice with sucrose added), temperature (30, 40, and 50°C) and state of the fruit (fresh and frozen). All these conditions were linked to seed proprieties (texture, structure, and colour). The study of osmotic dehydration parameters (water loss (WL), solids gain (SG) and weight reduction (WR)) showed that most significant changes of mass transfer took place during the first 20 min of dewatering using frozen seeds, independently of temperature and sugar type. During this period, seeds water loss was estimated at 46% in sucrose, 41% in sucrose/glucose mix, 39% in date juice, and 37% in glucose. Mass transfer was slower starting from fresh fruit but led to a higher rate of WL at the end of the process. This fact can be explained by scanning electron microscopy, which showed damage of seed cell structure after freezing. This has practical consequences in terms of the modification of seeds texture. The same process also revealed a modification of seed texture and cell structure after osmotic dehydration. Using a sucrose solution and a temperature of 50°C favoured the best mass transfer. The determination of different water fractions of seed by differential scanning calorimetry (DSC) showed that the % of frozen water decreased 3.5 times contrary the % of unfreezable water that increased 2.5 times. This favours a better seeds conservation. During osmotic dehydration, there was a non negligible leaching of natural solutes from seeds into the solution, which might have an important impact on the sensorial and nutritional value of seeds. Using only osmotic dehydration could not maintain the stability of seeds during conservation. In fact, after the osmotic process, water activity of seeds was found to be higher than 0.9, allowing to the development of microorganisms and some undesirable reactions. As a consequence, a drying of the pomegranate seeds (during four hours) was investigated at three different temperatures (40, 50, and 60 °C) with air flow rate of 2 ms-1. Prior to the drying process, seeds were osmodehydrated in a sucrose solution (55°Brix) during 20 min at 50°C. The drying kinetics and the effects of OD and air-drying temperature on antioxidant capacity, total phenolic, colour, and texture were determined. This work is a contribution to the study of physico-chemical properties of pomegranate seeds (Punica granatum L.) during freezing, osmotic dehydration and drying. After the global process, the pomegranate seed characteristics lead to new industrial developments.