Made available in DSpace on 2014-06-11T19:24:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-25Bitstream added on 2014-06-13T20:11:56Z : No. of bitstreams: 1 cefali_lc_me_arafcf.pdf: 635100 bytes, checksum: 20424d01dd8e9cc7f5c20d87bb20eec3 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O licopeno é um carotenóide com poderosa ação antioxidante, encontrado em maior quantidade no tomate, utilizado no combate a inúmeras doenças como vários tipos de câncer, dentre eles o de próstata, e doenças cardiovasculares. Sua ação tópica é pouco explorada e, por isso, a proposta de ser utilizado no combate à aceleração do envelhecimento cutâneo, incorporado em uma emulsão. Um estudo preliminar foi realizado para a escolha do tipo de tomate que apresenta maior concentração de licopeno e/ou maior atividade antioxidante. O método de quantificação do fitoquímico foi validado e, em função dos testes de avaliação antioxidante in vitro, o tomate do tipo salada foi o escolhido para o desenvolvimento do fitocosmético. Além disso, o extrato foi submetido à avaliação da citotoxicidade in vitro que constatou a não ocorrência de toxicidade em fibroblastos e macrófagos. Assim, o cosmético foi desenvolvido contendo fase oleosa constituída de derivados de karité e submetido a testes para avaliar sua estabilidade, identificar as características da emulsão, avaliar seu comportamento reológico e sua atividade cosmética pelos testes de permeação cutânea e verificando a eficácia quanto à ação antioxidante do licopeno incorporado na emulsão. Foi possível observar que o fitocosmético é estável, de acordo com as condições experimentais realizadas neste estudo, permite a retenção do licopeno na epiderme e na derme e apresenta atividade antioxidante, sendo promissor para o combate à aceleração do envelhecimento cutâneo. / Lycopene, a carotenoid with high antioxidant activity, is found in greater quantities in tomatoes used to combat many diseases such as various types of cancers, including of the prostate, and cardiovascular diseases. Its topical action is not explored and therefore the proposal to be used to combat aging, incorporated into an emulsion. A preliminary study was conducted to evaluate which tomato had higher concentration of lycopene and/or higher antioxidant activity. The method of quantification of the phytochemical was validated and the lycopene extract was evaluated by testing in vitro antioxidant activity. Tomato salad was chosen for the development of the phytocosmetic. Furthermore, this extract was subjected to the evaluation of cytotoxicity in vitro activity and it was found that the non-occurrence of toxicity in fibroblasts and macrophages. Thus was developed a product containing oily phase consists only derived about shea which was submitted to tests to assess its stability, to identify the characteristics of the emulsion, to evaluate the rheological behavior and cosmetic activity carried out tests such as skin permeation and checking the effectiveness in the antioxidant action of lycopene incorporated into emulsion. Through the results it was possible to observe that the phytocosmetic is stable, allows the retention of lycopene in the epidermis and dermis, shows antioxidant activity and it’s promising to combat the acceleration of skin aging

Amphibians are facing an extinction crisis, and in many cases it has become necessary to conserve species in captivity. Unfortunately, our understanding of the nutritional requirements of amphibians in captivity is currently limited. There have been anecdotal reports that captive bred amphibians have duller skin colouration than wild members of the same species. Many amphibians use carotenoid pigments in skin colouration. Carotenoids are yellow-red pigments synthesised by photosynthetic tissues, however vertebrates cannot synthesise them de novo and rely entirely on dietary sources. Reduced colour in captive bred amphibians could therefore result from limited carotenoid availability in the diet. Limited access to carotenoids could have further negative consequences on health and reproductive success since carotenoids are known to function in the immune, antioxidant and reproductive systems of other vertebrate taxa. The role of carotenoids in amphibian fitness is currently unknown, and the aim of this PhD was to assess the importance of carotenoids to anuran amphibians. Skin colour may be influenced by carotenoid availability, and it was therefore important to establish a suitable method for quantifying skin colour in amphibians. In Chapter 1 I assessed two methods for colour quantification, including digital photography and spectrometry. Neither method was significantly more accurate than the other, however I chose to use photography for my studies for reasons of practicality. In Chapters 2 and 3 I assessed the role of carotenoids in the reproductive systems of wild frogs. I found that carotenoid-based skin colouration was involved in the breeding behaviour of wild Agalychnis moreletii frogs. I found positive assortative mating by colour in that frogs were found mating with individuals with similar carotenoid-based colouration. This assortative mating by colour may be driven by mutual mate choice, or may have evolved to prevent mismatched pairing with a sympatric and phenotypically similar species (A. callidryas). I then analysed the carotenoid composition of eggs produced by wild A. moreletii and Phyllomedusa trinitatis, which are tree frogs with similar reproductive ecology but different egg deposition strategies: Agalychnis moreletii deposits green eggs on the surface of leaves while P. trinitatis wraps pale cream eggs in leaves. The concentration and diversity of carotenoids was significantly higher in A. moreletii than P. trinitatis and potential ecological explanations for this are discussed. In Chapter 4 I investigated carotenoid availability in the diet of captive amphibians by analysing the carotenoid composition of commonly used feeder-invertebrates. I assessed interspecific variation in carotenoid accumulation in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus), which were all fed one of three diets (wheat-bran, fish-food based diet, fresh fruit and vegetables). All three cricket species were a poor source of carotenoids unless they were gut-loaded on a carotenoid-rich diet. Nutrient retention over a two-day period was poor across species. Finally, there were significant interspecific differences in gut-loading capacity, with G. bimaculatus having the greatest capacity. This study shows that carotenoid availability to captive amphibians will be limited unless they are fed specific feeder invertebrate species, recently gut-loaded on carotenoid-rich foods. In Chapters 5, 6 and 7 I assessed the influence of carotenoids on fitness related traits in captive anurans. I firstly assessed colour degradation in captive-reared A. moreletii frogs and looked at whether skin colour could be improved through increased carotenoid availability in the diet. I found that carotenoid-based skin colour degraded quickly in captivity but could be improved through dietary supplementation with carotenoids, however there was a critical period during post-metamorphic growth for deposition of carotenoids in the skin. Next, I investigated the effect of carotenoids on larval growth and development, and post-metamorphic growth, development, skin colour and reproductive success in captive A. callidryas frogs. I found no direct effect of carotenoids during larval stages, however there were carry-over effects on post-metamorphic growth and skin colour. Increased post-metamorphic carotenoid availability positively influenced growth, skin colour and reproductive success. Similarly to A. moreletii, there was a critical period during post-metamorphic growth for deposition of carotenoids in the skin. Finally, I examined the protective potential of carotenoids in Silurana (Xenopus) tropicalis tadpoles that were exposed to ultraviolet (UV) light. Exposure to UV light significantly reduced tadpole survival and there was no evidence that carotenoids afforded any protection. Nevertheless, in tadpoles that were not exposed to enhanced UV light, carotenoids increased survival. Furthermore, carotenoids had a significantly positive effect on the developmental rate of tadpoles in both UV limited and UV enhanced environments. The studies in this PhD show that carotenoid availability has important consequences on fitness related traits in anuran amphibians, which include effects on growth, skin colour, reproductive success and survival. Carotenoid availability to captive amphibians will, however, be low unless they are provided with feeder invertebrates that have been recently gut-loaded on carotenoid-rich foods. These findings should be considered when recommendations are made on the nutritional requirements of amphibians in captivity as they could significantly improve the fitness of captive-bred individuals, and thus increase the success of ex situ conservation programmes.

Un excès d’énergie lumineuse peut être délétère pour les organismesphotosynthétiques ; en effet, il en résulte la formation d’espèces réactives de l’oxygène ausein des centres réactionnels. Les cyanobactéries ont adopté divers mécanismes dephotoprotection afin de contrer ce phénomène. L’un d’eux repose sur l’activité de l’OrangeCarotenoid Protein (OCP), protéine soluble qui attache un kéto-caroténoïde (hydroxyechinenone).Subissant de fortes intensités de lumière bleu-verte, l’OCP se convertit d’uneforme inactive/orange vers sa forme active/rouge. L’OCP ainsi photoactivée possède la facultéd’interagir avec les phycobilisomes - principales antennes collectrices de lumière - induisantla dissipation de l’énergie collectée par ces gigantesques complexes sous forme de chaleur. Lapression d’excitation au niveau des centres réactionnels ainsi que la fluorescence du systèmedécroissent alors.L’OCP photoactivée se fixe au coeur des phycobilisomes qui sont majoritairementconstitués de protéines chromophorylées de la famille des allophycocyanines (APC). J’aiconstruit différentes souches mutantes de Synechocystis PCC 6803 en modifiant ousupprimant les sous-unités mineures d’APC (ApcD, ApcF et ApcE). Ces sous-unités jouent lerôle essentiel d’émetteurs terminaux des phycobilisomes, véhiculant l’énergie qu’ellesreçoivent à la Chlorophylle a. J’ai aussi démontré que le mécanisme photoprotectif associé àl’OCP chez ces mutants restait inchangé, aussi bien in vivo que in vitro. Ces résultatssuggèrent qu’aucun émetteur terminal n’est nécessairement requis pour l’attachement del’OCP aux phycobilisomes et sous-entendent que l’OCP interagit probablement avec unesous-unité majeure d’APC.Divers phycobilisomes, contenant 2, 3 ou 5 cylindres d’APC dans leur coeur, ont étéisolés à partir de cyanobactéries variées. Les OCPs de Synechocytis et d’Arthrospira ont étépurifiées à partir de souches mutantes de Synechocystis. J’ai alors mené une étude in vitro desinteractions entre ces OCPs et les phycobilisomes. Le nombre de cylindres d’APC présents ausein des phycobilisomes n’affecte en rien la diminution de fluorescence. De plus, j’ai constatéque l’OCP de Synechocystis est spécifique pour ses propres phycobilisomes alors que l’OCPd’Arthrospira interagit avec tous les phycobilisomes employés ici. Des hypothèses, fondéessur les structures disponibles, ont été formulées pour élucider ces différences.Les domaines N- et C-terminaux de l’OCP d’Arthrospira ont été dissociés parprotéolyse. Le domaine N-terminal isolé conserve le caroténoïde attaché, ayant uneconformation similaire à celle observée lorsque l’OCP est photoactivée. Ce domaine Nterminalest aussi capable d’induire une importante diminution de la fluorescence desphycobilisomes. A l’inverse, le domaine C-terminal isolé est incolore et n’a aucun effet sur lafluorescence des phycobilisomes. Ces résultats suggèrent que seul le domaine N-terminal del’OCP est impliqué dans l’interaction avec les phycobilisomes. Le domaine C-terminal quantà lui module son activité. / Too much light can be lethal for photosynthetic organisms. Under such conditionsharmful reactive oxygen species are generated at the reaction center level. Cyanobacteria havedeveloped photoprotective mechanisms to avoid this. One of them relies on the solubleOrange Carotenoid Protein (OCP) that binds a ketocarotenoid (hydroxyechinenone, hECN).Under strong blue-green illumination, OCP gets photoconverted from an orange inactive form(OCPo) to a red active one (OCPr). OCPr interacts with phycobilisomes, the majorcyanobacterial light harvesting antennae, and triggers heat dissipation of the excess lightenergy collected by these gigantic pigment-protein complexes. Consequently, excitationpressure on reaction centers and fluorescence emission decrease.OCPr binds to phycobilisome cores, containing mainly chromophorylated proteins ofthe allophycocyanin (APC) family. I constructed Synechocystis PCC 6803 mutants affected insome minor APC forms (ApcD, ApcF and ApcE). These special APCs play the role ofterminal emitters, i.e. funnel light energy to Chlorophyll a. Strong-blue green illuminationtriggered normal OCP-related fluorescence quenching in all mutant cells. The fluorescencedecrease induced by Synechocystis OCP in vitro was similar when using phycobilisomesisolated from wild-type or mutant cells. These results demonstrated that the terminal emittersare not needed for interaction with the OCP and they strongly suggested that OCPr interactswith one of the major APC forms of the phycobilisome core.Phycobilisomes containing 2, 3 or 5 APC cylinders per core were isolated fromdifferent cyanobacterial strains. Synechocystis and Arthrospira OCPs were purified from overexpressingSynechocystis mutant strains. I then performed in vitro OCP/phycobilisomeinteraction studies. The number of APC cylinders per core had no clear influence on theamount of fluorescence quenching. Both OCPs behaved very differently, one appearing muchmore species-specific than the other. Structure-based hypotheses were emitted to explain suchdissimilarity.Arthrospira OCP N-terminal and C-terminal domains were separated throughproteolysis. The isolated N-terminal domain retained a bound carotenoid, which displayedsimilar conformation than in OCPr. This isolated N-terminal domain triggered importantphycobilisome fluorescence quenching even under dark conditions. In contrast, the isolated Cterminaldomain attached no pigment and had no visible effect on phycobilisome emission. Itwas then proposed that only the N-terminal domain of OCP is implied in interactions withphycobilisomes. The C-terminal domain modulates its activity.

Carotenoid pigments were extracted from Corynebacteriuma poinsettiae (wild type) ATCC 9682, and from 108 mutants obtained by exposure of a streptomycin resistant strain of C. poinsettiae to ultra-violet light irradiation and N-methyl- N'-nitro-N-nitrosoguanidine. The pigments were characterized by their absorption maxima, Rf-values, and partition ratios in petroleum ether and methanol. Thin layer chromatography was used to compare pigments of the wild type with those of the mutants. Possible biosynthetic pathways in carotenoid synthesis of the wild type were postulated on the basis of the observed genetic blocks. Mutants were found which suggested the existence of a linear pathway in carotenoid synthesis from the aliphatic C4 0 molecule to the bi-cyclic C50-diol. Other mutants suggested possible alternative pathways in the biosynthesis of these pigments or the presence of intermediates not detectable by thin layer chromatography.

Master of Science / Food Science Institute - Food, Nutrition, Dietetics and Health / Weiqun Wang / Sorghum is a staple crop consumed in certain regions of Africa and Asia, where vitamin A deficiency is prevalent. However, the correlation of sorghum intake and vitamin A deficiency is inconsistent. The objective of this study was to identify and quantify the carotenoids and pro-vitamin A in the selected sorghum accessions with various pericarp pigments by using LC-MS. Among of total five carotenoids (α-carotene, β-carotene, lutein, zeaxanthin, and β-cryptoxanthin) that were identified and quantitated, three (α-carotene, β-carotene and β-cryptoxanthin) are precursors of vitamin A. The highest content of total carotenoids was detected in the sorghum accessions with yellow pericarp (PI656096, PI585374, PI563448, PI585351), while the highest β-carotene content was found in the accessions with brown or yellow pericarp (PI655996, PI656096, PI585374, PI563448, PI585351). The lowest carotenoids were found in the accessions with white pericarp (PI533943, PI656112, PI565121, PI560493). The pro-vitamin A was 584.9 ± 38.9 ng/g DW in yellow pericarp, 250.6 ± 28.9 ng/g DW in brown pericarp, and 89.0 ± 12.3 ng/g DW in white pericarp, respectively. It appeared the phenotypic diversity of sorghum pericarp colors was strongly associated with the contents of carotenoids and pro-vitamin A, indicating a different impact of various sorghum varieties on vitamin A deficiency and suggesting a possible prevention of vitamin A deficiency by breeding certain sorghum varieties with pericarp pigments.

Past research conducted by our lab demonstrated that potatoes contain significant levels of phytochemicals important to human health. However, since potatoes are not consumed raw, it is important to determine the effects of processing on these levels. Therefore, the changes in carotenoid content, antioxidant activity, and phenolic content were investigated using combinations of cultivars, cooking methods, storage treatments, and low-dose ionizing irradiation. Carotenoid content was measured via absorbance at 445 nm, 450 nm, and HPLC identification. Antioxidant activity was measured initially and at stabilization via the DPPH method and phenolic content was measured via the Folin method and HPLC identification. Microwaved, baked, fried, and raw potato samples contained more carotenoids than boiled samples. The samples microwaved, baked, and fried contained higher antioxidant activity and phenolics than the boiled or raw samples. However, the compound quercetin dihydrate appeared to decrease with cooking. Carotenoids, antioxidant activity, and phenolics appeared to decrease with storage; however, high storage temperatures and long storage times were believed to cause a dehydration and concentration of compounds, which caused levels to be equal to or greater than before storage. However, this decreasing trend was not linear and there were multiple significant interactions. The compound chlorogenic acid appeared to be quite sensitive to high temperature storage. Irradiation dose appeared to have only a minor, if any, effect on carotenoid levels. The interaction between storage time and irradiation dose was very influential on antioxidant activity. In early stages of storage, higher doses of irradiation had greater antioxidant activity, while, with continued storage, low doses had higher antioxidant activity. Exposure to irradiation appeared to cause an increase in phenolic content, determined by the Folin method. There may be a stimulation, induction, or release of some compounds due to processing; however, its magnitude is not believed to be as great as genetic control. The effects of processing can not be denied and should continue to be investigated. Future studies investigating the health properties of fruits and vegetables, particularly potatoes should include processing effects.

Plants contain a host of secondary metabolites that may be of dietary use to man. A comprehensive approach to plant-based nutrition would include investigating all aspects of a nutrient, from creation through storage and consumption. Here, experiments address each of these facets for a group of important antioxidant and pigment compounds, the carotenoids. The carotenoid biosynthetic pathway regulatory mechanisms leading to lycopene accumulation are well defined in the model fruit, tomato. Those leading to accumulation of other carotenoids and flesh colors, however, are poorly understood. The variety of flesh colors available in watermelon fruit (red, orange, salmon yellow, and canary yellow) makes it an ideal candidate for investigating the regulation of the full pathway. Carotenoid accumulation was measured in ten watermelon varieties, representing the four flesh colors and three ploidy levels, throughout fruit maturation. It was found that the putative regulatory mechanisms controlling lycopene accumulation in red-fleshed fruit may be applied in a generalized fashion to each flesh color in respect to the major carotenoid accumulated at maturity. Additionally, triploid varieties were generally found to have higher accumulation levels than diploids, and tetraploids were intermediate to both. In addition to total carotenoid content, many factors are important in determining perceived benefit. Several of these factors involve components of the food matrix, cellular and subcellular species-specific characteristics of the food which act as barriers to nutrient release. Cell size, cell wall, and chromoplast (the carotenoid storage organelle) characteristics were observed in nine fruits and vegetables using light and transmission electron microscopy. Watermelon, tomato, and melon have the largest cells. Sweet potato, butternut squash, carrot, and mango have the most fibrous cell walls; mango and papaya additionally had the thickest walls. Chromoplast globular, tubular, crystalline, and membranous substructures were described for each food. These food matrix factors may be related to differences in carotenoid bioaccessibility between food sources. An in vitro digestion experiment was used to determine carotenoid bioaccessibility for each of these foods. Per serving, grapefruit yielded the most lycopene while carrot gave the most ?-carotene, ?-carotene, lutein, and phytoene, and mango proved a good source of violaxanthin.

Lutein is a lipid soluble plant pigment with recognized health benefits, although intake levels by the general population and bioavailability are generally low. These factors have led to interest in producing high lutein functional foods, including baked products. Cookies, muffins, and flatbreads, were produced at three enrichment levels (equivalent to 0.5, 1.0, and 2.0 mg per serving) and then subjected to an in vitro simulation of human gastric and duodenal digestion coupled with Caco-2 monolayers. Lutein transfer to the aqueous phase during digestion (i.e. bioaccessibility) and monolayer absorption were determined as estimates of potential bioavailability. The higher fat products (muffins and cookies) resulted in higher overall bioaccessibility (p<0.05) and absorption at most levels of enrichment. Digestive conditions representative of the fed and fasted state were compared, with the fed model resulting in much higher estimates of bioavailability. Lutein concentration in the aqueous was the most important factor in determining subsequent monolayer absorption. Overall, the cookie was the most effective product for bioaccessibility, and enriching them to the highest level would result in the greatest delivery of bioavailable lutein to the body. / Agriculture and Agri-Food Canada

No description available.

Lycopene has recently received interest as an antioxidant in human tissues. These same antioxidant properties present challenges in preventing oxidative degradation within food products. In this research, degradation of lycopene in model emulsion systems was examined to better understand the chemical stability of this potential functional food ingredient.