The vast majority of exogenous substances is metabolized in the liver. In the course of the biotransformation, partly biologically non-active products, partly reactive species leading to cell structure injury and even to the liver failure are produced. Oxidative stress plays a significant role in the toxic- and drug-induced liver damage. Endogenous and exogenous antioxidants contribute to equilibrium between the production and the elimination of reactive oxygen species and thus prevent the oxidative stress. In acute experiments in rats we examined the ability of natural antioxidants silymarin, naringin and resveratrol and of synthetic chelator deferipron to protect against liver damage induced by paracetamol, thioacetamide and tamoxifen. The following parameters of oxidative stress were measured in the liver homogenates: level of lipid peroxidation (LP), concentration of reduced glutathione (GSH), activities of glutathione peroxidase (GPx) and of catalase (CAT); in some cases the iron liver content. The following markers of liver damage were measured in serum: alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH). Concernig markers of oxidative status, silymarin exerted the most efficient antioxidant properties amelioratig the TAA- and TAM-induced lipid...

Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-20T12:34:53Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CarlaFontouraFerrreira.pdf: 19008440 bytes, checksum: b5b118a8e2abb810388a00dc8e27ac80 (MD5) / Made available in DSpace on 2018-08-20T12:34:53Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CarlaFontouraFerrreira.pdf: 19008440 bytes, checksum: b5b118a8e2abb810388a00dc8e27ac80 (MD5) Previous issue date: 2017-03-30 / Reactive species (ERs) and oxidative stress contribute to the pathophysiology of several diseases including dementia. An innovative alternative for protecting organs such as the brain is the use of antioxidant-like flavonoids such as naringin and naringenin. However, these two compounds have low bioavailability when administered orally. An alternative to overcome this limitation is the use of nanocarriers, such as nanocapsules (NC). Therefore, the present study aimed to evaluate the neuroprotective effect of naringin and naringenin in a model of streptozotocin (STZ) -induced dementia in mice. The profile of drug release from in vitro suspensions was evaluated as well as the effects of nanoencapsulated drugs on cell viability with Vero cell line. In addition, the involvement of oxidative stress in the brain tissue of mice was verified. Naringin and naringenin NC had acid pH, particle diameter less than 95 nm, polydispersity index (IPD) of less than 0.2. The zeta potential was negative, between -12.46 and -17.6 mV, and the encapsulation efficiency was 93% for naringin and 95% for naringenin. For the study of the release profile, the dialysis technique was used, with 46.5% of naringin and 6.9% of naringenin being released in the medium, in a period of 9h. The results of the cell viability assay showed that the NC suspensions caused a reduction in cell viability of Vero cells at concentrations of 5, 50 and 500 μg / ml when compared to the control at the 24 and 72h incubation periods. For in vivo evaluation of neuroprotection the mice were pretreated for 15 days by oral (vo) with the suspension of white nanocapsules (NB), NC containing the mixture naringin and naringenin (N-NANG), suspension of naringin and naringenin in the form Free (NANG) and vehicle (Sham) at dose 10 mg / kg body weight. Subsequently, stereotactic surgery was performed for intracerebroventricular (i.c.v) infusion of STZ or FAC (cerebral artificial fluid). Behavioral tasks were then initiated. In the open field task the locomotor activity differed in the test section in the NB + STZ group evidenced by a hyperlocomotion between the mice of this experimental group. For exploratory activity there was no significant difference between groups. In the evaluation of the short-term memory in the task of object recognition the animals treated with N-NANG did not recognize the new object. For the long-term memory there was learning only for the mice treated with NB. The mice treated with NB + STZ had memory impairment assessed in the task of inhibitory avoidance, and pre-treatment with N-NANG prevented this effect. In the evaluation of the anti-depressive and anxiolytic-type effects, it was observed that the NNANG + STZ induced greater body activity in the twist parameter in the tail suspension task and in the high "zero" labyrinth there was an increase in the number of spies Relative to the free drug. Regarding the levels of brain antioxidants, there were no changes in the levels of reduced glutathione (GSH) and catalase activity (CAT). The NB + STZ group significantly increased levels of brain lipid peroxidation of thiobarbituric acid reactive species (TBA). N-NANG administration reduced the peroxidation induced by STZ. Thus, it can be concluded that the CNs present characteristics suitable for oral administration. In vivo studies demonstrate that pre-treatment with naringin and naringenin NC was preventative and able to reverse memory deficits, type-depressive and anxiolytic behavior caused by STZ in mice. However, this preventive effect was not observed with the flavonoids in the free form. / As espécies reativas (ERs) e o estresse oxidativo contribuem para a fisiopatologia de diversas doenças entre elas a demência. Uma alternativa inovadora de proteção aos órgãos como o cérebro é o uso de flavonoides com ação antioxidante como a naringina e naringenina. No entanto, esses dois compostos apresentam baixa biodisponibilidade quando administrados pela via oral. Uma alternativa para contornar esta limitação é o uso de nanocarreadores, como as nanocápsulas (NC). Diante disso, o presente estudo teve por objetivo avaliar o efeito neuroprotetor de NC contendo naringina e naringenina em modelo de demência induzida por estreptozotocina (STZ) em camundongos. Foram avaliados o perfil de liberação dos fármacos a partir das suspensões in vitro assim como determinados os efeitos dos fármacos nanoencapsulados na viabilidade celular com linhagem de células Vero. Além disso, foi verificado o envolvimento do estresse oxidativo no tecido cerebral dos camundongos. As NC de naringina e naringenina apresentaram pH ácido, diâmetro de partícula inferior a 95 nm, índice de polidispersão (IPD) menor que 0,2. O potencial zeta foi negativo, entre -12,46 e -17,6 mV e a eficiência de encapsulação foi de 93% para naringina e 95% para a naringenina. Para o estudo do perfil de liberação, foi empregada a técnica de diálise, sendo que 46,5% da naringina e 6,9% da naringenina foram liberadas no meio, em um período de 9h. Os resultados do ensaio de viabilidade celular mostraram que as suspensões de NC causaram redução da viabilidade celular das células Vero nas concentrações de 5, 50 e 500 μg/mL quando comparadas ao controle nos períodos de 24 e 72h de incubação. Para avaliação in vivo da neuroproteção os camundongos foram pré-tratados durante 15 dias via oral (v.o) com a suspensão de nanocápsulas brancas (NB), NC contendo a mistura naringina e naringenina (N-NANG), suspensão de naringina e naringenina na forma livre (NANG) e veículo (Sham) na dose 10 mg/kg corporal. Subsequentemente foi realizada a cirurgia estereotáxica para a infusão via intracerebroventricular (i.c.v) de STZ ou FAC (fluido artificial cerebral). Posteriormente foram iniciadas as tarefas comportamentais. Na tarefa do campo aberto a atividade locomotora diferiu na seção teste no grupo NB+STZ evidenciada por uma hiperlocomoção entre os camundongos deste grupo experimental. Para atividade exploratória não houve diferença significativa entre os grupos. Na avaliação da memória de curto prazo na tarefa de reconhecimento de objetos os animais tratados com N-NANG não reconheceram o objeto novo. Para a memória de longo prazo houve aprendizagem somente para os camundongos tratados com NB. Os camundongos tratados com NB+STZ tiveram prejuízo de memória avaliado na tarefa da esquiva inibitória, e o pré-tratamento com N-NANG preveniu esse efeito. Na avaliação do efeito tipo anti-depressivo e tipo-ansiolítico observa-se que as N-NANG+STZ induziram maior atividade corporal no parâmetro torções na tarefa da suspensão da cauda e no labirinto em “zero” elevado houve um aumento do número de espiadas em relação ao fármaco livre. Com relação aos níveis de antioxidantes cerebrais não houve alterações nos níveis de Glutationa reduzida (GSH) e na atividade da catalase (CAT). O grupo NB+STZ aumentou significativamente os níveis de peroxidação lipídica cerebral de espécies reativas ao ácido tiobarbitúrico (TBA). Já administração de N-NANG reduziu a peroxidação induzida pela STZ. Com isso pode-se concluir que as NC apresentam características adequadas para administração via oral. Os estudos in vivo demonstram que o pré- tratamento com as NC de naringina e naringenina foi preventivo e capaz de reverter os déficits de memória, comportamento tipo-depressivo e ansiolítico causado pela STZ nos camundongos. Contudo, esse efeito preventivo não foi observado com os flavonoides na forma livre.

Limonin and naringin are the two major bitter compounds in Citrus paradisi (grapefruit), and tissue-specific patterns on their distribution are well-established. This study was undertaken to determine the distribution of these compounds within Duncan, Marsh, and Thompson Pink tissues using three-dimensional fruit dissection (600-900 samples per fruit) and highly specific radioimmunoassays for limonin and naringin quantification. Results from a GLM ANOVA showed that there was no radial distribution pattern of limonin or naringin accumulation in these fruit. There were statistically significant differences in the axial distribution of these compounds within the fruit tissues. The limonin concentration in flavedo, albedo, outer segment memberane, and juice vesicles increased toward the distal end of the fruit. Naringin concentrations in flavedo, albedo, and outer segment membranes tended to be higher in the center portion of the fruit. Limonoate A-ring monolactone levels are also reported.

The vast majority of exogenous substances is metabolized in the liver. In the course of the biotransformation, partly biologically non-active products, partly reactive species leading to cell structure injury and even to the liver failure are produced. Oxidative stress plays a significant role in the toxic- and drug-induced liver damage. Endogenous and exogenous antioxidants contribute to equilibrium between the production and the elimination of reactive oxygen species and thus prevent the oxidative stress. In acute experiments in rats we examined the ability of natural antioxidants silymarin, naringin and resveratrol and of synthetic chelator deferipron to protect against liver damage induced by paracetamol, thioacetamide and tamoxifen. The following parameters of oxidative stress were measured in the liver homogenates: level of lipid peroxidation (LP), concentration of reduced glutathione (GSH), activities of glutathione peroxidase (GPx) and of catalase (CAT); in some cases the iron liver content. The following markers of liver damage were measured in serum: alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH). Concernig markers of oxidative status, silymarin exerted the most efficient antioxidant properties amelioratig the TAA- and TAM-induced lipid...

Flavonoids play crucial roles in plant life cycles and in human welfare. Grapefruit plants produce several glycosylated flavonoids and the glycosylation reactions are catalyzed by UDP-glucose: glucosyltransferases (GTs). Our objective was to use the SMART RACE RT-PCR strategy to obtain cDNA sequences of putative grapefruit flavonoid GTs. Gene specific primers were designed from the plant secondary product glucosyltransferase (PSPG) box and used to amplify 5’GT clones. Clone-specific primers were designed from 5’clones to amplify 3’ GT clones. We obtained 5 5’ clones and 1 3’ clone as candidate GTs. We used 3 of these clones to predict 2 compiled GT sequences. Structural comparison of the putative GTs with functionally known GTs from other plants showed an overall low pair-wise sequence identity (11-31%), but high identity (52.2-75%) within the PSPG box. We conclude that assignment of function from sequence information is not appropriate; assignment should depend on biochemical characterization of expressed GT enzymes.

Flavonoids are plant secondary metabolites that are integral to our lives. Grapefruits are well-known for production of unique glucosylated products and the enzymes responsible are UDP-glucose:glucosyltransferases (GTs). The objective of this research was to obtain full-length clones of putative grapefruit GTs, express them, and characterize them. Previously, gene specific primers (from conserved PSPG box) and clone specific primers (from partial 5' clones) were designed, and a compiled sequence attained using SMART RACE RT-PCR. A full-length clone was obtained using primers designed from the extreme ends of the compiled sequence. The full-length clone was inserted into expression vector (pET32a) and transformed into expression host BL21(DE3)RIL. Expressed protein was tested for GT activity using different flavonoid aglycones and UDP-14C-glucose as glucose donor. Results indicated that the expressed protein was probably not a flavonoid GT. A directionally cloned grapefruit leaf cDNA library is undergoing EST mining to identify additional GT candidates.

Yes / Herein the potential of a relatively new water soluble fiber, resistant maltodextrin (RMD) to encapsulate grapefruit polyphenol, naringin, using spray drying was evaluated. Full factorial Design Of Experiments (DOE) for spray drying with two levels of fiber–naringin ratio and spray dryer inlet temperature was executed. Resulting powders were characterized with respect to particle size and morphology, crystallinity, thermal properties, moisture sorption and naringin aqueous solubility increase. A 60–80% encapsulation was achieved. Thermal and moisture sorption behaviors of these dispersions were found to be dominated by RMD. By varying fiber–naringin ratio and spray drying temperatures, naringin was able to disperse in amorphous form in RMD matrix, which led to 20–55% increase in aqueous solubility. Solubility enhancement was found to correlate positively with increasing fiber: naringin ratio and spray drying temperature due to multiple factors discussed in this study. In conclusion, fiber–polyphenol bicomponent nutraceutical was successfully developed based on a well-established encapsulation technology i.e. spray-drying.

No / Polymeric materials are described which have a bioflavonoid coating, the bioflavonoid content of the coating comprising at least naringin and neohesperidin. The use of such coated polymeric materials is also described as well as the process for making the coated polymeric materials.

Flavonoids are chemically modified by glucosylation, hydroxylation, methylation, etc. During glucosylation, the sugar moiety from UDP-sugar is transferred to aglycone flavonoid substrates by glucosyltransferases (GTs). Grapefruit contains 5 different glucosyltransferases that demonstrate differences in not only substrate but also position specificity. Previous research obtained 3 putative 5’ grapefruit GT clones using SMART RACE RT-PCR with a degenerate gene specific primer based on a highly conserved sequence area in the Plant Secondary Product Glucosyltransferase box. The objective of this research was to use clone specific primers to obtain 3’ clones of the 3 previously mentioned 5’ clones as well as verify putative GT candidacy based on sequence data. Two of the 3 putative GT candidates were designated non-GTs following 3’end sequencing. During pursuit of sequence for the remaining 5’ clone, 1 full-length clone and 1 partial putative GT clone were obtained. To verify GT status, the clones must undergo expression/biochemical characterization.

Naringin is a flavonoid glycoside (C27H32O14) found in citrus fruits and grapes, recognized for exercising antioxidant, antiatherogenic, hypoglycemic activity, among others. Contractile and electrical effects of naringin were characterized on the heart muscle of rats. The experiments were performed in the left atrium isolated rat (tub with 8 ml, Krebs-Hanseilet, 29 ± 0.1 ° C; Stimulation: 1 gf, 1 Hz, 100 V, 1.5 ms). The force data were obtained by isometric transducer (Grass FT03), amplified (Grass P11T), digitized (DATAQ DI710) and stored in a computer for analysis. The naringin (0.003 to 6 mM) was added cumulatively to the bath to determine their influence on the contractile parameters. Curves concentration-effect of naringin were obtained after atrial preincubation with 1 uM propranolol or 1 uM nifedipine or 1 uM ryanodine or still, using atria of animals with depletion of catecholamine. The effect of naringin on electrocardiograms were obtained by Langendorff technique (10 ml / min - Milan peristaltic pump; Krebs solution at 34 ± 0.1 °C aerated with carbogen), with measurement of the left intraventricular pressure (PVE) by inserting the balloon. Data were expressed as mean ± standard error of the mean and the results were evaluated by one-way analysis of variance (ANOVA) with Tukey post test or Student t test. P values ≤ 0.05 were considered significant and statistical analyzes were performed with the GraphPad Prism© version 5.0 (GraphPad Software Inc., San Diego CA, USA). Naringin (0.03-2 mM) induced a positive inotropic effect on atrium (147%; EC50 of 0.32 ± 0.01 mM, n=5) dependent on concentration. From 3 mM, naringin reduced the contractile force. At maximum positive inotropic effect of naringin there was a decrease of systole duration of 0.11 ± 0.006 sec to 0.09 ± 0.002 sec (p <0.05) and increase in the diastole duration of 0.84 ± 0.019 sec to 0.88 s ± 0.0024 sec (p <0.05). Observed increase dT/dt (+) of 6.16 ± 1.76 gf/sec to 19.74 ± 2.64 gf/sec (p <0.01) and dT/dt (-) of 6.21 ± 1.14 gf/sec to 13.52 ± 1.78 gf /sec (p <0.01). Naringin also promoted diastolic relaxation (44%). Preincubation of the atria with propranolol (Non-selective β-adrenoceptor antagonist) or nifedipine (L- type calcium channels antagonist) or ryanodine (ryanodine receptors antagonist) abolished the positive inotropic effect induced by naringin, as well as no detectable increase in contractile force in atria of animals with depletion of catecholamines. With regard to electrical parameters, naringin shortened PRi of 48.42 ± 0.81ms to 47.31 ± 0.89ms (n = 5, p <0.05) and reduced QT intervals (QTc) of 66, 75 ms ± 2.35 to 64.36 ± 2.24 ms. Conversely, the QRS complex increased (Control: 18.5 ± 1.0 ms and Naringin: 20.83 ± 1.24 ms). This flavonoid also influenced the activity of the cardiac pacemaker, increasing heart rate of 226.9 ± 1.12 bpm to 240.2 ± 3.94 bpm. No cardiac arrhythmia event was recorded during the perfusion of the heart with naringin. The PVE suffered increase of 6%. Naringin exerts positive inotropic and chronotropic effect on cardiac muscle by indirect activation of β-adrenergic receptors through endogenous catecholamines release and promotes significant electrocardiographic changes, reducing PRi, QTc and RRi, and slow down the speed of the QRS. / A naringina é um glicosídeo flavonoide (C27H32O14) encontrado em uvas e frutas cítricas, reconhecida por exercer atividades antioxidante, antiaterogênica, hipoglicemiante, dentre outras. Os efeitos contráteis e elétricos da naringina foram caracterizados sobre o músculo cardíaco de rato. Os experimentos foram realizados em átrio esquerdo isolado de rato (cuba com 8 mL, Krebs-Hanseilet, 29 ± 0,1 °C; Estimulação: 1 gf, 1 Hz; 100 V; 1,5 ms). Os dados de força foram captados por transdutor isométrico (Grass FT03), amplificados (Grass P11T), digitalizados (DATAQ DI710) e armazenados em computador para análise. A naringina (0,003 - 6 mM) foi adicionada cumulativamente ao banho para determinar sua influência sobre parâmetros contráteis. Curvas concentração-efeito da naringina foram obtidas após a pré-incubação do átrio com 1 μM de propranolol ou 1 μM nifedipina ou 1 μM de rianodina ou ainda, usando átrios de animais com depleção de catecolaminas. Os efeitos da naringina sobre o eletrocardiograma foram obtidos através da técnica de Langendorff (10 mL/min - Bomba peristáltica Milan; Solução de Krebs a 34 ± 0,1 °C aerada com carbogênio), com mensuração da pressão intraventricular esquerda (PVE) por inserção de balonete. Os dados foram expressos pela média ± erro padrão da média e os resultados foram avaliados pela análise de variância de uma via (ANOVA) com pós-teste de Tukey ou pelo teste t de Student. Valores de p ≤ 0,05 foram considerados significativos e as análises estatísticas foram realizadas com o GraphPad Prism© versão 5.0 (GraphPad Software Inc., San Diego CA, USA). A Naringina (0,03 - 2 mM) promoveu efeito inotrópico positivo em átrio (147%; CE50 de 0,32 ± 0,01 mM; n = 5) dependente de concentração. A partir de 3 mM, a naringina reduziu a força contrátil. No efeito inotrópico positivo máximo da naringina, houve redução da duração da sístole de 0,11 ± 0,006 s para 0,09 ± 0,002 s (p < 0,05) e aumento na duração da diástole de 0,84 ± 0,019 s para 0,88 ± 0,0024 s (p < 0,05). Observado aumento da dT/dt(+) de 6,16 ± 1,76 gf/s para 19,74 ± 2,64 gf/s (p < 0,01) e da dT/dt(-) de 6,21 ± 1,14 gf/s para 13,52 ± 1,78 gf/s (p < 0,01). A naringina também promoveu relaxamento diastólico (44 %). A pré-incubação dos átrios com propranolol (antagonista β-adrenérgico não-seletivo) ou nifedipina (antagonista de canais de cálcio tipo-L) ou rianodina (antagonista de receptores de rianodina) aboliu o efeito inotrópico positivo induzido pela naringina, assim como, não se evidenciou aumento de força contrátil em átrios obtidos de animais previamente reserpinizados. Quanto aos parâmetros elétricos, a naringina encurtou o PRi de 48,42 ± 0,81 ms para 47,31 ± 0,89 ms (n = 5, p < 0,05) e reduziu o intervalo QT(QTc) de 66,75 ± 2,35 ms para 64,36 ± 2,24 ms. Por outro lado, a duração do complexo QRS aumentou (Controle: 18,5 ± 1,0 ms e Naringina: 20,83 ± 1,24 ms). Este flavonoide também influenciou a atividade do marcapasso cardíaco, aumentando a frequência cardíaca 226,9 ± 1,12 bpm para 240,2 ± 3,94 bpm. Nenhum evento de arritmia cardíaca foi registrado durante a perfusão do coração com a naringina. A PVE sofreu aumento de 6%. A naringina exerce efeito cronotrópico e inotrópico positivos em coração de rato por ativação indireta de receptores β-adrenérgicos através da liberação catecolaminas endógenas e promove alterações eletrocardiográficas significativas, ao reduzir PRi, QTc e RRi, além de lentificar a velocidade do QRS.