Estudos cinéticos com a L-Malato desidrogenase mitocondrial de coração bovino

Orientador: Anníbal de Paiva CampelloDissertação (mestrado) -Universidade Federal do Paraná, Curso de Pós-Graduação em BioquímicaInclui referências: p. 85-89Resumo: Um estudo cinético com a L-malato desidrogenase mitocondrial de coração bovino foi realizado, analisando-se as anomalias cinéticas causadas por altas concentrações de oxaloacetato, NADH e L-malato e o efeito da força iônica. A inibição de substrato pelo oxaloacetato pode ser enquadrada no mecanismo de adição ordenada sequencial de dois substratos, porém, a inibição por substrato causada pelo NADH não pode ser enquadrada. As anomalias cinéticas causadas por altas concentrações de L-malato que também não podem ser enquadradas no mecanismo de adição ordenada de dois substratos, sugerem a existência de vias alternativas que levam à formação de produtos. O efeito causado pela força iônica é em geral inibitório e é simples quando os eventos que tem lugar no centro ativo da enzima são relativamente simples. Há um efeito assimétrico da força iônica nas curvas de saturação de oxaloacetato e NADH. O efeito da força iônica nas curvas de saturação com oxaloacetato e NADH, em comparação com o efeito causado às curvas de pH, apresenta diversas semelhanças. Um aumento na força iônica em pouco altera a afinidade do NADH para com a enzima mas altera substancialmente as constantes de Michaelis de ambos os substratos bem como a velocidade máxima

Biotechnological, nutritional and therapeutic uses of Pleurotus spp. (Oyster mushroom) related with its chemical composition: a review on the past decade findings

The particular characteristics of growth and development of mushrooms in nature result in the accumulation of a variety of secondary metabolites, several of them with biological activities. The genus Pleurotus is a cosmopolitan group of mushrooms with high nutritional value and therapeutic properties, besides a wide array of biotechnological and environmental applications. Scope and approach: The present report aims to provide a critical review on aspects related to chemical compounds isolated from the genus Pleurotus with possible biotechnological, nutritional and therapeutic uses. Investigations on the genus have immensely accelerated during the last ten years, so that only reports published after 2005 have been considered. Key findings and conclusions: The most important Pleurotus species cultivated in large scale are P. ostreatus and P. pulmonarius. However, more than 200 species have already been investigated to various degrees. Both basidiomata and mycelia of Pleurotus are a great renewable and easily accessible source of functional foods/nutraceuticals and pharmaceuticals with antioxidant, antimicrobial, anti-inflammatory, antitumor and immunomodulatory effects. A series of compounds have already been precisely defined including several polysaccharides, phenolics, terpenes and sterols. However, intensification of structure determination is highly desirable and demands considerable efforts. Further studies including clinical trials need to be carried out to ascertain the safety of these compounds as adequate alternatives to conventional drugs. Not less important is to extend the search for novel bioactives to less explored Pleurotus species.The authors are grateful to the Foundation for Science and Technology (FTC, Portugal) for financial support to CIMO (Pest-OE/AGR/UI0690/2014). R.C.G. Correa thanks CAPES Foundation, Ministry of Education of Brazil (CAPES fellow, process number BEX 3974/14-6). R.M. Peralta and A. Bracht are Research Fellows of CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico)

Hepatic zonation of carbon and nitrogen fluxes derived from glutamine and ammonia transformations

<p>Abstract</p> <p>Background</p> <p>Glutaminase predominates in periportal hepatocytes and it has been proposed that it determines the glutamine-derived nitrogen flow through the urea cycle. Glutamine-derived urea production should, thus, be considerably faster in periportal hepatocytes. This postulate, based on indirect observations, has not yet been unequivocally demonstrated, making a direct investigation of ureogenesis from glutamine highly desirable.</p> <p>Methods</p> <p>Zonation of glutamine metabolism was investigated in the bivascularly perfused rat liver with [U-¹⁴C]glutamine infusion (0.6 mM) into the portal vein (antegrade perfusion) or into the hepatic vein (retrograde perfusion).</p> <p>Results</p> <p>Ammonia infusion into the hepatic artery in retrograde and antegrade perfusion allowed to promote glutamine metabolism in the periportal region and in the whole liver parenchyma, respectively. The results revealed that the space-normalized glutamine uptake, indicated by ¹⁴CO₂production, gluconeogenesis, lactate production and the associated oxygen uptake, predominates in the periportal region. Periportal predominance was especially pronounced for gluconeogenesis. Ureogenesis, however, tended to be uniformly distributed over the whole liver parenchyma at low ammonia concentrations (up to 1.0 mM); periportal predominance was found only at ammonia concentrations above 1 mM. The proportions between the carbon and nitrogen fluxes in periportal cells are not the same along the liver acinus.</p> <p>Conclusions</p> <p>In conclusion, the results of the present work indicate that the glutaminase activity in periportal hepatocytes is not the rate-controlling step of the glutamine-derived nitrogen flow through the urea cycle. The findings corroborate recent work indicating that ureogenesis is also an important ammonia-detoxifying mechanism in cells situated downstream to the periportal region.</p

New phytochemicals as potential human anti-aging compounds: reality, promise, and challenges

Aging is an inevitable process influenced by genetic, lifestyle, and environmental factors. Indirect evidence shows that several phytochemicals can have anti-aging capabilities, although direct evidence in this field is still limited. This report aims to provide a critical review on aspects related to the use of novel phytochemicals as anti-aging agents, to discuss the obstacles found when performing most anti-aging study protocols in humans, and to analyze future perspectives. In addition to the extensively studied resveratrol, epicatechin, quercetin, and curcumin, new phytochemicals have been reported to act as anti-aging agents, such as the amino acid L-theanine isolated from green tea, and the lignans arctigenin and matairesinol isolated from Arctium lappa seeds. Furthermore, this review discusses the application of several new extracts rich in phytochemicals with potential use in anti-aging therapies. Finally, this review also discusses the most important biomarkers to test anti-aging interventions, the necessity of conducting epidemiological studies and the need of clinical trials with adequate study protocols for humans.R.C.G. Correa thanks Coordena¸c~ao de Aperfei¸coamento do Pessoal do Ensino Superior (CAPES) and Funda¸c~ao Arauc aria for the financial support provided for her postgraduate studies in Federal Technological University of Paran a (contract 100/2014). R.M. Peralta (Project number 307944/2015-8), C.W.I. Haminiuk (Project number 303238/2013-5), and A. Bracht (Project number 302615/2011-3) are research grant recipients of Conselho Nacional de Desenvolvimento CientÍfico e Tecnologia (CNPq). The authors are also grateful to (FCT, Portugal) and FEDER-COMPETE/ QREN/EU for financial support through the research project PEst-OE/ AGR/UI0690/2014.info:eu-repo/semantics/publishedVersio

A natural food ingredient based on ergosterol: Optimization of the extraction from: Agaricus blazei, evaluation of bioactive properties and incorporation in yogurts

In recent years, mycosterols have emerged as potential functional ingredients for the development of sterol-enriched food products and dietary supplements. Agaricus blazei is a mushroom rich in bioactive compounds. For commercial purposes, their fruiting bodies must obey rigid morphological criteria. Those not conforming to these criteria are usually discarded, although this does not mean impairment of their content in bioactives. The aim of the present work was to propose the use of commercially discarded A. blazei fruiting bodies for obtaining an extract rich in ergosterol as a fortifier ingredient for yogurts. For extraction, the Soxhlet technology was used and the highest ergosterol yield (around 12%) was achieved in the 5th cycle, yielding 58.53 ± 1.72 μg of ergosterol per 100 g of mushroom (dry weight). The ergosterol rich extract presented notable antioxidant and antimicrobial properties, besides showing no hepatotoxicity. When added to the yogurts it significantly enhanced their antioxidant properties. Furthermore, it did not significantly alter the nutritional or the individual fatty acid profiles of the final dairy products. Thus, A. blazei fruiting bodies that do not conform to the commercial requirements of the market and are normally discarded could be exploited for obtaining a natural high added-value food additive, following the circular bioeconomy concept.R. C. G. Correa thanks the CAPES Foundation, Ministry of Education, Brazil (CAPES fellow, process number 88881.120010/2016-01), for the financial support provided for her postdoctoral research in the Polytechnic Institute of Bragança. The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and the FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/ 00690/2013), L. Barros contract and A. Fernandes grant (SFRH/ BPD/114753/2016). This work was also funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador ValorNatural®. Rosane Marina Peralta and Adelar Bracht are recipients of scientific productivity research grants from CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil), grants numbers 307944/2015- 8 and 304090/2016-6, respectively. M. Sokovic is grateful for financial support to the Ministry of Education, Science and Technological Development of Republic of Serbia, Grant No. 173032.info:eu-repo/semantics/publishedVersio

Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured “Serra da Estrela” cheese

Chestnut flowers, lemon balm plants and their decoctions were incorporated into "Serra da Estrela" cheese, to assess their potential to preserve its nutritional properties and provide new foodstuffs. The analyses were carried out after the normal ripening period of 1month and after 6months of storage. The most abundant nutrients were proteins and fats. The most abundant minerals were Ca and Na, while C16:0 and C18:1 were the main fatty acids. Saturated fatty acids were the most abundant, followed by the monounsaturated. Moisture seemed to be lower in the samples with the plants incorporated. The dried plants, when incorporated, seemed to be more efficient as preservers then the decoctions, although these better preserved the proteins. These plants can be regarded as promising natural preservers in foodstuffs cheese, given the preservation of key parameters and the slight impact on the nutritional value.The authors are grateful to Queijos Casa Matias, Lda and Mais Ervas, Lda. For providing the cheese and M. officinalis samples, respectively. The authors also acknowledge PRODER project No. 46577-PlantLact, the Foundation for Science and Technology (FCT, Portugal) for financial support to the CIMO research centre (Pest-OE/AGR/UI0690/2014) and ALIMNOVA research group (UCM-951505/2012), J.C.M. Barreira acknowledges the FCT for his post-doctoral grant (BPD/72802/2010)

An overview of structural aspects and health beneficial effects of antioxidant oligosaccharides

Background: Non-digestible oligosaccharides are versatile sources of chemical diversity, well known for their prebiotic actions, found naturally in plants or produced by chemical or enzymatic synthesis or by hydrolysis of polysaccharides. Compared to polyphenols or even polysaccharides, the antioxidant potential of oligosaccharides is still unexplored. The aim of the present work was to provide an up-to-date, broad and critical contribution on the topic of antioxidant oligosaccharides. Methods: The search was performed by crossing the words oligosaccharides and antioxidant. Whenever possible, attempts at establishing correlations between chemical structure and antioxidant activity were undertaken. Results: The most representative in vitro and in vivo studies were compiled in two tables. Chitooligosaccharides and xylooligosaccharides and their derivatives were the most studied up to now. The antioxidant activities of oligosaccharides depend on the degree of polymerization and the method used for depolymerization. Other factors influencing the antioxidant strength are solubility, monosaccharide composition, the type of glycosidic linkages of the side chains, molecular weight, reducing sugar content, the presence of phenolic groups such as ferulic acid, and the presence of uronic acid, among others. Modification of the antioxidant capacity of oligosaccharides has been achieved by adding diverse organic groups to their structures, thus increasing also the spectrum of potentially useful molecules. Conclusion: A great amount of high-quality evidence has been accumulating during the last decade in support of a meaningful antioxidant activity of oligosaccharides and derivatives. Ingestion of antioxidant oligosaccharides can be visualized as beneficial to human and animal health.This work was funded by the Conselho Nacional de Desenvolvimento Cientffico e Tecnológico (CNPq), Brazil; grants numbers 40898/2016-5 and 307944/2015-8).info:eu-repo/semantics/publishedVersio

Biological activities and chemical constituents of Araucaria angustifolia: An effort to recover a species threatened by extinction

Background: Araucaria angustifolia (Bert.) O. Kuntze (A. brasiliensis), known as Paraná pine, is the sole native gymnosperm of the Atlantic forest in Brazil and has great economic, cultural and social importance. Its seed, known as pinhão, has been consumed since prehistoric times. Besides the nutritional aspects, different parts of A. angustifolia are also used in the Brazilian folk medicine for the treatment of rheumatism, respiratory infections, fatigue, anemia, among other disorders. Timber exploration has dramatically reduced the species population, and currently, A. angustifolia is classified as vulnerable regarding the risk of extinction. Scope and Approach: This review presents the most recently uncovered details about the chemical composition of the various parts of the plant. Emphasis is given to the main isolated and identified compounds or fractions and their corresponding bioactivities. Key Findings and Conclusions:.Apart from the nutritional properties of the pinhão, particularly as a starch source, this review reveals that a number of biological activities have been found in different parts of A. angustifolia (leaves, bark and pinhão coat), such as protection against DNA UV-induced damage, antioxidant, antiinflammatory, antiviral and digestive enzyme inhibiting activities. Further investigations should include parts of A. angustifolia that are currently discarded, such as the bark, bracts and the pinhão coat, with potential for use in pharmaceutical and cosmetic industries. Studies on A. angustifolia must combine two important elements: the need for preservation of a typical ecosystem and the implementation of the A. angustifolia forests as a true economic alternative for local residents.The authors thank the Fundação Araucária for funding this study. R.F. Oliveira, R.C.G. Correa, L. Bertonha and V.G. Correa thank Coordenação de Aperfeiçoamento do Pessoal do Ensino Superior (CAPES) for the financial support provided for their post-graduate studies in Universidade Estadual de Maringá. R.M. Peralta and A. Bracht are research grant recipients of Conselho Nacional de Desenvolvimento Científico e Tecnologia (CNPq)

Effects of a Myrciaria jaboticaba peel extract on starch and triglyceride absorption and the role of cyanidin-3- O -glucoside

The purpose of this study was to perform a parallel and comparative investigation of the effects of a Myrciaria jaboticaba (common name jabuticaba) peel extract and of its constituent cyanidin-3-O-glucoside on the overall process of starch and triglyceride intestinal absorption. The peel extract inhibited both the porcine pancreactic α-amylase and the pancreatic lipase but was 13.6 times more potent on the latter (IC50 values of 1963 and 143.9 μg mL-1, respectively). Cyanidin-3-O-glucoside did not contribute significantly to these inhibitions. The jabuticaba peel extract inhibited starch absorption in mice at doses that were compatible with its inhibitory action on the α-amylase. No inhibition of starch absorption was found with cyanidin-3-O-glucoside doses compatible with its content in the extract. The extract also inhibited triglyceride absorption, but at doses that were considerably smaller than those predicted by its strength in inhibiting the pancreatic lipase (ID50 = 3.65 mg kg-1). In this case, cyanidin-3-O-glucoside was also strongly inhibitory, with 72% inhibition at the dose of 2 mg kg-1. When oleate + glycerol were given to mice, both the peel extract and cyanidin-3-O-glucoside strongly inhibited the appearance of triglycerides in the plasma. The main mechanism seems, thus, not to be the lipase inhibition but rather the inhibition of one or more steps (e.g., transport) in the events that lead to the transformation of free fatty acids in the intestinal tract into triglycerides. Due to the low active doses, the jabuticaba peel extract presents many favourable perspectives as an inhibitor of fat absorption and cyanidin-3-O-glucoside seems to play a decisive role. This journal is.This work was financially supported by grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq-304090/2016-6) and Coordenação do Aperfeiçoamento de Pessoal do Ensino Superior (CAPES). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020) and through the institutional scientific employment program-contract for L. Barros contract. This work was also funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®.info:eu-repo/semantics/publishedVersio