Gastrointestinal-active oligosaccharides from human milk and functional foods

Keywords: human milk oligosaccharides (HMOs), galacto-oligosaccharides (GOS), konjac glucomannan (KGM), breast milk, baby feces, gastrointestinal metabolization, blood-group specific conjugates, CE-LIF-MSn Oligosaccharides, as present in human milk or supplemented to food, are renowned for their biological activity in the gastrointestinal tract. So far, little is known about the implication of oligosaccharide structures on their gastrointestinal fate. The influence of diet-related oligosaccharides on the postnatal gastrointestinal development and on the establishment of a balanced microflora is of special interest. Therefore, the present research aimed at an advanced understanding of the gastrointestinal metabolization of diet-related oligosaccharides, focusing on infant nutrition. Capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was introduced as a sensitive, qualitative and quantitative method for the analysis of individual galactooligosaccharides (GOS) from complex food matrices. The method also showed to be useful for the monitoring and characterization of complex konjac glucomannan (KGM) oligosaccharides, resulting from enzymatic digestion of the KGM polysaccharide andin vitro fermentation with human gut flora. The analysis and identification of human milk oligosaccharides (HMOs) in breast milk and the characterization of oligosaccharides as present in the feces of breast-, formula- and mixed-fed babies was performed by CE-LIF coupled to a mass spectrometer (CE-LIF-MSn). The type of feeding determines the presence of diet-related oligosaccharides in baby feces. For breast-fed babies a gradual change in fecal oligosaccharide profile was found during the first six months postpartum. Three continuous stages of fecal oligosaccharide profiles were defined, comprising the presence of the genetically determined HMO-profile of the breast milk consumed (stage 1), the presence of HMO-units conjugated to blood group determinants from gastrointestinal mucins (stage 2) and predominantly oligosaccharides characteristic for follow-up feeding when solid food is introduced (stage 3). In total, sixteen fecal oligosaccharides, which pointed to the degradation and gastrointestinal metabolization of diet-related oligosaccharides and which were not present in human milk or infant formula, were identified in this research. Monitoring the gastrointestinal fate of diet-related oligosaccharides pointed to an individual-dependent gastrointestinal adaptation to enteral food during the postnatal period. </p

Drug Discovery

Natural products are a constant source of potentially active compounds for the treatment of various disorders. The Middle East and tropical regions are believed to have the richest supplies of natural products in the world. Plant derived secondary metabolites have been used by humans to treat acute infections, health disorders and chronic illness for tens of thousands of years. Only during the last 100 years have natural products been largely replaced by synthetic drugs. Estimates of 200 000 natural products in plant species have been revised upward as mass spectrometry techniques have developed. For developing countries the identification and use of endogenous medicinal plants as cures against cancers has become attractive. Books on drug discovery will play vital role in the new era of disease treatment using natural products

A global review on short peptides: frontiers and perspectives

Peptides are fragments of proteins that carry out biological functions. They act as signaling entities via all domains of life and interfere with protein-protein interactions, which are indispensable in bio-processes. Short peptides include fundamental molecular information for a prelude to the symphony of life. They have aroused considerable interest due to their unique features and great promise in innovative bio-therapies. This work focusing on the current state-of-the-art short peptide-based therapeutical developments is the first global review written by researchers from all continents, as a celebration of 100 years of peptide therapeutics since the commencement of insulin therapy in the 1920s. Peptide “drugs” initially played only the role of hormone analogs to balance disorders. Nowadays, they achieve numerous biomedical tasks, can cross membranes, or reach intracellular targets. The role of peptides in bio-processes can hardly be mimicked by other chemical substances. The article is divided into independent sections, which are related to either the progress in short peptide-based theranostics or the problems posing challenge to bio-medicine. In particular, the SWOT analysis of short peptides, their relevance in therapies of diverse diseases, improvements in (bio)synthesis platforms, advanced nano-supramolecular technologies, aptamers, altered peptide ligands and in silico methodologies to overcome peptide limitations, modern smart bio-functional materials, vaccines, and drug/gene-targeted delivery systems are discussed

Polysaccharide-Based Nanocarriers for Improved Drug Delivery

The field of drug delivery has provided a solution to the limited efficacy and high toxicity of many drugs. Nano-sized drug carriers are popular because their size allows for selective accumulation in the diseased area. Polysaccharides are non-toxic and biodegradable natural polymers that can serve as the basis for these nano-sized carriers. Polysialic acid (PSA) is such a polysaccharide with strong hydrophilicity that may reduce uptake by the reticuloendothelial system and prolong drug circulation. In this study, we developed PSA-based nanocarriers, specifically micelles and nanoparticles, for improved drug delivery with improved efficacy and minimized toxicity. PSA-based micelle systems were developed via conjugation with two hydrophobic groups, decylamine (DA) and polycaprolactone (PCL). Nanoparticles were fabricated via ionic complexation of the negatively charged PSA with positively charged N, N, N-trimethyl chitosan (TMC). All three nanocarriers possessed sizes close to 100 nm with low polydispersity (PDI) and high zeta potential values. Literature suggested that these characteristics would allow the nanocarriers to be physiologically stable and would facilitate passive accumulation within diseased areas. Rheumatoid arthritis (RA) was selected as the primary disease model for evaluation of our nanocarriers. PSA-PCL micelles and PSA-TMC nanoparticles showed low cytotoxicity, as demonstrated by high IC50 values (PSA-PCL: 10.5 ± 1.7 mg/ml; PSA-TMC: 7.65 ± 0.07 mg/ml) to synovial cells, the so-called conductors of joint destruction in rheumatoid arthritis. The synovial cells were also used to demonstrate effective uptake of fluorescently tagged nanocarriers. Three disease modifying anti-rheumatic drugs (DMARDs) were selected for loading into the nanocarriers. Cyclosporine A (CyA) was encapsulated within the PSA-PCL micelles, while methotrexate (MTX), and dexamethasone (DM) were entrapped within the PSA-TMC nanoparticles. PSA-PCL micelles were loaded with 0.09 ± 0.02 mg CyA per mg of PSA- PCL, while PSA-TMC nanoparticles were loaded with 0.10 ± 0.03 mg MTX and 0.10 ± 0.02 mg DM per mg of PSA-TMC. Controlled release of the DMARDs from the nanocarriers was demonstrated. An in vitro model of rheumatoid arthritis was used to demonstrate the anti-inflammatory nature of the MTX- and DM-loaded PSA-TMC nanoparticles. To the author\u27s knowledge, this is the first time that PSA-based nanocarriers were successfully developed and evaluated for improved drug delivery

Facettes de glycobioinformatique (applications à l'étude des interactions protéines-sucres)

Le travail décrit dans ce manuscrit rassemble les résultats obtenus au cours de ma thèse de doctorat. Ils s'inscrivent dans le domaine de la glycobioinformatique. Ils ont impliqué des développements de bases de données structurales et des applications en modélisation moléculaire des interactions protéines-sucres. Les méthodes de modélisation moléculaire ont été utilisées dans la reconstruction et dans la prédiction des structures tridimensionnelles de polysaccharides et d'oligosaccharides, ces dernières étant également établies par une approche de type haut-débit par application d'un algorithme génétique à des fins de minimisation énergétique. Les données ainsi générées ont été organisées sous la forme de bases de données relationnelles, proprement annotées (PolySca3DB et BiOligo) qui sont en libre accès pour consultation sur internet. Ces méthodes de modélisation moléculaire ont été appliquées à la caractérisation, par RMN en solution, des conformations de basse énergie d'une souche pathogène d'un polysaccharide de la bactérie E. coli. D'autres bactéries pathogènes de type gram négatif, interagissent avec des oligosaccharides par l'intermédiaire de protéines secrétées, telles que des lectines. Nous avons testé, au travers de l'utilisation de méthodes d'amarrage moléculaire, la possibilité d'identifier de manière automatique, la nature de ces interactions, en prenant comme cibles des épitopes oligosaccharidiques fucosylés. Les résultats de ces recherches ont été comparés, de manière critique, à ceux issus de l'application de bio-puces à sucres et de calorimétrie isotherme de titration. Les conclusions et perspectives de ces travaux sont présentées dans un article de revue consacré à l'application des méthodes de chimie computationnelle dans l'étude des interactions protéines-glucides qui viennent compléter l'arsenal des outils dédiés au champs de recherche couvert par la glycobiologie structurale et moléculaire.This thesis presents an account of two important facets of glycobioinformatics, comprising database development and molecular modeling of 3D structures of carbohydrates alongside the simulation of protein-carbohydrate interactions. Classical molecular modeling techniques were used to reconstruct 3D polysaccharide structures from experimentally determined atomic coordinates, or known starting points about their structures were used as guidelines to model them. A genetic algorithm search was employed as a high-throughput technique to characterize low energy conformers of bioactive oligosaccharides. The data generated were organized into two open-access relational databases, namely, PolySac3DB and BiOligo, for use by the scientific community. The validation of the molecular techniques used were performed using solution phase NMR experiments on four entero aggregative pathogenic E. coli strains, and were found to be robust and realistic. Further, the impact of the presentation of human fucosylated oligosaccharide epitopes to lectins from opportunistic gram negative bacteria, was investigated in a screening study using molecular docking studies, which could help in evaluating the feasibility of using automated docking procedures in such instances as well as deciphering binding data from glycan array experiments and also correlated to isothermal calorimetry data. On comparison with high-resolution experimental crystal complexes, automated docking was found to delineate the present level of applicability, while emphasizing the need of constant monitoring and possible filtering of the results obtained. Finally, a review of the present status of the computational aspects of protein-carbohydrate interaction studies is discussed in the perspectives of using molecular modeling and simulation studies to probe this aspect of molecular and structural glycobiology.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

A global review on short peptides: frontiers and perspectives

Peptides are fragments of proteins that carry out biological functions. They act as signaling entities via all domains of life and interfere with protein-protein interactions, which are indispensable in bio-processes. Short peptides include fundamental molecular information for a prelude to the symphony of life. They have aroused considerable interest due to their unique features and great promise in innovative bio-therapies. This work focusing on the current state-of-the-art short peptide-based therapeutical developments is the first global review written by researchers from all continents, as a celebration of 100 years of peptide therapeutics since the commencement of insulin therapy in the 1920s. Peptide “drugs” initially played only the role of hormone analogs to balance disorders. Nowadays, they achieve numerous biomedical tasks, can cross membranes, or reach intracellular targets. The role of peptides in bio-processes can hardly be mimicked by other chemical substances. The article is divided into independent sections, which are related to either the progress in short peptide-based theranostics or the problems posing challenge to bio-medicine. In particular, the SWOT analysis of short peptides, their relevance in therapies of diverse diseases, improvements in (bio)synthesis platforms, advanced nano-supramolecular technologies, aptamers, altered peptide ligands and in silico methodologies to overcome peptide limitations, modern smart bio-functional materials, vaccines, and drug/gene-targeted delivery systems are discussed

Alimentos funcionais com ingredientes inovadores com origem em algas e cogumelos

Doutoramento em QuímicaRecursos naturais, como algas e cogumelos podem ser usados para a obtenção de novos produtos, oferecendo uma forma alternativa e sustentável de originar novos alimentos ou ingredientes funcionais com propriedades biológicas que podem ajudar a desenvolver novas estratégias baseadas na saúde preventiva. A principal força motriz desta tese foi encontrar em algas e cogumelos, extratos com compostos bioativos naturais que possam ser usados no desenvolvimento de novos alimentos funcionais. Com este objectivo, foi efectuada uma abordagem integrada e vários passos foram seguidos numa ordem cronológica. Em primeiro lugar, selecionou-se um conjunto de espécies de algas marinhas assim como um conjunto de espécies de cogumelos comestíveis que foram caracterizados quanto à sua composição química e compostos bioativos potenciais. Tendo sido realizada a sua caracterização, surgiu a necessidade de se aplicar metodologias de extracção adequadas, rentáveis e amigas do ambiente, capazes de extrair ingredientes naturais biologicamente ativos de interesse tanto de algas como de cogumelos. Este objetivo nesta fase levou à segunda etapa do trabalho experimental que envolveu o estudo de várias técnicas de extração (extração com água quente, extração assistida por enzimas e por ultra-sons e extracção sob alta pressão hidrostática), a fim de se caracterizar plenamente o potencial das diferentes fontes naturais, introduzindo em simultâneo diferentes seletividades e eficiências, preservando o máximo de bioatividade. A etapa seguinte desta pesquisa integrada esteve relacionada com a caracterização química mais aprofundada de compostos bioativos presentes nos quatro extratos enzimáticos selecionados de algas (extrato S. muticum obtido com Alcalase e extrato O. pinnatifida obtido com Viscozyme) e de cogumelos (extratos de Ph. nameko obtidos com Celulase e com Flavourzyme) onde as propriedades biológicas alvo foram confirmadas ou verificadas como as mais promissoras. Os extratos selecionados com potenciais propriedades biológicas, após a caracterização química foram avaliados no que respeita à sua estabilidade in vitro para confirmar e consolidar o seu potencial biológico e ser mais explorado na perspectiva do alimento funcional. A última etapa deste trabalho envolveu o desenvolvimento de um novo alimento funcional incorporando-se os dois extratos mais promissores e validados previamente (extrato O. pinnatifida obtido com Viscozyme e extrato Ph. nameko obtido com Flavourzyme) num creme lácteo para barrar, procedendo-se à avaliação do seu potencial biológico e tecnológico. Um creme lácteo de barrar funcional, combinando requeijão e iogurte tipo grego com incorporação dos extratos selecionados foi formulado e explorado com sucesso. O desenvolvimento de alimentos funcionais, ou mesmo de nutracêuticos, a partir de extratos de algas e de cogumelos comestíveis é viável podendo-se estender o estudo da incorporação destes extratos em outros tipos de alimentos como bebidas ou sorvete.Natural resources such as seaweed and mushrooms can be used to obtain new products, providing an alternative and sustainable manner to provide new functional foods or ingredients with biological properties that may help to develop new strategies based on preventive health. The main driving force of this thesis was to find in seaweeds and mushrooms, extracts with natural bioactive compounds to be used in the development of new functional foods. In order to do so, an integrated approach was established and the various steps were followed chronologically. Firstly, a set of edible seaweeds species and a set of edible mushrooms species were characterised for their proximate composition and potential bioactive compounds. Once the characterization was achieved the need for suitable, fast, cost-effective and environmentally friendly extraction methodologies capable of extracting the biologically active natural ingredients of interest from both the seaweeds and mushrooms led to the second stage. This stage involved the study of several extraction techniques (hot water extraction; enzyme- and ultrasound-assisted extraction and high hydrostatic pressure) in order to fully characterize the potential of the different natural sources, introducing different extraction selectivity and efficiency while aiming at maximum preservation of bioactivity. The next stage in this integrated research was related with the deeper chemical characterization of the bioactive components present in the four enzymatic selected extracts from seaweeds (S. muticum extract obtained with Alcalase and O. pinnatifida extract obtained with Viscozyme) and mushrooms (Ph. nameko extracts obtained with Cellulase and with Flavourzyme) where target biological properties were confirmed or found to be more promising. The selected extracts with potential biological properties, following the chemical characterization went through the evaluation of in vitro stability to confirm and consolidate its biological potential to be further explored within the functional food perspective. The last stage of this thesis involved the development of a new functional food by incorporating the two most promising and validated extracts (O. pinnatifida obtained with Viscozyme and Ph. nameko obtained with Flavourzyme) in a spreadable dairy cream with assessment of their biological and technological potential. A functional dairy spreadable dairy cream combining whey cheese and greek type yoghurt with incorporation of the selected extracts was successfully formulated and explored. The development of functional foods, or even nutraceuticals, from edible seaweed and mushroom extracts is feasible and could be extended studying the incorporation of these extracts in other types of food such as beverages or ice cream

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2021–2022

The use of matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well‐established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo‐ and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing

Essential Oils

Over the years, natural products such as essential oils have been gaining more and more prominence due to their perceived health benefits. Plants rich in essential oils represent a viable source of biomolecules for use in the most varied human activities, such as agricultural, cosmetic, and pharmaceutical applications. Essential oils are natural volatile fractions extracted from aromatic plants that are formed by classes of substances such as fatty acid esters, mono and sesquiterpenes, phenylpropanoids, and aldehyde alcohols, and in some cases, aliphatic hydrocarbons, among others. In this context, this book includes twelve chapters that present new information on the extraction and application of essential oils in various industrial segments. It is divided into three sections that discuss the general concepts of essential oils and techniques for their extraction, topics in food science and technology, and essential oils and their pharmacological properties in various activities and applications

Investigations of anti-adhesion and endothelial environment for plasmodium falciparum cytoadherence

A unique feature of mature Plasmodium falciparum (P. falciparum) parasitized RBC (pRBC) is that they bind to surface molecules of microvasculature endothelium via the parasite-derived surface protein PfEMP1. This ligand is associated with the cytoadherence pathology seen in severe malaria (SM) and recently our group has shown that even when treated with effective anti-malarial drug, pRBC are still able to cytoadhere, therefore, there is a need to find an adjunct treatment (in addition to antimalarial drugs) that can inhibit and reverse the adhesion process. Previous reports have suggested that sulphated glycoconjugates are highly effective at disrupting P. falciparum pRBC rosettes. Here, we investigate that effect by using sulphated polysaccharides and modified heparin for their effect to interrupt pRBC sequestration. We found that not all sulphated compounds or modified heparins were able to interrupt the sequestration process. Consideration of the inhibitory compounds generated some 18rules 19 fore exhibition of inhibitory properties: Sulphate position either at 6-O, or/and 2-O sulphate and N-sulphate is necessary for each compound. In addition, the multivalent effect and drug exhibit low anticoagulant activity also determined an active response to inhibit and de-sequestered P. falciparum pRBC on protein and endothelial cells. Here, we provide evidence that polysaccharides that possess a different level of sulphate, conformational structure and sulphate position act differently. This study also addressed the importance of pH host environment and extracellular matrix (glycocalyx) on the surface of endothelial cells on mediating pRBC binding. It found that pRBC bind significantly higher at pH 7-7.2 to CD36 and ICAM-1. Meanwhile, glycocalyx might interact as an instantaneous binder before pRBC reached ICAM-1 or CD36, unfortunately we cannot prove this due to methods and antibody chosen. The work reported in this thesis opens up new possibilities for therapeutic strategies targeting binding interaction of pRBC to host cells