Relevant bibliographies by topics / Polyphenolic oligomers

Academic literature on the topic 'Polyphenolic oligomers'

Author: Grafiati
Published: 28 June 2023

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Journal articles on the topic "Polyphenolic oligomers"

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Alattiya, Reem Halim, Farah Khalid Tarish, Lina Loai Hashim, and Saad Abdulrahman Hussain. "The Role of Polyphenols in the Treatment of Alzheimer's Disease: Narrative Review." Al-Rafidain Journal of Medical Sciences ( ISSN: 2789-3219 ) 1 (October 13, 2021): 53–61. http://dx.doi.org/10.54133/ajms.v1i.31.

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Many epidemiological studies have suggested that consuming a diet rich in polyphenols can help prevent Alzheimer's disease (AD). Based on well-known in vitro and in vivo models of cerebral Aβ amyloidosis, we examined the data on the effects of various natural polyphenols on the aggregation of amyloid-protein (Aβ). These polyphenols effectively prevent oligomerization and fibril formation of Aβ through differential binding patterns, lowering Aβ oligomer-induced synaptic and neuronal toxicity, according to in vitro investigations. Furthermore, in a transgenic mouse model fed orally with such polyphenolic compounds, soluble Aβ oligomers as well as insoluble Aβ deposits in the brain were significantly reduced. Natural polyphenols exhibit anti-amyloidogenic effects on Aβ, in addition to well-known anti-oxidative and anti-inflammatory activities, according to an updated assessment of the literature, implying their potential as therapeutic and/or preventive agents for AD treatment. To prove polyphenols' efficacy as disease-modifying agents, well-designed clinical trials or preventive treatments using various polyphenols are required.
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Saéz, Riquelme, Baer, and Vallverdú-Queralt. "Phenolic Profile of Grape Canes: Novel Compounds Identified by LC-ESI-LTQ-Orbitrap-MS." Molecules 24, no. 20 (October 18, 2019): 3763. http://dx.doi.org/10.3390/molecules24203763.

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Grape canes (Vitis vinifera L.) are a viticulture industry by-product with an important content of secondary metabolites, mainly polyphenols with a broad spectrum of demonstrated health benefits. Grape canes, therefore, have considerable economic potential as a source of high-value phytochemicals. In this work, liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole-Orbitrap mass spectrometry (LC–LTQ-Orbitrap) was used for the comprehensive identification of polyphenolic compounds in grape canes. Identification of polyphenols was performed by comparing their retention times, accurate mass measured, and mass fragmentation patterns with those of reference substances or available data in the literature. A total of 75 compounds were identified, including phenolic acids, flavanols, flavonols, flavanonols, flavanones, and stilbenoids. The most abundant polyphenols were proanthocyanidins and stilbenoids and their oligomers. Moreover, the high-resolution mass spectrometry analysis revealed the occurrence of 17 polyphenols never described before in grape canes, thereby providing a more complete polyphenolic profile of this potentially valuable by-product.
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Ono, Kenjiro, Mayumi Tsuji, Tritia R. Yamasaki, and Giulio M. Pasinetti. "Anti-aggregation Effects of Phenolic Compounds on α-synuclein." Molecules 25, no. 10 (May 24, 2020): 2444. http://dx.doi.org/10.3390/molecules25102444.

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The aggregation and deposition of α-synuclein (αS) are major pathologic features of Parkinson’s disease, dementia with Lewy bodies, and other α-synucleinopathies. The propagation of αS pathology in the brain plays a key role in the onset and progression of clinical phenotypes. Thus, there is increasing interest in developing strategies that attenuate αS aggregation and propagation. Based on cumulative evidence that αS oligomers are neurotoxic and critical species in the pathogenesis of α-synucleinopathies, we and other groups reported that phenolic compounds inhibit αS aggregation including oligomerization, thereby ameliorating αS oligomer-induced cellular and synaptic toxicities. Heterogeneity in gut microbiota may influence the efficacy of dietary polyphenol metabolism. Our recent studies on the brain-penetrating polyphenolic acids 3-hydroxybenzoic acid (3-HBA), 3,4-dihydroxybenzoic acid (3,4-diHBA), and 3-hydroxyphenylacetic acid (3-HPPA), which are derived from gut microbiota-based metabolism of dietary polyphenols, demonstrated an in vitro ability to inhibit αS oligomerization and mediate aggregated αS-induced neurotoxicity. Additionally, 3-HPPA, 3,4-diHBA, 3-HBA, and 4-hydroxybenzoic acid significantly attenuated intracellular αS seeding aggregation in a cell-based system. This review focuses on recent research developments regarding neuroprotective properties, especially anti-αS aggregation effects, of phenolic compounds and their metabolites by the gut microbiome, including our findings in the pathogenesis of α-synucleinopathies.
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Denis, Marie-Claude, Pascal Dubé, Stéphanie Dudonné, Yves Desjardins, Cristina Matei, Edgard Delvin, Emile Levy, and Alexandra Furtos. "Characterization of bioactive cranberry fractions by mass spectrometry." Canadian Journal of Chemistry 98, no. 9 (September 2020): 589–96. http://dx.doi.org/10.1139/cjc-2020-0070.

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Increasing evidence indicates that fruits contain functional bio-active compounds that have several preventive and therapeutic health benefits. Our group has recently conducted studies to assess the potential effects of cranberry polyphenolic fractions on intestinal Caco-2/15 epithelial cells and a substantial reduction in oxidative stress and inflammation was observed. The aim of the present work was to determine the polyphenolic species most likely responsible for the observed biological activity. Low, medium, and high molecular weight cranberry fractions were generated with a Sephadex LH-20 column by elution with 60% MeOH, 100% MeOH, and 70% acetone, respectively. The total phenolic content in these fractions was determined by the Folin–Ciocalteu method. A combination of LC–MS and MALDI-TOF methods were used to characterize the nature of polyphenolic compounds in the cranberry extracts. High resolution mass spectrometry was used to generate empirical formulae for the detected species. The low molecular weight fraction was essentially constituted of small phenolic acids (hydroxycinnamic and hydroxybenzoic acids). The medium fraction was mostly composed of anthocyanin, flavonols (quercetin, myricetin, isorhamnetin, kaempferol), procyanidins monomers (epicatechin, catechin), dimers, and few small oligomers. The heavy fraction was devoid of phenolic acids and anthocyanins, and it contained for the most part oligomers and polymers of procyanidins. Proanthocyanidins oligomers up to n = 22 were detected, which is, to our knowledge, the largest individual polymers reported to date. With this approach, it was also possible to distinguish between the A-type and B-type linkages.
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Zhang, Lei, Ling-Yan Jiang, Ke Zheng, Hua Duan, Min Li, and Yuan-Chen Cui. "Enzymatic Synthesis of p-Cresol Oligomers and Evaluation of their Free Radical Scavenging Activity." Australian Journal of Chemistry 68, no. 2 (2015): 282. http://dx.doi.org/10.1071/ch13734.

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An environmentally benign aqueous micelle system was successfully used as reaction medium to perform enzymatic polymerization of p-cresol using horseradish peroxidase as catalyst. The polymerization maintains high yield over a wide pH range from 5 to 10. The resulting polymer is completely soluble in common solvent such as acetone, THF, DMF, and DMSO. Infrared spectroscopy analysis shows that polymer chains are composed of phenylene and oxyphenylene units. The formation of p-cresol polymer is according to a mechanism of free radical step polymerization. Because quinone structures are formed at the end of the molecular chain, p-cresol oligomers with an average degree of polymerization of less than 10 are obtained. p-Cresol oligomers possess several advantages such as simple synthetic route, good stability in air, and no significant smell. Importantly, the structure of p-cresol oligomers is similar to that of polyphenolic compounds in natural plants. As a result, p-cresol oligomers show good free radical scavenging activity and good prospects as novel antioxidant.
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Caruana, Mario, Tobias Högen, Johannes Levin, Andreas Hillmer, Armin Giese, and Neville Vassallo. "Inhibition and disaggregation of α-synuclein oligomers by natural polyphenolic compounds." FEBS Letters 585, no. 8 (March 26, 2011): 1113–20. http://dx.doi.org/10.1016/j.febslet.2011.03.046.

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Ono, Kenjiro, Daisy Zhao, Qingli Wu, James Simon, Jun Wang, Aurelian Radu, and Giulio Maria Pasinetti. "Pine Bark Polyphenolic Extract Attenuates Amyloid-β and Tau Misfolding in a Model System of Alzheimer’s Disease Neuropathology1." Journal of Alzheimer's Disease 73, no. 4 (February 18, 2020): 1597–606. http://dx.doi.org/10.3233/jad-190543.

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Plant-derived polyphenolic compounds possess diverse biological activities, including strong anti-oxidant, anti-inflammatory, anti-microbial, and anti-tumorigenic activities. There is a growing interest in the development of polyphenolic compounds for preventing and treating chronic and degenerative diseases, such as cardiovascular disorders, cancer, and neurological diseases including Alzheimer’s disease (AD). Two neuropathological changes of AD are the appearance of neurofibrillary tangles containing tau and extracellular amyloid deposits containing amyloid-β protein (Aβ). Our laboratory and others have found that polyphenolic preparations rich in proanthocyanidins, such as grape seed extract, are capable of attenuating cognitive deterioration and reducing brain neuropathology in animal models of AD. Oligopin is a pine bark extract composed of low molecular weight proanthocyanidins oligomers (LMW-PAOs), including flavan-3-ol units such as catechin (C) and epicatechin (EC). Based on the ability of its various components to confer resilience to the onset of AD, we tested whether oligopin can specifically prevent or attenuate the progression of AD dementia preclinically. We also explored the underlying mechanism(s) through which oligopin may exert its biological activities. Oligopin inhibited oligomer formation of not only Aβ1-40 and Aβ1-42, but also tau in vitro. Our pharmacokinetics analysis of metabolite accumulation in vivo resulted in the identification of Me-EC-O-β-Glucuronide, Me-(±)-C-O-β-glucuronide, EC-O-β-glucuronide, and (±)-C-O-β-glucuronide in the plasma of mice. These metabolites are primarily methylated and glucuronidated C and EC conjugates. The studies conducted provide the necessary impetus to design future clinical trials with bioactive oligopin to prevent both prodromal and residual forms of AD.
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Faleva, Anna V., Nikolay V. Ul’yanovskii, Danil I. Falev, Aleksandra A. Onuchina, Nikolay A. Budaev, and Dmitry S. Kosyakov. "New Oligomeric Dihydrochalcones in the Moss Polytrichum commune: Identification, Isolation, and Antioxidant Activity." Metabolites 12, no. 10 (October 14, 2022): 974. http://dx.doi.org/10.3390/metabo12100974.

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One of the most widespread representatives of mosses in the temperate and boreal latitudes of the Northern Hemisphere is common haircap (Polytrichum commune), which is known as the largest moss in the world and widely used in traditional herbal medicine. Polyphenolic compounds constitute one of the most important groups of biologically active secondary metabolites of P. commune, however, the available information on their chemical composition is still incomplete and contradictory. In the present study, a group of dihydrochalcone polyphenolic derivatives that were not previously found in mosses was isolated from P. commune biomass using pressurized liquid extraction with aqueous acetone. The combination of two-dimensional NMR spectroscopy and high-performance liquid chromatography–high-resolution mass spectrometry allowed for identifying them as 3-hydroxyphloretin oligomers formed through a carbon–carbon bond between phloroglucinol and pyrocatechol moieties (“head-to-tail” coupling), with a polymerization degree of 2–5. The individual compounds isolated by preparative reverse-phase HPLC had a purity of 71 to 97% and demonstrated high radical scavenging activity (17.5–42.5 % with respect to Trolox) determined by the photochemiluminescence method. Along with the low toxicity predicted by QSAR/QSTR algorithms, this makes 3-hydroxyphloretin oligomers a promising source for the production of biologically active food additives and pharmaceuticals.
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Zaidi, Fatima Kamal, and Shashank Deep. "Scutellarin inhibits the uninduced and metal-induced aggregation of α-Synuclein and disaggregates preformed fibrils: implications for Parkinson's disease." Biochemical Journal 477, no. 3 (February 11, 2020): 645–70. http://dx.doi.org/10.1042/bcj20190705.

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The aggregation of the protein alpha synuclein (α-Syn), a known contributor in Parkinson's disease (PD) pathogenesis is triggered by transition metal ions through occupational exposure and disrupted metal ion homeostasis. Naturally occurring small molecules such as polyphenols have emerged as promising inhibitors of α-Syn fibrillation and toxicity and could be potential therapeutic agents against PD. Here, using an array of biophysical tools combined with cellular assays, we demonstrate that the novel polyphenolic compound scutellarin efficiently inhibits the uninduced and metal-induced fibrillation of α-Syn by acting at the nucleation stage and stabilizes a partially folded intermediate of α-Syn to form SDS-resistant, higher-order oligomers (∼680 kDa) and also disaggregates preformed fibrils of α-Syn into similar type of higher-order oligomers. ANS binding assay, fluorescence lifetime measurements and cell-toxicity experiments reveal scutellarin-generated oligomers as compact, low hydrophobicity structures with modulated surface properties and significantly reduced cytotoxicity than the fibrillation intermediates of α-Syn control. Fluorescence spectroscopy and isothermal titration calorimetry establish the binding between scutellarin and α-Syn to be non-covalent in nature and of moderate affinity (Ka ∼ 105 M−1). Molecular docking approaches suggest binding of scutellarin to the residues present in the NAC region and C-terminus of monomeric α-Syn and the C-terminal residues of fibrillar α-Syn, demonstrating inhibition of fibrillation upon binding to these residues and possible stabilization of the autoinhibitory conformation of α-Syn. These findings reveal interesting insights into the mechanism of scutellarin action and establish it as an efficient modulator of uninduced as well as metal-induced α-Syn fibrillation and toxicity.
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Maisto, Maria, Elisabetta Schiano, Ettore Novellino, Vincenzo Piccolo, Fortuna Iannuzzo, Emanuela Salviati, Vincenzo Summa, Giuseppe Annunziata, and Gian Carlo Tenore. "Application of a Rapid and Simple Technological Process to Increase Levels and Bioccessibility of Free Phenolic Compounds in Annurca Apple Nutraceutical Product." Foods 11, no. 10 (May 17, 2022): 1453. http://dx.doi.org/10.3390/foods11101453.

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Insoluble bound polyphenols (ISBP) are polyphenolic compounds linked to the food matrix with different interactions limiting both their water extractability and consequent bioaccessibility. The health-promoting potential of polyphenols is historically known and well-demonstrated; specifically, Annurca apple polyphenols were studied both in vitro and in vivo for their effect in controlling cholesterol plasma levels. The aim of the study was the preparation of nutraceutical products based on Annurca apple polyphenolic fraction through the application of a technological process (acid treatment) able to release the ISBP from Annurca apple food matrix and increase polyphenol bioaccessibility. Lyophilized annurca apple (LAA) underwent acid treatment (ATLAA), and differences in released polyphenol levels were analysed by DAD-HPLC. Free-polyphenol levels in samples treated under acid conditions were higher than in untreated ones; in particular, for oligomeric flavan-3-ols (+168% procyanidin B2, +42.97% procyanidin B1 and B2, +156.99% procyanidin C1), catechin (+512.20%), and gallic acid (+707.77%). Furthermore, ATLAA underwent an in vitro gastrointestinal digestion to evaluate the bioaccessibility of contained polyphenols, in comparison to the untreated Annurca apple. The bioaccessibility study indicates a valuable preservation of polyphenolic fraction compared to the control.
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Dissertations / Theses on the topic "Polyphenolic oligomers"

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Pion, Florian. "L'acide férulique, un synthon naturel pour la préparation de nouveaux polymères aromatiques." Electronic Thesis or Diss., Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0007.

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La lignine est le principal composant du bois après la cellulose, et en est séparée lors de la production de papier. Au sein de cette biomasse ligno-cellulosique, chez les graminés, l'acide férulique est l'agent qui ponte la lignine aux fibres polysaccharides afin de fortifier cet ensemble. Si la lignine est complexe et difficilement dégradable, cet acide férulique, puisqu'il est présent libre, est extractible de nombreuses ressources en milieu alcalin (pulpe de betterave, son de blé, de maïs, de riz…). De par sa nature aromatique, cet acide p-hydroxycinnamique se montre intéressant pour préparer de nouveaux polymères incorporant des noyaux aromatiques d'origine biosourcée. En effet, si les polymères biosourcés sont de plus en plus courants et diversifiés, aujourd'hui aucune solution effective n'est proposée pour l'incorporation de noyaux aromatiques biosourcés. Dans ce but, au sein de l'équipe APSYNTH, nous avons développé une nouvelle classe de bisphénols totalement biosourcés obtenus par voie enzymatique. Ces bisphénols ont ensuite été mis en jeu dans différentes stratégies pour préparer de nouveaux copolyesters, polyuréthanes et oligomères polyphénoliques. Ces travaux présentent la synthèse et la caractérisation de ces nouveaux bisphénols issus de l'acide férulique, ainsi que des différents polymères en résultant
Lignin is the most abundant component of wood after cellulose and is separated from whilepaper production. Within this lingo-cellulosic biomass, in case of graminous, ferulic acid is a crosslinkingagent binding lignin to polysaccharide fibers to increase its mechanical properties. If lignin iscomplex and poorly degradable, ferulic acid, as it is present free, is extractible in alkali media frommany resources (beetroot pulp, wheat, corn, rice...).By its aromatic nature, this p-hydroxycinnamic acid seems interesting to prepare new polymersincorporating biobased aromatic units. Indeed, if biobased polymers are more and more nowadays,today biobased aromatic units are still missing.In this aim, into the APSYNTH team, we developed a new class of biobased bisphenols obtainedthrough enzymatic catalysis. These bisphenols were then implicated in different strategies to developnew copolyesters, polyurethanes and polyphenolic oligomers. This work describes the synthesis andcharacterization of this new bisphenols derived from ferulic acid, as well as the resulting polymers
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Reed, Kyle Andrew. "Identification of Phenolic Compounds from Peanut Skin using HPLC-MSn." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30160.

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Consumers view natural antioxidants as a safe means to reduce spoilage in foods. In addition, these compounds have been reported to be responsible for human health benefits. Identification of these compounds in peanut skins may enhance consumer interest, improve sales, and increase the value of peanuts. This study evaluated analytical methods which have not been previously incorporated for the analysis of peanut skins. Toyopearl size-exclusion chromatography (SEC) was used for separating phenolic size-classes in raw methanolic extract from skins of Gregory peanuts. This allowed for an enhanced analysis of phenolic content and antioxidant activity based on compound classes, and provided a viable preparatory separation technique for further identification. Toyopearl SEC of raw methanolic peanut skin extract produced nine fractions based on molecular size. Analysis of total phenolics in these fractions indicated Gregory peanut skins contain high concentrations of phenolic compounds. Further studies revealed the fractions contained compounds which exhibited antioxidant activities that were significantly higher than that of butylated hydroxyanisole (BHA), a common synthetic antioxidant used in the food industry. This indicates peanut skin extracts are a viable antioxidant source, and that synthetic antioxidants can be replaced with those naturally-derived from peanut by-products. Structures contained in each fraction were identified using high performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) ion trap mass spectrometry (MSn). Prior to this study, approximately 20 compounds have been identified in peanut skins. The combination of Toyopearl SEC with ESI-HPLC-MSn allowed for the identification of 314 phenolic-based compounds, most of which are newly discovered compounds in peanut skins. Many compounds identified are known to have powerful antioxidant effects, and also have been reported to exhibit numerous beneficial chemical and biological activities, including the treatment of various human health-related conditions. It is evident that peanut skins may be a potential untapped source for the extraction of natural food antioxidants, nutracueticals, and even pharmaceuticals. Because peanut skins are largely a wasted resource to peanut processors, the novel polyphenols identified in this research could have a significant financial impact on the peanut industry.
Ph. D.
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Hur, Hum-Fa, and 賀鴻發. "Antioxidant activity of Monascus rice extract fermented from various medium and oligomeric tea polyphenol." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/36scpa.

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碩士
元培科學技術學院
生物技術研究所
96
Oxidative stress contributes to skin aging and can adversely affect skin health, which means supplement antioxidants active may support skin health, and suppress the production that the epidermis bacterium can reduce the whelk and comedo. Our objective supplemented carbon source: glucose, glycerol, trehalose, maltose and citric acid; or extra 2% nitrogen source: KNO3 and MSG fermentation 5, 10 and 15 days to obtain aqueous extract and methanolic extracts of Monascus rice with different oligomeric tea extracts to experimental valuate the antioxidant properties, antibacterial activity and protective effects on UV-induced damage in HaCaT keratinocytes effect. Supplement KNO3 and MSG fermentation extracts have higher reducing powers, DPPH radical scavenging ability, inhibition of tyrosinase activity and NO-suppressing activity, and furthermore them has higher phenolic and kojic acid yield. Both extracts were active against S. aurous. Suppress MSG ferment 10 days water exctracts protect UV-induced damage in HaCaT keratinocytes, and protect nitric oxide induced damage. Oligomeric tea fraction to medium molecular weight tea (MMT), high molecular weight tea (HMT), and unfractionated total molecular weight tea (TMT). The results showed that HMT has well yield at phenolic and kojic acid. Our data showed that MMT has the highest antioxidant activity and higher antibacterial activity than Monascus rice extracts. Three kinds of tea extracts have the bioactivity on against S. aurous, but it’s no different of statistics. The results showed MMT has the best protective effects on UV-induced damage in HaCaT keratinocytes. And the various extracts from tea can increased cell viability at the concentration of 100 μg/ml in HaCaT cell line. It’s no apparent different of statistics. The research proves that Monascus has phenolic acid, anti-oxidatives and antibiotic ability. And it’s can protect cell against UV and free radical damage. Supplement KNO3 and MSG fermentation extracts can increase antioxidant activity. High polyphenolic tea extract showed higher activity than Monasucs rice extract. The medium oligomeric polyphenolic tea has more excellent effects than high oligomeric polyphenolic tea.
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Wang, Shao-Cheng, and 王韶晟. "The influence of oligomeric polyphenolics from tea and longan flower on growth in human colorectal carcinoma cell lines." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/t8jwp9.

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碩士
元培科技大學
生物技術研究所
96
Previous research is proved that absorption of consumption polyphenolic-rich subsidiaries can decrease the incidence of diseases, such as cancer and coronary artery disease. The aim of this thesis was to investigate the influence of oligomeric polyphenolics from tea and longan flower on the growth of human colorectal carcinoma cell lines（SW480 and Colo 320DM）. The tea was fractionated to oligomer-rich and polymer-rich extract by membrane separation. Cell cycle analysis, mitochondria membrane potential, membrane alteration and protein expression were determined in this thesis. All the extracts contained polyphenolic compounds and showed prominent antioxidant activity. The results showed that oligomeric polyphenolics, especially longan flower, systemically inhibited the proliferation of SW480 and Colo 320DM in a dose dependent manner. Longan flower tea extract showed strong S phase blocking activity at the concentration of 200 μg/mL to 400 μg/mL on these two cell lines. Protein expression results showed the close relationship between S phase arrest and cell cycle regulators cyclin A and cyclin E. The mitochondria membrane potential of treated cells was also loss. Longan flower extract increased apoptoic cell death at the concentration of 400 μg/mL on SW480 and 200 μg/mL on Colo 320DM. According to these results revealed that oligomeric polyphenol have anti-proliferative, S phase blocking, mitochondria membrane potential loss and apoptosis inducing activity. These results provide a further evaluation for its application as a nature cancer chemopreventive agent and health food.
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Matos, Ana Marta de Jesus Gomes de. "From a multitarget antidiabetic glycosyl isoflavone towards new molecular entities against diabetes and Alzheimer’s disease : generation of lead series and target assessment." Doctoral thesis, 2018. http://hdl.handle.net/10451/42532.

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Type 2 diabetes and Alzheimer’s disease are closely related amyloid diseases globally affecting millions of people. However, the pathophysiological mechanisms connecting both diseases still require further investigation. In this work, we compile the existing evidence in the literature to allow the establishment of etiological links needed for drug discovery against diabetes-induced dementia. Furthermore, we provide an extensive revision of bioactive lead molecules that encourage further studies, particularly focusing on polyphenol sugar conjugates endowed with antidiabetic and neuroprotective activities. The state-of-the-art synthetic approaches for the generation of these types of molecules are also covered, thus setting the organic chemistry background for the original research work here developed. The use of carbohydrate-based molecules in drug research and development has multiple recognized benefits. In addition to enhanced solubility, bioavailability, and antidiabetic effects as previously reported, in this work we show, for the first time, that C-glucosylation is able to reverse the membrane dipole potential decrease induced by planar lipophilic polyphenols, elsewhere described as Pan-Assay Interference Compounds. This is a relevant discovery for drug development, particularly in the context of this thesis due to the polyphenolic nature of the compounds here presented. One of these compounds, 8-β-D-glucosylgenistein, was investigated in a diet-induced obese mouse of type 2 diabetes and found to exert a multitarget antidiabetic mechanism of action that goes beyond prior conjectures. Indeed, this antihyperglycemic glucosyl isoflavone reduces the renal threshold for glucose reabsorption, ameliorates diabetes-associated non-alcoholic fatty liver disease and hypercholesterolemia, normalizes insulin-degrading enzyme expression, and increases glucosestimulated insulin secretion. However, the detected inability of this polyphenol to permeate the blood brain barrier and to exert neuroprotective effects encouraged the pursuit of new scaffolds with therapeutic potential against diabetes-induced dementia. The role of amyloid β in the neurodegenerative processes occurring in Alzheimer’s disease and diabetes-induced dementia is, nowadays, unquestionable. Yet, targeted therapies aimed at inhibiting amyloid secretion or aggregation have, so far, failed clinical trials. In the past decade, the role of the cellular prion protein (PrPC) – a high-affinity ligand of amyloid β oligomers (Aβo) – has, in fact, been regarded as the limiting step in the cascade of events leading to neurodegeneration. Fyn kinase is one of the key players in this cascade, which culminates with the formation of neurofibrillary tangles composed by hyperphosphorylated tau, eventually leading to cell death. In this perspective, we have identified innovative N-methylpiperazinyl flavones and their glucosyl derivatives as Aβo-binders and non-toxic disruptors of Aβo-PrPC interactions. Furthermore, easily accessed glucosyl polyphenols with improved pharmacokinetic properties were also investigated and revealed to inhibit Aβ-induced Fyn activation with concomitant decrease in tau phosphorylation. Fyn kinase inhibition is considered a novel therapeutic strategy for Alzheimer’s disease, and these compounds are the first to accomplish this goal, with proven downstream effects. These molecules thus share the potential for further development against Alzheimer’s disease and diabetes-induced dementia. The work presented in this thesis elucidates the therapeutic relevance of natural and nature-inspired C-glucosyl polyphenols in the studied biological context, and highlights the usefulness of carbohydrate-based molecules for medicinal chemistry applications.
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Book chapters on the topic "Polyphenolic oligomers"

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Mattice, Wayne L. "Fluorescence of Oligomers that Contain Catechin or Epicatechin." In Plant Polyphenols, 447–58. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3476-1_25.

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Fulcrand, Hélène, Sylvain Guyot, Erwan Le Roux, Sophie Remy, Jean-Marc Souquet, Thierry Doco, and Véronique Cheynier. "Electrospray Contribution to Structural Analysis of Condensed Tannin Oligomers and Polymers." In Plant Polyphenols 2, 223–44. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4139-4_12.

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Cheynier, Véronique, Jacques Rigaud, and Jorge M. Ricardo da Silva. "Structure of Procyanidin Oligomers Isolated From Grape Seeds in Relation to Some of their Chemical Properties." In Plant Polyphenols, 281–94. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3476-1_16.

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Davies, Alan P., Chris Goodsall, Ya Cai, Adrienne L. Davis, John R. Lewis, John Wilkins, Xiaochun Wan, et al. "Black Tea Dimeric and Oligomeric Pigments—Structures and Formation." In Plant Polyphenols 2, 697–724. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4139-4_39.

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Hatano, Tsutomu, Akira Okonogi, and Takuo Okuda. "Oligomeric Hydrolyzable Tannins From Liquidambar Formosana and Spectral Analysis of the Orientation of Valoneoyl Groups in Their Molecules." In Plant Polyphenols, 195–207. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3476-1_11.

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Kolodziej, Herbert. "1H NMR Spectral Studies of Procyanidin Derivatives: Diagnostic 1H NMR Parameters Applicable to the Structural Elucidation of Oligomeric Procyanidins." In Plant Polyphenols, 295–319. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3476-1_17.

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Snyder, Scott A. "Strategies for the Controlled Synthesis of Oligomeric Polyphenols." In Recent Advances in Polyphenol Research, 311–51. Oxford, UK: Wiley-Blackwell, 2012. http://dx.doi.org/10.1002/9781118299753.ch13.

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Tobiason, Fred L., Richard W. Hemingway, and Gérard Vergoten. "Modeling the Conformation of Polyphenols and Their Complexation with Polypeptides: Self-Association of Catechin and Its Complexation with L-Proline Glycine Oligomers." In Plant Polyphenols 2, 527–44. Boston, MA: Springer US, 1999. http://dx.doi.org/10.1007/978-1-4615-4139-4_29.

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Zongo, Luc, and Heiko Lange. "Lignins and Lignans – Recent Developments and Trends Regarding their Pharmaceutical Properties." In Flavonoids and Phenolics, 196–248. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815079098122010010.

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Abstract:
Lignins and lignans as natural polyphenols exhibit a rather broad variety of common physico-chemical features that can be of interest with respect to their use in the pharmaceutical sector. While polyphenol types have antioxidant, antiinflammatory, antibacterial and eventually antiviral activities in common, structural features beyond the polyphenol aspect differ enormously: isolated lignins are oligomers and/or polymers of monolignol C9-building blocks, while lignans are based on dimers thereof. The structural differences caused lignin to be exploited in the pharmaceutical sector mainly as material for the generation of matrices and carrier for drug delivery, while lignans are tested for the suitability as APIs. The chapter gives an overview of this situation, including the biological backgrounds of the two interesting natural polyphenols, isolation and methods for their characterisation.<br>
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Ray, Sidhartha, and Debasis Bagchi. "Roles of Polyphenols, Flavonoids, and Oligomeric Proanthocyanidins in Cancer Chemoprevention." In Phytopharmaceuticals in Cancer Chemoprevention. CRC Press, 2004. http://dx.doi.org/10.1201/9780203506707.ch22.

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