Verweigerte Ich-Ausdehnung, historische Kontinuitätsbildung und mikroskopierte Wirklichkeit: Familienroman im 19. Jahrhundert (original) (raw)
Related papers
2007
Representing the most common flavonoid consumed in the American diet, the flavanols and their polymeric condensation products, the proanthocyanidins, are regarded as functional ingredients in various beverages, whole and processed foods, herbal remedies and supplements. Their presence in food affects food quality parameters including astringency, bitterness, sourness, sweetness, salivary viscosity, aroma, and color formation. The ability of flavonoids to aid food functionality has also been established in terms of microbial stability, foamability, oxidative stability, and heat stability. polymerize to form the flavonoid subclass proanthocyanidins (Figure 1.3)(Marais, Deavours et al. 2006). The proanthocyanidins. The use of various terms to describe polymeric flavan-3-ols has made understanding proanthocyanidin nomenclature a bit of a daunting task. Of the several terms used in literature (tannins, condensed tannins, vegetable tannins, flavans, flavolans, polyflavans, catechins, macromolecular phenolic substances, leucoanthocyanidins, condensed proanthocyanidins, polymeric proanthocyanidins, oligomeric proanthocyanidins, procyanidins, procyanidolic oligomers, plant polyphenols, and pycnogenols), the terms 'proanthocyanidins' and 'condensed tannins' are used most frequently (Chung, Wong et al. 1998; Haslam 1998; Khanbabaee and VanRee 2001; Ferreira, Marais et al. 2003). The term 'tannin' is also commonly employed, however its use should be carefully considered as it can refer to other classes of plant polyphenols such as the hydrolysable and complex tannins (Khanbabaee and VanRee 2001; Ferreira, Marais et al. 2003). The IUPAC system also works for naming proanthocyanidins. Although its use becomes troublesome in naming larger molecules, the system has more recently been adapted and applied to define absolute stereochemistry of flavonoids at all chiral centers. As most flavan-3-ols are 2R isomers, the prefix 'ent' is used in describing 2S isomers. Location and stereochemistry about the interflavanoid bond are denoted by the symbols α and β. Terms ending in-in possess a glycone, while those ending inidin lack a glycone (Ribereau-Gayon 1972). Proanthocyanidins can be further classified into two groups based on subunit A ring hydroxylation: the phloroglucinol type (meta-trihydroxylated) or resorcinol type
Identification and Quantitation of Flavanols and Proanthocyanidins in Foods: How Good are the Datas?
Clinical and Developmental Immunology, 2005
Evidence suggesting that dietary polyphenols, flavanols, and proanthocyanidins in particular offer significant cardiovascular health benefits is rapidly increasing. Accordingly, reliable and accurate methods are needed to provide qualitative and quantitative food composition data necessary for high quality epidemiological and clinical research. Measurements for flavonoids and proanthocyanidins have employed a range of analytical techniques, with various colorimetric assays still being popular for estimating total polyphenolic content in foods and other biological samples despite advances made with more sophisticated analyses. More crudely, estimations of polyphenol content as well as antioxidant activity are also reported with values relating to radical scavenging activity. High-performance liquid chromatography (HPLC) is the method of choice for quantitative analysis of individual polyphenols such as flavanols and proanthocyanidins. Qualitative information regarding proanthocyanidi...
Overview of Dietary Flavonoids: Nomenclature, Occurrence and Intake
The Journal of Nutrition, 2003
Flavonoids and their polymers constitute a large class of food constituents, many of which alter metabolic processes and have a positive impact on health. Flavonoids are a subclass of polyphenols. They generally consist of two aromatic rings, each containing at least one hydroxyl, which are connected through a three-carbon "bridge" and become part of a six-member heterocyclic ring. The flavonoids are further divided into subclasses based on the connection of an aromatic ring to the heterocyclic ring, as well as the oxidation state and functional groups of the heterocyclic ring. Within each subclass, individual compounds are characterized by specific hydroxylation and conjugation patterns. Many flavonoids in foods also occur as large molecules (tannins). These include condensed tannins (proanthocyanidins), derived tannins and hydrolysable tannins. For proanthocyanidins, three subclasses (15 characterized) have been identified in foods. Monomers are connected through specific carbon-carbon and ether linkages to form polymers. Derived tannins are formed during food handling and processing, and found primarily in black and oolong teas. Flavonoids are widely distributed in nature, albeit not uniformly. As a result, specific groups of foods are often rich sources of one or more subclasses of these polyphenols. The polyphenolic structure of flavonoids and tannins renders them quite sensitive to oxidative enzymes and cooking conditions. Scientists in several countries have estimated intakes of a few subclasses of flavonoids from limited food composition databases. These observations suggest large differences in consumption, due in part to cultural and food preferences among populations of each country. J. Nutr. 133: 3248S-3254S, 2003.
Flavonoids in Our Foods: A Short Review
Journal of Basic and Clinical Health Sciences
The aerobic metabolism in biological systems, produces reactive oxygen species (ROS) known as prooxidants even in basal conditions. If the formation of prooxidants increases, it leads to oxidative stress/damage. Various diseases in humans (cancer, chronic diseases, cardiovascular problems etc.) accompanies with prooxidant damage. Endogenous and exogenous antioxidants protect biomolecules against the damage of prooxidants. Flavonoids are potent antioxidant molecules, which scavenge free radicals in vitro. They are found in fruits, vegetables, bark, roots, flowers and certain beverages. It has been reported that these natural products produce a wide variety of biological effects, like antiviral, anti-allergic, anti-inflammatory, anti-carcinogenic, antidiabetic effects. Flavonoids are important for human diet and have beneficial effects on health like chelating trace elements involved in free radical production, scavenging ROS and upregulating or protecting antioxidant defenses. In addition, they have known to modulate different cytochrome P450 enzymes such as CYP1A1/1A2, CYP1B1, CYP2C9, and CYP3A4/3A5. Flavonoids and their metabolites in organism may cause flavonoid-drug interaction, and it may lead to toxicity of drug or inefficient therapeutic effects of drug. However, knowledge on the mechanisms of action of flavonoids is still not fully understood. The information about correlation of structurebiological effect is limited. There are six major subclasses of flavonoids are flavanols, flavanones, flavonols, flavones, anthocyanidins, and isoflavones. This review summarizes the types of flavonoids, possible mechanisms of action and pharmacokinetic specialties, bioavailability, properties and drug interactions of these flavonoids.
Flavonoids in Food and Their Health Benefits
Plant Foods for Human Nutrition, 2004
There has been increasing interest in the research of flavonoids from dietary sources, due to growing evidence of the versatile health benefits of flavonoids through epidemiological studies. As occurrence of flavonoids is directly associated with human daily dietary intake of antioxidants, it is important to evaluate flavonoid sources in food. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. However, there is still difficulty in accurately measuring the daily intake of flavonoids because of the complexity of existence of flavonoids from various food sources, the diversity of dietary culture, and the occurrence of a large amount of flavonoids itself in nature. Nevertheless, research on the health aspects of flavonoids for humans is expanding rapidly. Many flavonoids are shown to have antioxidative activity, freeradical scavenging capacity, coronary heart disease prevention, and anticancer activity, while some flavonoids exhibit potential for anti-human immunodeficiency virus functions. As such research progresses, further achievements will undoubtedly lead to a new era of flavonoids in either foods or pharmaceutical supplements. Accordingly, an appropriate model for a precise assessment of intake of flavonoids needs to be developed. Most recent research has focused on the health aspects of flavonoids from food sources for humans. This paper reviews the current advances in flavonoids in food, with emphasis on health aspects on the basis of the published literature, which may provide some guidance for researchers in further investigations and for industries in developing practical health agents.
Dietary Flavonoids: Bioavailability and Biosynthesis
2005
Flavonoids are one of the largest groups of natural plant products and are found in most, if not all, fruits and vegetables. As dietary components, flavonoids have widespread biological properties and have been associated with several health benefits, including reduced risk of cancer and cardiovascular disease. The flavonol, quercetin, Table of contents Abstract iü Table of contents vi List of figures xii List of tables xiv Author's declaration xv Abbreviations xvi Acknowledgements xvii Chapter 1: Introduction l 3.3. Results 3.3.1. HPLC-tandem mass spectrometry analysis of tomato juice 50 3.3.2. Identification and quantification of conjugated rutin metabolites in plasma and urine of healthy volunteers with a colon 3.32.1. Identification of conjugated rutin metabolites 3 .3 .2 2. Quantitative analysis of rutin metabolite accumulation in plasma 3.3.2.3. Quantitative analysis of rutin metabolite excretion in urine 61 vn 3.3.3. Identification and quantification of rutin metabolites in the ileal fluid, plasma and urine of ileostomy volunteers 65 3.33.1. Quantitative analysis of ileal fluid 3.3.3.2. Quantitative analysis of plasma 65 3.3.3.3. Quantitative analysis of urine 65 3.3.4. Identification and quantitative analysis of rutin catabolites in urine of volunteers with and without a colon 68 3.34.1.
Food chemistry, 2018
This study developed, optimized and validated an ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) method to identify and quantify metabolites and microbial-derived catabolites in urine, plasma and feces of rats following ingestion of 50 mg of a red wine proanthocyanidin-rich extract. The method was validated for specificity, linearity, limit of detection (LD) and quantification (LQ), intra-day and inter-day precision, recovery and matrix effects, which were determined for 34 compounds in the three biological matrices. After method validation, three parent flavan-3-ols, four 5-carbon side chain ring fission metabolites, and 27 phenolic acid and aromatic catabolites were quantified in plasma, urine and feces after red wine proanthocyanidin intake. These results establish the value of the UHPLC-HRMS protocol in obtaining a detailed picture of proanthocyanidin metabolites and their microbial-derived catabolites, along with their phase II metabo...
Flavonoids as Nutraceuticals: A Review
2008
Phenolic compounds form one of the main classes of secondary metabolites. They display a large range of structures and are responsible for the major organoleptic characteristics of plant-derived foods and beverages, particularly color and taste properties. They also contribute to the nutritional qualities of fruits and vegetables. Among these compounds, flavonoids constitute one of the most ubiquitous groups of plant phenolics. Owing to their importance in food organoleptic properties and human health, a better understanding of their structures and biological activities indicates their potentials as therapeutic agents and also for predicting and controlling food quality. Due to the variety of pharmacological activities in the mammalian body, flavonoids are more correctly referred as "nutraceuticals".
Foods, 2021
Previously, we reported that apple polyphenols and their major active compounds, the flavan-3-ols and the procyanidins, can result in various health benefits in animals and humans, according to clinical studies. Here, we developed a rapid method for quantifying flavan-3-ols and procyanidins using high-performance liquid chromatography with fluorescence detection, where we investigated the amounts of flavan-3-ols and procyanidins in the Japanese major apple production centre, the Aomori Prefecture, from 2016 to 2018. The non-bagged ‘Fuji (n = 609)’, the bagged ‘Fuji (n = 1101)’, and the ‘Orin (n = 504)’ apples were evaluated in terms of their differences in flavan-3-ols and procyanidins based on apple variety and the controlled atmosphere storage. The bagging treatments of the ‘Fuji’ apples resulted in significantly higher concentrations of procyanidins, while changes in flavan-3-ols concentrations were not clearly observed by treatment. In addition, ‘Orin’ had a significantly higher...