Eccentric Cleavage Products of Beta Carotene PDF Download
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Author: Damian P. Hruszkewycz
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
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Book Description
Abstract: The most important role of beta-carotene has long been thought to be the metabolic cleavage at the central double bond to produce two molecules of vitamin A (retinol). There is growing interest in the "eccentric cleavage" of dietary carotenoids at different double bond sites of beta-carotene to produce apocarotenals and their possible oxidation to apocarotenoic acids. However, there are no careful, quantitative analyses of the levels of these compounds in human foods and tissues, and little is known of the enzymology of their formation. This project is part of a larger effort to characterize the full family of putative metabolites of beta-carotenes and lycopene, their occurrence, and their biological significance. We are synthesizing and characterizing all of the possible aldehyde and acid metabolites of beta-carotene for use as analytical standards and for direct assay of their biological activity. Multi-step syntheses were employed to synthesize many of the molecules. Nuclear magnetic resonance spectroscopy, UV-visible spectroscopy, high performance liquid chromatography, and mass spectrometry are being used for characterization. The laboratory of Dr. Earl Harrison (Dept. of Nutrition) is currently studying the interaction of the eccentric cleavage products with the nuclear retinoic acid receptors (RARs), which are responsible for cell differentiation and aspects of the immune response. The interaction of these molecules with other nuclear receptors will be analyzed in the future. The samples will also be used as standards to quantitate the concentrations of eccentric cleavage products in biological samples. The synthesis of the molecules prepared to date will be described as well as aspects of the limited biological activity data gathered to date.
Author: Damian P. Hruszkewycz
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
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Book Description
Abstract: The most important role of beta-carotene has long been thought to be the metabolic cleavage at the central double bond to produce two molecules of vitamin A (retinol). There is growing interest in the "eccentric cleavage" of dietary carotenoids at different double bond sites of beta-carotene to produce apocarotenals and their possible oxidation to apocarotenoic acids. However, there are no careful, quantitative analyses of the levels of these compounds in human foods and tissues, and little is known of the enzymology of their formation. This project is part of a larger effort to characterize the full family of putative metabolites of beta-carotenes and lycopene, their occurrence, and their biological significance. We are synthesizing and characterizing all of the possible aldehyde and acid metabolites of beta-carotene for use as analytical standards and for direct assay of their biological activity. Multi-step syntheses were employed to synthesize many of the molecules. Nuclear magnetic resonance spectroscopy, UV-visible spectroscopy, high performance liquid chromatography, and mass spectrometry are being used for characterization. The laboratory of Dr. Earl Harrison (Dept. of Nutrition) is currently studying the interaction of the eccentric cleavage products with the nuclear retinoic acid receptors (RARs), which are responsible for cell differentiation and aspects of the immune response. The interaction of these molecules with other nuclear receptors will be analyzed in the future. The samples will also be used as standards to quantitate the concentrations of eccentric cleavage products in biological samples. The synthesis of the molecules prepared to date will be described as well as aspects of the limited biological activity data gathered to date.
Author: H. DeLuca
Publisher: Springer Science & Business Media
ISBN: 1461588707
Category : Science
Languages : en
Pages : 297
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Book Description
The first demonstration of the existence of a vitamin and the full recognition of this fact are often attributed to the work of McCollum, who found that a sub stance in butterfat and cod-liver oil was necessary for growth and health of ani mals fed purified diets. It became obvious that an organic substance present in microconcentrations was vital to growth and reproduction of animals. Following the coining of the word vitamine by Funk, McCollum named this fat-soluble sub stance vitamin A. We can, therefore, state that vitamin A was certainly one of the first known vitamins, yet its function and the function of the other fat-soluble vitamins had remained largely unknown until recent years. However, there has been an explosion of investigation and new information in this field, which had remained quiescent for at least two or three decades. It is now obvious that the fat-soluble vitamins function quite differently from their water-soluble counter parts. We have learned that vitamin D functions by virtue of its being converted in the kidney to a hormone that functions to regulate calcium and phosphorus metabolism. This new endocrine system is in the process of being elucidated in detail, and in addition, the medical use of these hormonal forms of vitamin D in the treatment of a variety of metabolic bone diseases has excited the medical com munity.
![Intestinal Absorption and Cleavage of [beta]-carotene in Rat, Hamster and Human Models PDF](https://books.google.com/books/content/images/frontcover/_AFGAAAAYAAJ?fife=w80-h100)
Author: Trinette van Vliet
Publisher:
ISBN:
Category : Carotenes
Languages : en
Pages : 172
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Book Description
Author: Delia B. Rodriguez-Amaya
Publisher: John Wiley & Sons
ISBN: 1118733304
Category : Technology & Engineering
Languages : en
Pages : 324
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Book Description
Carotenoids were first studied as natural pigments, then as precursors of vitamin A, and then as bioactive compounds against chronic diseases. These compounds have been and continue to be the subject of intense research worldwide, now with an expanded scope. Food Carotenoids: Chemistry, Biology and Technology gathers all the important information about these major compounds which impact both food quality and human health. It integrates in one volume various aspects of food carotenoids, such as: Structures and physicochemical properties Biosynthetic pathways and metabolism Analysis and composition of foods Stability and reactions during processing Commercial production as food colorants and precursors of aroma compounds Bioavailability and health benefits Having worked with carotenoids in various aspects for 44 years, Delia Rodriguez-Amaya is uniquely placed to pass on her wealth of knowledge in this field. This book will serve as solid background information for professionals in Food Science, Food Technology, Nutrition, Agriculture, Biology, Chemistry and Medical Sciences, whether in the academe, industry, governmental and non-governmental agencies.
Author: Sherry A. Tanumihardjo
Publisher: Springer Science & Business Media
ISBN: 1627032037
Category : Medical
Languages : en
Pages : 344
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Book Description
Carotenoids and Human Health provides an introduction to food sources and metabolism. Written by experts in their fields and including the most up-to-date information, this volume serves as an in-depth guide to studies that have been performed in humans and observations that have been made in population level assessments. Special emphasis is given to associations with disease, as well as the importance of carotenoids internationally, specifically as a source of vitamin A for the world. Comprehensive and easy to use, Carotenoids and Human Health is a very useful resource for nutritionists, registered dieticians, medical students, and graduate students.
Author: Abdulkerim Eroğlu
Publisher:
ISBN:
Category :
Languages : en
Pages : 129
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Book Description
Abstract: Beta-carotene (BC) is the major dietary source of provitamin A. Central cleavage of BC catalyzed by beta-carotene oxygenase 1 yields two molecules of retinaldehyde. Subsequent oxidation produces all-trans-retinoic acid (ATRA) which functions as a ligand for a family of nuclear transcription factors, the retinoic acid receptors (RARs). Eccentric cleavage of BC at non-central double bonds is catalyzed by other enzymes and can also occur non-enzymatically. The products of these reactions are beta-apocarotenals and beta-apocarotenones, whose biological functions in mammals are unknown. We used reporter gene assays to show that none of the beta-apocarotenoids significantly activated RARs and RXR[alpha]. Beta-Apo-13-carotenone was found to antagonize the activation of RXR[alpha] by 9-cis-retinoic acid and was effective at concentrations as low as 1 nM. Molecular modeling studies revealed that beta-apo-13-carotenone makes molecular interactions like an antagonist of RXR[alpha]. The results suggest a possible function of BACs on RXR[alpha] signaling. Moreover, beta-apo-14'-carotenal, beta-apo-14'-carotenoic acid, and beta-apo-13-carotenone antagonized ATRA-induced transactivation of RARs. Competitive radioligand binding assays demonstrated that these putative RAR antagonists compete directly with retinoic acid for high affinity binding to purified receptors. Molecular modeling studies confirmed that beta-apo-13-carotenone can directly interact with the ligand binding site of the retinoid receptors. Beta-Apo-13-carotenone and the beta-apo-14'-carotenoids inhibited ATRA-induced expression of retinoid responsive genes in Hep G2 cells. Finally, we developed an LC/MS method and found 3-5 nM beta-apo-13-carotenone was present in human plasma. These findings suggest that beta-apocarotenoids function as naturally-occurring retinoid antagonists. We have also tested apo-lycopenoids that have a structural resemblance to beta-apo-13-carotenone to see if they exert a similar action as beta-apo-13-carotenone in modulating retinoid receptor activation. We found that apo-13-lycopenone was able to block ATRA induced expression of RAR[beta] and CYP26A1 like the action of beta-apo-13-carotenone. This suggests that the ionone ring may not be prerequisite for beta-apo-13-carotenone's binding to RARs. The antagonism of retinoid signaling by these metabolites may have implications for the activities of dietary beta-carotene as a provitamin A and as a modulator of risk for cardiovascular disease and cancer.
Author: C. Sen
Publisher: Elsevier
ISBN: 0080538290
Category : Science
Languages : en
Pages : 1219
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Book Description
Interest in the science of exercise dates back to the time of ancient Greece. Today exercise is viewed not only as a leisurely activity but also as an effective preventive and therapeutic tool in medicine. Further biomedical studies in exercise physiology and biochemistry reports that strenuous physical exercise might cause oxidative lipid damage in various tissues. The generation of reactive oxygen species is elevated to a level that overwhelms the tissue antioxidant defense systems resulting in oxidative stress.The Handbook of Oxidants and Antioxidants in Exercise examines the different aspects of exercise-induced oxidative stress, its management, and how reactive oxygen may affect the functional capacity of various vital organs and tissues. It includes key related issues such as analytical methods, environmental factors, nutrition, aging, organ function and several pathophysiological processes.This timely publication will be of relevance to those in biomedical science and was designed to be readily understood by the general scientific audience.
Author: Jianbo Xiao
Publisher: Springer
ISBN: 9789811541476
Category : Technology & Engineering
Languages : en
Pages : 1953
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Book Description
This book summarizes recent advances in the chemistry, bioactivity, nutrition, and functional aspects of dietary phytochemicals, as well as the health and functional aspects of foods rich in phytochemicals. Consisting of forty-four chapters, it discusses the different chemical types of phytochemicals in our diets and food and presents data collected from animal or human experiments that are directly related to human health. Each chapter covers the chemistry, epidemiological study, bioavailability, bioactivity (animal experiments) function in humans and safety, as well as products on the market. Moreover, the more than 200 figures make it easy to grasp the main findings in each area.
Author: Eduardo Jacob-Lopes
Publisher: Springer Nature
ISBN: 3030509710
Category : Science
Languages : en
Pages : 653
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Book Description
The Pigments from Microalgae Handbook presents the current state of knowledge on pigment production using microalgae-based processes, and covers both the scientific fundamentals of this technology and its practical applications. It addresses biology, chemistry, biochemistry, analysis and engineering aspects, as well as applications of natural pigments in photosynthetic organisms. The book also describes the analytical procedures associated with the characterization of pigments and the engineering aspects of microalgal pigment production. It considers the three major classes of pigments(chlorophylls, carotenoids and phycobiliproteins) produced and surveys the main commercial applications of these chemicals. The book offers a valuable source of information for industrial researchers and practitioners in industrial biotechnology, as it covers various engineering aspects of microalgal pigment production, such as bioreactors and bioprocesses, industrial extraction processes, and the bioeconomy of production including life-cycle assessment. The book will also be of interest to undergraduate and graduate students of biochemistry, food chemistry, and industrial microbiology.
Author: Lee Russell McDowell
Publisher: John Wiley & Sons
ISBN: 0470376686
Category : Medical
Languages : en
Pages : 793
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Book Description
Vitamins in Animal and Human Nutrition contains concise, up-to-date information on vitamin nutrition for both animals and humans. The author defines these nutrients and describes their fascinating discovery, history and relationship to various diseases and deficiencies. Discussion of vitamins also includes their chemical structure, properties and antagonists; analytical procedures; metabolism; functions; requirements; sources; supplementation and toxicity. Vitamin-like substances, essential fatty acids and vitamin supplementation considerations are also examined. This book will be useful worldwide as a textbook and as an authoritative reference for research and extension specialists, feed manufacturers, teachers, students and others. It provides a well-balanced approach to both animal and clinical human nutrition and compares chemical, metabolic and functional aspects of vitamins and their practical and applied considerations. A unique feature of the book is its description of the implications of vitamin deficiencies and excesses and the conditions that might occur in human and various animal species.
