Nutrition Biofiles7

2007 Volume 2 Number 2 FOR LIFE SCIENCE RESEARCH DIETARY ANTIOXIDANTS OMEGA-3 FATTY ACIDS AND HEART DISEASE THE BIOACTIVE NUTRIENT EXPLORER METABOLITE LIBRARIES Examples of fruits and vegetables that contain antioxidants such as kaempferol, lycopene, and resveratrol. Nutrition Research sigma-aldrich.com Life Science Pathways Animated ATP Synthase & Glycolysis! The evolutionary pathway of life science research has brought today’s researchers full circle to a destination we now call metabolomics. n 1947, Sigma produced the first commercially The Enzyme Explorer’s Metabolic Pathways The Enzyme Explorer I available ATP. Since then, Sigma-Aldrich has Resource Center provides the online tools you need Assay Library consistently expanded its product portfolio to to explore the metabolome today. The largest collection of enzymatic maintain the most comprehensive line of organic • Metabolic Pathway Chart with 500 Hyperlinks assay procedures available online. More than 600 step-by-step metabolites, enzymes, and bio-analytical tools in to Product Listings, and Technical Data procedures for: the world. • Direct Access to 35 Nicholson Metabolic Mini-maps To strengthen our commitment to metabolic METABOLIC ENZYMES • Animated ATP Synthase Mechanism METABOLITE QUANTITATION education and research, Sigma-Aldrich is proud DIAGNOSTIC ENZYMES to announce the formation of a collaboration • Animated Glycolysis Pathway ANALYTICAL ENZYMES with the IUBMB to produce, animate, and • Isotopically Labeled Metabolites PROTEASES PROTEASE INHIBITORS publish the Nicholson Metabolic Pathway Charts. • Metabolite Libraries CELL SIGNALING ENZYMES PROTEIN QUANTITATION Visit the Assay Library at: sigma-aldrich.com/enzymeexplorer Visit us online today at: sigma-aldrich.com/metpath LEADERSHIP IN LIFE SCIENCE, HIGH TECHNOLOGY AND SERVICE sigma-aldrich.com SIGMA-ALDRICH CORPORATION • BOX 14508 • ST. LOUIS • MISSOURI 63178 • USA 1 Introduction For most of the world’s population, foods and other plant and animal materials are consumed not only for their nutritional value, but also because they contain bioactive FOR LIFE SCIENCE RESEARCH compounds that can prevent or treat diseases. Even in developed or rapidly developing 2007 economies, such as Japan, South Korea, China, and India, traditional medicines primarily derived from plant sources continue to be used along side, and often in preference to, Volume 2 modern pharmaceuticals. Throughout history, human populations have learned either by Number 2 serendipity or by observation the properties of materials present in their environment. Even the most primitive societies, by modern standards, often had fairly sophisticated knowledge of the medicinal properties of local plants. This knowledge may have been Table of Contents passed down orally for centuries as the exclusive province of medicine men or shamans. Over time, this knowledge often became documented and codified, as in the Greco- Nutrition Research Roman, Unani, Ayurvedic, or traditional Chinese pharmacopoeias and medical practices. More recently, research interest in complementary and alternative medicine has surged as Western societies have embraced traditional herbal preparations and functional foods Dietary Antioxidants ........................................2 for their purported disease prevention and therapeutic properties. The global market Amino Acids and Peptides .....................................3 for dietary supplements and functional foods was approximately $145 billion in 2005, Flavonoids ............................................................5 of which $48 billion was within the U.S. Consumers perceive herbal source materials as Coumarins, Lignins and Stibenes .........................10 safer than pharmaceuticals; in some cases there is research to support this view. Foods Isoprenoids and Carotenoids ...............................10 and herbs often contain several compounds with the same primary physiological effect Minerals .............................................................12 but differing secondary actions. Thus, the beneficial effect is due to the combined action Additional Antioxidants .......................................12 of several chemical entities, most of which are in low enough concentration to minimize secondary negative side effects. Omega-3 Fatty Acids and Heart Disease .....14 From micronutrients to drugs of abuse, nutritionists, pharmacologists, and medical Omega-3 Polyunsaturated researchers are studying the physiological, therapeutic, and chemopreventive properties Fatty Acids and Precursor ................................16 of foods and herbs and their constituents. This issue of BioFiles highlights some of the Omega-6 Polyunsaturated Fatty Acids .................17 product groups available from Sigma-Aldrich to further this research, with special focus Lipid Metabolism Related Products .....................17 on omega-3 (w-3) fatty acids and antioxidant compounds such as carotenoids and Lipid Mediator Related Products .........................17 polyphenols. We also introduce the Bioactive Nutrient Explorer, an interactive database on the Sigma-Aldrich web site that allows researchers to find plants of interest based on The Bioactive Nutrient Explorer ...................18 their physiological actions, plant constituents based on their chemical structure, and the chemical constituents of specific herbs and food plants. Metabolite Libraries .......................................20 Amino Acid Metabolite Library ............................20 Carbohydrate Metabolite Library .........................21 Lipid Metabolite Library ......................................22 LabwareNotes .................................................23 Stay One Step Ahead... Subscribe Now To BioFiles Discover the Features and Benefits of FTA® Technology in LabwareNotes (pages 23-24) Each issue highlights products and services speciﬁ c to the Life Sciences. Register to Receive Your BioFiles. To register visit us online at sigma-aldrich.com/bioﬁ les2 For Hazard Information and other information please refer to the Sigma Biochemicals, Reagents and Kits for Life Science Research Catalog or sigma-aldrich.com 2 Dietary Antioxidants Dietary Antioxidants OH Antioxidants protect biological systems from oxidative damage O produced by oxygen-containing free radicals and from redox- O active transition metal ions such as iron, copper, and cadmium.1 HO During the oxidative metabolism of glucose in the mitochondria, – superoxide anions (O2 ) are produced as a by-product of the Figure 2. Structure of astaxanthin reduction of coenzyme Q complex III. The enzyme superoxide dismutase converts superoxide anions to hydrogen peroxide Some antioxidants trap or scavenge the free radicals, and in (H2O2) that in turn can be converted to peroxyl radicals (RO2•), the process become radicals themselves. When the carotenoids – – hydroxyl radicals (OH •), or hypochlorite (ClO ) ions. Superoxide astaxanthin (see Figure 2), lutein, and zeaxanthin scavenge anions can also react with nitric oxide (NO) to form the highly oxygen free radicals, the charge of the unpaired electron becomes – 2 reactive peroxynitrite (ONOO •). Under normal conditions these delocalized over the entire polyene chain of the molecule.9 The cellular oxidants are reduced or scavenged by the intracellular flavonol quercetin is oxidized to a quinone that can react with antioxidants and antioxidant enzymes, the most important thiols.10 Flavonoids are also excellent metal ion chelators and can of which are glutathione, thioredoxin, superoxide dismutase, prevent copper-catalyzed peroxidation of LDL.1,4,11 The stilbene catalase, and peroxidase. Dietary antioxidants, such as ascorbic phytoalexin resveratrol is more potent than the flavonoids in acid (vitamin C), vitamin E, β-carotene and other carotenoids, and chelating copper and preventing peroxidation of LDL.12 This likely selenium have been recognized as important contributors to the contributes to the antiatherosclerotic actions of resveratrol and the total antioxidant capacity of cells and plasma. The carotenoids flavonoids. lutein and zeaxanthin are important antioxidants in the eye and Flavonoids and carotenoids, the major dietary antioxidants, are retina.3 Vitamin E, a mixture of tocopherols and tocotrienols, of ubiquitous in fruits and vegetables. Epidemiological studies which α-tocopherol is the major antioxidant,4 is the major lipid indicate that populations with diets high in these phytochemicals soluble antioxidant in cells and plays a major role in protecting 2 also have lower incidence rates of chronic diseases associated Dietary Antioxidants membrane lipids from peroxidation. Low density lipoproteins with oxidative stress, such as atherosclerosis, diabetes, (LDL) carry vitamin E into cells, which subsequently prevents neurodegenerative diseases, and cancer.8 However, there is much the peroxidation of LDL by donating hydrogen to fatty peroxyl disagreement concerning the mechanism of action of polyphenols radicals.5 Polyphenolic compounds, especially the flavonoids, have in vivo. Polyphenols are treated as xenobiotics by the body and recently been shown to be potent antioxidants in cultured cells. are rapidly metabolized and conjugated in the intestinal lining Human studies of flavonoids have also demonstrated effects that and liver. With the exception of the gallic acid conjugates of the can in part be attributed to their antioxidant action.6 catechins, such as epigallocatechin gallate,13 most flavonoids in Antioxidants can act

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