A glucoside is a glycoside, derived from glucose. Glucosides are rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes; the name was given to plant products of this nature, in which the other part of the molecule was, in the greater number of cases, an aromatic aldehydic or phenolic compound. It has now been extended to include synthetic ethers, such as those obtained by acting on alcoholic glucose solutions with hydrochloric acid, the polysaccharoses, e.g. cane sugar, which appear to be ethers also. Although glucose is the most common sugar present in glucosides, many are known which yield rhamnose or iso-dulcite. Much attention has been given to the non-sugar parts of the molecules; the simplest glucosides are the alkyl ethers which have been obtained by reacting hydrochloric acid on alcoholic glucose solutions. A better method of preparation is to dissolve solid anhydrous glucose in methanol containing hydrochloric acid.
A mixture of alpha- and beta-methylglucoside results. Classification of the glucosides is a matter of some intricacy. One method based on the chemical constitution of the non-glucose part of the molecules has been proposed that posits four groups: alkyl derivatives, benzene derivatives, styrolene derivatives, anthracene derivatives. A group may be constructed to include the cyanogenic glucosides, i.e. those containing prussic acid. Alternate classifications follow a botanical classification. In this article the chemical classification will be followed, only the more important compounds will be discussed herein; these are mustard oils, which are characterized by a burning taste. Sinigrin, or the potassium salt of inyronic acid not only occurs in mustard seed, but in black pepper and in horseradish root. Hydrolysis with baryta, or decomposition by the ferment myrosin, gives glucose, allyl mustard oil and potassium hydrogen sulfate. Sinalbin occurs in white pepper. Jalapin or scammonin occurs in scammony.
These are oxy and oxyaldehydic compounds. Benzoic acid derivativesThe. Populin, which occurs in the leaves and bark of Populus tremula, is benzoyl salicin. Benzoyl-beta-D-glucoside is a compound found in Pteris ensiformis. Phenol derivativesThere are a number of glucosides found in natural phenols and polyphenols, as, for example, in the flavonoids chemical family. Arbutin, which occurs in bearberry along with methyl arbutin, hydrolyses to hydroquinone and glucose. Pharmacologically it acts as a urinary diuretic; the enzymes ptyalin and emulsin convert it into ortho-oxybenzylalcohol. Oxidation gives the aldehyde helicin; this group contains a benzene and an ethylene group, being derived from styrolene. Coniferin, C16H22O8, occurs in the cambium of conifer wood. Emulsin converts it into glucose and coniferyl alcohol, while oxidation gives glycovanillin, which yields with emulsin and vanillin. Syringin, which occurs in the bark of Syringa vulgaris, is a methoxyconiferin. Phloridzus occurs in the root-bark of various fruit trees.
It is related to the pentosides naringin, C27H32O14, which hydrolyses to rhamnose and naringenin, the phioroglucin ester of para-oxycinnamic acid, hesperidin, which hydrolyses to rhamnose and hesperetin, the phloroglucin ester of meta-oxy-para-methoxycinnamic acid or isoferulic acid, C10H10O4. Aesculin, occurring in horse-chestnut and California buckeye, daphnin, occurring in Daphne alpina, are isomeric. Fraxin, occurring in Fraxinus excelsior, with aesculin, hydrolyses to glucose and fraxetin, 7,8-dihydroxy-6-methoxycoumarin. Flavone or benzo-7-pyrone derivatives are numerous. Quercitrin is a yellow dyestuff found in Quercus velutina. Rhamnetin, a splitting product of the glucosides of Rhamnus, is monomethyl quercetin. Saponarin, a glucoside found in Saponaria officinalis, is a related compound. Strophanthin is the name given to two different compounds, g-strophanthin obtained from Strophanthus gratus and k-strophanthin from Stroph. Kombé; these are substituted anthraquinones. Chrysophanic acid, a dioxymethylanthraquinone, occurs in rhubarb, which contains emodin, a trioxymethylanthraquinone.
The most important cyanogenic glucoside is amygdalin. The enzyme maltase decomposes it into glucose and mandelic nitrile glucoside.
Bayer AG is a German multinational pharmaceutical and life sciences company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, where its illuminated corporate logo, the Bayer cross, is a landmark, Bayer's areas of business include human and veterinary pharmaceuticals; the company is a component of the Euro Stoxx 50 stock market index. Werner Baumann has been CEO since 2016. Founded in Barmen in 1863 as a dyestuffs factory, Bayer's first and best-known product was aspirin. In 1898 Bayer trademarked the name heroin for the drug diacetylmorphine and marketed it as a cough suppressant and non-addictive substitute for morphine until 1910. Bayer introduced phenobarbital. In 1925 Bayer was one of six chemical companies that merged to form IG Farben, the world's largest chemical and pharmaceutical company; the Allied Control Council seized IG Farben after World War II, because of its role in the Nazi war effort and involvement in the Holocaust, which included using slave labour from concentration camps.
It was split into its six constituent companies in 1951 split again into three: BASF, Bayer and Hoechst. Bayer played a key role in the Wirtschaftswunder in post-war West Germany regaining its position as one of the world's largest chemical and pharmaceutical corporations. In 2006 the company acquired Schering, in 2014 it acquired Merck & Co.'s consumer business, with brands such as Claritin, Coppertone and Dr. Scholl's, in 2018 it acquired Monsanto, a leading producer of genetically engineered crops, for $63 billion. Bayer CropScience develops genetically modified pesticides. Bayer AG was founded as a dyestuffs factory in 1863 in Barmen, Germany, by Friedrich Bayer and his partner, Johann Friedrich Weskott, a master dyer. Bayer was responsible for the commercial tasks. Fuchsine and aniline became; the headquarters and most production facilities moved from Barmen to a larger area in Elberfeld in 1866. Friedrich Bayer, son of the company's founder, was a chemist and joined the company in 1873. After the death of his father in 1880, the company became a joint-stock company, Farbenfabriken vorm.
Friedr. Bayern & Co known as Elberfelder Farbenfabriken. A further expansion in Elberfeld was impossible, so the company moved to the village Wiesdorf at Rhein and settled in the area of the alizarin producer Leverkus and Sons. A new city, was founded there in 1930 and became home to Bayer AG's headquarters; the company's corporate logo, the Bayer cross, was introduced in 1904, consisting of the word BAYER written vertically and horizontally, sharing the Y and enclosed in a circle. An illuminated version of the logo is a landmark in Leverkusen. Bayer's first major product was acetylsalicylic acid—first described by French chemist Charles Frederic Gerhardt in 1853—a modification of salicylic acid or salicin, a folk remedy found in the bark of the willow plant. By 1899 Bayer's trademark Aspirin was registered worldwide for Bayer's brand of acetylsalicylic acid, but it lost its trademark status in the United States and the United Kingdom after the confiscation of Bayer's US assets and trademarks during World War I by the United States, because of the subsequent widespread usage of the word.
The term aspirin continued to be used in the US, UK and France for all brands of the drug, but it is still a registered trademark of Bayer in over 80 countries, including Canada, Mexico and Switzerland. As of 2011 40,000 tons of aspirin were produced each year and 10–20 billion tablets consumed in the United States alone for prevention of cardiovascular events, it is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. There is an unresolved controversy over the roles played by Bayer scientists in the development of aspirin. Arthur Eichengrün, a Bayer chemist, said he was the first to discover an aspirin formulation that did not have the unpleasant side effects of nausea and gastric pain, he said he had invented the name aspirin and was the first person to use the new formulation to test its safety and efficacy. Bayer contends. Various sources support the conflicting claims. Most mainstream historians attribute the invention of aspirin to Hoffmann and/or Eichengrün.
Heroin, now illegal as an addictive drug, was introduced as a non-addictive substitute for morphine, trademarked and marketed by Bayer from 1898 to 1910 as a cough suppressant and over-the-counter treatment for other common ailments, including pneumonia and tuberculosis. Bayer scientists were not the first to make heroin, but the company led the way in commercializing it. Heroin was a Bayer trademark until after World War I. In 1903 Bayer licensed the patent for the hypnotic drug diethylbarbituric acid from its inventors Emil Fischer and Joseph von Mering, it was marketed under the trade name Veronal as a sleep aid beginning in 1904. Systematic investigations of the effect of structural changes on potency and duration of action at Bayer led to the discovery of phenobarbital in 1911 and the discovery of its potent anti-epileptic activity in 1912. Phenobarbital was among the most used drugs for the treatment of epilepsy through the 1970s, as of 2014 it remains on the World Health Organization's list of essential medications.
During World War I, Bayer's assets, including the rights to
Sahachirō Hata was a prominent Japanese bacteriologist who assisted in developing the Arsphenamine drug in 1909 in the laboratory of Paul Ehrlich. He was nominated for the Nobel Prize in Chemistry in 1911 and for the Nobel Prize in Physiology or Medicine in 1912 and 1913. Hata was born in Tsumo Village, Mino District and completed his medical education in Okayama, he studied epidemic diseases under the famous Dr. Kitasato Shibasaburō at Kitasato's Institute for the Study of Infectious Diseases in Tokyo, studied immunology at the Robert Koch Institute in Berlin. In Germany, Hata was invited to learn about chemotherapy at the German National Institute for Experimental Therapeutics in Frankfurt. In exchange, Hata was able to instruct his technique of infecting rabbits with Treponema pallidum and assist Paul Ehrlich in the discovery of arsphenamine, which proved effective in curing syphilis, it was called Salvarsan 606. After his return to Japan, Hata helped, he lectured at Keio University. In 1927, he was elected a member of the Academy of Sciences Leopoldina.
Low, Morris. Building a Modern Japan: Science and Medicine in the Meiji Era and Beyond. Palgrave Macmillan. ISBN 1-4039-6832-2 Porter, Roy. Blood and Guts: A Short History of Medicine. W. W. Norton & Company. ISBN 0-393-32569-5 Waller, John; the Discovery of the Germ: Twenty Years That Transformed the Way We Think About Disease. Columbia University Press, ISBN 0-231-13150-X Hata Sahachiro Memorial Museum, Shimane
Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions; the molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. All metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps; the study of enzymes is called enzymology and a new field of pseudoenzyme analysis has grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, reflected in their amino acid sequences and unusual'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins; the latter are called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction rate by lowering its activation energy; some enzymes can make their conversion of substrate to product occur many millions of times faster.
An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH, many enzymes are denatured when exposed to excessive heat, losing their structure and catalytic properties; some enzymes are used commercially, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.
By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified. French chemist Anselme Payen was the first to discover an enzyme, diastase, in 1833. A few decades when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that this fermentation was caused by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms, he wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."In 1877, German physiologist Wilhelm Kühne first used the term enzyme, which comes from Greek ἔνζυμον, "leavened" or "in yeast", to describe this process. The word enzyme was used to refer to nonliving substances such as pepsin, the word ferment was used to refer to chemical activity produced by living organisms.
Eduard Buchner submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts when there were no living yeast cells in the mixture, he named the enzyme that brought about the fermentation of sucrose "zymase". In 1907, he received the Nobel Prize in Chemistry for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate or to the type of reaction; the biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others argued that proteins were carriers for the true enzymes and that proteins per se were incapable of catalysis. In 1926, James B. Sumner crystallized it; the conclusion that pure proteins can be enzymes was definitively demonstrated by John Howard Northrop and Wendell Meredith Stanley, who worked on the digestive enzymes pepsin and chymotrypsin.
These three scientists were awarded the 1946 Nobel Prize in Chemistry. The discovery that enzymes could be crystallized allowed their structures to be solved by x-ray crystallography; this was first done for lysozyme, an enzyme found in tears and egg whites that digests the coating of some bacteria. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail. An enzyme's name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase. Examples are alcohol dehydrogenase and DNA polymerase. Different enzymes that catalyze the same chemical reaction are called isozymes; the International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers. The first number broadly classifies the enzyme based on its mechanism; the top-level classification is: EC 1, Oxidoreductases: catalyze oxidation/reducti
A glucuronide known as glucuronoside, is any substance produced by linking glucuronic acid to another substance via a glycosidic bond. The glucuronides belong to the glycosides. Glucuronidation, the conversion of chemical compounds to glucuronides, is a method that animals use to assist in the excretion of toxic substances, drugs or other substances that cannot be used as an energy source. Glucuronic acid is attached via a glycosidic bond to the substance, the resulting glucuronide, which has a much higher water solubility than the original substance, is excreted by the kidneys. Enzymes that cleave the glycosidic bond of a glucuronide are called glucuronidases. Miquelianin Morphine-6-glucuronide Scutellarein-7-glucuronide
Drug metabolism is the metabolic breakdown of drugs by living organisms through specialized enzymatic systems. More xenobiotic metabolism is the set of metabolic pathways that modify the chemical structure of xenobiotics, which are compounds foreign to an organism's normal biochemistry, such as any drug or poison; these pathways are a form of biotransformation present in all major groups of organisms, are considered to be of ancient origin. These reactions act to detoxify poisonous compounds; the study of drug metabolism is called pharmacokinetics. The metabolism of pharmaceutical drugs is an important aspect of medicine. For example, the rate of metabolism determines the duration and intensity of a drug's pharmacologic action. Drug metabolism affects multidrug resistance in infectious diseases and in chemotherapy for cancer, the actions of some drugs as substrates or inhibitors of enzymes involved in xenobiotic metabolism are a common reason for hazardous drug interactions; these pathways are important in environmental science, with the xenobiotic metabolism of microorganisms determining whether a pollutant will be broken down during bioremediation, or persist in the environment.
The enzymes of xenobiotic metabolism the glutathione S-transferases are important in agriculture, since they may produce resistance to pesticides and herbicides. Drug metabolism is divided into three phases. In phase I, enzymes such as cytochrome P450 oxidases introduce reactive or polar groups into xenobiotics; these modified compounds are conjugated to polar compounds in phase II reactions. These reactions are catalysed by transferase enzymes such as glutathione S-transferases. In phase III, the conjugated xenobiotics may be further processed, before being recognised by efflux transporters and pumped out of cells. Drug metabolism converts lipophilic compounds into hydrophilic products that are more excreted; the exact compounds an organism is exposed to will be unpredictable, may differ over time. The major challenge faced by xenobiotic detoxification systems is that they must be able to remove the almost-limitless number of xenobiotic compounds from the complex mixture of chemicals involved in normal metabolism.
The solution that has evolved to address this problem is an elegant combination of physical barriers and low-specificity enzymatic systems. All organisms use cell membranes as hydrophobic permeability barriers to control access to their internal environment. Polar compounds cannot diffuse across these cell membranes, the uptake of useful molecules is mediated through transport proteins that select substrates from the extracellular mixture; this selective uptake means that most hydrophilic molecules cannot enter cells, since they are not recognised by any specific transporters. In contrast, the diffusion of hydrophobic compounds across these barriers cannot be controlled, organisms, cannot exclude lipid-soluble xenobiotics using membrane barriers. However, the existence of a permeability barrier means that organisms were able to evolve detoxification systems that exploit the hydrophobicity common to membrane-permeable xenobiotics; these systems therefore solve the specificity problem by possessing such broad substrate specificities that they metabolise any non-polar compound.
Useful metabolites are excluded since they are polar, in general contain one or more charged groups. The detoxification of the reactive by-products of normal metabolism cannot be achieved by the systems outlined above, because these species are derived from normal cellular constituents and share their polar characteristics. However, since these compounds are few in number, specific enzymes can remove them. Examples of these specific detoxification systems are the glyoxalase system, which removes the reactive aldehyde methylglyoxal, the various antioxidant systems that eliminate reactive oxygen species; the metabolism of xenobiotics is divided into three phases:- modification and excretion. These reactions act in concert to remove them from cells. In phase I, a variety of enzymes act to introduce polar groups into their substrates. One of the most common modifications is hydroxylation catalysed by the cytochrome P-450-dependent mixed-function oxidase system; these enzyme complexes act to incorporate an atom of oxygen into nonactivated hydrocarbons, which can result in either the introduction of hydroxyl groups or N-, O- and S-dealkylation of substrates.
The reaction mechanism of the P-450 oxidases proceeds through the reduction of cytochrome-bound oxygen and the generation of a highly-reactive oxyferryl species, according to the following scheme: O2 + NADPH + H+ + RH → NADP+ + H2O + ROHPhase I reactions may occur by oxidation, hydrolysis, cyclization and addition of oxygen or removal of hydrogen, carried out by mixed function oxidases in the liver. These oxidative reactions involve a cytochrome P450 monooxygenase, NADPH and oxygen; the classes of pharmaceutical drugs that utilize this method for their metabolism include phenothiazines and steroids. If the metabolites of phase I reactions are sufficiently polar, they may be excreted at this point. However, many phase I products are not eliminated and undergo a subsequent reaction in which an endogenous substrate combines with the newly incorporated functional group to
International Union of Pure and Applied Chemistry
The International Union of Pure and Applied Chemistry is an international federation of National Adhering Organizations that represents chemists in individual countries. It is a member of the International Council for Science. IUPAC is registered in Zürich and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States; this administrative office is headed by IUPAC's executive director Lynn Soby. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry, its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee on Nomenclature and Symbols is the recognized world authority in developing standards for the naming of the chemical elements and compounds.
Since its creation, IUPAC has been run by many different committees with different responsibilities. These committees run different projects which include standardizing nomenclature, finding ways to bring chemistry to the world, publishing works. IUPAC is best known for its works standardizing nomenclature in chemistry and other fields of science, but IUPAC has publications in many fields including chemistry and physics; some important work IUPAC has done in these fields includes standardizing nucleotide base sequence code names. IUPAC is known for standardizing the atomic weights of the elements through one of its oldest standing committees, the Commission on Isotopic Abundances and Atomic Weights; the need for an international standard for chemistry was first addressed in 1860 by a committee headed by German scientist Friedrich August Kekulé von Stradonitz. This committee was the first international conference to create an international naming system for organic compounds; the ideas that were formulated in that conference evolved into the official IUPAC nomenclature of organic chemistry.
IUPAC stands as a legacy of this meeting, making it one of the most important historical international collaborations of chemistry societies. Since this time, IUPAC has been the official organization held with the responsibility of updating and maintaining official organic nomenclature. IUPAC as such was established in 1919. One notable country excluded from this early IUPAC is Germany. Germany's exclusion was a result of prejudice towards Germans by the Allied powers after World War I. Germany was admitted into IUPAC during 1929. However, Nazi Germany was removed from IUPAC during World War II. During World War II, IUPAC was affiliated with the Allied powers, but had little involvement during the war effort itself. After the war and West Germany were readmitted to IUPAC. Since World War II, IUPAC has been focused on standardizing nomenclature and methods in science without interruption. In 2016, IUPAC denounced the use of chlorine as a chemical weapon; the organization pointed out their concerns in a letter to Ahmet Üzümcü, the director of the Organisation for the Prohibition of Chemical Weapons, in regards to the practice of utilizing chlorine for weapon usage in Syria among other locations.
The letter stated, "Our organizations deplore the use of chlorine in this manner. The indiscriminate attacks carried out by a member state of the Chemical Weapons Convention, is of concern to chemical scientists and engineers around the globe and we stand ready to support your mission of implementing the CWC." According to the CWC, "the use, distribution, development or storage of any chemical weapons is forbidden by any of the 192 state party signatories." IUPAC is governed by several committees. The committees are as follows: Bureau, CHEMRAWN Committee, Committee on Chemistry Education, Committee on Chemistry and Industry, Committee on Printed and Electronic Publications, Evaluation Committee, Executive Committee, Finance Committee, Interdivisional Committee on Terminology and Symbols, Project Committee, Pure and Applied Chemistry Editorial Advisory Board; each committee is made up of members of different National Adhering Organizations from different countries. The steering committee hierarchy for IUPAC is as follows: All committees have an allotted budget to which they must adhere.
Any committee may start a project. If a project's spending becomes too much for a committee to continue funding, it must take the issue to the Project Committee; the project committee either decides on an external funding plan. The Bureau and Executive Committee oversee operations of the other committees. IUPAC committee has a long history of naming organic and inorganic compounds. IUPAC nomenclature is developed so that any compound can be named under one set of standardized rules to avoid duplicate names; the first publication on IUPAC nomenclature of organic compounds was A Guide to IUPAC Nomenclature of Organic Compounds in 1900, which contained information from the International Congress of Applied Chemistry. IUPAC organic nomenclature has three basic parts: the substituents, carbon chain length and chemical ending; the substituents are any functional groups attached to the main carbon chain. The main carbon chain is the longest possible continuous chain; the chemical ending denotes. For example, the ending ane denotes a single bonded carbon chain, as in "hexane".
Another example of IUPAC organic no