1.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
2.
ChEMBL
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ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties. It is maintained by the European Bioinformatics Institute, of the European Molecular Biology Laboratory, based at the Wellcome Trust Genome Campus, Hinxton, the database, originally known as StARlite, was developed by a biotechnology company called Inpharmatica Ltd. later acquired by Galapagos NV. The data was acquired for EMBL in 2008 with an award from The Wellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, the ChEMBL database contains compound bioactivity data against drug targets. Bioactivity is reported in Ki, Kd, IC50, and EC50, data can be filtered and analyzed to develop compound screening libraries for lead identification during drug discovery. ChEMBL version 2 was launched in January 2010, including 2.4 million bioassay measurements covering 622,824 compounds and this was obtained from curating over 34,000 publications across twelve medicinal chemistry journals. ChEMBLs coverage of available bioactivity data has grown to become the most comprehensive ever seen in a public database, in October 2010 ChEMBL version 8 was launched, with over 2.97 million bioassay measurements covering 636,269 compounds. ChEMBL_10 saw the addition of the PubChem confirmatory assays, in order to integrate data that is comparable to the type, ChEMBLdb can be accessed via a web interface or downloaded by File Transfer Protocol. It is formatted in a manner amenable to computerized data mining, ChEMBL is also integrated into other large-scale chemistry resources, including PubChem and the ChemSpider system of the Royal Society of Chemistry. In addition to the database, the ChEMBL group have developed tools and these include Kinase SARfari, an integrated chemogenomics workbench focussed on kinases. The system incorporates and links sequence, structure, compounds and screening data, the primary purpose of ChEMBL-NTD is to provide a freely accessible and permanent archive and distribution centre for deposited data. July 2012 saw the release of a new data service, sponsored by the Medicines for Malaria Venture. The data in this service includes compounds from the Malaria Box screening set, myChEMBL, the ChEMBL virtual machine, was released in October 2013 to allow users to access a complete and free, easy-to-install cheminformatics infrastructure. In December 2013, the operations of the SureChem patent informatics database were transferred to EMBL-EBI, in a portmanteau, SureChem was renamed SureChEMBL. 2014 saw the introduction of the new resource ADME SARfari - a tool for predicting and comparing cross-species ADME targets
3.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
4.
European Chemicals Agency
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ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
5.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
6.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure
7.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
8.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
9.
Pistacia lentiscus
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Pistacia lentiscus is a dioecious evergreen shrub or small tree of the pistacio genus growing up to 4 m tall which is cultivated for its aromatic resin, mainly on the Greek island of Chios. It resists heavy frosts and grows on all types of soils and it is also found in woodlands, dehesas, Kermes oak wood, oaks wood, garrigue, maquis, hills, gorges, canyons, and rocky hillsides of the entire Mediterranean area. It is a hardy pioneer species dispersed by birds. When older, it develops some large trunks and numerous thicker and longer branches, in appropriate areas, when allowed to grow freely and age, it often becomes a tree of up to 7 m. However, logging, grazing, and fires often prevent its development, the leaves are alternate, leathery, and compound paripinnate with five or six pairs of deep-green leaflets. It presents very small flowers, the male with five stamens, the fruit is a drupe, first red and then black when ripe, about 4 mm in diameter. In tourist areas, with palmitos or Mediterranean dwarf palm, and exotic plants, it is chosen to repopulate gardens and resorts, because of its strength. Unlike other species of Pistacia, it retains its leaves throughout the year, a related species, P. saportae, has been shown by DNA analysis to be a hybrid between maternal P. lentiscus and paternal P. terebinthus. The hybrid has imparipinnate leaves, with leaflets semipersistent, subsessile terminal, Pistacia lentiscus is native throughout the Mediterranean region, from Morocco and Iberian peninsula in the west through southern France and Turkey to Iraq and Iran in the east. It is also native to the Canary Islands, the word mastic derives from the Latin word Masticare, in Greek, μαστιχάω verb mastichein or massein. Within the European Union, mastic production in Chios is granted protected designation of origin, although the tree is native to all of the Mediterranean region, only on southern Chios is the mastic trees bark scored to weep the masticha resin. The islands mastic production is controlled by a co-operative of medieval villages, collectively known as the Mastichochoria, originally liquid, it is hardened, when the weather turns cold, into drops or patties of hard, brittle, translucent resin. When chewed, the resin softens and becomes a bright white, the resin is collected by bleeding the trees from small cuts made in the bark of the main branches, and allowing the sap to drip onto the specially prepared ground below. The harvesting is done during the summer between June and September, after the mastic is collected, it is washed manually and is set aside to dry, away from the sun, as it will start melting again. Mastic resin is a relatively expensive kind of spice, it has been used principally as a chewing gum for at least 2,400 years, the flavour can be described as a strong, slightly smoky, resiny aroma and can be an acquired taste. Some scholars identify the bakha בכא mentioned in the Bible—as in the Valley of Baca of Psalm 84—with the mastic plant, the Valley of Baca is thought to be a valley near Jerusalem that was covered with low mastic shrubbery, much like some hillsides in northern Israel today. Mastic is known to have been popular in Roman times when children chewed it and it was the Sultans privilege to chew mastic, and it was considered to have healing properties. The spices use was widened when Chios became part of the Ottoman Empire, and it remains popular in North Africa, the Mastichochoria are located in the southern part of Chios
10.
Tannic acid
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Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity is due to the numerous groups in the structure. Commercial tannic acid is extracted from any of the following plant part, Tara pods. Sometimes extracts from chestnut or oak wood are also described as tannic acid and it is a yellow to light brown amorphous powder,2850 grams dissolves in one litre of water. While tannic acid is a type of tannin, the two terms are sometimes used interchangeably. The long-standing misuse of the terms, and its inclusion in scholarly articles has compounded the confusion and this is particularly widespread in relation to green tea and black tea, both of which contain tannin but not tannic acid. Tannic acid is not a standard for any type of tannin analysis because of its poorly defined composition. Quercitannic acid is one of the two forms of acid found in oak bark and leaves. The other form is called gallotannic acid and is found in oak galls, the quercitannic acid molecule is also present in quercitron, a yellow dye obtained from the bark of the Eastern black oak, a forest tree indigenous in North America. It is described as a yellowish brown amorphous substance, in 1838, Jöns Jacob Berzelius wrote that quercitannate is used to dissolve morphine. In 1865 in the volume of A dictionary of chemistry, Henry Watts wrote. It differs however from the latter in not being convertible into gallic acid and it is precipitated by sulfuric acid in red flocks. According to Rochleder, the acid of black tea is the same as that of oak-bark. In 1880, Etti gave for it the molecular formula C17H16O9 and he described it as an unstable substance, having a tendency to give off water to form anhydrides, one of which is called oak-red. For him, it was not a glycoside, in Allen’s Commercial Organic Analysis, published in 1912, the formula given was C19H16O10. Other authors gave other molecular formulas like C28H26O15, while another formula found is C28H24O11, according to Lowe, two forms of the principle exist – one soluble in water, of the formula C28H28O14, and the other scarcely soluble, C28H24O12. Both are changed by the loss of water into oak red, quercitannic acid was for a time a standard used to assess the phenolic content in spices, given as quercitannic acid equivalent. In an interesting note, the inventor Edward G. Acheson discovered that gallotannic acid greatly improved the plasticity of clay
11.
Depside
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A depside is a type of polyphenolic compound composed of two or more monocyclic aromatic units linked by an ester bond. Depsides are most often found in lichens, but have also been isolated from higher plants, depsides have antibiotic, anti-HIV, antioxidant, and anti-proliferative activity. As inhibitors of synthesis and leukotriene B4 biosynthesis, depsides are potent non-steroidal anti-inflammatories. A depsidase is a type of enzyme that cuts depside bonds, gyrophoric acid, found in the lichen Cryptothecia rubrocincta, is a depside. Salsalate homodimer formed from self-condensation of salicylic acid to form ester linkage
12.
Gallic acid
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Gallic acid is a trihydroxybenzoic acid, a type of phenolic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula of gallic acid is C6H23COOH and it is found both free and as part of hydrolyzable tannins. The gallic acid groups are bonded to form dimers such as ellagic acid. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, gallic acid forms intermolecular esters such as digallic and trigallic acids, and cyclic ether-esters. Gallic acid can also be used as a material in the synthesis of the psychedelic alkaloid mescaline. The name is derived from oak galls, which were used to prepare tannic acid. Despite the name, gallic acid does not contain gallium, salts and esters of gallic acid are termed gallates. Pliny the Elder describes his experiments with it and writes that it was used to produce dyes, galls from oak trees were crushed and mixed with water, producing tannic acid. Gallic acid was one of the used by Angelo Mai, among other early investigators of palimpsests, to clear the top layer of text off. Mai was the first to employ it, but did so with a heavy hand, gallic acid was first studied by the Swedish chemist Carl Wilhelm Scheele in 1786. Gallic acid is a component of some pyrotechnic whistle mixtures, gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3, 5-didehydroshikimate. This latter compound tautomerizes to form the redox equivalent gallic acid, gallate dioxygenase is an enzyme found in Pseudomonas putida that catalyses the reaction gallate + O2 → -4-oxobut-1-ene-1,2, 4-tricarboxylate. Gallate decarboxylase is another enzyme in the degradation of gallic acid, gallate 1-beta-glucosyltransferase is an enzyme that uses UDP-glucose and gallate, whereas its two products are UDP and 1-galloyl-beta-D-glucose. It is a carbonic anhydrase inhibitor. In basic research, gallic acid extracted from seeds has been shown to inhibit the formation of amyloid fibrils, one of the potential causes of Alzheimers disease. One study indicated that gallic acid has this effect on amyloid protein formation by modifying the properties of alpha-synuclein, gallic acid is classified as a mutagen and a teratogen. Gallic acid is found in a number of plants, such as the parasitic plant Cynomorium coccineum, the aquatic plant Myriophyllum spicatum. Gallic acid is found in various oak species, Caesalpinia mimosoides
13.
PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby
14.
Glucogallin
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Glucogallin is chemical compound formed from gallic acid and β-D-glucose. It can be found in species like the North American white oak, European red oak. It is formed by a gallate 1-beta-glucosyltransferase, an enzyme performing the esterification of two substrates, UDP-glucose and gallate to yield two products, UDP and glucogallin and this enzyme can be found in oak leaf preparations. This the first step in the biosynthesis of gallotannins, the molecule is then used by enzymes in the gallotannins synthetis pathway like beta-glucogallin O-galloyltransferase or beta-glucogallin-tetrakisgalloylglucose O-galloyltransferase. Half-life of β-Glucogallin in human body seems to be unknown
15.
1,2,3,4,6-Pentagalloyl glucose
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1,2,3,4, 6-Pentagalloylglucose is the pentagallic acid ester of glucose. It is a gallotannin and the precursor of ellagitannins, pentagalloyl glucose can precipitate proteins including human salivary α-amylase. It may also be used in radioprotection,1,2,3,4, 6-Pentagalloyl glucose can be found in Punica granatum, Elaeocarpus sylvestris, Rhus typhina, and Paeonia suffruticosa. The enzyme beta-glucogallin-tetrakisgalloylglucose O-galloyltransferase uses 1-O-galloyl-beta-D-glucose and 1,2,3, 6-tetrakis-O-galloyl-beta-D-glucose to produce D-glucose, tellimagrandin II is formed from pentagalloyl glucose by oxidative dehydrogenation and coupling of 2 galloyl groups. Pentagalloyl glucose can undergo oxidation reactions which are depending on the pH
16.
Phenols
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In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group. The simplest of the class is phenol, which is also called carbolic acid C 6H 5OH, phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule. Synonyms are arenols or aryl alcohols, phenolic compounds are synthesized industrially, they also are produced by plants and microorganisms, with variation between and within species. Although similar to alcohols, phenols have unique properties and are not classified as alcohols and they have higher acidities due to the aromatic rings tight coupling with the oxygen and a relatively loose bond between the oxygen and hydrogen. The acidity of the group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids. Phenols can have two or more hydroxy groups bonded to the ring in the same molecule. The simplest examples are the three benzenediols, each having two groups on a benzene ring. Organisms that synthesize phenolic compounds do so in response to pressures such as pathogen and insect attack, UV radiation. As they are present in food consumed in human diets and in used in traditional medicine of several cultures, their role in human health. Some phenols are germicidal and are used in formulating disinfectants, others possess estrogenic or endocrine disrupting activity. They can also be classified on the basis of their number of phenol groups and they can therefore be called simple phenols or monophenols, with only one phenolic group, or di-, tri- and oligophenols, with two, three or several phenolic groups respectively. The phenolic unit can be found dimerized or further polymerized, creating a new class of polyphenol, two natural phenols from two different categories, for instance a flavonoid and a lignan, can combine to form a hybrid class like the flavonolignans. Nomenclature of polymers, Plants in the genus Humulus and Cannabis produce terpenophenolic metabolites, phenolic lipids are long aliphatic chains bonded to a phenolic moiety. The majority of compounds are solubles molecules but the smaller molecules can be volatiles. Many natural phenols present chirality within their molecule, an example of such molecules is catechin. Cavicularin is an unusual macrocycle because it was the first compound isolated from nature displaying optical activity due to the presence of planar chirality, natural phenols chemically interact with many other substances. Stacking, a property of molecules with aromaticity, is seen occurring between phenolic molecules. When studied in mass spectrometry, phenols easily form adduct ions with halogens and they can also interact with the food matrices or with different forms of silica
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