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Azadirachtin
Azadirachtin, a chemical compound belonging to the limonoid group, is a secondary metabolite present in neem seeds. It is a highly oxidized tetranortriterpenoid which boasts a plethora of oxygen-bearing functional groups, including an enol ether, acetal, hemiacetal, tetra-substituted epoxide and a variety of carboxylic esters. Chemical synthesis Azadirachtin has a complex molecular structure; it presents both secondary and tertiary hydroxyl groups and a tetrahydrofuran ether in its molecular structure, alongside 16 stereogenic centres, 7 of which are tetrasubstituted. These characteristics explain the great difficulty encountered when trying to prepare this compound from simple precursors, using methods of synthetic organic chemistry. Hence, the first total synthesis was published over 22 years after the compound's discovery: this first synthesis was completed by the research group of Steven Ley at the University of Cambridge in 2007. The described synthesis was a relay approa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nimbecidine
Azadirachtin, a chemical compound belonging to the limonoid group, is a secondary metabolite present in neem seeds. It is a highly oxidized tetranortriterpenoid which boasts a plethora of oxygen-bearing functional groups, including an enol ether, acetal, hemiacetal, tetra-substituted epoxide and a variety of carboxylic esters. Chemical synthesis Azadirachtin has a complex molecular structure; it presents both secondary and tertiary hydroxyl groups and a tetrahydrofuran ether in its molecular structure, alongside 16 stereogenic centres, 7 of which are tetrasubstituted. These characteristics explain the great difficulty encountered when trying to prepare this compound from simple precursors, using methods of synthetic organic chemistry. Hence, the first total synthesis was published over 22 years after the compound's discovery: this first synthesis was completed by the research group of Steven Ley at the University of Cambridge in 2007. The described synthesis was a relay appr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azadirachta Indica
''Azadirachta indica'', commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus ''Azadirachta'', and is native to the Indian subcontinent and most of the countries in Africa. It is typically grown in tropical and semi-tropical regions. Neem trees also grow on islands in southern Iran. Its fruits and seeds are the source of neem oil. Description Neem is a fast-growing tree that can reach a height of , and rarely . It is deciduous, shedding many of its leaves during the dry winter months. The branches are wide and spreading. The fairly dense crown is roundish and may reach a diameter of . The neem tree is similar in appearance to its relative, the chinaberry ('' Melia azedarach''). The opposite, pinnate leaves are long, with 20 to 30 medium to dark green leaflets about long. The terminal leaflet often is missing. The petioles are short. White and fragrant flowers are arranged in more-or-less drooping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neem
''Azadirachta indica'', commonly known as neem, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of two species in the genus '' Azadirachta'', and is native to the Indian subcontinent and most of the countries in Africa. It is typically grown in tropical and semi-tropical regions. Neem trees also grow on islands in southern Iran. Its fruits and seeds are the source of neem oil. Description Neem is a fast-growing tree that can reach a height of , and rarely . It is deciduous, shedding many of its leaves during the dry winter months. The branches are wide and spreading. The fairly dense crown is roundish and may reach a diameter of . The neem tree is similar in appearance to its relative, the chinaberry ('' Melia azedarach''). The opposite, pinnate leaves are long, with 20 to 30 medium to dark green leaflets about long. The terminal leaflet often is missing. The petioles are short. White and fragrant flowers are arranged in more-or-less drooping ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetranortriterpenoid
The tetranortriterpenoid class of chemical compounds most noted for the chemical azadirachtin, extracted from the neem tree (''Azadirachta indica'') that displays insecticidal properties. Azadirachtin mimics insect hormones called ecdysones that regulate pupation of insects; application of azadirachtin interrupts the development and pupation of insects, which eventually kills them. The name indicates that the basic skeleton of such compounds contains 26 carbon atoms (4 fewer than triterpene Triterpenes are a class of chemical compounds composed of three terpene units with the molecular formula C30H48; they may also be thought of as consisting of six isoprene units. Animals, plants and fungi all produce triterpenes, including squa ...s). Azadirachtin is a tetranortriterpenoid and a limonoid. References {{insecticides Plant toxin insecticides Triterpenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limonoid
Limonoids are phytochemicals of the triterpenoid class which are abundant in sweet or sour-scented citrus fruit and other plants of the families Cucurbitaceae, Rutaceae, and Meliaceae. Certain limonoids are antifeedants such as azadirachtin from the neem tree.{{cite journal, title=Biological activity of limonoids from the rutales, journal=Phytochemistry, volume=31, pages=377–394, authors=Donald E.Champagne, Opender Koul, Murray B. Isman, Geoffrey G. E.Scudder, G. H. Neil Towers, year=1992, issue=2, doi=10.1016/0031-9422(92)90003-9 Chemically, the limonoids consist of variations of the furanolactone core structure. The prototypical structure consists of four six-membered rings and a furan ring. Limonoids are classed as tetranortriterpenes. Citrus fruits contain the limonoids limonin, nomilin and nomilinic acid, while both neem seeds and leaves contain the limonoid azadirachtin, although higher concentrations are present in the former. See also * Tetranortriterpenoid Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spodoptera Littoralis
''Spodoptera littoralis'', also referred to as the African cotton leafworm or Egyptian cotton leafworm or Mediterranean brocade, is a species of moth in the family Noctuidae. ''S. littoralis'' is found widely in Africa, Mediterranean Europe and Middle Eastern countries. It is a highly polyphagous organism that is a pest of many cultivated plants and crops. As a result, this species was assigned the label of A2 quarantine pest by the EPPO and was cautioned as a highly invasive species in the United States. The devastating impacts caused by these pests have led to the development of both biological and chemical control methods. This moth is often confused with '' Spodoptera litura''. Taxonomy Egyptian cotton leafworm is one of the many species of genus ''Spodoptera'' and family Noctuidae. The family Noctuidae was named by a French zoologist, Pierre André Latreille, in 1809 and the genus Noctuidae was named by a French entomologist, Achille Guenée, in 1852. Many of the species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steven Ley
Steven Victor Ley (born 10 December 1945) is Professor of Organic Chemistry in the Department of Chemistry at the University of Cambridge, and is a Fellow of Trinity College, Cambridge. He was President of the Royal Society of Chemistry (2000–2002) and was made a CBE in January 2002, in the process. In 2011, he was included by ''The Times'' in the list of the "100 most important people in British science". Education Ley was educated at Stamford and Loughborough University of Technology where he was awarded a Bachelor of Science and PhD. Research Ley's main research field are the total synthesis of biomolecules. His group has published extensively on this topic, and has completed the synthesis of more than 140 natural target compounds, with notable examples including indanamycin, routiennocin, avermectin B1a, okadaic acid, spongistatin, thapsigargin, epothilone A, antascomicin B, bengazole A and rapamycin. His total synthesis of azadirachtin, completed in 2007, is widely r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insecticide
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain. Insecticides can be classified into two major groups: systemic insecticides, which have residual or long term activity; and contact insecticides, which have no residual activity. The mode of action describes how the pesticide kills or inactivates a pest. It provides another way of classifying insecticides. Mode of action can be important in understanding whether an insecticide will be toxic to unrelated species, such as fish, birds and mammals. Insecticides may be repellen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodegradable
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances. The process of biodegradation is threefold: first an object undergoes biodeterioration, which is the mechanical weakening of its structure; then follows biofragmentation, which is the breakdown of materials by microorganisms; and finally assimilation, which is the incorporation of the old material into new cells. In practice, almost all chemical compounds and materials are subject to biodegradation, the key element being time. Things like vegetables may degrade within days, while glass and some plastics take many millennia to decompose. A standard for biodegradability used by the European Union is that greater than 90% of the original material must be converted into , water and minerals b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicity
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell ( cytotoxicity) or an organ such as the liver ( hepatotoxicity). By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or society at large. Sometimes the word is more or less synonymous with poisoning in everyday usage. A central concept of toxicology is that the effects of a toxicant are dose-dependent; even water can lead to water intoxication when taken in too high a dose, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N2, a colorless and odorless diatomic gas. N2 forms about 78% of Earth's atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids ( DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere. Many indus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla ( hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla (cetaceans and even-toed ungulates), and the Carnivora ( cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
