|
Valoneic Acid Dilactone
Valoneic acid dilactone is a hydrolysable tannin that can be isolated from the heartwood of '' Shorea laevifolia''5A-Reductase inhibitory tannin-related compounds isolated from Shorea laevifolia. Yoshio Hirano, Ryuichiro Kondo and Kokki Sakai, Journal of wood science, Volume 49, Number 4, pp.339-343, and in oaks species like the North American white oak (''Quercus alba'') and European red oak (''Quercus robur ''Quercus robur'', the pedunculate oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native plant, native to most of Europe and western Asia, and is widely cultivated in other temperate regions. It ...'').Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. Pirjo Mämmelä, Heikki Savolainenb, Lasse Lindroosa, Juhani Kangasd and Terttu Vartiainen, Journal of Chromatography A, Volume 891, Issue 1, 1 September 2000, Pages 75-83, It shows an inhibitory effect on 5α-reductase, an enzyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysable Tannin
A hydrolysable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids. At the center of a hydrolysable tannin molecule, there is a carbohydrate (usually D-glucose but also cyclitols like quinic or shikimic acids). The hydroxyl groups of the carbohydrate are partially or totally esterified with phenolic groups such as gallic acid in gallotannins or ellagic acid in ellagitannins. Hydrolysable tannins are mixtures of polygalloyl glucoses and/or poly-galloyl quinic acid derivatives containing in between 3 up to 12 gallic acid residues per molecule. Hydrolysable tannins are hydrolysed by weak acids or weak bases to produce carbohydrate and phenolic acids. Examples of gallotannins are the gallic acid esters of glucose in tannic acid (C76H52O46), found in the leaves and bark of many plant species. Hydrolysable tannins can be extracted from different vegetable plants, such as chestnut wood (''Cast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shorea Laevifolia
''Shorea laevis'' is a species of tree in the family Dipterocarpaceae. It is native to Myanmar, Thailand, Sumatra, Peninsular Malaysia and Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda .... It is considered Vulnerable due to deforestation for agriculture and being logged for its timber. References laevis Trees of Thailand Trees of Myanmar Trees of Sumatra Trees of Peninsular Malaysia Dipterocarps of Borneo Plants described in 1922 Taxonomy articles created by Polbot {{Dipterocarpaceae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercus Alba
''Quercus alba'', the white oak, is one of the preeminent hardwoods of eastern and central North America. It is a long-lived oak, native to eastern and central North America and found from Minnesota, Ontario, Quebec, and southern Maine south as far as northern Florida and eastern Texas. Specimens have been documented to be over 450 years old. Although called a white oak, it is very unusual to find an individual specimen with white bark; the usual colour is a light gray. The name comes from the colour of the finished wood. In the forest it can reach a magnificent height and in the open it develops into a massive broad-topped tree with large branches striking out at wide angles. Description ''Quercus alba'' typically reaches heights of at maturity, and its canopy can become quite massive as its lower branches are apt to extend far out laterally, parallel to the ground. Trees growing in a forest will become much taller than ones in an open area which develop to be short and mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quercus Robur
''Quercus robur'', the pedunculate oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native plant, native to most of Europe and western Asia, and is widely cultivated in other temperate regions. It grows on soils of near neutral Soil pH, acidity in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens. Description Pedunculate oak is a deciduous tree up to tall, with a single stout trunk that can be as much as in girth (circumference at breast height) or even 14 m in Pollarding, pollarded specimens. Older trees tend to be pollarded, with boles (the main trunk) about 3 m long. They often live longer and become more stout than unpollarded trees. The crown is spreading and unevenly domed, and trees often have massive lower branches. The bark is greyish-brown and closely grooved, with vertical plates. There are often large burrs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ellagitannins
image:Castalagin.svg, 130px, Castalagin is a representative ellagitannin, characterized by coupled gallic acid substituents The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl groups are linked through C-C bonds, whereas the galloyl groups in gallotannins are linked by depside bonds. Ellagitannins contain various numbers of Hexahydroxydiphenic acid, hexahydroxydiphenoyl units, as well as galloyl units and/or Sanguisorbic acid, sanguisorboyl units bounded to sugar moiety. In order to determine the quantity of every individual unit, the hydrolysis of the extracts with trifluoroacetic acid in methanol/water system is performed. Hexahydroxydiphenic acid, created after hydrolysis, spontaneously lactonized to ellagic acid, and sanguisorbic acid to sanguisorbic acid dilactone, while gallic acid remains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactones
Lactones are cyclic carboxylic esters. They are derived from the corresponding hydroxycarboxylic acids by esterification. They can be saturated or unsaturated. Lactones are formed by lactonization, the intramolecular esterification of the corresponding hydroxycarboxylic acids. Nomenclature Greek prefixes in alphabetical order indicate ring size. Lactones are usually named according to the precursor acid molecule (''aceto'' = 2 carbon atoms, ''propio'' = 3, ''butyro'' = 4, ''valero'' = 5, ''capro'' = 6, etc.), with a ''-lactone'' suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH and the -COOH groups along said backbone. The first carbon atom after the carbon in the -COOH group on the parent compound is labelled α, the second will be labeled β, and so forth. Therefore, the prefixes also indicate the size of the lactone ring: α-lactone = 3-membered ring, β-lactone = 4-membered, γ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
