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Representative chemical structure of one of many plant-derived polyphenols that comprise tannic acid. Such compounds are formed by esterification of phenylpropanoid-derived gallic acid to a monosaccharide (glucose) core. Polyphenols (/ ˌ p ɒ l i ˈ f iː n oʊ l,-n ɒ l /) are a large family of naturally occurring phenols. [1]
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. [1] The simplest is phenol, C 6 H 5 OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the ...
The main source of polyphenols is dietary, since they are found in a wide array of phytochemical-bearing foods.For example, honey; most legumes; fruits such as apples, blackberries, blueberries, cantaloupe, pomegranate, cherries, cranberries, grapes, pears, plums, raspberries, aronia berries, and strawberries (berries in general have high polyphenol content [5]) and vegetables such as broccoli ...
The phenolic unit can be found dimerized or further polymerized, creating a new class of polyphenol. For example, ellagic acid is a dimer of gallic acid and forms the class of ellagitannins, or a catechin and a gallocatechin can combine to form the red compound theaflavin , a process that also results in the large class of brown thearubigins in ...
isoflavonoids, derived from 3-phenylchromen-4-one (3-phenyl-1,4-benzopyrone) structure; neoflavonoids, derived from 4-phenylcoumarin (4-phenyl-1,2-benzopyrone) structure; The three flavonoid classes above are all ketone-containing compounds and as such, anthoxanthins (flavones and flavonols). [1] This class was the first to be termed bioflavonoids.
[1] The phenomenon of dual fluorescence (due to excited state intramolecular proton transfer or ESIPT) is induced by tautomerism of flavonols (and glucosides) and could contribute to plant UV protection and flower colour .
Gross anatomy has become a key part of visual arts. Basic concepts of how muscles and bones function and deform with movement is key to drawing, painting or animating a human figure. Many books such as Human Anatomy for Artists: The Elements of Form, are written as a guide to drawing the human body anatomically correctly. [4]
Schematic chemical structure of an A type proanthocyanidin dimer. A-type linkage is a less common feature in proanthocyanidins with both 4β→8 and 2β→O→7 interflavanoid bonds. [2] A-type proanthocyanidin glycosides can be isolated from cocoa liquor. [3]