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The name derives from the Ancient Greek word πολύς (polus, meaning "many, much") and the word ‘phenol’ which refers to a chemical structure formed by attachment of an aromatic benzenoid ring to a hydroxyl (-OH) group (hence the -ol suffix). The term "polyphenol" has been in use at least since 1894. [4]
Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a stilbenoid, a type of natural phenol or polyphenol and a phytoalexin produced by several plants in response to injury or when the plant is under attack by pathogens, such as bacteria or fungi.
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 tea.
In 1836, Auguste Laurent coined the name "phène" for benzene; [45] this is the root of the word "phenol" and "phenyl". In 1843, French chemist Charles Gerhardt coined the name "phénol". [46] The antiseptic properties of phenol were used by Sir Joseph Lister in his pioneering technique of antiseptic surgery. Lister decided that the wounds had ...
Phenols are more acidic than typical alcohols. The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pK a is usually between 10 and 12).
Flax seeds and sesame seeds contain high levels of lignans. [1] [8] The principal lignan precursor found in flaxseeds is secoisolariciresinol diglucoside.[1] [8] Other foods containing lignans include cereals (rye, wheat, oat and barley), soybeans, tofu, cruciferous vegetables, such as broccoli and cabbage, and some fruits, particularly apricots and strawberries. [1]
It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from catechu , which is the tannic juice or boiled extract of Mimosa catechu ( Acacia catechu L.f).
Mean flavonoid intake in mg/d per country, the pie charts show the relative contribution of different types of flavonoids. [16] Food composition data for flavonoids were provided by the USDA database on flavonoids. [11] In the United States NHANES survey, mean flavonoid intake was 190 mg per day in adults, with flavan-3-ols as the main ...