Chlorogenic acid

Chlorogenic acid (CGA) is the ester of caffeic acid and (−)-quinic acid, functioning as an intermediate in lignin biosynthesis. The term 'chlorogenic acids' refers to a related polyphenol family of esters, including hydroxycinnamic acids (caffeic acid, ferulic acid and p-coumaric acid) with quinic acid. Chlorogenic acid (CGA) is the ester of caffeic acid and (−)-quinic acid, functioning as an intermediate in lignin biosynthesis. The term 'chlorogenic acids' refers to a related polyphenol family of esters, including hydroxycinnamic acids (caffeic acid, ferulic acid and p-coumaric acid) with quinic acid. Despite the 'chloro' of the name, chlorogenic acids contain no chlorine. Instead, the name comes from the Greek χλωρός (light green) and -γένος (a suffix meaning 'giving rise to'), pertaining to the green color produced when chlorogenic acids are oxidized. Structurally, chlorogenic acid is the ester formed between caffeic acid and the 3-hydroxyl of L-quinic acid. Isomers of chlorogenic acid include the caffeoyl ester at other hydroxyl sites on the quinic acid ring: 4-O-caffeoylquinic acid (cryptochlorogenic acid or 4-CQA) and 5-O-caffeoylquinic acid (neochlorogenic acid or 5-CQA). The epimer at position 1 has not yet been reported. Structures having more than one caffeic acid group are called isochlorogenic acids, and can be found in coffee. There are several isomers, such as 3,4-dicaffeoylquinic acid and 3,5-dicaffeoylquinic acid. and cynarine (1,5-dicaffeoylquinic acid) The biosynthetic precursor to chlorogenic acid is 4-coumaroyl-CoA, containing a single hydroxyl group on the aryl ring, which in turn is produced from cinnamic acid. The hydroxylation of the coumaryl ester, i.e. installing the second hydroxy group, is catalyzed by a cytochrome P450 enzyme. Chlorogenic acid can be found in the bamboo Phyllostachys edulis. as well as in many other plants. Chlorogenic acid can be found in the shoots of common heather (Calluna vulgaris). Chlorogenic acid and the related compounds cryptochlorogenic acid, and neochlorogenic acid have been found in the leaves of Hibiscus sabdariffa. Isomers of chlorogenic acid are found in potatoes. Chlorogenic acid is present in the flesh of eggplants, peaches, and prunes. Taken as a dietary supplement or in coffee, chlorogenic acid slightly reduces blood pressure, It has been investigated for possible anti-inflammatory effects. Chlorogenic acid has been studied as a possible chemical sensitizer involved in respiratory allergy to certain plant materials.