Formula C16H18O9 Density 1.28 g/cm³ | Molar mass 354.31 g/mol | |
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Chlorogenic acid
Chlorogenic acid (CGA) is a natural chemical compound which is the ester of caffeic acid and (−)-quinic acid. It is an important biosynthetic intermediate. Chlorogenic acid is an important intermediate in lignin biosynthesis. This compound, known as an antioxidant, may also slow the release of glucose into the bloodstream after a meal.
Contents
- Chlorogenic acid
- Pure green coffee bean with chlorogenic acid as seen on dr oz
- Chemical properties
- Natural occurrences
- Presence in food
- Food additive
- Biological effects
- References
The term chlorogenic acids can also refer to a related family of esters of 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"), because of the green color produced when chlorogenic acids are oxidized.
Pure green coffee bean with chlorogenic acid as seen on dr oz
Chemical properties
Structurally, chlorogenic acid is the ester formed between caffeic acid and the 3-hydroxyl position 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.
It should be noted that there is considerable ambiguity about the atom-numbering of chlorogenic acid. The order of numbering of atoms on the quinic acid ring was reversed in 1976 following IUPAC guidelines, with the consequence that 3-CQA became 5-CQA, and 5-CQA became 3-CQA. This article uses the original numbering, which was exclusive prior to 1976, (chlorogenic acid being 3-CQA, while neochlorogenic acid is 5-CQA). Thereafter researchers and manufacturers have been divided, with both numbering systems in use. Even the 1976 IUPAC recommendations are not entirely satisfactory when applied to some of the less common chlorogenic acids.
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).
Chlorogenic acid is freely soluble in ethanol and acetone.
Natural occurrences
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).
Presence in food
Chlorogenic acid and the related compounds cryptochlorogenic acid, and neochlorogenic acid have been found in the leaves of Hibiscus sabdariffa, a popular tea product worldwide. Isomers of chlorogenic acid are found in potatoes. Chlorogenic acid is the most abundant phenolic acid in the flesh of eggplants.
It is one of the major phenolic compounds identified in peach. It is also found in prunes.
It also is one of the phenols found in green coffee bean extract and in green tea.
Food additive
Chlorogenic acid is marketed under the tradename Svetol, a standardized green coffee extract, as a food additive used in coffee products, chewing gum, and mints, and also as a stand-alone product. Dried sunflower leaves collected immediately after opening are processed into 98.38% chlorogenic acid extract and marketed in Bulgaria under the name of "Yamiagra" or "Yummyiagra".
Biological effects
Review articles in 2011 and 2014 report modest blood pressure lowering effects from chlorogenic acid administration. No studies have appeared to assess possible interactions with antihypertensive drugs or advisability in patients being treated for low blood pressure.
Chlorogenic acid is reported to be a chemical sensitizer responsible for human respiratory allergy to certain types of plant materials.
It could be involved in the laxative effect observed in prunes.