Chlorogenic acid

Chlorogenic acid is a family of esters formed between certain trans cinnamic acids and (-)-quinic acid and is a major phenolic compound in coffee, found widespread in plants, and can be isolated from the leaves and fruit. This compound, long known as an antioxidant, also slows the release of glucose into the bloodstream after a meal.

Chemical properties
Structurally, chlorogenic acid (CGA) is the ester formed between certain trans cinnamic acid and (L)-quinic acid (1L-1(OH),3,4/5-tetrahydroxycyclohexanecarboxylic acid) . Isomerisation of chlorogenic acid have been reported with 3 isomerisations of the quinic acid in position 3, (3-CQA), 4 (4-CGA) and 5 (5-CQA). Isomerisation at position 1 and 6 has not yet been reported.

Biological importance
This acid is an important factor in plant metabolism. It is also an antioxidant and an inhibitor of the tumor promoting activity of phorbol esters; at concentrations as high as 100 µg/L, does not inhibit the 5-lipoxygenase activity of ionophore-stimulated human polymorphonuclear leukocytes.

Chlorogenic acid and caffeic acid are antioxidants in vitro and might therefore contribute to the prevention of Type 2 Diabetes Mellitus and cardiovascular disease.

Pharmaceutical & industrial applications
This substance is claimed to have antiviral, antibacterial and antifungal effects with relatively low toxicity and side effects, alongside properties that do not lead antimicrobial resistance. Potential uses are suggested in pharmaceuticals, foodstuffs, feed additives, and cosmetics.

Chlorogenic acid is marketed under the tradename Svetol® in Norway and the United Kingdom as a food active ingredient used in coffee, chewing gum, and mints to promote weight reduction.

Recent studies
Chlorogenic acid has been proven in animal studies in vitro to inhibit the hydrolysis of the glucose-6-phosphate enzyme in an irreversible fashion. This mechanism allows chlorogenic acid to reduce hepatic glycogenolysis (transformation of glycogen into glucose) and to reduce the absorption of new glucose. In addition, in vivo studies on animal subjects have demonstrated that the administration of chlorogenic acid lessens the hyperglycemic peak resulting from the glycogenolysis brought about by the administering of glucagon, a hyperglycemiant hormone. The studies also confirmed a reduction in blood glucose levels and an increase in the intrahepatic concentrations of glucose-6-phosphate and of glycogen.