Doc:Coffee

Chlorogenic Acids

Chlorogenic acids (CGA) are esters of trans-cinnamic acids with (1)-quinic acids, including caffeoylquinic acids, dicaffeoylquinic acids, teruloylquinic acids, p-coumaroylquinic acids and their mixed esters. CGA and related compounds form the major components of green coffee beans, up to 10% in dried C. canephora species. During roasting, CGA undergo various transformations. In roasted beans, quinolactones and melanoidins are observed.

After drinking coffee, 30% of CGA are absorbed to the body. Caffeic acid-3-O-sulfate, ferulic acid-4-O-sulfate, and sulfates of 3- and 4-caffeoylquinic acid lactones reach maximum concentrations in the plasma within 1 hour due to absorption in the small intestine. In contrast, dihydroferulic acid, its O-sulfate and dihydrocaffeic acid-3-O-sulfate exhibit highest plasma concentrations in excess of 4 hours, probably due to the absorption in the colon. These metabolites, ferulic acid-4-O-sulfate, and dihydroferulic acid-4-O-glucuronide together form major urinary components after drinking coffee.