Chlorogenic acid-water complexes in chlorogenic acid containing food products

Chlorogenic acid (CQA), the ester of caffeic acid with quinic acid, has been one of the most studied polyphenols due to its potential biological activity and usefulness in pharmaceutical treatment. We found that in an aqueous solution of each chlorogenic acid isomer, 3-, 4- and 5-CQA, its two complexes with water are formed. In the RP chromatographic system, these CQA-water derivatives differ in retention data from that of their precursors and do not decompose, which indicates their considerable stability. The formation of CQA-water complexes has not been reported yet. Comprehensive NMR research of CQA-water derivatives complexes shows that their significant stability results from the formation of hydrogen bonds between water and CQA isomer – e.g., between water and OH3, OH4 and ester groups of CQA molecule in the case of 5-CQA-water derivative. The existence of CQA-water derivatives in CQA containing food products was in the paper shown. It should be noted that the stable CQA-water complexes may exhibit a different biological activity than CQA. This issue requires separate biomedical research.