LC-MSn analysis of the cis isomers of chlorogenic acids

• Published in: Food chemistry Vol. 106; no. 1; pp. 379 - 385
• Main Authors: Clifford, M.N, Kirkpatrick, J, Kuhnert, N, Roozendaal, H, Salgado, P.R
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier 2008
• Subjects: 1,3-dicaffeoylquinic acid; 1-acyl chlorogenic acid; Biological and medical sciences; chlorogenic acid; cis isomers; coffee beans; coffee products; Coffee, tea and other stimulative beverage industries; food analysis; food composition; Food industries; food irradiation; Fundamental and applied biological sciences. Psychology; isomers; leaves; liquid chromatography; mass spectrometry; ultraviolet radiation; Feruloylquinic acids; LC-MSn; Phenolic acid; Dicaffeoylquinic acids; Chlorogenic acids; Chlorogenic acid; Liquid chromatography; Plant leaf; Caffeoylquinic acids; Coffee; Isomer; Leaves; Plant part; Ultraviolet irradiation; UV-irradiation; Analysis; Cynarin; p-Coumaroylquinic acids
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2007.05.081

The behaviour of cis isomers of selected mono- and di-acyl chlorogenic acids produced by UV-irradiation has been investigated by LC-MSn. cis Isomers fragment identically to the more common trans isomers. cis-5-Acyl chlorogenic acids are more hydrophobic and elute later than their mono- or di-trans counterparts whereas the reverse is true for cis-3-acyl and cis-4-acyl chlorogenic acids. The cis isomers of 1,3-dicaffeoylquinic acid, the only 1-acyl chlorogenic acid investigated, are also more hydrophobic than the di-trans isomer. Coffee leaves had a proportionately greater content of cis isomers relative to trans isomers compared with coffee beans suggesting that UV-irradiation in vivo may also cause geometric isomerisation.