title: Degradation kinetics of chlorogenic acid at various pH values and effects of ascorbic acid and epigallocatechin gallate on its stability under alkaline conditions.
abstract: 5-Caffeoylquinic acid (5-CQA) is generally referred to as chlorogenic acid and exhibits various biological activities such as antioxidant activity and porcine pancreas α-amylase inhibitory activities. 5-CQA may be useful as an antioxidant for food and to prevent diabetes and obesity. The degradation of 5-CQA and caffeic acid (CA) in an aqueous solution at 37 °C and pH 5.0-9.0 was studied. The degradation of 5-CQA and CA, demonstrating time and pH dependence (i.e., the rate constant, k, was higher at higher pH), was satisfactorily described by the Weibull equation. The stability of 5-CQA at pH 7.4 and 9.0 was improved by adding (-)-epigallocatechin gallate (EGCG) and ascorbic acid (AA). Moreover, the degradation of 5-CQA in the presence of EGCG or AA could be described by the Weibull equation. The k value in the presence of EGCG or AA was dependent on their concentration.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Narita
authors.forename: Kuniyo
authors.initials: K
authors.lastname: Inouye
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D002109:Caffeic Acids / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002726:Chlorogenic Acid / Q000737:chemistry*; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011801:Quinic Acid / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D002109:Caffeic Acids; C472707:caffeoylquinic acid; D011801:Quinic Acid; D002726:Chlorogenic Acid; D002392:Catechin; C045651:epigallocatechin gallate; D001205:Ascorbic Acid; C040048:caffeic acid