Abstract
Caffeoylquinic acids (CQAs) are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA) and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs) under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation). The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MSn, inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.
Highlights
Chlorogenic acids (CGAs) are a family of natural phenolic compounds, named by Clifford in 1985, that including caffeoylquinic acids (CQAs), p-coumaroylquinic acids (p-CoQAs) and feruloyl quinic acids (FQAs), etc. [1]
3,5-diCQA, is stability similar the results reported by Y Li was muchetmore more stablethan than
Total ion current chromatograms of 7 CQAs and its degradation products stored in transparent bottle at room temperature after 7 days. (A) 5-caffeoylquinic acid; (B) 3-caffeoylquinic transparent bottle at room temperature after 7 days. (A) 5-caffeoylquinic acid; (B) 3-caffeoylquinic acid; (C) 4-caffeoylquinic acid; (D) 1,3-dicaffeoylquinic acid; (E) 3,4-dicaffeoylquinic acid; (F)
Summary
Chlorogenic acids (CGAs) are a family of natural phenolic compounds, named by Clifford in 1985, that including caffeoylquinic acids (CQAs), p-coumaroylquinic acids (p-CoQAs) and feruloyl quinic acids (FQAs), etc. [1]. They are formed by esterification of quinic acid with caffeic acids [2,3,4] They are the most common CGAs and can be found in a wide variety of consumer goods, including vegetables, fruits, and herbs [5]. 100–200 temperature range of 100–200 °C caused isomerization and other transformations [11]. 3,4-diCQA andoccurred occurred [12] Extreme conditions such temperature or acidic conditions have a great influence the stability of some. As high temperature or acidic conditions have a greatoninfluence on the stability of some the study ofthe stability mono- and di-acyl. CQAs will be much more realistically meaningful and study of stability of monoand di-acyl. Our study examined the thermal-, photo-, and solvent-stability of monoand di-acyl.
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