Quantitative Profiling and Metabolic Study of Caffeoylquinic Acids and Their Metabolites by Liquid Chromatography-Tandem Mass Spectrometry in Rats and Laying Hens

Caffeoylquinic acids are natural polyphenolic compounds with notable antioxidant and anti-inflammatory activities. This study developed and validated a sensitive high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of isochlorogenic acid A (ICQA) and 22 metabolites in serum. The method exhibited excellent sensitivity with limits of quantification of 0.625–1.25 µg/L (signal-to-noise ratio = 10), inter/intra-day precision below 15%, and comprehensive coverage of phase I/II and microbial metabolites. Application of the method in rats and laying hens demonstrated its robustness for pharmacokinetic profiling and cross-species validation, revealing a triphasic metabolic pattern of ICQA, the consistent metabolic endpoints of the accumulation of microbial metabolites, and a critical role of gut microbiota in ICQA metabolism. The developed platform provides a reliable analytical tool for comprehensive metabolism studies of phenolic compounds, with high throughput and reproducibility.