Identification of the metabolites of isochlorogenic acid A in rats by UHPLC-Q-Exactive Orbitrap MS.

CONTENT: Isochlorogenic acid A, one of the main components of Duhaldea nervosa (Wallich ex Candolle) A. Anderberg (Asteraceae), is a folk medicine used to treat a variety of diseases including fracture and rheumatoid arthritis. Despite its widespread use, the metabolism of isochlorogenic acid A in vivo has not been fully studied. OBJECTIVE: An analytical strategy based on UHPLC-Q-Exactive Orbitrap MS is proposed for the detection and identification of the metabolites of isochlorogenic acid A in rats. MATERIALS AND METHODS: Six male Sprague-Dawley rats (180 ± 20 g) were randomly divided into two groups. Then, blood and tissue samples were obtained after oral administration of isochlorogenic acid A (200 mg/kg). All the samples were pre-treated by the Solid Phase Extraction (SPE) method. Next, the samples were analysed by UHPLC-Q-Exactive Orbitrap MS. Finally, the metabolites were identified based on the metabolomic workflow template. RESULTS: A total of 33 metabolites were identified in rat plasma, with 30 of them being reported for the first time. The distribution of all metabolites in tissues was first investigated, three of them were widely distributed in liver, lungs, and kidneys. The corresponding reactions including methylation, hydrolysis, sulphate conjugation, glucuronide conjugation, as well as their composite reactions, are reported in this study. DISCUSSION AND CONCLUSIONS: This method has wide-scale application prospects in the identification of metabolites. Considering that limited research has been conducted in this area, this study proposes metabolic pathways to further understand mechanisms of isochlorogenic acid A and the forms that are truly effective in vivo.

Identification of the Constituents of Percutaneous Absorption from Duhaldea nervosa Based on UHPLC-Q-Exactive Orbitrap MS and Microdialysis Technique.

Duhaldea nervosa (D. nervosa) has been used for treatment of bone fracture by external use. Thus, the percutaneous absorption was crucial to the effect of D. nervosa, especially the constituents of percutaneous absorption. However, the constituents in vivo were never investigated to date. In this study, an efficient method was developed for the identification of constituents of percutaneous absorption using UHPLC-Q-Exactive Orbitrap MS and microdialysis technique. A total of 20 constituents including 15 chlorogenic acid analogues, 3 amino acids, and 2 organic acids were unambiguously or tentatively identified based on high-resolution mass data including MS and MS2, chromatography retention time, and bibliography data. To the best of our knowledge, this is the first study to report the constituents of percutaneous absorption from D. nervosa, which will be very helpful for understanding the bioactive compounds and quality control.