No abstract

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.

Aurantio-obtusin (AO) is a major anthraquinone compound isolated from Cassiae Semen or Duhaldea nervosa, which possesses diverse pharmacological effects. Previous studies have shown that it has a good effect on lowering blood lipids and treating various diseases. A few studies have also reported about its metabolites. A rapid and reliable method using ultra-high-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry and multiple data-processing technologies was established to investigate the metabolites of AO in the plasma and various tissues of rats, including the heart, liver, spleen, lung, kidneys, and brain. Finally, a total of 36 metabolites were identified in the plasma of rats, which could be very beneficial for understanding the effective form of AO metabolites leading to new drug discovery. The result demonstrated that this strategy, especially parallel reaction monitoring, has shown a wide range of applications in the identification of metabolites.

The purpose of this study is to identify and quantify the chlorogenic acids (CGAs) from the root bark of Acanthopanax gracilistylus , which is conventionally regarded as a tonic in folk Chinese Traditional medicine. The effective methods for identification and quantification analysis of CGAs were developed based on ultra high performance liquid chromatography-Q-exactive orbitrap mass spectrometry (UHPLC-Q-Orbitrap MS) in parallel reaction monitoring (PRM) and selected reaction monitoring (SIM), which showed high sensitivity and resolution for screening and quantifying compounds. The root bark of A. gracilistylus was extracted under ultrasonication with 70% methanol. Ultimately, a for total of 70 CGAs, 64 of these were tentatively identified for the first time. Moreover, a methodological study of seven kinds of CGAs was carried out. The proposed procedure was optimized and validated in terms of selectivity, linearity of analytical curves ( r 2 > 0.990), accuracy (recovery range from 96.7 to 105%), and repeatability (relative standard deviation <5%). Then it was applied to determine the content of the CGAs in A. gracilistylus roots from 66 of different batches. The total CGAs was quantified in a range between 2.150 and 33.51 mg/g, which could be considered as excellent source of natural bioactive compound. The result was extremely useful for understanding the bioactive substance and quality control of A. gracilistylus in depth.

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.