Online polar two phase countercurrent chromatography×high performance liquid chromatography for preparative isolation of polar polyphenols from tea extract in a single step.

Herein, we report an on-line two-dimensional system constructed by counter-current chromatography (CCC) coupling with preparative high-performance liquid chromatography (prep-HPLC) for the separation and purification of polar natural products. The CCC was used as the first dimensional isolation column, where an environmental friendly polar two-phase solvent system of isopropanol and 16% sodium chloride aqueous solution (1:1.2, v/v) was introduced for low toxicity and favorable resolution. In addition, by applying the stop-and-go flow technique, effluents pre-fractionated by CCC was further purified by a preparative column packed with octadecyl silane (ODS) as the second dimension. The interface between the two dimensions was comprised of a 6-port switching valve and an electronically controlled 2-position 10-port switching valve connected with two equivalent holding columns. To be highlighted here, this rationally designed interface for the purpose of smooth desalination, absorption and desorption, successfully solved the solvent compatibility problem between the two dimensional separation systems. The present integrated system was successfully applied in a one-step preparative separation and identification of 10 pure compounds from the water extracts of Tieguanyin tea (Chinese oolong tea). In short, all the results demonstrated that the on-line 2D CCC×LC method is an efficient and green approach for harvesting polar targets in a single step, which showed great promise in drug discovery.

Comparative pharmacokinetics of naringin in rat after oral administration of chaihu-shu-gan-san aqueous extract and naringin alone.

Chaihu-Shu-Gan-San (CSGS), a traditional Chinese medicine (TCM) formula containing seven herbal medicines, has been used in the clinical treatment of gastritis, peptic ulcer, irritable bowel syndrome and depression in China. In order to explore the interaction between naringin and other constituents in CSGS, the pharmacokinetic difference of naringin in rats after oral administration of CSGS aqueous extract and naringin alone was investigated. The pharmacokinetic parameters of naringin in rats were achieved by quantification of its aglycone, naringenin by LC-MS/MS method. The double peaks phenomenon was observed in both serum profiles of rats after orally administered CSGS aqueous extract and naringin alone. However, the T1/2b was significantly decreased in rats given CSGS aqueous extract compared with naringin alone, and the mean residence time (MRT) and the area under the serum concentration-time curve (AUC0-τ) were higher than those of naringin, which indicated that naringin in CSGS had higher bioavailability, longer term efficacy and somewhat faster metabolism and excretion than those of naringin. The results suggested that certain ingredients co-exist in CSGS could influence pharmacokinetic behavior of naringin. This also provides a reference for human studies.

Urinary metabonomics study of anti-depressive effect of Chaihu-Shu-Gan-San on an experimental model of depression induced by chronic variable stress in rats.

Chaihu-Shu-Gan-San (CSGS), a traditional Chinese medicine (TCM) formula, has been effectively used for the treatment of depression in clinic. However, studies of its anti-depressive mechanism are challenging, accounted for the complex pathophysiology of depression, and complexity of CSGS with multiple constituents acting on different metabolic pathways. The variations of endogenous metabolites in rat model of depression after administration of CSGS may offer deeper insights into the anti-depressive effect and mechanism of CSGS. In this study, metabonomics based on ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to profile the metabolic fingerprints of urine obtained from chronic variable stress (CVS)-induced depression model in rats with and without CSGS treatment. Through partial least squares-discriminate analysis, it was observed that metabolic perturbations induced by chronic variable stress were restored in a time-dependent pattern after treatment with CSGS. Metabolites with significant changes induced by CVS, including 3-O-methyldopa (1), pantothenic acid (2), kynurenic acid (3), xanthurenic acid (4), 2,8-dihydroxyquinoline glucuronide (5), 5-hydroxy-6-methoxyindole glucurnoide (8), l-phenylalanyl-l-hydroxyproline (9), indole-3-carboxylic acid (10), proline (11), and the unidentified metabolites (6, 2.11min_m/z 217.0940; 7, 2.11min_m/z 144.0799), were characterized as potential biomarkers involved in the pathogenesis of depression. The derivations of all those biomarkers can be regulated by CSGS treatment except indole-3-carboxylic acid (10), which suggested that the therapeutic effect of CSGS on depression may involve in regulating the dysfunctions of energy metabolism, tryptophan metabolism, bone loss and liver detoxification. This study indicated that the rapid and noninvasive urinary metabonomics approach may be a powerful tool to study the efficacy and mechanism of complex TCM prescriptions.