In vitro metabolism of corydaline in human liver microsomes and hepatocytes using liquid chromatography-ion trap mass spectrometry

Rapid analysis of components in Qizhiweitong tablets and plasma after oral administration in rats by UPLC-Q-TOF-MS/MS based on self-developed database

Qizhiweitong is a famous traditional Chinese prescription medicine. It has been used to treat various stomach disorders, such as functional dyspepsia, chronic gastritis, and intestinal stress syndrome for a long time and gives favorable therapeutic effects in clinical settings. However, its chemical composition and possible bioactive components are not completely known. In the present study, we used ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS) and qualitatively analyzed the chemical composition of Qizhiweitong tablet extract and the absorbed prototype constituents along with corresponding metabolites in rat plasma following oral administration of Qizhiweitong tablet on the basis of our self-developed component database that was established accurately and rapidly. We detected a total of 119 compounds and 61 xenobiotics in the Qizhiweitong tablet, which included 32 prototypes and 28 metabolites. The results of the present study laid a solid foundation for quality marker screening and integrative pharmacology-based study on the Qizhiweitong tablet.

Integrated Strategy From In Vitro, In Situ, In Vivo to In Silico for Predicting Active Constituents and Exploring Molecular Mechanisms of Tongfengding Capsule for Treating Gout by Inhibiting Inflammatory Responses

The study of screening active constituents from traditional Chinese medicine (TCM) is important for explicating the mechanism of action of TCM and further evaluating the safety and efficacy effectively. However, detecting and identifying the active constituents from complicated biological samples still remain a challenge. Here, a practical, quick, and novel integrated strategy from in vitro, in situ, in vivo to in silico for rapidly screening the active constituents was developed. Firstly, the chemical profile of TCM in vitro was identified using UPLC-Q Exactive-Orbitrap HRMS. Secondly, the in situ intestinal perfusion with venous sampling (IPVS) method was used to investigate the intestinal absorption components. Thirdly, after intragastric administration of the TCM extract, the in vivo absorbed prototype components were detected and identified. Finally, the target network pharmacology approach was applied to explore the potential targets and possible mechanisms of the absorbed components from TCM. The reliability and availability of this approach was demonstrated using Tongfengding capsule (TFDC) as an example of herbal medicine. A total of 141 compounds were detected and identified in TFDC, and among them, 64 components were absorbed into the plasma. Then, a total of 35 absorbed bioactive components and 50 related targets shared commonly by compounds and gout were integrated via target network pharmacology analysis. Ultimately, the effects of the absorbed components on metabolism pathways were verified by experiments. These results demonstrated that this original method may provide a practical tool for screening bioactive compounds from TCM treating particular diseases. Furthermore, it also can clarify the potential mechanism of action of TCM and rationalize the application of TFDC as an effective herbal therapy for gout.

The Analgesic Properties of Corydalis yanhusuo

Corydalis yanhusuo extract (YHS) has been used for centuries across Asia for pain relief. The extract is made up of more than 160 compounds and has been identified as alkaloids, organic acids, volatile oils, amino acids, alcohols, and sugars. However, the most crucial biological active constituents of YHS are alkaloids; more than 80 have been isolated and identified. This review paper aims to provide a comprehensive review of the phytochemical and pharmacological effects of these alkaloids that have significant ties to analgesia.

In vivo and in vitro metabolism study of traditional Chinese medicine formula Dingkun Dan in rats by using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Dingkun Dan (DKD), a reputable traditional Chinese medicine formula, has been used to treat gynecological diseases and showed significant clinical effects since ancient times. However, the application and development of DKD are seriously hampered by the unclear active substances. Structural characterization of compounds absorbed in vivo and their corresponding metabolites is significant for clarifying the pharmacodynamic material basis. In this study, an integrated strategy using ultra-performance liquid chromatography, coupled with quadrupole time-of-flight mass spectrometry and UNIFI™ software, was used to identify prototypes and metabolites after oral administration of DKD in rats. As a result, a total of 261 compounds, including 140 prototypes and 121 metabolites, were tentatively characterized in rat plasma, urine, and feces. The metabolic pathways of prototypes have been studied to clarify their possible transformation process in vivo. Moreover, an in vitro metabolism study was applied for verifying the metabolites under simulating the metabolic environment in vivo. This first systematic metabolic study of DKD is important for elucidating the metabolites and metabolic pathways and could provide a scientific basis for explaining the integrative mechanism in further pharmacology study.

Identification and characterization of plant-derived alkaloids, corydine and corydaline, as novel mu opioid receptor agonists

Pain remains a key therapeutic area with intensive efforts directed toward finding effective and safer analgesics in light of the ongoing opioid crisis. Amongst the neurotransmitter systems involved in pain perception and modulation, the mu-opioid receptor (MOR), a G protein-coupled receptor, represents one of the most important targets for achieving effective pain relief. Most clinically used opioid analgesics are agonists to the MOR, but they can also cause severe side effects. Medicinal plants represent important sources of new drug candidates, with morphine and its semisynthetic analogues as well-known examples as analgesic drugs. In this study, combining in silico (pharmacophore-based virtual screening and docking) and pharmacological (in vitro binding and functional assays, and behavioral tests) approaches, we report on the discovery of two naturally occurring plant alkaloids, corydine and corydaline, as new MOR agonists that produce antinociceptive effects in mice after subcutaneous administration via a MOR-dependent mechanism. Furthermore, corydine and corydaline were identified as G protein-biased agonists to the MOR without inducing β-arrestin2 recruitment upon receptor activation. Thus, these new scaffolds represent valuable starting points for future chemical optimization towards the development of novel opioid analgesics, which may exhibit improved therapeutic profiles.

Corydalis Rhizoma as a model for herb-derived trace metabolites exploration: A cross-mapping strategy involving multiple doses and samples

Deciphering the metabolites of multiple components in herbal medicine has far-reaching significance for revealing pharmacodynamic ingredients. However, most chemical components of herbal medicine are secondary metabolites with low content whose in vivo metabolites are close to trace amounts, making it difficult to achieve comprehensive detection and identification. In this paper, an efficient strategy was proposed: herb-derived metabolites were predicted according to the structural characteristics and metabolic reactions of chemical constituents in Corydalis Rhizoma and chemical structure screening tables for metabolites were conducted. The fragmentation patterns were summarized from representative standards combining with specific cleavage behaviors to deduce structures of metabolites. Ion abundance plays an important role in compound identification, and high ion abundance can improve identification accuracy. The types of metabolites in different biological samples were very similar, but their ion abundance might be different. Therefore, for trace metabolites in biological samples, we used the following two methods to process: metabolites of high dose herbal extract were analyzed to characterize those of clinical dose herbal extracts in the same biological samples; cross-mapping of different biological samples was applied to identify trace metabolites based on the fact that a metabolite has different ion abundance in different biological samples. Compared with not using this strategy, 44 more metabolites of clinical dose herbal extract were detected. This study improved the depth, breadth, and accuracy of current methods for herb-derived metabolites characterization.

Pharmacokinetic parameters explain the therapeutic activity of antimicrobial agents in a silkworm infection model

Poor pharmacokinetic parameters are a major reason for the lack of therapeutic activity of some drug candidates. Determining the pharmacokinetic parameters of drug candidates at an early stage of development requires an inexpensive animal model with few associated ethical issues. In this study, we used the silkworm infection model to perform structure-activity relationship studies of an antimicrobial agent, GPI0039, a novel nitrofuran dichloro-benzyl ester, and successfully identified compound 5, a nitrothiophene dichloro-benzyl ester, as a potent antimicrobial agent with superior therapeutic activity in the silkworm infection model. Further, we compared the pharmacokinetic parameters of compound 5 with a nitrothiophene benzyl ester lacking chlorine, compound 7, that exerted similar antimicrobial activity but had less therapeutic activity in silkworms, and examined the metabolism of these antimicrobial agents in human liver fractions in vitro. Compound 5 had appropriate pharmacokinetic parameters, such as an adequate half-life, slow clearance, large area under the curve, low volume of distribution, and long mean residence time, compared with compound 7, and was slowly metabolized by human liver fractions. These findings suggest that the therapeutic effectiveness of an antimicrobial agent in the silkworms reflects appropriate pharmacokinetic properties.

Metabolic profiles of corydaline in rats by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

1. Corydaline, an isoquinoline alkaloid obtained from the rhizomes of Corydalis yanhusuo, exhibits anti-acetylcholinesterase, anti-angiogenic, anti-allergic and gastric-emptying activities. In this study, a rapid and reliable ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) method was developed and employed for the comprehensive study of the metabolites of corydaline in rats. 2. Altogether, 43 metabolites were identified in the plasma (11), bile (9), urine (34) and feces (21) of rats after oral administration of corydaline at a dose of 4.5mg/kg. 3. It was demonstrated that demethylation, hydroxylation, sulfation and glucuronidation were the major metabolic transformation pathways. Among these, two metabolites were identified as tetrahydropalmatine and isocorybulbine, and 33 phase I and phase II products were inferred to be new metabolites arising from the in vivo metabolism of corydaline. 4. Importantly, this research provides scientific and reliable support for full understanding of the metabolic profiles of corydaline and the results could help to elucidate its safety and efficacy.

In-vivo absorption of pinocembrin-7-O-β-D-glucoside in rats and its in-vitro biotransformation

Pinocembrin-7-O-β-D-glucoside (PCBG), a flavonoid isolated from Penthorum chinense Pursh., has significant liver-protecting effects. The pharmacokinetics of PCBG and its major metabolite pinocembrin (PCB) in rats were investigated in this study. A sensitive and accurate UPLC-MS/MS method was developed and validated for the simultaneous quantitative determination of PCBG and PCB in rat plasma after oral and intravenous administration of PCBG. After intravenous administration, PCBG was the main form in plasma. In contrast, after oral administration, the concentration of PCB was about 4-fold higher than that of PCBG, indicating that PCBG was metabolized to PCB. We also investigated the biotransformation of PCBG in vitro in order to understand whether the pH and the intestinal flora of gastrointestinal tract could affect the metabolism of PCBG. PCBG was incubated in rat plasma, liver homogenization, gastrointestial contents, liver microsomes (RLM) and hepatocytes in vitro. The data showed that PCB was quickly formed in the gastrointestinal incubation but PCBG was converted to PCB gradually in other incubations. The results indicated that the majority of PCBG was converted to its aglycone PCB in digestive system after oral administration, and PCB could be the active ingredient in the body.

Pharmacokinetics of chlorogenic acid and corydaline in DA-9701, a new botanical gastroprokinetic agent, in rats

1.Few studies describing the pharmacokinetic properties of chlorogenic acid (CA) and corydaline (CRD) which are marker compounds of a new prokinetic botanical agent, DA-9701, have been reported. The aim of the present study is to evaluate the pharmacokinetic properties CA and CRD following intravenous and oral administration of pure CA (1-8 mg/kg) or CRD (1.1-4.5 mg/kg) and their equivalent dose of DA-9701 to rats. 2.  Dose-proportional AUC and dose-independent clearance (10.3-12.1 ml/min/kg) of CA were observed following its administration. Oral administration of CA as DA-9701 did not influence the oral pharmacokinetic parameters of CA. Incomplete absorption of CA, its decomposition in the gastrointestinal tract, and/or pre-systemic metabolism resulted in extremely low oral bioavailability (F) of CA (0.478-0.899%). 3.  CRD showed greater dose-normalized AUC in the higher dose group than that in lower dose group(s) after its administration due to saturation of its metabolism via decreased non-renal clearance (by 51.3%) and first-pass extraction. As a result, the F of CRD following 4.5 mg/kg oral CRD (21.1%) was considerably greater than those of the lower dose groups (9.10 and 13.8%). However, oral administration of CRD as DA-9701 showed linear pharmacokinetics as a result of increased AUC and F in lower-dose groups (by 182% and 78.5%, respectively) compared to those of pure CRD. The greater oral AUC of CRD for DA-9701 than for pure CRD could be due to decreased hepatic and/or GI first-pass extraction of CRD by other components in DA-9701.

Preclinical pharmacokinetics, tissue distribution and excretion studies of a potential analgesics - corydaline using an ultra performance liquid chromatography-tandem mass spectrometry

A rapid resolution ultra performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) mass spectrometry method was developed and validated for the quantitative analysis of corydaline in rats' plasma and various tissues for pharmacokinetic, tissue distribution and excretion studies of corydaline. The analytes were separated on an Acquity UPLC BEH C18 column (2.1mm×100mm, 1.7μm) and detected with a triple quadrupole mass spectrometer using positive ion ESI in the multiple reaction monitoring (MRM) mode. The MS/MS ion transitions monitored were m/z 370.0→192.0 for corydaline and 354.1→188.0 for IS, respectively. Calibration curves (1/x(2) weighted) offered satisfactory linearity (r(2)>0.9984) within 1-1000ng/mL. The accuracy and precision ranged from -7.4% to 8.5% and 3.4% to 12.8%, respectively. The absolute matrix effect (94.2-119.2%), relative matrix effect (1.7-9.6%) and recoveries (81.4-93.7%) were satisfactory in all the biological matrices examined. The assay was successfully applied to the plasma pharmacokinetics, tissue distribution and excretion studies of corydaline in rats. The pharmacokinetic parameters such as half-life (t1/2), mean residence time (MRT) and maximum concentration (Cmax) were determined. These preclinical data of corydaline would be useful for the clinical reference.