A HPLC–MS/MS method for the simultaneous quantitation of six alkaloids of Rhizoma Corydalis Decumbentis in rat plasma and its application to a pharmacokinetic study

Protoberberine alkaloids: A review of the gastroprotective effects, pharmacokinetics, and toxicity

BACKGROUND

Stomach diseases have become global health concerns. Protoberberine alkaloids (PBAs) are a group of quaternary isoquinoline alkaloids from abundant natural sources and have been shown to improve gastric disorders in preclinical and clinical studies. The finding that PBAs exhibit low oral bioavailability but potent pharmacological activity has attracted great interest.

PURPOSE

This review aims to provide a systematic review of the molecular mechanisms of PBAs in the treatment of gastric disorders and to discuss the current understanding of the pharmacokinetics and toxicity of PBAs.

METHODS

The articles related to PBAs were collected from the Web of Science, Pubmed, and China National Knowledge Infrastructure databases using relevant keywords. The collected articles were screened and categorized according to their research content to focus on the gastroprotective effects, pharmacokinetics, and toxicity of PBAs.

RESULTS

Based on the results of preclinical studies, PBAs have demonstrated therapeutic effects on chronic atrophic gastritis and gastric cancer by activating interleukin-4 (IL-4)/signal transducer and activator of transcription 6 (STAT6) pathway and suppressing transforming growth factor-beta 1 (TGF-β1)/phosphoinositide 3-kinase (PI3K), Janus kinase-2 (JAK2)/signal transducers and activators of transcription 3 (STAT3), and mitogen-activated protein kinase (MAPK) pathways. The major PBAs exhibit similar pharmacokinetic properties, including rapid absorption, slow elimination, and low bioavailability. Notably, the natural organ-targeting property of PBAs may account for the finding of their low blood levels and high pharmacological activity. PBAs interact with other compounds, including conventional drugs and natural products, by modulation of metabolic enzymes and transporters. The potential tissue toxicity of PBAs should be emphasized due to their high tissue accumulation.

CONCLUSION

This review highlights the gastroprotective effects, pharmacokinetics, and toxicity of PBAs and will contribute to the evaluation of drug properties and clinical translational studies of PBAs, accelerating their transfer from the laboratory to the bedside.

Pharmacokinetics, tissue distribution, and plasma protein binding ratio of bicuculline following intragastric and intravenous administration in rats using ultra-high-performance liquid chromatography-tandem mass spectrometry

Bicuculline is a natural isoquinoline alkaloid that works as a gamma-aminobutyric acid receptor antagonist. It is widely found in Papaveraceae plants used in traditional Chinese medicines. Bicuculline not only has been shown to have favorable analgesic, memory-improving, and anxiolytic effects but may also cause adverse effects such as convulsions and epilepsy. A simple, rapid, and sensitive method was developed and validated for the determination of bicuculline in the plasma and tissue samples in rats by ultra-high-performance liquid chromatography-tandem mass spectrometry (MS/MS). The chromatographic separation was performed on a Thermo Scientific C18 column. The MS/MS system was operated in the positive multiple reaction monitoring mode, and the precursor-product ion transitions were optimized as m/z 368.0 → 307.1 for bicuculline and as 354.1 → 188.1 for protopine (internal standard). The linearity, accuracy, precision, recovery, and matrix effect were within acceptable limits. The experimental data showed that bicuculline was rapidly absorbed and eliminated in rats, with a moderate plasma protein binding ratio and low bioavailability. The main tissues of distribution were the kidney, liver, and brain; bicuculline could exert its pharmacological effects across the blood-brain barrier. This study has positive implications for the clinical use of herbal medicines containing bicuculline and for further development.

Simultaneous qualitative and quantitative analysis of eight alkaloids in Corydalis Decumbentis Rhizoma (Xiatianwu) and Corydalis Rhizoma (Yanhusuo) by HPLC and high-resolution MS combined with chemometric methods

In this study, we established a comprehensive high-performance liquid chromatography coupled with diode array detection and high-resolution mass spectrometry method to identify ten and quantified eight constituents in Corydalis Decumbentis Rhizoma ('Xiatianwu' in Chinese) and Corydalis Rhizoma ('Yanhusuo' in Chinese). Chemometric methods were applied to distinguish the botanical origins of the Xiatianwu and Yanhusuo samples. Chromatographic separation was achieved using an Agilent Poroshell EC-C₁₈ column with mobile phases A (1000 mL of 0.2% acetic acid solution containing 2.8 mL of triethylamine) and B (acetonitrile) and stepwise gradient elution. The analytical method was fully validated in terms of linearity, sensitivity, intra- and interday precision and repeatability, limit of detection, limit of quantitation and recovery. Twenty-six Xiatianwu samples and ten Yanhusuo samples were analysed for quality evaluation. In addition, hierarchical clustering analysis and principal component analysis were used to discriminate among samples of different botanical origins. The results showed that the contents of eight alkaloids in Xiatianwu and Yanhusuo were significantly different. Moreover, it was found that chemometric methods could be applied to accurately distinguish these two often conflated Chinese medicinal materials. In conclusion, this study provides a relatively comprehensive method for botanical origin identification and Xiatianwu and Yanhusuo quality control. This article is protected by copyright. All rights reserved.

An integrated strategy for the establishment of a protoberberine alkaloid profile: Exploration of the differences in composition between Tinosporae radix and Fibraurea caulis

INTRODUCTION

Accurate species and content identification of major active components in herbals are the guarantee of the safety and effectiveness for medical and commodity purposes.

OBJECTIVES

In this study, an integrated strategy used to establish the protoberberine alkaloid profile was applied to explore the differences in composition between the pieces of Tinosporae radix and Fibraurea caulis, both of which had morphological similarities.

MATERIALS AND METHODS

First, an in-house library including possible protoberberine alkaloids based on different substituents was predicted by systematic literature survey. Meanwhile, diagnostic fragments of protoberberine alkaloids were investigated using the corresponding standards. Second, ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) was used to obtain multidimensional mass spectral data. Then, the identifications were confirmed by targeted filter of the acquired data based on the library.

RESULTS

As a result, 10 protoberberine alkaloid molecules including 46 isomers were identified or characterised. The qualitative distribution and relative content of protoberberine alkaloids revealed the fundamental difference between Tinosporae radix and Fibraurea caulis. 25 alkaloids were present in both herbals, while five compounds were detected only in Tinosporae radix. Furthermore, the contents of four alkaloids in Tinosporae radix were significantly higher than those in its adulterant, Fibraurea caulis.

CONCLUSION

The five unique ingredients in Tinosporae radix can be used as a better indicator for distinguishing the pieces of Tinosporae radix and Fibraurea caulis. The protoberberine alkaloid profile established in this study can be applied to quality evaluation of the two herbals or other herbals containing major protoberberine alkaloids.

Screening of bioactive components from traditional Chinese medicine by immobilized β2 adrenergic receptor coupled with high performance liquid chromatography/mass spectrometry

Traditional Chinese medicine (TCM) represents a valuable resource for lead compounds discovery. Given the complexity of TCM components, analytical methods play a key role in novel drug development. In our study, we established a high specific and reliable bio-active components screen system, where β₂ adrenergic receptor (β₂-AR) was immobilized on silica by non-covalent bonds and packed into a stainless steel column (4.6 × 50 mm, 7 μm) to form β₂-AR chromatography column. The column was further coupled with high performance liquid chromatography-time of flight tandem mass spectrometry (TOF-MS/MS). By utilizing this strategy, we successfully identified four β₂-AR-targeting compounds: tetrahydroberberine, tetrahydrocolumbamine, fumarine and corydaline from Corydalis Rhizome. The association constants between β₂-AR and tetrahydroberberine (9.04 × 10⁴/M) as well as fumarine (4.30 × 10⁴/M) were determined by frontal chromatography. We also found that these two compounds shared the identical binding site on immobilized β₂-AR with corresponding concentrations of 6.67 × 10^-4 M and 5.88 × 10^-4 M, respectively. The newly established method represents an efficient tool to identify the target specific natural compounds.

Determination of armepavine in mouse blood by UPLC-MS/MS and its application to pharmacokinetic study

The purpose of this study was to develop an ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method to determine armepavine in mouse blood. Nuciferine was used as internal standard. Chromatographic separation was performed on a UPLC BEH (2.1 × 50 mm, 1.7 μm) column with a gradient elution of acetonitrile and 10 mmol/L ammonium acetate solution (containing 0.1% formic acid). The quantitative analysis was conducted in multiple reaction monitoring mode with m/z 314.1 → 106.9 for armepavine and m/z 296.2 → 265.1 for nuciferine. Calibration curves were linear (r > 0.995) over the concentration range 1-1000 ng/mL in mouse blood with a lowest limit of quantitation of 1 ng/mL. The intra- and inter-day precisions of armepavine in mouse were < 13.5 and 10.8%, respectively. The accuracy ranged between 86.8 and 103.3%. Meanwhile, the average recovery was >70.7% and the matrix effect was within the range 109.5-113.7%. All of the obtained data confirmed the satisfactory sensitivity and selectivity of the developed method which was then successfully applied to evaluate the pharmacokinetic behavior of armepavine in mouse for the first time. The bioavailability of armepavine in mouse was calculated to be 11.3%.

Comparative study on alkaloids and their anti-proliferative activities from three Zanthoxylum species

Background

Alkaloids have been considered as the most promising bioactive ingredients in plant species from the genus Zanthoxylum. This study reports on the compositions and contents of the Zanthoxylum alkaloids (ZAs) from three Zanthoxylum species, and their potential anti-proliferation activities.

Methods

An HPLC-UV/ESI-MS/MS method was established and employed to analyze the alkaloids in different Zanthoxylum extracts. The common and unique peaks and their relative contents were summarized and compared to evaluate the similarity and dissimilarity of the three Zanthoxylum species. Meanwhile, inhibitory activity tests to four carcinoma cell lines, i.e., stomach tumor cells (SGC-7901), cervical tumor cells (Hela), colon tumor cells (HT-29) and Hepatic tumor cells (Hep G2), were carried out in vitro to evaluate the bioactivities of the ZAs.

Results

Seventy peaks were detected in the crude total alkaloid samples, and 58 of them were identified. As a result, 13 common peaks were found in the extracts of all the three Zanthoxylum species, while some unique peaks were also observed in specific species, with 17 peaks in Z. simulans, 15 peaks in Z. ailanthoides and 11 peaks in Z. chalybeum, respectively. The comparison of the composition and relative contents indicated that alkaloids of benzophenanthridine type commonly present in all the three Zanthoxylum species with high relative contents among the others, which are 60.52% in Z. ailanthoides, 30.52% in Z. simulans and 13.84% in Z. chalybeum, respectively. In terms of activity test, Most of the crude alkaloids extracts showed remarkable inhibitory activities against various tumor cells, and the inhibitory rates ranged from 60.71 to 93.63% at a concentration of 200 μg/mL. However, SGC-7901 cells seemed to be more sensitive to the ZAs than the other three cancer cells.

Conclusion

The alkaloid profiles detected in this work revealed significant differences in both structures and contents among Zanthoxylum species. The inhibitory rates for different cancer cells in this study indicated that the potential anti-cancer activity should be attributed to quaternary alkaloids in these three species, which will provide great guidance for further exploring this traditional medicinal resource as new healthcare products.

Development and validation of a high performance liquid chromatography quantification method of levo-tetrahydropalmatine and its metabolites in plasma and brain tissues: application to a pharmacokinetic study

Levo-tetrahydropalmatine (l-THP) is an alkaloid isolated from Chinese medicinal herbs of the Corydalis and Stephania genera. It has been used in China for more than 40 years mainly as an analgesic with sedative/hypnotic effects. Despite its extensive use, its metabolism has not been quantitatively studied, nor there a sensitive reliable bioanalytical method for its quantification simultaneously with its metabolites. As such, the objective of this study was to develop and validate a sensitive and selective HPLC method for simultaneous quantification of l-THP and its desmethyl metabolites l-corydalmine (l-CD) and l-corypalmine (l-CP) in rat plasma and brain tissues. Rat plasma and brain samples were processed by liquid-liquid extraction using ethyl acetate. Chromatographic separation was achieved on a reversed-phase Symmetry® C18 column (4.6 × 150 mm, 5 μm) at 25°C. The mobile phase consisted of acetonitrile-methanol-10 mm ammonium phosphate (pH 3) (10:30:60, v/v) and was used at a flow rate of 0.8 mL/min. The column eluent was monitored at excitation and emission wavelengths of 230 and 315 nm, respectively. The calibration curves were linear over the concentration range of 1-10,000 ng/mL. The intra- and interday reproducibility studies demonstrated accuracy and precision within the acceptance criteria of bioanalytical guidelines. The validated HPLC method was successfully applied to analyze samples from a pharmacokinetic study of l-THP in rats. Taken together, the developed method can be applied for bioanalysis of l-THP and its metabolites in rodents and potentially can be transferred for bioanalysis of human samples.

Quantification of permanent positively charged compounds in plasma using one-step dilution to reduce matrix effect in MS

Background: Bioanalysis of conventional methods for compounds with permanent positive charge leads to peak tailing in separation and matrix effects in MS. This study describes a novel, rapid and sensitive method for quinolinium-containing compounds quantification. Results & methodology: A charged surface hybrid chromatography-tandem MS/MS using one-step protein precipitation dilution technique has been developed for determining analytes in plasma. We found symmetric peak and high recoveries for the analytes without matrix effect. All calibration curves had good linearity (r 0.991). The intra- and inter-assay precision was within 15% and the accuracy ranged from 88 to 103%. The method has been successfully applied to the PK study. Conclusion: The proposed method was sensitive, reproducible and applicable to other permanent positively charged compounds.

The influence of compatibility of processed radix Aconiti Kusnezoffii on the pharmacokinetic of four components in Glycyrrhiza uralensis Fisch

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza uralensis Fisch. and processed radix Aconiti kusnezoffii are the main components in many Chinese traditional patent medicines with the ratio of 1:1, which are used for treatment of rheumatoid arthritis, heart failure and so on. Glycyrrhizic acid, glycyrrhetic acid, liquiritigenin and isoliquiritigenin are the essential bioactive triterpenes and flavones in the extract of G. uralensis, which were analysis by a simple but accurate method.

MATERIALS AND METHODS

In the present study, a specific HPLC method was developed and validated for simultaneous determination of pharmacokinetic parameters of glycyrrhizic acid, glycyrrhetic acid, liquiritigenin and isoliquiritigenin in G. uralensis after oral administration of single herb extract and a combination of two herbs extracts respectively.

RESULTS

The calibration curves of the four components had good linearity higher than 0.9991 in the measured range. The intra-day and inter-day precisions (RSD) at different levels were both within 9.73%, and the accuracies (RE) were in the range of -7.9-8.0%. Compared with pharmacokinetic parameters of G. uralensis administered orally, values of AUC and Cmax of liquiritigenin and isoliquiritigenin decreased significantly (p<0.05), plasma concentrations of glycyrrhizic acid rose slightly and bimodal phenomenon of concentration-time of isoliquiritigenin and glycyrrhetinic acid disappeared after combined administration.

DISCUSSION AND CONCLUSIONS

Some components in the extract of processed radix A. kusnezoffii showed different effects on the pharmacokinetics of the four ingredients in G. uralensis.