Absorption and interaction of the main constituents from the traditional Chinese drug pair Shaoyao-Gancao via a Caco-2 cell monolayer model

Advances in flavonoid bioactivity in chronic diseases and bioavailability: transporters and enzymes

Flavonoids, abundant in the human diet, have been extensively studied for their therapeutic bioactivities. Recent research has made significantly advances in our understanding of the biological activities of flavonoids, demonstrating their therapeutic effects for various chronic diseases. However, the generally low bioavailability of flavonoids limits their effectiveness. Therefore, it is essential to explore the pharmacokinetics of flavonoids, paying particular attention to the roles of transporters and metabolizing enzymes. This paper reviews recent studies on the bioactivity of flavonoids, highlighting the importance of transporters and metabolic enzymes in their pharmacokinetics.

Pharmacokinetics and tissue distribution of 12 major active components in normal and chronic gastritis rats after oral administration of Weikangling capsules

ETHNOPHARMACOLOGICAL RELEVANCE

Weikangling Capsules (WKLCs) have been used in the clinic for the treatment of gastrointestinal disorders for more than 30 years. However, the pharmacokinetic characteristics and tissue distribution of its major bioactive components in rats under different physiological and pathological conditions are unclear.

AIM OF THE STUDY

In this study, we aimed to clarify the differences in pharmacokinetic parameters and tissue distribution of the major active components in WKLCs under physiological and pathological states.

MATERIALS AND METHOD

Normal and ethanol-induced chronic gastritis rats received 2.16 g/kg WKLCs by gavage, and urine, feces, plasma, and tissue (heart, liver, spleen, lung, kidney, stomach, and small intestine) samples were obtained. The active components in urine, feces and plasma were detected by ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). A rapid and sensitive analytical method, ultra-high-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS), was established and validated to clarify and compare the pharmacokinetics and tissue distribution of the major active components in normal and chronic gastritis rats.

RESULTS

A total of 36 chemical components in the feces, urine, and plasma of chronic gastritis rats were identified by UHPLC-Q-TOF-MS/MS. Among them, 20 were the prototype components of WKLCs, and 16 were metabolites. The pharmacokinetic characteristics and tissue distribution of 12 prototype components were successfully analyzed by UHPLC-QTRAP-MS/MS. The pharmacokinetic results showed that the C_max, AUC_0-t, and AUC_0-∞ of paeoniflorin, glycyrrhizic acid, and glycyrrhetinic acid were distinctly higher than those of the other components in normal and chronic gastritis rats. Compared to normal rats, the C_max, AUC_0-t, and AUC_0-∞ of albiflorin, liquiritin apioside, liquiritin, isoliquiritin, ononin, isoliquiritigenin, dactylorhin A, and glycyrrhizic acid were significantly increased in chronic gastritis rats (P < 0.05), while the C_max, AUC_0-t and AUC_0-∞ of militarine and liquiritigenin had significantly lower decreases in chronic gastritis rats (P < 0.05). The results of the tissue distribution showed that the 12 components were widely distributed in the heart, liver, spleen, lung, kidney, stomach, and small intestine of rats, of which the liver, kidney, stomach, and small intestine were the main accumulative organs. Compared with normal rats, the concentrations of 12 components in the liver, kidney, stomach, and small intestine of chronic gastritis rats were widely higher than those of normal rats at the same time points.

CONCLUSION

The pharmacokinetic characteristics and tissue distribution of 12 active components of WKLCs were comprehensively characterized and elucidated in normal and chronic gastritis rats. These findings laid a solid foundation for revealing the pharmacodynamic material basis of WKLCs in treating gastrointestinal disorders.

Quantification of Paeoniflorin by Fully Validated LC-MS/MS Method: Its Application to Pharmacokinetic Interaction between Paeoniflorin and Verapamil

A rapid, sensitive, and specific LC-MS/MS method was developed and fully validated for the detection of paeoniflorin only in rat plasma, and applied to pharmacokinetic studies, including intravenous, multi-dose oral and combined administrations with verapamil. In this study, tolbutamide was used as the internal standard, and the protein precipitation extraction method, using acetonitrile as the extraction agent, was used for the sample preparation. Subsequently, the supernatant samples were analyzed on a Phenomenex Gemini® NX-C18 column with a flow rate of 1.0 mL/min in a gradient elution procedure. In the extracted rat plasma, the method exhibited high sensitivity (LLOQ of 1.0 ng/mL) upon selecting ammonium adduct ions ([M+NH4]+) as the precursor ions and good linearity over the concentration range of 1.0−2000 ng/mL, with correlation coefficients >0.99. The intra- and inter-batch accuracy RE% values were within ±8.2%, and the precision RSD% values were ≤8.1% and ≤10.0%, respectively. The results show that the method can be successfully applied to quantitate paeoniflorin in biological samples. Additionally, paeoniflorin is subsequently confirmed to be the substrate of the P-gp transporter in vivo and in vitro for the first time, which would be necessary and beneficial to investigate the clinical safety and efficacy of PF with other drugs in the treatment of rheumatoid arthritis.

Pharmacological activities and pharmacokinetics of liquiritin: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Liquiritin is a flavonoid derived from Radix et Rhizoma Glycyrrhizae, which is a widely used traditional Chinese medicine with the effects of invigorating spleen qi, clearing heat, resolving toxins, and dispelling phlegm to stop coughs.

AIM OF THE STUDY

In this review,the pharmacokinetics and pharmacological activities of liquiritin have been summarized.

MATERIALS AND METHODS

The information on liquiritin up to 2021 was collected from PubMed, Web of Science, Springer Link, and China National Knowledge Infrastructure databases. The key words were "liquiritin", "nerve", "tumor", "cardiac", etc. RESULTS: The absorption mechanism of liquiritin conforms to the passive diffusion and first-order kinetics while with low bioavailability. Liquiritin can penetrate the blood-brain-barrier. Besides, liquiritin displays numerous pharmacological effects including anti-Alzheimer's disease, antidepressant, antitumor, anti-inflammatory, cardiovascular protection, antitussive, hepatoprotection, and skin protective effects. In addition, the novel preparations, new pharmacological effects,and cdusafty of liquiritin are also discussed in this review.

CONCLUSION

This review provides a comprehensive state of knowledge on the pharmacokinetics and pharmacological activities of liquiritin, and makes a forecast for its research directions and applications in clinic.

Impact of Drug Metabolism/Pharmacokinetics and their Relevance Upon Traditional Medicine-based anti-COVID-19 Drug Research

BACKGROUND

The representative anti-COVID-19 herbs, i.e. Poria cocos, Pogostemon, Prunus, and Glycyrrhiza plants, are commonly used in the prevention and treatment of COVID-19, a pandemic caused by SARS-CoV-2. Diverse medicinal compounds with favorable anti-COVID-19 activities are abundant in these plants, and their unique pharmacological/pharmacokinetic properties are being revealed. However, the current trends of drug metabolism/pharmacokinetic (DMPK) investigations of anti-COVID-19 herbs have not been systematically summarized.

METHODS

Here, the latest awareness, as well as the perception gaps of DMPK attributes, in the anti-COVID-19 drug development and clinical usage was elaborated and critically commented.

RESULTS

The extracts and compounds of P. cocos, Pogostemon, Prunus, and Glycyrrhiza plants show distinct and diverse absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. The complicated herb-herb interactions (HHIs) and herb-drug interactions (HDIs) of anti-COVID-19 Traditional Chinese Medicine (TCM) herb pair/formula dramatically influence the PK/pharmacodynamic (PD) performance of compounds thereof, which may inspire researchers to design innovative herbal/compound formulas for optimizing the therapeutic outcome of COVID-19 and related epidemic diseases. The ADME/T of some abundant compounds in anti-COVID-19 plants have been elucidated, but DMPK studies should be extended to more compounds of different medicinal parts, species and formulations, and would be facilitated by various omics platforms and computational analyses.

CONCLUSION

In the framework of systems pharmacology and pharmacophylogeny, the DMPK knowledge base would promote the translation of bench findings into the clinical practice of anti-COVID-19, and speed up the anti-COVID-19 drug discovery and development.

A comprehensive strategy to clarify the pharmacodynamic constituents and mechanism of Wu-tou decoction based on the constituents migrating to blood and their in vivo process under pathological state

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese medicine (TCM) formula, Wu-tou decoction has been used for treating rheumatoid arthritis (RA) for more than a thousand years. Identifying pharmacodynamic constituents (PCs) of WTD and exploring their in vivo process are very meaningful for promoting the modernization of TCM. However, the pathological state might change this process.

AIM OF THE STUDY

Hence, it is necessary and significant to compare the process in vivo of drugs both in normal and disease state and clarify their action mechanism.

MATERIALS AND METHODS

Taking Wu-tou decoction (WTD) as the research object, a comprehensive strategy based on liquid chromatography coupled with mass spectrometry (LC-MS) was developed to identify PCs, clarify and compare their absorption and distribution in normal and model rats, and then explore the potential mechanism of TCM. Firstly, the PCs in WTD were identified. Then, the pharmacokinetics (PK) and tissue distribution of these ingredients were studied. Finally, the constituents with the difference between normal and model rats were selected for target network pharmacological analysis to clarify the mechanism.

RESULTS

A total of 27 PCs of WTD were identified. The absorption and distribution of 20 PCs were successfully analyzed. In the disease state, the absorption and distribution of all these components were improved to have better treatment effects. The results of target network pharmacological analysis indicated that PTGS1, PTGS2, ABCB1, SLC6A4, CHRM2, ESR1, ESR2, CDK2, TNF and IL-6 are 10 key targets for WTD against RA. The regulatory effects of WTD on the expression of PTGS2 and TNF were further verified. Pathway enrichment analysis showed that the key mechanism of WTD against RA is to reduce inflammation and regulate the immune response.

CONCLUSION

These results indicated that this strategy could better understand the in vivo process and mechanism of WTD under the pathological state. Furthermore, this strategy is also appropriate for other TCM.

An Integrated Approach Exploring the Synergistic Mechanism of Herbal Pairs in a Botanical Dietary Supplement: A Case Study of a Liver Protection Health Food

Herbal pairs are used as a bridge between single herb and polyherbal formulas in Traditional Chinese Medicine (TCM) to provide rationale for complicated TCM formulas. The effectiveness and rationality of TCM herbal pairs have been widely applied as a strategy for dietary supplements. However, due to the complexity of the phytochemistry of individual and combinations of herbal materials, it is difficult to reveal their effective and synergistic mechanisms from a molecular or systematic point of view. In order to address this question, UPLC-Q-TOF/MS analysis and System Pharmacology tools were applied to explore the mechanism of action, using a White Peony (Paeoniae Radix Alba) and Licorice (Glycyrrhizae Radix et Rhizoma)-based dietary supplement. A total of sixteen chemical constituents of White Peony and Licorice were isolated and identified, which interact with 73 liver protection-related targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were then performed along with network analysis. Results showed that the synergistic mechanism of the White Peony and Licorice herbal pair was associated with their coregulation of bile secretion and ABC transporter pathways. In addition, Licorice exhibits a specific response to drug and xenobiotic metabolism pathways, whereas White Peony responds to Toll-like receptor signaling, C-type lectin receptor signaling, IL-17 signaling, and TNF signaling pathways, resulting in the prevention of hepatocyte apoptosis and the reduction of immune and inflammation-mediated liver damage. These findings suggest that a White Peony and Licorice herbal pair supplement would have a liver-protecting benefit through complimentary and synergistic mechanisms. This approach provides a new path to explore herbal compatibility in dietary supplements derived from TCM theory.

Effects of glycyrrhizin on the pharmacokinetics of paeoniflorin in rats and its potential mechanism

Context: Paeoniflorin is reported to possess numerous pharmacological activities. Paeoniflorin and glycyrrhizin are always used together for the treatment of disease in China clinics; however, the drug-drug interaction between glycyrrhizin and paeoniflorin is still unknown. Objective: This study investigates the effects of glycyrrhizin on the pharmacokinetics of paeoniflorin in rats. Materials and methods: The pharmacokinetics of orally administered paeoniflorin (20 mg/kg) with or without glycyrrhizin pre-treatment (at a dose of 100 mg/kg/day for 7 days) were investigated in male Sprague-Dawley rats using LC-MS/MS. Additionally, Caco-2 cell transwell model and rat liver microsome incubation experiments were also conducted to investigate its potential mechanism. Results: The results showed that when the rats were pre-treated with glycyrrhizin, the C_max of paeoniflorin decreased from 59.57 ± 10.24 to 45.36 ± 8.61 ng/mL, and AUC_0-inf also decreased from 282.02 ± 35.06 to 202.29 ± 28.28 μg·h/L. The t_1/2 value of paeoniflorin decreased from 8.48 ± 2.01 to 5.88 ± 1.15 h (p < 0.05). The Caco-2 cell transwell experiments indicated that glycyrrhizin could increase the efflux ratio of paeoniflorin from 2.71 to 3.52, and the rat liver microsome incubation experiments showed that glycyrrhizin could significantly increase its intrinsic clearance rate from 53.7 ± 4.6 to 85.6 ± 7.1 μL/min/mg protein. Conclusions: These results indicated that glycyrrhizin could affect the pharmacokinetics of paeoniflorin, and it might work through decreasing the absorption of paeoniflorin by inducing the activity of P-gp or through increasing the clearance rate in rat liver by inducing the activity of CYP450 enzyme.

Exploring the compatibility mechanism of ShengDiHuang Decoction based on the in situ single-pass intestinal perfusion model

Affecting the absorption of active ingredients in the intestine serves as one of the important compatibility mechanisms of traditional Chinese medicine. The aim of this study was to investigate the compatibility mechanism of ShengDiHuang Decoction (SDHD) by using the single-pass intestinal perfusion in situ model. The major effective ingredients, catalpol, aucubin, acteoside, rehmannioside D, rehmannioside A, rhein, aloe emodin, emodin, chrysophanol, and physcion, were determined by HPLC. By analysing the effects of different concentrations, different pH, intestinal segments, protein inhibitors, and tight junction regulators on SDHD absorption, it was found that catalpol, aucubin, rehmannioside D, rehmannioside A, acteoside, rhein, and chrysophanol may undergo active transport, while aloe-emodin and emodin may undergo passive transport. Catalpol, aucubin, and rehmannioside D may be substrates of BCRP and MRP2, while rehmannioside A and rhein may be substrates of BCRP, and acteoside and chrysophanol may be substrates of P-gp, BCRP and MRP2. By comparing the P_app values of the major effective ingredients between single herb and herb-pairs, the compatibility of rehmannia and rheum could significantly promote the absorption of components in rehmannia. It is verified that rheum has a synergistic effect on the absorption of rehmannia in SDHD.

The Regulatory Effects of Paeoniflorin and Its Derivative Paeoniflorin-6'-O-Benzene Sulfonate CP-25 on Inflammation and Immune Diseases

The plant extract "total glucosides of peony" (TGP) constitutes a mixture of glycosides that is isolated from the roots of the well-known traditional Chinese herb Paeonia lactiflora Pall. Paeoniflorin (Pae) is the most abundant component and the main biologically active ingredient of TGP. Pharmacologically, Pae exhibits powerful anti-inflammatory and immune regulatory effects in some animal models of autoimmune diseases including Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE). Recently, we modified Pae with an addition of benzene sulfonate to achieve better bioavailability and higher anti-inflammatory immune regulatory effects. This review summarizes the pharmacological activities of Pae and the novel anti-inflammatory and immunomodulatory agent Paeoniflorin-6'-O-benzenesulfonate (CP-25) in various chronic inflammatory and autoimmune disorders. The regulatory effects of Pae and CP-25 make them promising agents for other related diseases, which require extensive investigation in the future.

Gancao (Glycyrrhizae Radix) provides the main contribution to Shaoyao-Gancao decoction on enhancements of CYP3A4 and MDR1 expression via pregnane X receptor pathway in vitro

BACKGROUND

Chinese herbal formula Shaoyao Gancao decoction (SGD) is often used as an adjuvant with chemotherapeutic agents to treat cancer. Due to the herb-drug interactions, the alternations of drug metabolic enzyme and drug transporters induced by SGD deserve to be explored. We aimed to investigate the effect of SGD on the pregnane X receptor (PXR)-mediated transcriptional regulation of cytochrome P450 3A4 (CYP3A4) and drug transporter multidrug resistance protein 1 (MDR1) in vitro. Besides, we assessed the contribution of constituent herbs to SGD on the regulation of CYP3A4 and MDR1.

METHODS

The dual luciferase reporter gene system containing the hPXR expression plasmid and the reporter gene plasmid of CYP3A4 or MDR1 was co-transfected to HepG2 and Caco2 cells. Luciferase activities were determined using a Dual-luciferase reporter assay kit. The gene expression of CYP3A4 and MDR1 in the hPXR-transfected LS174T cells were assessed by real-time qPCR. Finally, the contribution of constituent herbs from SGD was evaluated.

RESULTS

SGD, Shaoyao and Gancao concentration-dependently increased promoter activities of CYP3A4 and MDR1 in vitro. Moreover, SGD, Shaoyao and Gancao up-regulated CYP3A4 and MDR1 mRNA in hPXR-transfected LS174T cells. As the herbal constituent of SGD, Gancao possesses significantly higher levels of metabolic enzyme and drug transporters compared with Shaoyao.

CONCLUSION

SGD tends to enhance CYP3A4 and MDR1 expression via PXR pathway, especially Gancao provides the main contribution. This study highlights a potential in vitro mechanism for SGD on the regulation of drug metabolic enzymes and drug transporters.

Simultaneous determination of intestinal permeability and potential drug interactions of complex mixtures using Caco-2 cells and high-resolution mass spectrometry: Studies with Rauwolfia serpentina extract

Caco-2 cells are a commonly used model for estimating the intestinal bioavailability of single chemical entity pharmaceuticals. Caco-2 cells, when induced with calcitriol, also express other biological functions such as phase I (CYP) and phase II (glucuronosyltransferases) drug metabolizing enzymes which are relevant to drug-supplement interactions. Intestinal bioavailability is an important factor in the overall safety assessment of products consumed orally. Foods, including herbal dietary supplements, are complex substances with multiple chemical components. Because of potential interactions between components of complex mixtures, more reliable safety assessments can be obtained by studying the commercial products "as consumed" rather than by testing individual chemical components one at a time. The present study evaluated the apparent intestinal permeability (P_app) of a model herbal extract, Rauwolfia serpentina, using both whole plant extracts and the individual purified Rauwolfia alkaloids. All test compounds, endpoint substrates, and their metabolites were quantified using liquid chromatography and high-resolution mass spectrometry. The P_app values for individual Rauwolfia alkaloids were comparable whether measured individually or as components of the complete extract. Both Rauwolfia extract and all individual Rauwolfia alkaloids except yohimbine inhibited CYP3A4 activity (midazolam 1'-hydroxylation). Both Rauwolfia extract and all individual Rauwolfia alkaloids except corynanthine and reserpic acid significantly increased glucuronosyltransferase activity (glucuronidation of 4-methylumbelliferone). The positive control, ketoconazole, significantly inhibited both CYP3A4 and glucuronosyltransferase activities. These findings suggest that the Caco-2 assay is capable of simultaneously identifying both bioavailability and potentially hazardous intestinal drug-supplement interactions in complex mixtures.

Recent pharmaceutical evidence on the compatibility rationality of traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Chinese herbs have been used in China for thousands of years and are also becoming popular in Western medicine. Formulae of traditional Chinese medicine (TCM), which contain two or more herbs, can often obtain better curative efficacies and fewer side effects than single herbs. Though there are many reports on pharmaceutics, pharmacokinetics, and pharmacodynamics of TCM, there remains a serious lack of summarization and systemic analyses of these reported data to help uncover the compatibility rationale of TCM. This review therefore aims to provide such an overview mainly based on the reports published in the last decade. It could be served as an informative reference for researchers interested in compound prescriptions and holistic therapies.

MATERIALS AND METHODS

Relevant information was collected from various resources, including books on Chinese herbs, China Knowledge Resource Integrated (CNKI), and international databases, such as Web of Science, Scopus, and PubMed.

RESULTS

Thirty-six relevant TCM formulae were collected to illustrate the compatibility rationality of TCM from the perspective of pharmaceutics, pharmacokinetics, and/or pharmacodynamics.

CONCLUSIONS

Compatibility is a key characteristic of multi-herb prescriptions. It often results in the change of the therapeutic material basis and, thus, produces the effect of reducing toxicity and/or increasing curative efficacy.

Effect of glycyrrhizic acid on the oral absorption of paeoniflorin in rats in vivo

The effect of glycyrrhizic acid (GL) on the absorption of paeoniflorin (PF) was GL dosage dependent in rats. The C_max of PF decreased significantly when GL at the dosage of 300 mg kg⁻¹ BW, while it increased with the increase of the dosage of GL.

Potential mechanisms of an antiadenomyosis chinese herbal formula shaoyao-gancao decoction in primary cell culture model

Background. Shaoyao-Gancao Decoction (SGD), a well-known traditional Chinese medicine prescription, has been widely used to treat adenomyosis, dysmenorrhea, abdominal pain, and inflammation in Asia. However, the mechanism underlying the effectiveness of SGD in the treatment of adenomyosis still remains elusive. The present study aimed to investigate the bioactivity of SGD and its underlying molecular mechanisms using cultured human adenomyosis-derived cells. Methods. Human adenomyosis-derived cells were treated with SGD and its major constituents (paeoniflorin and liquiritin) in vitro. Effects of SGD, paeoniflorin, and liquiritin on cell proliferation and apoptosis were examined by MTT assay and flow cytometry analyses. The effects of SGD, paeoniflorin, and liquiritin on the production of PGE₂ and PGF_2α were assayed using ELISA. ER-α and OTR mRNA expression levels were also evaluated by real-time qRT-PCR. Results. SGD, paeoniflorin, and liquiritin inhibited proliferation and induced apoptosis of human adenomyosis-derived cells in a dose-dependent manner. SGD and paeoniflorin significantly reduced the PGE₂ and PGF_2α production. Furthermore, they remarkably decreased the mRNA levels of ER-α and OTR. Conclusions. The results of this study provide possible mechanisms for the bioactivity of SGD for treating adenomyosis and contribute to the ethnopharmacological knowledge about this prescription.

Deciphering the combination principles of Traditional Chinese Medicine from a systems pharmacology perspective based on Ma-huang Decoction

ETHNOPHARMACOLOGY RELEVANCE

The main therapeutic concept in Traditional Chinese Medicine (TCM) is herb formula, which treats various diseases via potential herb interactions to maximize the efficacy and minimize the adverse effects. However, the combination principle of herb formula still remains a mystery due to the lack of appropriate methods.

METHODS

A systems pharmacology method integrating the pharmacokinetic analysis, drug targeting, and drug-target-disease network is developed to dissect this rule embedded in the herbal formula. All these are exemplified by a representative TCM formula, Ma-huang decoction, made up of four botanic herbs.

RESULTS

Based on the deep investigation of the function and compatibility of each herb, in a molecular/systems level, we demonstrate the different pharmacological roles that each herb might play in the prescription. By the way of enhancing the bioavailability and/or making the pharmacological synergy among different herbs, the four herbs effectively combine together to be suitable for treating diseases.

CONCLUSIONS

The present work lays foundations for a more comprehensive understanding of the combination rule of TCM, which might also be beneficial to drug development and applications.