Comparative pharmacokinetics of major bioactive components from Puerariae Radix-Gastrodiae Rhizome extracts and their intestinal absorption in rats

Effects of schisandra lignans on the absorption of protopanaxadiol-type ginsenosides mediated by P-glycoprotein and protopanaxatriol-type ginsenosides mediated by CYP3A4

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng Radix et Rhizoma (GRR) and Schisandrae Chinensis Fructus (SCF) are frequently used as herb pairs in traditional herbal formulas especially for the synergetic beneficial effects on lung and heart. Shengmai-yin (SMY), a noted formula, was first published in the traditional Chinese medicine classic named Yixue Qiyuan written by Zhang Yuansu in the Jin Dynasty, and has been used for deficiency of both qi and yin, palpitation, shortness of breath and spontaneous sweating. In SMY, GRR, a sovereign herb, plays an essential role in tonifying lung and supplementing qi, and SCF as an adjuvant herb contributes to the effects of nourishing yin and promoting fluid production, both of which are traditionally used as invigorants in China, Korea, Japan, and Russia. However, the underlying compatibility mechanism of GRR-SCF has remained unknown.

AIM OF THE STUDY

In order to explore the impact and underlying mechanism of schisandra chinensis extract (SCE) on the absorption of ginsenosides Rb1, Rc, Rb2 and Rd belonging to protopanaxdiol (PPD)-type and ginsenosides Rg1 and Re belonging to protopanaxtriol (PPT)-type, pharmacokinetic studies, molecular docking technique and single-pass intestinal perfusion (SPIP) experiment were conducted.

MATERIAL AND METHODS

Preliminarily, pharmacokinetic characteristics of ginseng extract (GE) in the presence and absence of SCE were studied. Thereafter, molecular docking was used to predict whether ginsenosides were P-glycoprotein (P-gp) or cytochrome P450 isoenzyme 3A4 (CYP3A4) substrates. Finally, the effects and underlying mechanism of SCE on the absorption of GE were further investigated by in situ SPIP experiment.

RESULTS

Our findings indicated that SCE could increase exposure in vivo and the intestinal absorption of distinct ginsenosides. Additionally, we found that the PPD-type ginsenosides Rb1, Rc, Rb2, and Rd were substrates for P-gp, and the PPT-type ginsenosides Rg1 and Re were substrates for CYP3A4 rather than P-gp. SCE, which has been found with extensive inhibitory effects on P-gp and CYP3A4, could remarkably promote the intestinal absorption of ginsenosides Rg1, Re, Rb1, Rc, Rb2, and Rd, obtaining similar effects comparable with ketoconazole known as a classic dual inhibitor of P-gp and CYP3A4.

CONCLUSIONS

The study demonstrated that SCE could improve the absorption of GE, and revealed the underlying compatibility mechanism of GRR and SCF from the perspective of P-gp and CYP3A4-mediated interactions to some extent, which provided a certain scientific reference for the compatibility and clinical practice of GRR-SCF as common herb pairs in traditional prescriptions such as SMY. Moreover, this study also furnished a strategy for improving the oral bioavailability of different types of ginsenosides by drug combinations.

Elucidation of the Transport Mechanism of Puerarin and Gastrodin and Their Interaction on the Absorption in a Caco-2 Cell Monolayer Model

Puerarin (PUR) and gastrodin (GAS) are often used in combined way for treating diseases caused by microcirculation disorders. The current study aimed to investigate the absorption and transportation mechanism of PUR and GAS and their interaction via Caco-2 monolayer cell model. In this work, the concentration in Caco-2 cell of PUR and GAS was determined by HPLC method. The bidirectional transport of PUR and GAS and the inhibition of drug efflux including verapamil and cyclosporine on the transport of these two components were studied. The mutual influence between PUR and GAS, especially the effect of the latter on the former of the bidirectional transport were also investigated. The transport of 50 μg·mL⁻¹ PUR in Caco-2 cells has no obvious directionality. While the transport of 100 and 200 μg·mL⁻¹ PUR presents a strong directionality, and this directionality can be inhibited by verapamil and cyclosporine. When PUR and GAS were used in combination, GAS could increase the absorption of PUR while PUR had no obvious influence on GAS. Therefore, the compatibility of PUR and GAS is reasonable, and GAS can promote the transmembrane transport of PUR, the effect of which is similar to that of verapamil.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

Enhancing the bioaccessibility of puerarin through the collaboration of high internal phase Pickering emulsions with β-carotene

Puerarin is a medicinal and edible flavonoid compound found in the traditional Chinese medicine Pueraria lobata rhizome that has potential biological benefifits, including for the treatment of diabetes and memory...

Preliminary screening of the potential active ingredients in traditional Chinese medicines using the Ussing chamber model combined with HPLC-PDA-MS

An in vitro intestinal absorption model combined with high-performance liquid chromatography-photo diode array-tandem mass spectrometry (HPLC-PDA-MS) was used for preliminary screening of potential active ingredients from complex multi-component traditional Chinese medicine (TCM) system. Oral administration is one of the main administration methods for TCMs. Only the ingredients that could be absorbed have the opportunity to play a role. Thus, these were defined as potential active ingredients. Studying of intestinal absorption can provide a theoretical basis for the mechanism of TCMs. The Caco-2 cell model, the everted rat gut sac model, and the Ussing chamber model were established for TCMs. The degree of anastomosis between the in vitro intestinal model and the actual intestinal absorption of TCMs were evaluated by the gavage method in rats. The Ussing chamber model was best fit for oral experiments in rats and was selected as the research means to preliminarily screen potential active ingredients from eight TCMs, including Salvia miltiorrhiza Bunge, Astragalus propinquus Schischkin, Plantago asiatica L, Fallopia multiflora (Thunb.) Harald, Epimedium brevicornu Maxim, Moutan Cortex, Citrus reticulata Blanco, and Panax notoginseng (Burkill) F. H. Chen ex C. H. Chow. A total of 44 components were absorbed and screened as the potential active ingredients from the 80 components identified in eight TCMs by HPLC-PDA-MS.

Influence of Gegenqinlian Decoction on Pharmacokinetics and Pharmacodynamics of Atorvastatin Calcium in Hyperlipidemic Rats

BACKGROUND AND OBJECTIVES

Gegenqinlian decoction (GQD), a classic traditional Chinese medicine (TCM), was described in Shanghan Lun. GQD is often combined with antihyperlipidemic drugs (mainly atrovastatin calcium) in TCM clinics. However, the herb-drug interaction between GQD and atrovastatin calcium (AC) is still unknown. To determine whether the combination is safe, we evaluated the effects of GQD on the activities of cytochrome P450 (CYP) 3A2 enzyme and investigated the impact of GQD on the pharmacokinetics and pharmacodynamics of AC in rats.

METHODS

The pharmacokinetics of AC (10 mg/kg) with or without pretreatment with GQD (freeze-dried powder, 1.35 g/kg) were investigated using HPLC. The influence of GQD on pharmacodynamics of AC were determined by detecting the levels of serum total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Moreover, the probe drug method was used to explore the effect of GQD on CYP3A2 activity.

RESULTS

The pharmacokinetic parameters of AC combined with GQD were significantly affected (P < 0.05) in hyperlipidemic rats. The serum TC, TG and LDL-C levels of the combination were significantly reduced (P < 0.05), and the serum HDL-C level was significantly increased (P < 0.05) compared with AC/GQD alone. AST and ALT activities treated with both GQD and AC+GQD group were significantly reduced (P < 0.05) compared with AC group. There was a significant difference in the pharmacokinetic parameters of midazolam between control and GQD groups (P < 0.05). Maximum concentration (C_max), area under the concentration-time curve (AUC) from time 0 to the last quantifiable concentration (AUC_0-t) and AUC from time 0 to infinity (AUC_0-∞) increased significantly in GQD group.

CONCLUSIONS

The result suggested that GQD combined with AC can improve the lipid-lowering effect of AC and reduce the damage of AC to the liver simultaneously. However, GQD can inhibit the activity of CYP3A2 in hyperlipidemic rats and increase the blood concentration of AC. Therefore, the clinical dose of AC should be adjusted when they are combined. Since the study was conducted in rats,  further research should be carried out to assess the uniformity of the pharmacokinetics and pharmacodynamics between rats and humans.

Modulation of the transport of valproic acid through the blood-brain barrier in rats by the Gastrodia elata extracts

HEADINGS ETHNOPHARMACOLOGICAL RELEVANCE

Valproic acid (VPA) is primarily used as a medicine for the treatment of seizures. Gastrodia elata (G. elata) extract has been used as an alternative medicine for epilepsy patients. Cotreatment with VPA and G. elata extract is commonly prescribed in Taiwan and mainland China. Nevertheless, the mechanism of the blood-brain barrier (BBB) transportation effect of G. elata extract on VPA has not been characterized.

AIM OF STUDY

Our hypothesis is that G. elata extract modulates the BBB penetration of VPA through specific transporter transfer.

MATERIALS AND METHODS

A validated liquid chromatography-tandem mass spectrometry and multiple microdialysis method was developed to simultaneously monitor VPA in the blood and brain of rats. To investigate the mechanism of BBB modulation by the G. elata extract on VPA in the brain, cyclosporin A, a P-glycoprotein (P-gp) inhibitor and organic anion transporting polypeptide (OATP) inhibitor, was coadministered with the G. elata extract and VPA.

RESULTS

The pharmacokinetic results demonstrated that the VPA penetration ratio of the BBB, determined by the area under the concentration curve (AUC) ratio of VPA (AUC_brain/AUC_blood), was approximately 0.36. After treatment with the G. elata extract (1 and 3 g/kg, p.o. for 5 consecutive days), the VPA penetration ratios were significantly enhanced to 1.47 and 1.02, respectively. However, in the experimental group coadministered cyclosporin A, the G. elata extract was unable to enhance the BBB transportation of VPA. Instead, the VPA penetration ratio in the brain was suppressed back to 0.38.

CONCLUSIONS

The present study reveals that the enhancement effect of the transporter mechanism of G. elata extract on VPA transport into the brain occurs through the OATP transporter but not the P-gp transporter.

Comparative pharmacokinetics, intestinal absorption and urinary excretion of six alkaloids from herb pair Phellodendri Chinensis cortex-Atractylodis Rhizoma

Phellodendri Chinensis Cortex (PCC) and Atractylodis Rhizoma (AR) are frequently used as herb pair to treat eczema and gout owing to their synergistic effects. Alkaloids are the major ingredients from PCC and the effect of their combination on the in vivo processing of alkaloids remains unclear. In this study, a simple and reliable UPLC-MS/MS method for simultaneous determination of six alkaloids in rat plasma was developed. This method was applied to a comparative pharmacokinetic study between PCC and PCC-AR in rats. Effect of AR on absorption of alkaloids was investigated by a single-pass intestinal perfusion study. The effect of AR on urinary excretion of alkaloids was studied. Pharmacokinetic studies showed that the values of rea under the concentration-time curve of phellodendrine, magnoflorine and palmatine were greater in the PCC-AR group than in the PCC group. The intestinal absorptive parameters absorption rate constant and effective permeability of phellodendrine and jatrorrhizine in PCC-AR groups were higher than those in the PCC group. Urinary excretion studies revealed that the excreted amount of alkaloids in the PCC-AR group was lower than that in the PCC group. The results revealed that the combination of PCC and AR improves intestinal absorption of alkaloids and reduces their urinary excretion, which enhances their systemic exposure. This study may explain the synergetic effects of PCC and AR in clinical applications.

Rapid Characterizaiton of Chemical Constituents of the Tubers of Gymnadenia conopsea by UPLC-Orbitrap-MS/MS Analysis

Gymnadenia conopsea R. Br. is a traditional Tibetan medicinal plant that grows at altitudes above 3000 m, which is used to treat neurasthenia, asthma, coughs, and chronic hepatitis. However, a comprehensive configuration of the chemical profile of this plant has not been reported because of the complexity of its chemical constituents. In this study, a rapid and precise method based on ultra-high performance liquid chromatography (UPLC) combined with an Orbitrap mass spectrometer (UPLC–Orbitrap–MS/MS) was established in both positive- and negative-ion modes to rapidly identify various chemical components in the tubers of G. conopsea for the first time. Finally, a total of 91 compounds, including 17 succinic acid ester glycosides, 9 stilbenes, 6 phenanthrenes, 19 alkaloids, 11 terpenoids and steroids, 20 phenolic acid derivatives, and 9 others, were identified in the tubers of G. conopsea based on the accurate mass within 3 ppm error. Furthermore, many alkaloids, phenolic acid derivates, and terpenes were reported from G. conopsea for the first time. This rapid method provides an important scientific basis for further study on the cultivation, clinical application, and functional food of G. conopsea.

Online coupling of the Ussing chamber, solid-phase extraction and high-performance liquid chromatography for screening and analysis of active constituents of traditional Chinese medicines

A semi-automated online platform was established successfully for preliminary screening of potential active flavonoids of traditional Chinese medicines (TCMs) in multicomponent system. Online coupling of the in vitro intestinal absorption model, solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) was actualized at the first time. The Ussing chamber model was selected to absorb the constituents of TCMs. A mini chromatographic column filled with C18 was used as a SPE column for online enrichment of flavonoids. HPLC was applied to analyze the constituents screened by platform. With the use of rutin as a model flavonoid, the specifications of SPE column, eluting solvent, elution time and flow rate of eluent were systematically investigated to optimize online system. Under the optimal conditions, the linear range of rutin was 0.125-368 µg/mL with the correlation coefficient (R²) greater than 0.9947. The limit of detection (LOD) was as low as 0.0500 µg/mL and the limit of quantification (LOQ) was 0.125 µg/mL. The intra-day relative standard deviation (RSD) and inter-day RSD was 2.5% and 3.8%, respectively. The recoveries of rutin in the intestinal absorption samples ranged from 93.2% to 94.0%. Finally, the online system was applied to screen the potential active flavonoids of Scutellaria baicalensis Georgi (Huangqin, HQ) and Polygoni Cuspidati Rhizoma et Radix (Huzhang, HZ). A total of 14 flavonoids of these two TCMs were identified by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and 12 flavonoids of them were screened as the potential active components by online Ussing chamber-SPE-HPLC. In comparison with offline method and gavage in rats, the online system can screen the active constituents from TCMs more accurately and completely. The results demonstrated that the online system was reliable and sufficiently accurate for screening and determination of the potential active flavonoids of TCMs in multicomponent system.

Pharmacokinetics and drug delivery systems for puerarin, a bioactive flavone from traditional Chinese medicine

Pueraria lobata (Willd.) Ohwi is a medicinal and edible homologous plant with a long history in China. Puerarin, the main component isolated from the root of Pueraria lobata, possesses a wide range of pharmacological properties. Daidzein and glucuronides are the main metabolites of puerarin and are excreted in the urine and feces. As active substrates of P-gp, multidrug resistance-associated protein and multiple metabolic enzymes, the pharmacokinetics of puerarin can be influenced by different pathological conditions and drug-drug interactions. Due to the poor water-solubility and liposolubility, the applications of puerarin are limited. So far, only puerarin injections and eye drops are on the market. Recent years, researches on improving the bioavailability of puerarin are developing rapidly, various nanotechnologies and preparation technologies including microemulsions and SMEDDS, dendrimers, nanoparticles and nanocrystals have been researched to improve the bioavailability of puerarin. In order to achieve biocompatibility and desired activity, more effective quality evaluations of nanocarriers are required. In this review, we summarize the pharmacokinetics and drug delivery systems of puerarin up to date.