High hepatic exposure of furanocoumarins in Radix Angelica dahuricae is associated with transporter mediated active uptake

The potential habitat of Angelica dahurica in China under climate change scenario predicted by Maxent model

Since the 20th century, global climate has been recognized as the most important environmental factor affecting the distribution of plants. Angelica dahurica (A. dahurica) has been in great demand as a medicinal herb and flavoring, but the lack of seed sources has hindered its development. In this study, we utilized the Maxent model combined with Geographic Information System (GIS) to predict the potential habitat of A. dahurica in China based on its geographical distribution and 22 environmental factors. This prediction will serve as a valuable reference for the utilization and conservation of A. dahurica resources.The results indicated that: (1) the Maxent model exhibited high accuracy in predicting the potential habitat area of A. dahurica, with a mean value of the area under the ROC curve (AUC) at 0.879 and a TSS value above 0.6; (2) The five environmental variables with significant effects were bio6 (Min temperature of the coldest month), bio12 (Annual Precipitation), bio17 (Precipitation of Driest Quarter), elevation, and slope, contributing to a cumulative total of 89.6%. Suitable habitats for A. dahurica were identified in provinces such as Yunnan, Guizhou, Guangxi, Sichuan, Hunan, and others. The total area of suitable habitat was projected to increase, with expansion primarily in middle and high latitudes, while areas of decrease were concentrated in lower latitudes. Under future climate change scenarios, the centers of mass of suitable areas for A. dahurica were predicted to shift towards higher latitudes in the 2050s and 2090s, particularly towards the North China Plain and Northeast Plain. Overall, it holds great significance to utilize the Maxent model to predict the development and utilization of A. dahurica germplasm resources in the context of climate change.

Radix Angelica dahuricae extract ameliorates oestrogen deficiency-induced dyslipidaemia in ovariectomized (OVX) rats by modulating the gut microbiota and bile acid signalling

BACKGROUND

Radix Angelica dahuricae (RAD), a well-known traditional Chinese medicine, displays a promising effect on alleviating lipid metabolism. However, the improvement of RAD on oestrogen deficiency-induced dyslipidaemia and the underlying mechanism are unclear.

PURPOSE

The aim of this study was to study the effect of RAD on oestrogen deficiency-induced dyslipidaemia in ovariectomized (OVX) rats and investigate the involvement of the gut microbiota and bile acid signalling in the protective effects.

METHODS

Bilateral ovariectomy was executed to establish an oestrogen deficiency model. Serum biochemical indexes, liver lipids, inflammatory cytokines and histomorphology were evaluated. Gut microbes were analysed via 16S rRNA sequencing. Faecal short-chain fatty acids (SCFAs) and serum bile acids were quantified by gas chromatography-flame ionization detection (GC-FID) and ultra-high-performance chromatography-tandem mass spectrometry (UPLC-MS/MS), respectively. The expression of genes related to bile acid synthesis, metabolism and enterohepatic circulation in the liver and caecum was measured by real-time PCR.

RESULTS

The results displayed that RAD administration markedly decreased body weight, TC and TG levels in the serum and liver, and hepatic steatosis and inflammation in OVX rats. RAD administration could significantly regulate the gut microbial composition, increasing the abundance of Lactobacillus, increasing the content of bile salt hydrolase (BSH), and reestablishing the SCFA profile and bile acid metabolism profile in OVX rats. RAD administration could increase the gene expression of HMG-CoA reductase (HMGCR) and cytochrome P450 7A1(CYP7A1) and regulate the gene expression of the related receptors as well as proteins in enterohepatic circulation.

CONCLUSIONS

RAD alleviated oestrogen deficiency-induced dyslipidaemia in OVX rats. Modulation of the gut microbiota composition and bile acid signalling may be the underlying mechanism.

Simultaneous separation and determination of six furanocoumarins in Radix Angelicae dahuricae by CZE with dual CDs system

A novel, simple and efficient capillary electrophoresis method was developed to simultaneous determination of six furanocoumarins (psoralen, isopsoralen, imperatorin, isoimperatorin, phellopterin, and cnidilin). The separation buffer consisted of 30 mM boric acid, 12 mM sulfobutylether-β-cyclodextrin and 1.5 mM 2-hydroxypropyl-β-cyclodextrin (pH 7.8); the voltage was 20 kV, the temperature was 25 °C and the detection wavelength was at 246 nm with a diode array detector (DAD). Under the above conditions, the analytes could be separated with high resolution in less than 7 min. This method was used to simultaneously determine the content of psoralen, imperatorin, isoimperatorin and phellopterin in Angelica Dahurica Radix. And good linearities were obtained with correlation coefficients from 0.9992 to 0.9999. The limits of detection (LOD, S/N = 3) and the limits of quantitation (LOQ, S/N = 10) ranged from 0.6 to 3.0 μg/mL and from 2.1 to 9.9 μg/mL, respectively. The recoveries ranged between 98.8% and 101.8%. The results indicated the method can achieve baseline separation and quantitative analysis of furanocoumarins in Chinese herbal medicines and formulations.

Preclinical Pharmacokinetics and Bioavailability of Oxypeucedanin in Rats after Single Intravenous and Oral Administration

Oxypeucedanin, a furanocoumarin extracted from many traditional Chinese herbal medicines, has a variety of pharmacological effects. However, the independent pharmacokinetic characteristics and bioavailability of this compound remains elusive. In this study, a rapid, sensitive, and selective method using ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) was developed for evaluating the intravenous and oral pharmacokinetics of oxypeucedanin. After intravenous administration of oxypeucedanin (2.5, 5, and 10 mg/kg), and intragastric administration of oxypeucedanin (20 mg/kg), blood samples were collected periodically from the tail vein. The plasma concentration-time curves were plotted, and the pharmacokinetic parameters were calculated using a non-compartmental model analysis. After intravenous administration of oxypeucedanin (single dosing at 2.5, 5, and 10 mg/kg) to rats, the pharmacokinetics fit the linear kinetics characteristics, which showed that some parameters including average elimination half-life (T_1/2Z of 0.61~0.66 h), mean residence time (MRT of 0.62~0.80 h), apparent volume of distribution (V_Z of 4.98~7.50 L/kg), and systemic clearance (CL_Z of 5.64~8.55 L/kg/h) are dose-independent and the area under concentration-time curve (AUC) increased in a dose-proportional manner. Single oral administration of oxypeucedanin (20 mg/kg) showed poor and slow absorption with the mean time to reach the peak concentration (T_max) of 3.38 h, MRT of 5.86 h, T_1/2Z of 2.94 h, and a mean absolute bioavailability of 10.26% in rats. These results provide critical information for a better understanding of the pharmacological effect of oxypeucedanin, which will facilitate its research and development.

A novel strategy for screening angiotensin-converting enzyme inhibitors from natural products based on enzyme-immobilized ligand fishing combined with active-site blocking and directional enrichment

Some natural products are important sources of treatments for hypertension based on their potential inhibitory effects on angiotensin-converting enzyme (ACE); however, it is difficult to identify natural ACE inhibitors (ACEIs) due to the complex secondary metabolite environment of natural products. Enzyme immobilization is an important method for screening active constituents in natural products, but this method can sometimes return false-positive and false-negative results. To improve the accuracy and reliability of ligand-fishing methods, we established a novel strategy based on enzyme-immobilized ligand fishing combined with active-site blocking and directional enrichment technologies. We first synthesized ACE-immobilized mesoporous magnetic beads and then verified the screened compounds by molecular docking and in vitro activity detection. We then used active-site blocking to exclude non-specific binding constituents and applied directional enrichment to enrich the low-content constituents for ligand fishing. The screening identified six potential ACEIs from Scutellariae Radix and eight potential ACEIs from Lonicerae japonicae flos, and their inhibitory activity was confirmed by molecular docking simulations and in vitro activity detection. This process screened six additional compounds and excluded two false-positive results as compared with results exclusively using enzyme immobilization. This strategy provides a feasible method for screening active compounds in natural products.

Oxypeucedanin: Chemotaxonomy, Isolation, and Bioactivities

The present review comprehensively gathered phytochemical, bioactivity, and pharmacokinetic reports on a linear furanocoumarin, namely oxypeucedanin. Oxypeucedanin (OP), which structurally contains an epoxide ring, has been majorly isolated from ethyl acetate-soluble partitions of several genera, particularly Angelica, Ferulago, and Prangos of the Apiaceae family; and Citrus, belonging to the Rutaceae family. The methanolic extract of Angelica dahurica roots has been analytically characterized as the richest natural OP source. This naturally occurring secondary metabolite has been described to possess potent antiproliferative, cytotoxic, anti-influenza, and antiallergic activities, as assessed in preclinical studies. In order to explore potential drug candidates, oxypeucedanin, its derivatives, and semi-synthetically optimized analogues can be considered for the complementary assessments of biological assays.

Imperatorin: A review of its pharmacology, toxicity and pharmacokinetics

As a naturally occurring furanocoumarin, the medicinal value of imperatorin has been studied more and more. We hope to provide useful information for the further development of imperatorin by analyzing the literature of imperatorin in recent years. By collating the literature on the pharmacology of imperatorin, we found that the pharmacological activity of imperatorin is wide and imperatorin can be used for anti-cancer, neuroprotection, anti-inflammatory, anti-hypertension and antibacterial. In addition, we found that some researchers confirmed the toxicity of imperatorin. Pharmacokinetic studies demonstrated that oxidation metabolism is the main metabolic pathways of imperatorin. At present, the shortcomings of research on imperatorin mainly include: most pharmacological studies are concentrated in vitro, lacking enough in vivo experimental data; more and more studies showed that imperatorin has synergistic effect with other drugs in anticancer and other aspects, but lacking the detailed explanation of the mechanism of the synergistic effect; imperatorin has side effect, but it lacks enough experimental conclusions. Based on the above defects, we believe that more in vivo experiments of imperatorin should be carried out in the future; future research need to explore synergistic mechanisms of imperatorin with other drugs, especially in anticancer; the dose affects both the pharmacological activity and the side effect of imperatorin. The relationship between the dose and the two aspects need to be further studied in order to reduce the side effect. In addition, through structural modification of imperatorin, it is possible to improve the treatment effect and reduce side effect.

Metabolite identification, tissue distribution, excretion and preclinical pharmacokinetic studies of ET-26-HCl, a new analogue of etomidate

ET-26-HCl, a novel anaesthetic agent with promising pharmacological properties, lacks extensive studies on pharmacokinetics and disposition in vitro and in vivo. In this study, we investigated the metabolic stability, metabolite production and plasma protein binding (PPB) of ET-26-HCl along with its tissue distribution, excretion and pharmacokinetics in animals after intravenous administration. Ultra-high performance liquid chromatography–tandem quadrupole time-of-flight mass spectrometry identified a total of eight new metabolites after ET-26-HCl biotransformation in liver microsomes from different species. A hypothetical cytochrome P450-metabolic pathway including dehydrogenation, hydroxylation and demethylation was proposed. The PPB rate was highest in mouse and lowest in human. After intravenous administration, ET-26-HCl distributed rapidly to all tissues in rats and beagle dogs, with the highest concentrations in fat and liver. High concentrations of ET-26-acid, a major hydroxylation metabolite of ET-26-HCl, were found in liver, plasma and kidney. Almost complete clearance of ET-26-HCl from plasma occurred within 4 h after administration. Only a small fraction of the parent compound and its acid form were excreted via the urine and faeces. Taken together, the results added to a better understanding of the metabolic and pharmacokinetic properties of ET-26-HCl, which may contribute to the further development of this drug.

Antioxidant Activity and Sensory Improvement of Angelica dahurica cv. Yubaizhi Essential Oil on Sunflower Oil during High-temperature Storage

The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at 65 °C, ADEO (800 ppm) was able to markedly inhibit the development of the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), thiobarbituric acid reactive substances (TBARS), total polar compounds (TPC), and the absorbance at 232 and 268 nm (p < 0.01 or p < 0.05) of sunflower oil and to prominently inhibit the transformation between unsaturated fatty acids (UFA) and saturated fatty acids (SFA). Interestingly, the synergistic effect of ADEO (400 ppm) and tert-butyl hydroquinone (TBHQ, 100 ppm) was demonstrated. Furthermore, the sensory attributes such as flavor, taste, and overall acceptability of oxidized sunflower oil added by ADEO at 200, 400, and 800 ppm were memorably elevated (p < 0.05). Besides, one of its main compounds, myrcene, was demonstrated to be its active compound during the whole investigation. Consequently, TBHQ at 200 ppm could be substituted by ADEO at 800 ppm and myrcene at 69.8 ppm in the high-temperature storage at 65 °C of sunflower oil.

Effect of co-administration of Acori Tatarinowii Rhizoma volatile oil on pharmacokinetic fate of xanthotoxol, oxypeucedanin hydrate, and byakangelicin from Angelicae Dahuricae Radix in rat

A combination of Angelicae Dahuricae Radix and Acori Tatarinowii Rhizoma has been widely used as the herb pair in traditional Chinese medicine to treat stroke, migraine, and epilepsy. However, the underlying synergistic mechanism of the herb pair remains unknown. This study was aimed at investigating the effects of Acori Tatarinowii Rhizoma volatile oil on the pharmacokinetic parameters of xanthotoxol, oxypeucedanin hydrate, and byakangelicin from Angelicae Dahuricae Radix in rat, and in vitro absorption behavior of the three compounds using rat everted gut sac, in situ single-pass intestinal perfusion, and Caco-2 cell monolayer models. The pharmacokinetic study exhibited clear changes in the key pharmacokinetic parameters of the three main coumarins through co-administering with Acori Tatarinowii Rhizoma volatile oil (50 mg/kg), the area under curve and the maximum plasma concentration of xanthotoxol increased 1.36 and 1.31 times; the area under curve, the maximum plasma concentration, mean residence time, half-life of elimination, and the time to reach peak concentration of oxypeucedanin hydrate increased by 1.35, 1.18, 1.24, 1.19 and 1.49 times, respectively; the area under curve, mean residence time, half-life of elimination, and time to reach peak concentration of byakangelicin climbed 1.29, 1.27, 1.37, and 1.28 times, respectively. The three coumarin components were absorbed well in the jejunum and ileum in the intestinal perfusion model, when co-administered with Acori Tatarinowii Rhizoma volatile oil (100 μg/mL). The in vivo and in vitro experiments showed good relevance and consistency. The results demonstrated that the three coumarin compounds from Angelicae Dahuricae Radix were absorbed through the active transportation, and Acori Tatarinowii Rhizoma volatile oil could promote the intestinal absorption and transport of these compounds by inhibiting P-glycoprotein (P-gp)-mediated efflux.

Involvement of organic anion-transporting polypeptides and organic cation transporter in the hepatic uptake of jatrorrhizine

Jatrorrhizine possesses a wide spectrum of pharmacological activities. However, the mechanism underlying hepatic uptake of jatrorrhizine remains unclear.Rat liver slices, isolated rat hepatocytes and human embryonic kidney 293 (HEK293) cells stably expressing human organic anion-transporting polypeptide (OATP) and organic cation transporter (OCT) were used to evaluate the hepatic uptake of jatrorrhizine in this study.Uptake of jatrorrhizine in rat liver slices and isolated rat hepatocytes was significantly inhibited by glycyrrhizic acid (Oatp1b2 inhibitor) and prazosin (Oct1 inhibitor), but not by ibuprofen (Oatp1a1 inhibitor) or digoxin (Oatp1a4 inhibitor). Uptake of jatrorrhizine in OATP1B3 and OCT1-HEK293 cells indicated a saturable process with the K_m of 8.20 ± 1.28 and 4.94 ± 0.55 μM, respectively. However, the transcellular transport of jatrorrhizine in OATP1B1-HEK293 cells was not observed. Rifampicin (OATP inhibitor) for OATP1B3-HEK293 cells and prazosin for OCT1-HEK293 cells could inhibit the uptake of jatrorrhizine with the IC₅₀ of 5.49 ± 1.05 and 2.77 ± 0.72 μM, respectively.The above data indicate that hepatic uptake of jatrorrhizine is involved in both OATP and OCT, which may have important roles in jatrorrhizine liver disposition and potential drug-drug interactions.

Pharmacokinetics, tissue distribution and plasma protein binding study of SM-1, a novel PAC-1 derivative

As a PAC-1 derivative, SM-1 exhibts a promising antitumour property. To better understand the relationship between the drug concentrations and pharmacological effects, both liquid chromatography coupled with tandem mass spectrometry and high performance liquid chromatography methods were developed and validated in the work. Those methods were then applied to the pharmacokinetics (PK), tissue distribution and plasma protein binding (PPB) studies of SM-1. As a results, the proposed methods were demonstrated to be accurate, precise and stable for the analysis of the SM-1 in plasma and tissue samples. Meanwhile, the PK parameters of SM-1 showed that SM-1 had good PK properties. SM-1 had good absorption in the body, with 59.01% of the absolute bioavailability in rats and 55.63% of that in dogs. SM-1 rapidly distributed to all tissues, with the highest distribution in the lung and less in the brain and muscle. The PPB rates in rat plasma, dog plasma, and human plasma were 91.1%, 91.2%, and 90.7%, respectively. These good PK properties will contribute SM-1 to be a promising anti-tumour candidate. These results also provide insights into the further pharmacological investigation of SM-1.

Apoptosis effects of imperatorin on synoviocytes in rheumatoid arthritis through mitochondrial/caspase-mediated pathways

Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease associated with a potential imbalance between the growth and death of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). Imperatorin (IPT) is a naturally occurring furanocoumarin found in umbelliferous vegetables, citrus fruits, and some herbs. The effects of IPT on the proliferation and apoptosis of RA-FLSs and its potential underlying mechanisms have remained unclear. RA-FLSs obtained from RA patients were induced by interleukin-1β (IL-1β) and treated with IPT. Cell viability was determined by MTT assay. Apoptotic cell death was analyzed by Annexin V-FITC/PI double staining and Hoechst 33342 staining. The loss in the mitochondrial membrane potential (ΔΨm) was visualized on the basis of JC-1 staining via fluorescence microscopy, and protein expression changes were assessed by western blot, whereas in vivo studies were conducted in male Wistar rats followed by histopathological assessment via TUNEL assay and HE staining of tissues. The results showed that IPT significantly reduced cell viability, accelerated cell apoptosis and decreased matrix metalloproteinases-1/-3 expression in IL-1β-induced RA-FLSs. Furthermore, IPT exposure was found to disrupt the ΔΨm compared to the IL-1β-induced treatment. Moreover, IPT increased the release of mitochondrial cytochrome C, the ratio of Bax/Bcl-2, and the cleavage of caspase-9, caspase-3 and poly (ADP-ribose) polymerase. In vivo studies showed that IPT not only significantly reduced the collagen induced arthritis by reducing synovial hyperplasia, and pannus formation but also enhanced the apoptotic index of ankle joint cells. Conclusively, our findings suggest that IPT inhibits cell proliferation and induces apoptosis in RA-FLSs that may be associated with mitochondrial/caspase-mediated signalling pathways.

A Metabolism-Based Synergy for Total Coumarin Extract of Radix Angelicae Dahuricae and Ligustrazine on Migraine Treatment in Rats

Radix Angelicae dahuricae, containing coumarins, which might affect cytochrome P450 enzyme (CYP450) activity, has been co-administered with ligustrazine, a substrate of CYP450s, for the clinical treatment of migraine. However, whether a pharmacokinetic-based synergy exists between Radix Angelicae dahuricae and ligustrazine is still unknown. In this study, the total coumarin extract (TCE) of Radix Angelicae dahuricae (50 mg/kg, orally) reinforced the anti-migraine activity of ligustrazine by declining head scratching, plasma calcitonin gene-related peptide, and serum nitric oxide, as well as increasing plasma endothelin levels in rats (p < 0.05). Moreover, the pharmacokinetic study reflected that TCE potentiated the area under the concentration⁻time curve of ligustrazine and prolonged its mean retention time in rats (p < 0.05). Besides, the IC₅₀ for TCE, imperatorin and isoimperatorin inhibiting ligustrazine metabolism were 5.0 ± 1.02, 1.35 ± 0.46, 4.81 ± 1.14 µg/mL in human liver microsomes, and 13.69 ± 1.11, 1.19 ± 1.09, 1.69 ± 1.17 µg/mL in rat liver microsomes, respectively. Moreover, imperatorin and isoimperatorin were CYP450s inhibitors with IC₅₀ < 10 µM for CYP1A2, 2C9, 2D6, and 3A4. Therefore, this study concluded that Radix Angelicae dahuricae could increase ligustrazine plasma concentration and then reinforce its pharmacological effect by inhibiting its metabolism through interference with CYP450s. This could be one mechanism for the synergy between Radix Angelicae dahuricae and ligustrazine on migraine treatment.