Pharmacokinetic-pharmacodynamic modeling analysis and anti-inflammatory effect of Wangbi capsule in the treatment of adjuvant-induced arthritis.

Clinically, Wangbi Capsule (WBC) is widely used in the treatment of Rheumatoid arthritis (RA) because of its remarkable therapeutic effect. To reveal the mechanism, a pharmacokinetic-pharmacodynamic (PK-PD) model was developed for the first time to assess the relationship between time-concentration (dose)-effect. Freund's Complete Adjuvant was used to induce the adjuvant-induced arthritis model. Multi-indices were used to evaluate the therapeutic effect and an S-Imax PK-PD model was established based on the concentrations of osthole, 5-O-methylvisamminoside, cimifugin, albiflorin, paeoniflorin and icariin and the levels of interleukin-1ß and prostaglandin E2 using a two-compartment PK model together with a PD model with an effect-site compartment. The results suggest that WBC can treat RA by regulating the levels of prostaglandin E2 and interleukin-1ß. For the PK-PD model, the parameters indicated that WBC had a large safety margin and all six bioactive ingredients of WBC have therapeutic effects on RA. Among them icariin, osthole and 5-O-methylvisamminoside may be the main effective substances. This study provided a scientific basis for further study of population pharmacokinetics / population pharmacodynamics (PPK/PPD), to develop a reasonable administration plan and improve individualized drug therapy.

A pH-responsive dissociable mesoporous silica-based nanoplatform enabling efficient dual-drug co-delivery and rapid clearance for cancer therapy.

The balance between tumor accumulation and renal clearance has severely limited the efficacy of mesoporous silica-based drug nanocarriers in cancer therapy. Herein, a pH-responsive dissociable mesoporous silica-based nanoplatform with efficient dual-drug co-delivery, tumor accumulation and rapid clearance for cancer therapy is achieved by adjusting the wetting of the mesoporous silica surface. At pH 7.4, the synthesized spiropyran- and fluorinated silane-modified ultrasmall mesoporous silica nanoparticles (SP-FS-USMSN) self-assemble to form larger nanoclusters (denoted as SP-FS-USMSN cluster) via hydrophobic interactions, which can effectively co-deliver anticancer drugs, doxorubicin hydrochloride (Dox) and curcumin (Cur), based on the mesopores within SP-FS-USMSN and the voids among the stacked SP-FS-USMSN. At pH 4.5-5.5, the conformational conversion of spiropyran from a "closed" state to an "open" state causes the wetting of the SP-FS-USMSN surface, leading to the dissociation of the SP-FS-USMSN cluster for drug release and renal clearance. The in vitro and in vivo studies demonstrate that the Cur and Dox co-loaded SP-FS-USMSN cluster (Cur-Dox/SP-FS-USMSN cluster) possesses great combined cytotoxicity, and can accumulate into tumor tissue by its large size-favored EPR effect and potently suppress tumor growth in HepG2-xenografted mice. This research demonstrates that the SP-FS-USMSN cluster may be a promising drug delivery system for cancer therapy and lays the foundation for practical mesoporous silica-based nanomedicine designs in the future.

Development and Characterization of the Neuroregenerative Xanthohumol C/Hydroxypropyl-ß-cyclodextrin Complex Suitable for Parenteral Administration.

The chroman-like chalcone Xanthohumol C, originally found in hops, was demonstrated to be a potent neuroregenerative and neuroprotective natural product and therefore constitutes a strong candidate for further pharmaceutical research. The bottleneck for in vivo experiments is the low water solubility of this chalcone. Consequently, we developed and validated a suitable formulation enabling in vivo administration. Cyclodextrins were used as water-soluble and nontoxic complexing agents, and the complex of Xanthohumol C and 2-hydroxypropyl-ß-cyclodextrin was characterized using HPLC, HPLC-MS, NMR, and differential scanning calorimetry. The water solubility of Xanthohumol C increases with increasing concentrations of cyclodextrin. Using 50 mM 2-hydroxypropyl-ß-cyclodextrin, solubility was increased 650-fold. Furthermore, in vitro bioactivity of Xanthohumol C in free and complexed form did not significantly differ, suggesting the release of Xanthohumol C from 2-hydroxypropyl-ß-cyclodextrin. Finally, a small-scaled in vivo experiment in a rat model showed that after i. p. administration of the complex, Xanthohumol C can be detected in serum, the brain, and the cerebrospinal fluid at 1 and 6 h post-administration. Mean (± SD) Xanthohumol C serum concentrations after 1, 6, and 12 h were determined as 463.5 (± 120.9), 61.9 (± 13.4), and 9.3 (± 0.8) ng/mL upon i. v., and 294.3 (± 22.4), 45.5 (± 0.7), and 13 (± 1.0) ng/mL after i. p. application, respectively. Accordingly, the formulation of Xanthohumol C/2-hydroxypropyl-ß-cyclodextrin is suitable for further in vivo experiments and further pharmaceutical research aiming for the determination of its neuroregenerative potential in animal disease models.

In vitro investigation of permeability and metabolism of licoricidin.

Aim Licoricidin has multiple pharmacological activities. The present study was designed to investigate the permeability and pharmacokinetic behavior of licoricidin using in vitro models. MATERIAL AND METHODS: First, human liver microsomes and recombinant human supersomes were used to investigate the interactions between metabolic enzymes and licoricidin. In addition, rat, minipig, rabbit, dog, monkey, and human liver microsomes were used to determine metabolic differences among species. The parallel artificial membrane permeability assay (PAMPA) was used to explore licoricidin permeability behavior. KEY FINDINGS: At 100 µM, licoricidin strongly inhibited CYP2C9, CYP2C19, CYP3A4, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT2B4, UGT2B7, UGT2B15, and UGT2B17. Licoricidin metabolism exhibited considerable differences among species; dog, pig, and rat liver microsomes showed higher metabolic capacity than the other species. Seven licoricidin metabolites were identified by liquid chromatography-tandem mass spectrometry, and hydration and hydroxylation were the major metabolic pathways. The PAMPA permeability of licoricidin was moderate at both pH 4.0 and 7.4. SIGNIFICANCE: The present study will support further pharmacological or toxicological research on licoricidin.

Short Communication: Discovery and molecular docking simulation of 7-hydroxy-6-methoxy-2H-chromen-2-one as a LOX Inhibitor.

Millettia ovalifolia is traditionally used in variety of diseases including inflammation. In our investigation in to the phytochemical constituents of Millettia ovalifolia an effort was made to find out bioactive constituent from medicinal Plant M. ovalifolia to scientifically validate its use in inflammatory disorders. The compound 7-hydroxy-6-methoxy-2H-chromen-2-one was isolated from the bark of M. ovalifolia and was found to exhibited significant lipoxygenase (LOX) inhibitory activity with (IC50 value: 116.83±0.02µM). The Standard compounds Baicalein and Tenidap sodium revealed IC50 value being 22.1±0.03µM and 41.6±0.02µM. Molecular docking study further displayed significant molecular interactions between 7-hydroxy-6-methoxy-2H-chromen-2-one and LOX showed potential for further optimization as a possible anti-inflammatory lead compound.

Development of a LC-MS/MS method to investigate the interference of pharmacokinetics of the main constituents in Saxifraga stolonifera: Involvement of drug metabolism enzymes.

A specific and sensitive LC-MS/MS method was established for the simultaneous determination of bergenin, protocatechuic acid and gallic acid, the main active constituents of Saxifraga stolonifera (L.) Meerb. herb, in rat plasma. After fully validated, the method was applied to the comparative pharmacokinetic studies of the three compounds orally administered alone and in combination in the S. stolonifera extract, respectively. The results showed that the pharmacokinetic parameters, including Cmax, Tmax, AUC, CLz/F, MRT0-∞, were significantly different for both bergenin and protocatechuic acid in the extract as compared to the corresponding compounds administered alone. However, the pharmacokinetic behavior of gallic acid in the extract did not differ from that administered alone. Further studies found that quercetin, coexisting in the herb extract, significantly decreased the glucuronidation of bergenin through inhibiting the activities of UGT1A1 and UGT1A3, and reduced the metabolism of protocatechuic acid by inhibiting the activity of catechol-O-methyltransferase. Quercetin and other flavonoids occurring in the S. stolonifera extract might increase the absorption and improve the bioavailability of bergenin and protocatechuic acid by slowing down the liver metabolism. The findings provide a good guidance for the development and clinical application of S. stolonifera.

Natural Korean Medicine Dang-Gui: Biosynthesis, Effective Extraction and Formulations of Major Active Pyranocoumarins, Their Molecular Action Mechanism in Cancer, and Other Biological Activities.

Angelica gigas Nakai (AGN) is a crucial oriental medicinal herb that grows especially in Korea and the Far-East countries. It contains chemically active compounds like pyranocoumarins, polyacetylenes and essential oils, which might be useful for treatment of several chronic diseases. It has been used for centuries as a traditional medicine in Southeast Asia, but in Western countries is used as a functional food and a major ingredient of several herbal products. The genus Angelica is also known as 'female ginseng' due to its critical therapeutic role in female afflictions, such as gynecological problems. However, it is well-documented that the AGN pyranocoumarins may play vital beneficial roles against cancer, neurodisorders, inflammation, osteoporosis, amnesia, allergies, depression, fungi, diabetes, ischemia, dermatitis, reactive oxygen species (ROS) and androgen. Though numerous studies revealed the role of AGN pyranocoumarins as therapeutic agents, none of the reviews have published their molecular mechanism of action. To the best of our knowledge, this would be the first review that aims to appraise the biosynthesis of AGN's major active pyranocoumarins, discuss effective extraction and formulation methods, and detail the molecular action mechanism of decursin (D), decursinol angelate (DA) and decursinol (DOH) in chronic diseases, which would further help extension of research in this area.

Prostate Cancer Xenograft Inhibitory Activity and Pharmacokinetics of Decursinol, a Metabolite of Angelica gigas Pyranocoumarins, in Mouse Models.

We have previously shown that the ethanol extract of dried Angelica gigas Nakai (AGN) root exerts anticancer activity against androgen receptor (AR)-negative human DU145 and PC-3 prostate cancer xenografts and primary carcinogenesis in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. The major pyranocoumarin isomers decursin (D) and decursinol angelate (DA), when provided at equi-molar intake to that provided by AGN extract, accounted for the inhibitory efficacy against precancerous epithelial lesions in TRAMP mice. Since we and others have shown in rodents and humans that D and DA rapidly and extensively convert to decursinol, here we tested whether decursinol might be an in vivo active compound for suppressing xenograft growth of human prostate cancer cells expressing AR. In SCID-NSG mice carrying subcutaneously inoculated human LNCaP/AR-Luc cells overexpressing the wild type AR, we compared the efficacy of 4.5[Formula: see text]mg decursinol per mouse with equi-molar dose of 6[Formula: see text]mg D/DA per mouse. The result showed that decursinol decreased xenograft tumor growth by 75% and the lung metastasis, whereas D/DA exerted a much less effect. Measurement of plasma decursinol concentration, at 3[Formula: see text]h after the last dose of respective dosing regimen, showed higher circulating level in the decursinol-treated NSG mice than in the D/DA-treated mice. In a subsequent single-dose pharmacokinetic experiment, decursinol dosing led to 3.7-fold area under curve (AUC) of plasma decursinol over that achieved by equi-molar D/DA dosing. PK advantage notwithstanding, decursinol represents an active compound to exert in vivo prostate cancer growth and metastasis inhibitory activity in the preclinical model.

Nanocomposites based on Soluplus and Angelica gigas Nakai extract fabricated by an electrohydrodynamic method for oral administration.

Nanocomposites (NCs) based on Soluplus (SP) were fabricated by an electrohydrodynamic (EHD) method for the oral delivery of Angelica gigas Nakai (AGN). Nano-sized particles were obtained after dispersing the resultant, produced by the EHD technique, in the aqueous environment. AGN/SP2 (AGN:SP=1:2, w/w) NC dispersion in aqueous media exhibited a 130nm mean diameter, narrow size distribution, and robust stability in the tested concentration range of the ethanol extract of AGN (AGN EtOH ext) and at pH 1.2 and 6.8. Amorphization of the components of AGN and their interactions with SP in the AGN/SP2 NC formulation were demonstrated by X-ray diffractometry (XRD) analysis. The released amounts of decursin (D) and decursinol angelate (DA), major components of AGN, from NCs were improved compared with those from the AGN EtOH ext group at both pH 1.2 and 6.8. As D and DA can be metabolized into decursinol (DOH) in the liver after oral administration, the DOH concentrations in plasma were quantitatively determined to evaluate the oral absorption of AGN. In a pharmacokinetic study in rats, higher oral absorption and the maximum concentration in plasma (Cmax) were presented in the AGN/SP2 NC group compared with the AGN EtOH ext and AGN NC groups. These findings indicate the successful application of developed SP-based NCs for the oral delivery of AGN.

Comparative pharmacokinetics of bergenin, a main active constituent of Saxifraga stolonifera Curt., in normal and hepatic injury rats after oral administration.

Bergenin, isolated from the herb of Saxifrage stolonifera Curt. (Hu-Er-Cao) has hepatoprotective, anti-inflammatory, antitussive, and neuroprotective activities. The aim of the present study was to establish a simple, rapid, and sensitive RP-HPLC method for determination of bergenin in rat plasma and compare its oral pharmacokinetic behaviors in normal and CCl4-induced hepatic injury rats. With norisoboldine as an internal standard, chromatographic separation was performed on a C18 analytical column with acetonitrile and water (11 : 89, V/V) containing 0.1% formic acid as the mobile phase. A good linearity was obtained over the range of 100-10 000 ng·mL-1. The lower limit of quantification was 50 ng·mL-1. The developed method was successfully applied to a study of the pharmacokinetic difference of bergenin (100 mg·kg-1) between normal and hepatic injury rats after oral administration. Marked alterations of pharmacokinetic parameters in hepatic injury rats were observed. Compared to normal rats, the AUC(0-∞) of bergenin in hepatic injury rats was elevated to 2.11-fold and Cmax was increased by 130%, whereas CL value was only 55% of the normal rats, suggesting that the systemic exposure of bergenin was significantly increased under hepatic injury status.

In Vitro Bioaccessibility, Human Gut Microbiota Metabolites and Hepatoprotective Potential of Chebulic Ellagitannins: A Case of Padma Hepaten® Formulation.

Chebulic ellagitannins (ChET) are plant-derived polyphenols containing chebulic acid subunits, possessing a wide spectrum of biological activities that might contribute to health benefits in humans. The herbal formulation Padma Hepaten containing ChETs as the main phenolics, is used as a hepatoprotective remedy. In the present study, an in vitro dynamic model simulating gastrointestinal digestion, including dialysability, was applied to estimate the bioaccessibility of the main phenolics of Padma Hepaten. Results indicated that phenolic release was mainly achieved during the gastric phase (recovery 59.38%-97.04%), with a slight further release during intestinal digestion. Dialysis experiments showed that dialysable phenolics were 64.11% and 22.93%-26.05% of their native concentrations, respectively, for gallic acid/simple gallate esters and ellagitanins/ellagic acid, in contrast to 20.67% and 28.37%-55.35% for the same groups in the non-dialyzed part of the intestinal media. Investigation of human gut microbiota metabolites of Padma Hepaten and pure ChETs (chebulinic, chebulagic acids) established the formation of bioactive urolithins (A, B, C, D, M5). The fact of urolithin formation during microbial transformation from ChETs and ChET-containing plant material was revealed for the first time. Evaluation of the protective effect of ChETs colonic metabolites and urolithins on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in cultured rat primary hepatocytes demonstrated their significant reversion of the t-BHP-induced cell cytotoxicity, malonic dialdehyde production and lactate dehydrogenase leakage. The most potent compound was urolithin C with close values of hepatoprotection to gallic acid. The data obtained indicate that in the case of Padma Hepaten, we speculate that urolithins have the potential to play a role in the hepatic prevention against oxidative damage.

The natural compound chebulagic acid inhibits vascular endothelial growth factor A mediated regulation of endothelial cell functions.

Vascular endothelial growth factor A (VEGFA) plays an important role in tumour angiogenesis and its angiogenic action is mainly mediated through its VEGF receptor 2 (VEGFR-2). Therefore drugs targeting VEGFA/VEGFR-2 are being presently used in the clinics for treatment of several types of solid malignant tumours. We here in report that low dose of chebulagic acid (CA), a hydrolysable tannin found in myrobalan fruits can inhibit VEGFA induced vascular permeability, endothelial cell proliferation, migration, tube formation and thereby, angiogenesis by suppressing VEGFR-2 phosphorylation. CA may thus be an effective and useful natural inhibitor of VEGFA mediated angiogenesis.

Blood pressure-decreasing effect of etamicastat alone and in combination with antihypertensive drugs in the spontaneously hypertensive rat.

Hyperactivation of the sympathetic nervous system has an important role in the development and progression of arterial hypertension. This study evaluated the efficacy of etamicastat, a dopamine-ß-hydroxylase (DßH) inhibitor, in controlling high blood pressure in the spontaneously hypertensive rat (SHR), either alone or in combination with other classes of antihypertensives. SHRs were administered with etamicastat by gavage, and its pharmacodynamic and pharmacokinetic properties were evaluated. Etamicastat induced a time-dependent decrease in noradrenaline-to-dopamine ratios in the heart and kidney, and had no effect on catecholamine levels in the frontal cortex of SHRs. Cardiovascular pharmacodynamic effects following administration of etamicastat alone or in combination with other classes of antihypertensive drugs were assessed by telemetry. Etamicastat was evaluated in combination with captopril, losartan, hydrochlorothiazide, metoprolol, prazosin and/or diltiazem. Etamicastat monotherapy induced a dose-dependent reduction in blood pressure without reflex tachycardia. Combination therapy amplified the antihypertensive effects of all tested drugs. In conclusion, inhibition of peripheral DßH with etamicastat, as a monotherapy or combination therapy, may constitute a valid alternative treatment for high blood pressure.

An LC-MS/MS method for the simultaneous determination and pharmacokinetic studies of bergenin, chlorogenic acid and four flavonoids in rat plasma after oral administration of a QingGanSanJie decotion extract.

A rapid, simple and sensitive, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of bergenin, chlorogenic acid and four flavonoids in a QingGanSanJie preparation in rat plasma. Puerarin was selected as the internal standard (IS). Plasma samples were precipitated with methanol and separated with a reverse phase Agilent Poroshell 120 EC-C18 column using a gradient mobile phase of methanol-water containing 0.1% formic acid (v/v). A triple quadruple mass spectrometer was used for quantification (limit of detection 0.36-5.55 ng/mL). Intra-day and inter-day precisions were within 15% and the average extraction recoveries ranged from 85 to 115% for each analyte. The method allowed simultaneous quantification for the first time of the pharmacokinetics of bergenin, chlorogenic acid and four flavonoids after intragastric administration of a QingGanSanJie extract in Sprague-Dawley rats. It was found that bergenin and chlorogenic acid had typical extravascular administration concentration-time curves; flavonoids had a bimodal distribution improving bioavailability and extending the pharmacodynamics period.

Pharmacokinetics and excretion study of sophoricoside and its metabolite in rats by liquid chromatography tandem mass spectrometry.

In this study, a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of sophoricoside and its metabolite genistein in rat plasma, bile, urine and feces after oral administration of sophoricoside, using sulfamethalazole as internal standard (IS). The separation was performed on a reverse phase C18 column with gradient elution consisting of 0.2‰ aqueous formic acid and methanol (containing 0.2‰ formic acid). The detection was accomplished by multiple-reaction monitoring (MRM) scanning after electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 431.2/268.2 for sophoricoside, 268.7/133.0 for genistein and 252.0/156.0 for IS. This developed method provides good linearity (r>0.9983), intra- and inter-day precisions (RSD<8.31%) with accuracies (RE, -6.91 to 6.66%), stability (RE, -7.45 to 6.59%), extract recovery (76.24 to 93.30%) and matrix effect (81.06-106.2%) of the analytes in plasma, bile, urine and feces. The mean elimination half-life (t1/2) of sophoricoside and genistein were 59.78±7.19 and 103.14±16.97min, respectively. The results showed that sophoricoside was rapidly absorbed and then eliminated from rat plasma. The total recoveries of sophoricoside in bile, urine and feces were about 0.0111%, 1.76% and 11.13%. The amounts excreted of genistein were 0.42±0.02µg in bile, 10.15±0.22µg in urine and 2.92±0.13µg in feces. This is the first report to evaluate the pharmacokinetics and excretion of sophoricoside and its metabolite in rats after oral administration of sophoricoside monomer. The results provided a meaningful basis for the clinical application of sophoricoside.

A simple high-performance liquid chromatographic method for the determination of brazilin and its application to a pharmacokinetic study in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Caesalpinia sappan is a medicinal plant native to China popularly used to treat chronic pelvic inflammation, dysmenorrhea and hysteromyoma. Its main bioactive component is brazilin which had presented antibacterial, anti-inflammatory and anti-platelet aggregation activities. To establish a sensitive, selective, reproducible, and accurate high performance liquid chromatographic (HPLC) method for the quantitative determination of brazilin in plasma, and study the pharmacokinetics of brazilin in rats after intravenous administration of brazilin. MATERIALS AND METHODS: Rats received intravenous injection of 25, 50 and 100mg/kg of brazilin. Concentrations of brazilin in plasma were determined by HPLC method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis with WinNonLin 6.2 software. RESULTS: After single intravenous doses of 25, 50 and 100mg/kg brazilin in rats, the main PK parameters were as follows: Cmax were 18.1 ± 4.1, 46.7 ± 8.7 and 82.2 ± 9.6 µg/mL; AUC0-24 were 20.4 ± 4.3, 48.7 ± 6.8 and 90.4 ± 10.3 µgh/mL; and t1/2 were 5.4 ± 1.5, 5.8 ± 0.9 and 6.2 ± 1.2h, respectively. CONCLUSION: It showed that the brazilin was eliminated moderately in rat by intravenous injection route with t1/2 of 6h and showed a dose-dependence profile of Cmax and AUC0-24 at the doses of 25~100mg/kg of brazilin for injection in rats.

An LC/MS/MS method for simultaneous quantitation of two homoisoflavones: protosappanin B and brazilin with hypoglycemic activity in rat plasma and its application to a comparative pharmacokinetic study in normal and streptozotocin-treated rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The heartwood of Caesalpinia sappan L. (Leguminosae), a widely used Chinese medicine in folk, has been used for the treatment of traumatic injury, stasis pain, amenorrhea, dysmenorrheal, as well as stabbing pain in the chest, abdomen and so on. Protosappanin B and brazilin, as the major bioactive homoisoflavones of Sappan Lignum, are used as the marker components for the quality control of the herb in China Pharmacopoeia. AIM OF THE STUDY: To establish a sensitive LC/MS/MS method for investigating the pharmacokinetic properties of protosappanin B and brazilin in rats after oral administration of Sappan Lignum extract, and compare their pharmacokinetics difference between normal and streptozotocin-treated rats. MATERIAL AND METHODS: A rapid, selective and sensitive LC/MS/MS method was developed and validated for the simultaneous quantification of protosappanin B and brazilin in rat plasma. Normal and streptozotocin-treated rats were orally administered with the Sappan Lignum extract at the same dose of 2.83 g extract/kg body weight (equivalent to 35.56 mg/kg of protosappanin B and 52.25 mg/kg of brazilin), respectively. RESULTS: After oral administration of Sappan Lignum extract, a remarkable increase (p<0.05) in the value of AUC0-24h, AUC0-∞, Cmax and T1/2 associated with protosappanin B and brazilin was observed in the streptozotocin-treated group. Compared with the normal rats, elimination of both compounds in the streptozotocin-treated rats was slower. CONCLUSION: The established method was successfully applied to compare the pharmacokinetic behaviors of protosappanin B and brazilin in rat plasma after oral administration of Sappan Lignum extract between normal and streptozotocin-treated groups; the results might suggest the accumulation of both compounds in diabetic pathologic states and the adverse reaction should be considered when it was used.

Single oral dose pharmacokinetics of decursin, decursinol angelate, and decursinol in rats.

Decursin and decursinol angelate are the major components in the alcoholic extract of the root of Angelica gigas Nakai. Our previous work convincingly demonstrated that both decursin and decursinol angelate were rapidly converted to decursinol in mice after administration by either oral gavage or i. p. injection. In the current study, we compared for the first time the plasma profiles of decursinol, when equal moles of decursin/decursinol angelate or decursinol were given to rats by oral gavage, and investigated the effect of different formulas and other chemicals in Angelica gigas extract on the bioavailability of decursinol. Our results show that gavage of decursinol led to a faster attainment of plasma decursinol peak (Tmax ~ 0.7 h) and much higher peak levels than an equal molar amount administered as decursin/decursinol angelate mixture or as Angelica gigas ethanol extract, resulting in 2-3 fold higher bioavailability as estimated by the area under the curve of the respective regimens (65 012 vs. 27 033 h · ng/mL for decursinol and decursin/decursinol angelate treatment groups, respectively). Compared to a formula based on ethanol-PEG400-Tween80, carboxyl methyl cellulose was a less optimized vehicle. In addition, we detected peak levels of decursin and decursinol angelate in the plasma of rats administered with decursin/decursinol angelate or Angelica gigas extract in the nM range (Tmax ~ 0.5 h) with a newly established sensitive UHPLC-MS/MS method. Furthermore, our data support the liver, instead of intestine, as a major organ site where decursin and decursinol angelate were hydrolyzed to decursinol with a S9 microsomal in vitro metabolism assay. Taken together, our study provided important PK, LC-MS/MS methodology, formulation and metabolism insights in a rodent model for the rational design of in vivo efficacy studies of the corresponding chemicals in the future.

A validated LC-MS/MS method for rapid determination of brazilin in rat plasma and its application to a pharmacokinetic study.

Brazilin is a major homoisoflavonoid component isolated from the dried heartwood of traditional Chinese medicine Caesalpinia sappan L., which is a natural red pigment used for histological staining. Herein a sensitive, specific and rapid analytical LC-MS/MS method was established and validated for brazilin in rat plasma. After a simple step of protein precipitation using acetonitrile, plasma samples were analyzed using an LC-MS/MS system. Brazilin and the IS (protosappanin B) were separated on a Diamonsil C18 analytical column (150 × 4.6 mm, 5 µm) using a mixture of water and 10 mm ammonium acetate in methanol (20:80, v/v) as mobile phase at a flow rate of 0.6 mL/min. The method was sensitive with a lower limit of quantitation of 10.0 ng/mL, with good linearity (r(2) ≥ 0.99) over the linear range 10.0-5000 ng/mL. All the validation data, such as accuracy and precision, matrix effect, extraction recovery and stability tests were within the required limits. The assay method was successfully applied to evaluate the pharmacokinetics parameters of brazilin after an oral dose of 100 mg/kg brazilin in rats.

Biopharmaceutical characterization of decursin and their derivatives for drug discovery.

Angelica gigas Nakai and its components are known to have neuroprotective, antiplatelet, and anticancer activities. The present study evaluated the in vitro and in vivo biopharmaceutical characterization of Angelica gigas component substances, including decursin (the main substance), decursinol angelate (decursin isomer), JH714 (ether form of decursin) and epoxide decursin (epoxide form of decursin). Decursin, decursinol angelate and JH714 exhibited acceptable metabolic stability (>50%) in liver microsomes from human and higher bound fraction (>90%) in human plasma operating ultrafiltration. Decursin and decursinol angelate in CYP1A2 and CYP2C19 indicated less than 50% CYP activity, suggesting inhibition of the CYP isoforms using Vivid® CYP screening kit. JH714 only showed an apparent permeability coefficient of <10 × 10⁻6 cm/s in MDCK cells, suggesting that it is poorly absorbed. Blood brain barrier permeability was examined after oral administration to male Sprague-Dawley (SD) rats, and pharmacokinetic studies were performed after oral and intravenous administration of 10 mg/kg compounds. Decursin, decursinol angelate and JH714 showed ratios of compound concentration in brain with respect to plasma (Cbrain/Cplasma) of >1.5, suggesting good brain/plasma ratio at 0.5, 1, 3, and 5 h. In contrast, Cbrain/Cplasma was <0.5 for epoxide decursin. For all test compounds, >1.5% of the dose remained in GI tract after 8 h, and the excretion rate in urine was <0.5% which suggests that gastro intestinal tract may be major site of disposition following oral administration. Finally, these results may be useful for the design of dosage regimens of decursin and its derivatives.