Quercetin Attenuates Visceral Hypersensitivity and 5-Hydroxytryptamine Availability in Postinflammatory Irritable Bowel Syndrome Rats: Role of Enterochromaffin Cells in the Colon.

Intestinal enterochromaffin (EC) cell hyperplasia and increased 5-hydroxytryptamine (5-HT) availability play key roles in the pathogenesis of abdominal hypersensitivity of irritable bowel syndrome (IBS). This study aims to study the effect of quercetin on visceral pain and 5-HT availability in postinflammatory IBS (PI-IBS) rats. PI-IBS model rats were administered quercetin by gavage at doses of 5, 10, and 20 mg/kg for 14 days. Compared with normal rats, the visceral pain threshold of PI-IBS rats was markedly decreased and the abdominal motor response to colon distension was markedly increased. The EC cell count and 5-HT level, as well as tryptophan hydroxylase (TPH) protein, were all significantly elevated in PI-IBS rats, while the 5-HT reuptake transporter (serotonin transporter) was reduced. Genes that are responsible for enteroendocrine cell differentiation, that is, Ngn3 and pdx1, were significantly increased in the PI-IBS group. Quercetin treatment markedly elevated the pain threshold pressure and decreased the visceral motor response of PI-IBS animals; and EC cell density and 5-HT level, as well as TPH expression, in the PI-IBS group were all reduced by quercetin. Quercetin treatment also significantly reduced colonic expression of Ngn3 and pdx1 of PI-IBS. Findings from the present study indicated that the analgesic effect of quercetin on PI-IBS may result from reduction of 5-HT availability in the colon, and the regulatory role of quercetin in endocrine progenitors may contribute to reduced EC cells.

Multicomponent determination of traditional Chinese medicine preparation yin-zhi-huang injection by LC-MS/MS for screening of its potential bioactive candidates using HepaRG cells.

Yin-zhi-huang (YZH) injection is an injectable multiherbal prescription derived from the ancient Chinese medicine formula of Yin-chen-hao-tang, which is widely used in the clinic for the treatment of jaundice and chronic liver diseases. To date, the systematic study of the components in this multiherbal prescription still lacks suitable analytical methods that are able to simultaneously detect a broad array of components at low concentrations. In this study, a new liquid chromatography-tandem mass spectrometry method using dynamic multiple reaction monitoring mode was developed to determine multiple peaks in traditional Chinese medicine preparation YZH injection. This simple, selective and sensitive method enabled the quantification of 22 components with standard materials with a lower limit of quantification of 1.46-12.5 ng/mL in cell lysates. This method was successfully applied to celluar uptake and binding investigation of components in YZH injection. The results indicated that this strategy might be a useful approach for rapidly screening of the potential bioactive candidates from YZH injection, and the discovered candidates could be used to investigate the pharmacodynamics in further studies.

Monoammonium glycyrrhizinate protects rifampicin- and isoniazid-induced hepatotoxicity via regulating the expression of transporter Mrp2, Ntcp, and Oatp1a4 in liver.

CONTEXT: Drug-induced liver injury (DILI) is associated with altering expression of hepatobiliary membrane transporters. Monoammonium glycyrrhizin (MAG) is commonly used for hepatic protection and may have a correlation with the inhibition effect of multidrug resistance-associated protein 2 (Mrp2). OBJECTIVE: This study evaluates the dynamic protective effect of MAG on rifampicin (RIF)- and isoniazid (INH)-induced hepatotoxicity in rats. MATERIALS AND METHODS: Male Wistar rats were randomly divided into four groups of 15 rats. Liver injury was induced by co-treatment with RIF (60 mg/kg) and INH (60 mg/kg) by gavage administration; MAG was orally pretreated at the doses of 45 or 90 mg/kg 3 h before RIF and INH. Rats in each group were sacrificed at 7, 14, and 21 d time points after drug administration. RESULTS: Liver function, histopathological analysis, and oxidative stress factors were significantly altered in each group. The expression of Mrp2 was significantly increased 230, 760, and 990% at 7, 14, and 21 time points, respectively, in RIF- and INH-treated rats. Compared with the RIF and INH groups, Mrp2 was reduced and Ntcp was significantly elevated by 180, 140, and 160% in the MAG high-dose group at the three time points, respectively. The immunoreaction intensity of Oatp1a4 was increased 170, 190, and 370% in the MAG low-dose group and 160, 290, and 420% in the MAG high-dose group at the three time points, respectively, compared with the RIF and INH groups. DISCUSSION AND CONCLUSION: These results indicated that MAG has a protective effects against RIF- and INH-induced hepatotoxicity. The underlying mechanism may have correlation with its effect on regulating the expression of hepatobiliary membrane transporters.

Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb-drug interaction study of metoprolol and breviscapine.

A simple, specific and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of metoprolol (MET), α-hydroxymetoprolol (HMT) and O-desmethylmetoprolol (DMT) in rat plasma. The plasma samples were prepared by protein precipitation, then the separation of the analytes was performed on an Agilent HC-C18 column (4.6 × 250 mm, 5 µm) at a flow rate of 1.0 mL/min, and post-column splitting (1:4) was used to give optimal interface flow rates (0.2 mL/min) for MS detection; the total run time was 8.5 min. Mass spectrometric detection was achieved using a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. The method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, matrix effect and recovery over a concentration range of 3.42-7000 ng/mL for MET, 2.05-4200 ng/mL for HMT and 1.95-4000 ng/mL for DMT. The analytical method was successfully applied to herb-drug interaction study of MET and breviscapine after administration of breviscapine (12.5 mg/kg) and MET (40 mg/kg). The results suggested that breviscapine have negligible effect on pharmacokinetics of MET in rats; the information may be beneficial for the application of breviscapine in combination with MET in clinical therapy.

Effect of Yin-Zhi-Huang on up-regulation of Oatp2, Ntcp, and Mrp2 proteins in estrogen-induced rat cholestasis.

CONTEXT: Yin-Zhi-Huang (YZH), a prescription of traditional Chinese medicine, is widely used to treat neonatal jaundice or cholestasis. OBJECTIVE: This study investigates the regulatory effect of YZH on the localization and expression of organic anion transporting polypeptides 2 (Oatp2), Na(+)-taurocholate co-transporting polypeptide (Ntcp), multidrug-resistance-associated protein 2 (Mrp2), and bile salt export pump (Bsep) in estrogen-induced cholestasis rats. MATERIAL AND METHODS: Cholestasis model rats were induced via subcutaneous injection of estradiol benzoate (EB, 5 mg/kg/d) for 5 d. Other EB-induced rats were treated with saline (2 ml) or YZH (1.5 g/kg, two times a day) for 7, 14, and 21 d. The biochemical and pathologic examinations were performed. Moreover, the localization and expression of Oatp2, Ntcp, Mrp2, and Bsep were determined by immunohistochemisty and Western blotting, respectively. RESULTS: YZH treatment could significantly decrease the serum total bile acids (TBA) (4.9 ± 0.6-2.8 ± 0.8) and direct bilirubin (DBIL) (2.6 ± 0.7-1.0 ± 0.1) levels, improve the histological disorganization, and, respectively, increase the expression of Oatp2 and Ntcp by 46% and 28% compared with saline-treated (p < 0.05) rats at 14 d. The expression of Mrp2 increased by 45% was observed in YZH treated compared with saline-treated (p < 0.05) rats at 7 d. However, there was a little change in the expression of Bsep (p > 0.05) after YZH treatment for 7, 14, and 21 d. DISCUSSION AND CONCLUSION: In conclusion, the therapeutic effect of YZH to cholestasis could be attributed to the regulation of Oatp2, Ntcp, Mrp2, and Bsep.

Development of a dynamic multiple reaction monitoring method for determination of digoxin and six active components of Ginkgo biloba leaf extract in rat plasma.

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method by using dynamic multiple reaction monitoring (DMRM) has been developed and validated for the simultaneous determination of digoxin (DGX) and six main components of Ginkgo biloba leaf extract (GBE) in rat plasma. Comparing with the conventional multiple reaction monitoring (MRM), DMRM dramatically decreases the number of concurrent MRM transitions, and significantly extended the dwell time, which provided much higher sensitivity and reproducibility than MRM when complex multi-component samples were quantified. The plasma samples were protein precipitated with methanol, the detection was accomplished with electro-spray ionization (ESI) as the ion source operating in the negative ionization mode, with methanol and water as mobile phase, and with an Agilent Zorbax eclipse plus C18 column (4.6 × 100 mm, 3.5 µm) as the analytical column. The total run time was 12.0 min. The validation of the method was implemented including specificity, linearity, accuracy, precision, recovery, matrix effect and stability. This method was successfully applied to the herb-drug pharmacokinetic interaction study of DGX combined with GBE after oral administration to rats. The result indicated that co-administration of GBE and DGX significantly influenced the pharmacokinetics of DGX when compared to that of single DGX-treated rats.

Preparation and in vitro evaluation of ethosomal total alkaloids of Sophora alopecuroides loaded by a transmembrane pH-gradient method.

A novel transmembrane pH gradient active loading method to prepare alkaloids binary ethosomes was developed in this work. Using this novel method, binary ethosomes containing total alkaloids extracted from Sophora alopecuroides (TASA) were prepared successfully at the temperature below the phase transition temperature (Tc) of the phosphatidyl choline (PC). Several factors affecting this method were investigated. The qualities of the TASA binary ethosomes were characterized by the shape, particle size, and encapsulation efficiency (EE). The percutaneous absorption study of TASA binary ethosomes was performed using confocal laser scanning microscopy and Franz diffusion cells. The results showed that more than 90% sophoridine, 47% matrine, 35% sophocarpine, and 32% lemannine in TASA were entrapped within 1 h at 40°C, with an efficiency improvement of 8.87, 8.10, 7.63, and 7.78-fold than those observed in passive loading method. Transdermal experiments showed that the penetration depth and fluorescence intensity of Rhodamine B from binary ethosome prepared by pH gradient active loading method were much greater than that from binary ethosome prepared by passive loading method or hydroalcoholic solution. These results suggested transmembrane pH gradient active loading method may be an effective method to prepare alkaloids ethosomal systems at the temperatures below the Tc of PC.

Extraction, separation and quantitative structure-retention relationship modeling of essential oils in three herbs.

The essential oils extracted from three kinds of herbs were separated by a 5% phenylmethyl silicone (DB-5MS) bonded phase fused-silica capillary column and identified by MS. Seventy-four of the compounds identified were selected as origin data, and their chemical structure and gas chromatographic retention times (RT) were performed to build a quantitative structure-retention relationship model by genetic algorithm and multiple linear regressions analysis. The predictive ability of the model was verified by internal validation (leave-one-out, fivefold, cross-validation and Y-scrambling). As for external validation, the model was also applied to predict the gas chromatographic RT of the 14 volatile compounds not used for model development from essential oil of Radix angelicae sinensis. The applicability domain was checked by the leverage approach to verify prediction reliability. The results obtained using several validations indicated that the best quantitative structure-retention relationship model was robust and satisfactory, could provide a feasible and effective tool for predicting the gas chromatographic RT of volatile compounds and could be also applied to help in identifying the compound with the same gas chromatographic RT.

[Effects of Yuquan pills on pharmacokinetics of metformin hydrochloride in diabetic rats].

OBJECTIVE: To study effects of Yuquan pills on the pharmacokinetics process of metformin hydrochloride in diabetic rats. METHOD: After administration Yuquan pills 7 day to the diabetic rats, the metformin hydrochloride was orally administrated, then the blood samples were collected at different time. The concentrations of metformin hydrochloride in plasma were determined by HPLC method and the pharmacokinetic parameters were calculated. RESULT: The pharmacokinetic parameter Cmax of the controlling group and the testing group were respectively, 18.95, 21.76 mg x L(-1); t1/2 were 1,069.8, 1,767.4 min, respectively; CL/F were 0.013, 0.008 L x min(-1) x kg(-1); AUC were 10,042.1, 10,712.2 mg z L(-1) x min(-1) respectively. CONCLUSION: The pharmacokinetics process of metformin hydrochloride in diabetic rats fits one-compartment model. Yuquan pills has a significant effect on the pharmacokinetics of metformin hydrochloride in diabetic rats.

Studies on chemical constituents of Rheum glabricaule.

OBJECTIVE: To study the chemical Constituents in the root of Rheum glabricaule. METHODS: Compounds were isolated by various column chromatographies with sillica gel. Their structures were identified by spectral analysis (MS, 1HNMR, 13 CNMR) and chemical evidences. RESULTS: Seven compounds were isolated from this plant, including n-hexacosnic acid (I), palmitic acid (II), daucosterol (III), chrysophanol-8-Me ether (IV), citreorosein (V), chrysophanol 8-O-beta-D-glucopyranoside (VI) and 2,5-dimethyl-7-methoxychromone (VII). CONCLUSION: All above compounds are obtained from this plant for the first time.

[Isolation and indentification of chemical compounds from Drynaria fortunei].

OBJECTIVE: To study the chemical components of Drynaria fortunei. METHOD: The herbal material was extracted with 75% ethanol. The chemical components were isolated by silica gel and sephadex LH-20 column chromatography. The structures were identified on the basis of chemical and spectroscopic data. RESULT: Four compounds were isolated, three of which were identified as (-)-epiafzelechin-3-O-beta-D-allopyranoside, (-)-epiafzelechin and beta-sitosterol. CONCLUSION: (-)-epiafzelechin-3-O-beta-D-allopyranoside, (-)-epiafzelechin were obtained from D. fortunei for the first time.

[Opinion of colon-targeting delivery about rhubarb extract as a purgative].

OBJECTIVE: To elucidate that rhubarb extract as a purgative should be delivered to colon from a pharmaceutical point of view. METHOD: Effects of anthranoids and free anthraquinones as purgatives on the colon motility and transit time, the absorption in vivo, and the loss in the processes of extraction, concentration and dryness were reviewed, based on the recent 60 years pharmacological, pharmaceutical and clinical experimental studies at home and abroad. RESULT AND CONCLUSION: Free anthraquinones in rhubarb extract should be regarded as purgative principles. Close attention should be paid to the loss of free anthraquinones not only in the processes of extraction, concentration and dryness, but also in the process of transit in the upper gastrointestinal tract. Colon-targeting delivery of rhubarb extract, as a purgative, may prevent absorption of free anthraquinones in the upper gastrointestinal tract, thus improving clinical effects and lowering dosage.