Pharmacokinetic study of multicomponent in Hong-Hua-Xiao-Yao tablet.

Hong-Hua-Xiao-Yao tablet (HHXYT) is attracting attention increasingly because of its use in treatment of mammary gland hyperplasia (MGH) and menopausal syndrome. However, its pharmacokinetics remains unclear. This study developed a sensitive and rapid method for simultaneous determination of 10 compounds of HHXYT in rat plasma by liquid chromatography-tandem mass spectrometry and to compare the pharmacokinetics of these compounds in MGH rats and sham operated rats. The linearity, accuracy, precision, stability and matrix effect were within acceptable ranges. This established method was successfully applied to a pharmacokinetics study of 10 compounds in sham operated and MGH rats. According to the results, the bioavailability of glycyrrhetinic acid was highest in MGH rats and sham operated rats. The mean residence times of glycyrrhetinic acid and glycyrrhetinic acid 3-O-glucuronide were higher than those of the other compounds while the mean residence time and half-life of liquiritin, isoliquiritin and paeoniflorin were lower. Some pharmacokinetic parameters of ormononetin, liquiritigenin, isoliquiritigenin, liquiritin, isoliquiritin, paeoniflorin, protocatechuic acid and senkyunolide I were significantly different between MGH rats and sham operated rats. This study elucidated the dynamic changes of multiple components in rats after oral administration of HHXYT systematically and comprehensively, which provided guidance for clinical application.

Dissection of the potential pharmacological function of neohesperidin dihydrochalcone - a food additive - by in vivo substances profiling and network pharmacology.

Food additives are widely used in our daily life, and the side-effects caused by them have gained extensive attention around the world. Notably, constituent-oriented metabolites, in some sense, always contribute to pharmacological changes, inducing toxicity, therapeutic effects, etc. Characterization of the metabolites and their potential functions is of great importance to the practical applications. In this work, an integrated strategy by combining metabolite profiling and network pharmacology was applied to characterize the metabolic features and reveal pharmacological changes of neohesperidin dihydrochalcone (NHDC) in vivo to demonstrate its pharmacological mechanism and potential functions. As a result, a total of 19 metabolites (3 in plasma, 19 in urine, 8 in feces, 3 in heart, 5 in liver, 0 in spleen, 1 in lung, 2 in kidneys and 2 in brain) were screened and 18 of them were characterized for the first time. Phase I metabolic reactions of hydrolysis and phase II reactions of glucuronidation, sulfation, glutamylation, N-butyryl glycylation and lactylation were the main metabolic reactions of NHDC in vivo. Moreover, the results analyzed by network pharmacology revealed that, in addition to common pathways (steroid hormone biosynthesis) of NHDC, metabolites' targets were involved in pathways in cancer, ovarian steroidogenesis, proteoglycans in cancer, PI3K-Akt signaling pathway and progesterone-mediated oocyte maturation, indicating that these functional changes might result in potential novel functions or other side-effects, such as a disorder of steroid hormones. Our work provided the metabolic features and functional modifications of NHDC in vivo for the first time, and meaningful information for further pharmacological validations or potential functions is supplied.

Simultaneous characterization of multiple Psoraleae Fructus bioactive compounds in rat plasma by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry for application in sex-related differences in pharmacokinetics.

A method for the simultaneous quantification of 13 bioactive compounds (psoralen, isopsoralen, isobavachin, bakuchalcone, neobabaisoflavone, bavachin, corylin, psoralidin, isobavachalcone, bavachinin, corylifol A, bavachalcone, and bakuchiol) by ultra-high-performance liquid chromatography coupled with triple quadrupole mass spectrometry has been developed and validated in rat plasma. Osthol was used as an internal standard and plasma samples were pretreated with one-step liquid-liquid extraction. These analytes were separated using a gradient mobile phase system of water and acetonitrile at a flow rate of 0.2 mL/min on a reverse-phase C18 column and analyzed in the selected multiple reactions monitoring mode. All calibration curves were linear (r > 0.9952) over the tested ranges. The intra- and interday accuracy and precisions of these analytes at three different concentration levels were within the acceptable limits of <15% at all concentrations. The mean recoveries of these analytes at three concentrations were more than 60.2% and the matrix effects were in the range of 85-115%. Stability studies proved that the analytes were stable under the tested conditions. The developed method was applied to evaluating the pharmacokinetic study of 13 bioactive compounds after oral administration of Psoraleae Fructus in rat of different genders. Some active compounds in Psoraleae Fructus had sex-related pharmacokinetics.

Enhancement of Oral Bioavailability and Anti-hyperuricemic Activity of Isoliquiritigenin via Self-Microemulsifying Drug Delivery System.

The aim of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) for enhancement of the oral bioavailability of isoliquiritigenin (ISL) as well as evaluate its in vivo anti-hyperuricemic effect in rats. The ISL-loaded self-microemulsifying drug delivery system (ISL-SMEDDS) was comprised of ethyl oleate (EO, oil phase), Tween 80 (surfactant), and PEG 400 (co-surfactant). The ISL-SMEDDS exhibited an acceptable narrow size distribution (44.78 ± 0.35 nm), negative zeta potential (- 10.67 ± 0.86 mV), and high encapsulation efficiency (98.17 ± 0.24%). The in vitro release study indicated that the release rates of the formulation were obviously higher in different release media (HCl, pH 1.2; PBS, pH 6.8; double-distilled water, pH 7.0) compared with the ISL solution. The oral bioavailability of the ISL-SMEDDS was enhanced by 4.71 times in comparison with the free ISL solution. More importantly, ISL-SMEDDS significantly reduced uric acid level by inhibiting xanthine oxidase (XOD) activity in the model rats. Collectively, the prepared ISL-SMEDDS proved to be potential carriers for enhancing the solubility and oral bioavailability of ISL, as well as ameliorating its anti-hyperuricemic effect.

Simultaneous Determination and Pharmacokinetic Characterization of Glycyrrhizin, Isoliquiritigenin, Liquiritigenin, and Liquiritin in Rat Plasma Following Oral Administration of Glycyrrhizae Radix Extract.

Glycyrrhizae Radix is widely used as herbal medicine and is effective against inflammation, various cancers, and digestive disorders. We aimed to develop a sensitive and simultaneous analytical method for detecting glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin, the four marker components of Glycyrrhizae Radix extract (GRE), in rat plasma using liquid chromatography-tandem mass spectrometry and to apply this analytical method to pharmacokinetic studies. Retention times for glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin were 7.8 min, 4.1 min, 3.1 min, and 2.0 min, respectively, suggesting that the four analytes were well separated without any interfering peaks around the peak elution time. The lower limit of quantitation was 2 ng/mL for glycyrrhizin and 0.2 ng/mL for isoliquiritigenin, liquiritigenin, and liquiritin; the inter- and intra-day accuracy, precision, and stability were less than 15%. Plasma concentrations of glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin were quantified for 24 h after a single oral administration of 1 g/kg GRE to four rats. Among the four components, plasma concentration of glycyrrhizin was the highest and exhibited a long half-life (23.1 ± 15.5 h). Interestingly, plasma concentrations of isoliquiritigenin and liquiritigenin were restored to the initial concentration at 4-10 h after the GRE administration, as evidenced by liquiritin biotransformation into isoliquiritigenin and liquiritigenin, catalyzed by fecal lysate and gut wall enzymes. In conclusion, our analytical method developed for detecting glycyrrhizin, isoliquiritigenin, liquiritigenin, and liquiritin could be successfully applied to investigate their pharmacokinetic properties in rats and would be useful for conducting further studies on the efficacy, toxicity, and biopharmaceutics of GREs and their marker components.

Bioanalytical method development and validation for quantification of morachalcone A in rabbit plasma using high performance liquid chromatography.

Artocarpus champeden (A. champeden) ethanol extract has been reported as antimalarial activity and prospective to be developed as phytomedicine products. The active marker compound was identical with known prenylated chalcone compound, Morachalcone A. To further develop phytomedicine products from A. champeden especially in aspects of bioavailability and pharmacokinetic, a valid, selective and sensitive analytical method becomes important to determine morachalcone A in plasma. The aim of study was to develop and validate selectivity and sensitivity of High Performance Liquid Chromatography (HPLC) method to determine morachalcone A in rabbit plasma. This method was used a RP-18 Column (250 x 4.6 mm i.d, 5 µm), under isocratic elution and acetonitrile:water (50:50 v/v) was used as mobile phase with flow rate of 1.0ml/min. Detection was carried out at 368 nm, 4-hydroxychalcone and methanol were used as internal standard and precipitant. Results showed that this HPLC method was selective with good linearity in range of 3096.774 to 154.839ng/ml. LOD and LLOQ were 89.384 and 154.839ng/ml, respectively. The mean %different was found between 2.79 to 14.33%. Intra and inter-day precision were ≤15% and recovery from this extraction method of morachalcone A and Internal Standard were 80-120%.

Evaluation of estrogenic potency of a standardized hops extract on mammary gland biology and on MNU-induced mammary tumor growth in rats.

Supplements with estrogenic activities are intensively investigated as potential alternatives for the treatment of menopausal symptoms. These investigations include studies on their safety regarding potential breast cancer risks. Therefore, the aim of this study was to assess whether or not a standardized hops (Humulus lupulus) extract, containing 0.42% of the estrogenic flavanone, 8-prenylnaringenin, would stimulate growth of methyl-nitrosourea (MNU) induced mammary cancer in ovariectomized (OVX) Sprague-Dawley (SD) rats or would impact on the proliferative activity within the normal mammary gland of Wistar rats. To induce tumorigenesis SD-rats received an intraperitoneal injection of 50mg/kg body weight of MNU on postnatal days PND 50 and 52. 28days later animals were OVX or were SHAM operated (positive control) and randomly allocated and maintained for 140days on either a phytoestrogen-free placebo diet (SHAM and negative control) or on the hops fortified diet. For the investigations in the normal mammary gland young adult Wistar rats were bilaterally OVX and randomly allocated to a control group fed to a phytoestrogen-free diet, or to a diet supplemented either with E2-benzoate or the hops extract. As a major result, the tumor incidence was 15% (3 tumors totally) in OVX controls, whereas it was 85% (39 tumors totally) in SHAM operated positive controls. No tumors were detectable in the hops group. In addition, no estrogenic activity of the hops extract was detectable in uterus and liver of these animals. In investigations on the normal mammary gland, no impact of hops extract on the expression of estrogen dependent proliferation markers or of progesterone receptor became apparent. In conclusion, the lack of growth stimulation of MNU-induced breast cancer in OVX SD-rats and the lack of stimulation proliferative events in the normal mammary gland of OVX Wistar rats by standardized hops extracts provides an important piece of evidence regarding the safety of these extracts in the management of menopausal symptoms.

Quantitative bioanalysis of bavachalcone in rat plasma by LC-MS/MS and its application in a pharmacokinetics study.

This study aims to develop and validate a simple and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for investigating the pharmacokinetic characteristics of bavachalcone. Liquid-liquid extraction was used to prepare plasma sample. Chromatographic separation of bavachalcone and IS was achieved using a Venusil ASB C18 (2.1 × 50 mm, 5 µm) column with a mobile phase of methanol (A)-water (B) (70:30, v/v). The detection and quantification of analytes was performed in selected-reaction monitoring mode using precursor → product ion combinations of m/z 323.1 → 203.2 for bavachalcone, and m/z 373.0 → 179.0 for IS. Linear calibration plots were achieved in the range of 1-1000 ng/mL for bavachalcone (r2 > 0.99) in rat plasma. The recovery of bavachalcone ranged from 84.1 to 87.0%. The method was precise, accurate and reliable. It was fully validated and successfully applied to pharmacokinetic study of bavachalcone.

Simultaneous determination of ten bioactive constituents of Sanjie Zhentong Capsule in rat plasma by ultra-high-performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

Sanjie Zhentong capsule, a well-known traditional Chinese medicine prescription, are used for the treatment of endometriosis-related diseases. In this study, a simple, rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of ten bioactive constituents, including peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, and notoginsenoside R1 in rat plasma after oral administration of Sanjie Zhentong capsule. The sample preparations for protein removal was accomplished using a simple methanol precipitation method. The analytes were completely separated from the endogenous compounds on an Agilent Poroshell 120 SB-C18 column (4.6mm×150mm, 2.7µm) using an isocratic elution with methanol - 0.1% formic acid aqueous (4/1, v/v) as a mobile phase. The single-run analysis time was as short as 14.0min. The inter-day and intra-day precision of the quality control samples exhibited relative standard deviations (RSD) <9.5% and the accuracy values ranged from -8.6% to 15.0%. The lower limits of quantification (LLOQ) were 10, 10, 10, 10, 10, 10, 5, 10, 10 and 20ng/mL for peimine, peiminine, peimisine, loureirin A, loureirin B, 7,4'-dihydroxyflavone, pterostilbene, ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1, respectively. The analytical method was successfully applied to a pharmacokinetic study of the multi-components after oral administration of Sanjie Zhentong Capsule in rats.

Determination of panduratin A in rat plasma by HPLC-MS/MS and its application to a pharmacokinetic study.

Although panduratin A, a chalcone derivative isolated from the rhizome of Kaempferia pandurata Roxb., represents a variety of pharmacological activities, no validated method for determination of panduratin A levels in biological samples is yet available. Thus, we developed a liquid chromatographic method using a tandem mass spectrometry for the determination of panduratin A in rat plasma. After simple protein precipitation with methanol including flufenamic acid (internal standard, IS), the analytes were chromatographed on a reversed-phased column with a mobile phase of distilled water and acetonitrile including 2% of formic acid (2:8, v/v). The ion transitions of the precursor to the product ion were principally deprotonated ions [M-H]- at m/z 405.2→165.9 for panduratin A and 280.1→236.0 for the IS. The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. This analytical method was successfully applied to monitor the plasma concentrations of panduratin A following oral administration in rats.

The application of HPLC-MS/MS to studies of pharmacokinetics and interconversion of isoliquiritigenin and neoisoliquiritigenin in rats.

A specific and sensitive HPLC-MS/MS method was developed and validated for the simultaneously quantification of isoliquiritigenin (ISL) and neoisoliquiritin (NIS) in rat plasma by oral administration. Analytes were analyzed on an Agilent 6460 LC-MS/MS system (Agilent, USA) using an Agilent Zorbax SB-C18 column (4.6 × 150 mm, 5 µm). Gradient elution was applied for the analyte separation using a mobile phase composed of 0.1% formic acid aqueous solution and methanol at a flow rate of 1.0 mL/min with a total running time of 12 min. The calibration curves for ISL and NIS showed good linearity in the concentrations ranging from 0.001 to 4.000 µg/mL with correlation coefficients >0.998. The precision, accuracy, recovery and stability were deemed acceptable. The method was applied to the pharmacokinetics study of ISL and NIS in rats by single and combination administration. The result showed that Cmax and AUC0→t of ISL were markedly increased from 0.53 to 1.20 µg/mL, and from 69.63 to 200.74 min µg/mL by combination administration. The mean t1/2 value was also prolonged from 64.55 to 203.74 min in the combination group. These results indicated that NIS may have been metabolized to ISL which increased the absorption and extended the elimination of ISL. However, little difference was found for NIS pharmacokinetics parameters between single NIS and the combination group, which suggested that there was no significant biotransformation of ISL to NIS. Copyright © 2015 John Wiley & Sons, Ltd.

Gender-related pharmacokinetics and bioavailability of a novel anticancer chalcone, cardamonin, in rats determined by liquid chromatography tandem mass spectrometry.

A reversed phase liquid chromatography tandem mass spectrometry method was developed and validated for quantification of cardamonin, a potential anticancer chalcone, in rat serum. Curcumin was used as an internal standard. Following liquid-liquid extraction using n-hexane and ethyl acetate (60:40, v/v), the processed samples were chromatographed on a C18 column using acetonitrile and ammonium acetate buffer (0.01 M, pH 4.5) (85:15, v/v) as mobile phase at a flow rate of 0.6 mL min(-1). Mass spectrometric detection was performed in the negative electrospray ionization mode by multiple reaction monitoring (m/z 269→122 and 367→217 for cardamonin and curcumin, respectively). The method was validated in terms of selectivity, accuracy, precision, sensitivity, reproducibility, dilution integrity and stability. The linearity was established in the range of 1-200 ng mL(-1) (r≥0.999). The recovery of cardamonin from spiked serum was always >90%. The intra- and inter-day precision (%RSD) and accuracy (%bias) were well within the acceptable limits. The method was applied for single oral and intravenous dose pharmacokinetics in male and female Sprague Dawley rats. Following oral dose, cardamonin showed peak serum concentration that occurred at ∼2 h with very low bioavailability in both male (0.6%) and female (4.8%) rats. Cardamonin exhibited a significant gender influence on pharmacokinetics and bioavailability in rats.

Determination of isobavachalcone in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

A simple and selective specific high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of isobavachalcone (IBC) in rat plasma was developed. Neobavaisoflavone was used as an internal standard (IS). After protein precipitation with acetonitrile (2:1, v/v), the analyte and IS were separated on a 2.6 µm Kinetex C18 column (100 mm×2.1 mm i.d., Phenomenex) by isocratic elution with acetonitrile:water (60:40, v/v) as the mobile phase at a flow rate of 0.2 mL/min. An electrospray ionization (ESI) source was applied and operated in the negative ion mode; multiple reactions monitoring (MRM) mode was used for quantification, and the target fragment ions m/z 323.0→118.9 for IBC and m/z 321.1→265.0 for the IS were chosen. Good linearity was observed in the concentration range of 3.79-484.5 ng/mL for IBC in rat plasma. The recovery of IBC in plasma was in the range of 81.2-89.8%. Intra-day and inter-day precision were both lower than 10%. This method was suitable for pharmacokinetic studies after oral administration of 80 mg/kg IBC in rats. We also obtained pharmacokinetic parameters and concentration-time profiles for IBC after oral administration of IBC in rats.

A Rapid Centrifugation-Assisted Solid-Phase Extraction and Liquid Chromatography Method for Determination of Loureirin A and Loureirin B of Dragon's Blood Capsules in Rat Plasma and Urine After Oral Administration.

A simple, sensitive and rapid centrifugation-assisted solid-phase extraction (SPE) with high-performance liquid chromatography (SPE-HPLC) method was developed for simultaneous determination of the metabolites loureirin A and loureirin B from Dragon's blood in rat plasma and urine. The development of the extraction procedure included optimization of some important extraction phases. After evaluation, the metabolites of Dragon's blood were extracted by centrifugation-assisted SPE and separated by using HPLC. This method showed good linearity (r(2) > 0.99), and in the rat plasma and urine, the recoveries were 93.1 and 95.7% for loureirin A and were 90.1 and 94.2% for loureirin B. The relative standard deviation (RSD) values of intraday and interday precision in rat plasma and urine for loureirin A were <3.84 and 2.01%, respectively. The RSD values of the intraday and interday precision in rat plasma and urine for loureirin B were below 4.25 and 5.83%, respectively. Thus, the established method is suitable for metabolism studies of loureirin A and loureirin B in rat plasma and urine.

Application of a liquid chromatography-tandem mass spectrometry method to the pharmacokinetics, bioavailability and tissue distribution of neohesperidin dihydrochalcone in rats.

1. This study was aimed at developing a high sensitive and selective liquid chromatography-tandem mass spectrometry method to quantify neohesperidin dihydrochalcone (NHDC) in rat plasma and tissues for pharmacokinetic, bioavailability and tissue distribution studies. 2. Biological samples were processed with one-step protein precipitation. Rutin was chosen as the internal standard (IS). Chromatographical separation was achieved on an SB-C18 (2.1 mm× 150 mm, 5 µm) column with acetonitrile--0.1% formic acid in water as the mobile phase with gradient elution. Electrospray ionization (ESI) source was applied and operated in negative ion mode; selected ion monitoring mode was used for quantification using target fragment ions m/z 611.4 for NHDC and m/z 609.1 for IS. 3. Calibration plots were linear over the range of 10-3000 ng/mL for NHDC. Lower limit of quantification (LLOQ) for NHDC was 10 ng/mL. Mean recovery of NHDC from plasma and tissues was better than 80.3%. Coefficient of variation of intra-day and inter-day precision were both less than 15%. The bioavailability of NHDC was 21.8%. 4. In conclusion, a sensitive, simple and specific LC-ESI-MS method for the determination of NHDC in rat biological samples was developed. This developed method is successfully used in the pharmacokinetic and tissue distribution study of NHDC in rats.

Liquid chromatography tandem mass spectrometry method for determination of antidiabetic chalcones derivative S001-469 in rat plasma, urine and feces: application to pharmacokinetic study.

A sensitive and selective liquid chromatography tandem mass spectrometry assay was developed for quantitation of a novel antidiabetic chalcones derivative S001-469 in rat matrices. Plasma and urine samples were prepared by double liquid-liquid extraction with diethyl ether and feces by protein precipitation using acetonitrile. Chromatographic elution was carried on cyano guard column (30 mm × 4.6 mm i.d., 5 µm) in isocratic mode at a flow rate of 0.75 mL/min using mobile phase comprising of methanol: ammonium acetate buffer (pH 4.6, 10 mM) (90:10, v/v). Run time was 6 min. Detection was achieved by employing positive ionization mode on a triple-quadrupole LC-MS/MS system with an electrospray ionization (ESI) source. The calibration curves were linear over the range of 0.78-400 ng/mL for all 3 matrices. The method was validated and proved reliable through high and consistent intra- and inter- day accuracy and precision (<15%) values. Recoveries was >85% from spiked plasma, urine and feces samples. S001-469 was stable in plasma at room temperature till 8 h and at -60 °C for 30 d and 3 freeze-thaw cycles.

Determination of isoliquiritigenin and its distribution in mice by synchronous fluorescence spectrometry.

The aim of the present work was to develop a new method using synchronous fluorescence spectrometry (SFS) to determine the concentration of isoliquiritigenin (ISL) in mouse blood and tissues, and to investigate ISL's distribution among organs after an intraperitoneal (IP) dose of ISL. The synchronous fluorescence method was optimized with the sample pH, stability, metal ions, concentration of Al(3+), and surfactants. The proposed method was used to determine the ISL concentration in mouse blood, brain, heart, kidney, liver, spleen and lung after an IP injection of ISL. The optimal conditions for the determination of ISL using SFS were found to be: excitation and emission wavelengths of 469 and 557 nm, respectively; the use of 3% AlCl(3) as a fluorescence intensity enhancer; measuring samples within 1 h of collection, sample pH 7-8, isolation of samples from surfactants; and wavelength interval (Δλ) = 70 nm. After IP injection, the distribution of ISL in mouse organs was: liver > kidney > spleen > blood > lung > brain > heart. The blood concentration of ISL peaked at 60 min; concentrations of ISL in liver, kidney and spleen achieved maxima at 120 min. SFS provides a simple, but effective analytical method that will benefit the study of in vivo biological effects of ISL, including absorption, distribution, metabolism, and excretion.

Quantification of sofalcone in human plasma and urine by high performance liquid chromatography-mass spectrometry.

Sofalcone, isolated from the root of the Chinese medicinal plant Sophora subprostrata, is well known to be a mucosal protective agent for gastritis and peptic ulcer treatment. Although the LC-MS/MS and HPLC-DAD methods for assay of plasma concentration of sofalcone were reported before for the pharmacokinetic study, they were either too complicated or not sensitive enough for current pharmacokinetic study. In addition, no urinary assay method or pharmacokinetic information was available. Thus an improved high performance liquid chromatography-mass spectrometric method employing negative electrospray ionization was developed for the determination of sofalcone concentration in human plasma and urine sample. A liquid-liquid extraction method was utilized to extract sofalcone together with the indometacin (internal standards) from 0.5ml of human plasma or urine samples. Multiple reaction monitoring was used for quantification by monitoring the transition of m/z from 449.5 to 313.1 for sofalcone and 356.9 to 313.0 for IS. The validation of the method regarding to specificity, sensitivity, linearity, reproducibility, accuracy and stability was evaluated. The lower limit of quantification (LLOQ) of the developed assay method for sofalcone was 0.5ng/ml and the linear calibration curve was acquired with R(2)>0.99 between 0.5 and 500ng/ml for both plasma and urine samples. The intra- and inter-day variations of the current assay were evaluated with the relative standard deviation (RSD) within 13.77% at low concentration of quality control samples (QCs) and 8.71% for other QCs, whereas the mean accuracy ranged from 96.21 to 107.33%. The samples were found to be stable under the storage conditions at least for a month and other experimental conditions. This validated method was then utilized to test sofalcone concentration in clinical samples. Based on these data, the pharmacokinetic behavior of sofalcone in plasma as well as urine was described. As a conclusion, the present method proved to be a rapid and sensitive analytical tool for sofalcone in human plasma or urine samples and has been successfully applied to a clinical pharmacokinetic study of in healthy Chinese subjects.

In vitro biotransformation, in vivo efficacy and pharmacokinetics of antimalarial chalcones.

4'-n-Butoxy-2,4-dimethoxy-chalcone (MBC) has been described as protecting mice from an otherwise lethal infection with Plasmodium yoelii when dosed orally at 50 mg/kg/dose, daily for 5 days. In contrast, we found that oral dosing of MBC at 640 mg/kg/dose, daily for 5 days, failed to extend the survivability of P. berghei-infected mice. The timing of compound administration and metabolic activation likely contribute to the outcome of efficacy testing in vivo. Microsomal digest of MBC yielded 4'-n-butoxy-4-hydroxy-2-methoxy-chalcone and 4'-(1-hydroxy-n-butoxy)-2,4-dimethoxy-chalcone. We propose that the latter will hydrolyze in vivo to 4'-hydroxy-2,4-dimethoxy-chalcone, which has greater efficacy than MBC in our P. berghei-infected mouse model and was detected in plasma following oral dosing of mice with MBC. Pharmacokinetic parameters suggest that poor absorption, distribution, metabolism and excretion properties contribute to the limited in vivo efficacy observed for MBC and its analogs.

Identification and quantification of metabolites of orally administered naringenin chalcone in rats.

Naringenin chalcone is the main active component of tomato skin extract, which has an antiallergic activity. In this study, naringenin chalcone was orally administered to rats, and the chemical structures and levels of the major metabolites in the plasma and urine of rats were determined. HPLC analysis indicated the presence of three major metabolites in the urine. LC-MS and NMR analyses tentatively identified these as naringenin chalcone-2'-O-beta-D-glucuronide, naringenin-7-O-beta-D-glucuronide, and naringenin-4'-O-beta-D-glucuronide. Naringenin chalcone-2'-O-beta-D-glucuronide was the only metabolite detected in the plasma, and its peak plasma level was observed 1 h after naringenin chalcone administration. Naringenin chalcone-2'-O-beta-D-glucuronide also inhibited histamine release from rat peritoneal mast cells stimulated with compound 48/80. This activity might contribute to the antiallergic activity of naringenin chalcone in vivo. To the best of the authors' knowledge, this study is the first to report determination of naringenin chalcone metabolites in rat plasma and urine.