Pharmacokinetics and metabolism of trans-emodin dianthrones in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Polygonum multiflorum Thunb. (PM) is a common traditional Chinese medicine with diverse biological activities of resolving toxins, nourishing livers and promoting hairs. Nevertheless, in recent years hepatotoxic adverse reactions caused by the administration of PM have raised worldwide concerns. In our previous study, we found that emodin dianthrones showed hepatotoxicity and may be potential toxicity markers. However, the metabolic transformation and pharmacokinetic behavior of emodin dianthrones in vivo have still not been elucidated. AIM OF THE STUDY: Taking trans-emodin dianthrones (TED) as an example, the present study was conducted to investigate the pharmacokinetics and bioavailability of TED in rats and characterized its metabolic transformation in the plasma, urine and feces of rats. MATERIALS AND METHODS: A rapid and sensitive UPLC-qqq-MS/MS method was developed for accurate quantification of TED in plasma and successfully applied to the pharmacokinetic evaluation of TED in rats after intravenous and oral administration. A reliable UFLC-Q-TOF-MS high resolution mass spectrometry combined with a scientific metabolite identification strategy was used to comprehensively characterize the metabolic transformation of TED in plasma, urine and feces in rats. RESULTS: The established UPLC-qqq-MS/MS method had a linear range of 1-500 ng/mL, and the method was accurate and reliable to meet the quantitative requirements. When 20 mg/kg TED was given by gavage rats, it was rapidly absorbed into the circulatory system and had a long half-life time of 6.44 h and wide tissue distribution in vivo. While intravenous injection of 0.4 mg/kg TED in rats, it was rapidly metabolized and eliminated with a half-life time of 1.82 h. The oral absorption bioavailability of TED was only 2.83%. Furthermore with a sensitive UFLC-Q-TOF-MS technique and metabolite identification strategy, 21 metabolites were successfully identified, including 11 in plasma, 12 in urine and 18 in feces. The main Ⅰ and Ⅱ phase metabolic processes involved glucuronidation, oxidation, carbonylation, (de)methylation, sulfation and hydrogenation. CONCLUSION: TED could be rapidly absorbed into the blood circulation and widely distributed and slowly metabolized in the body and underwent extensive cleavage and metabolic transformation in vivo. The study provided a basis for in-depth elucidation of the toxicology and mechanism research of TED, but also laid the foundation for further research on the material basis of hepatotoxicity of PM.

Safety of natural anthraquinone emodin: an assessment in mice.

BACKGROUND: Emodin, a natural anthraquinone, has shown potential as an effective therapeutic agent in the treatment of many diseases including cancer. However, its clinical development is hindered by uncertainties surrounding its potential toxicity. The primary purpose of this study was to uncover any potential toxic properties of emodin in mice at doses that have been shown to have efficacy in our cancer studies. In addition, we sought to assess the time course of emodin clearance when administered both intraperitoneally (I.P.) and orally (P.O.) in order to begin to establish effective dosing intervals. METHODS: We performed a subchronic (12 week) toxicity study using 3 different doses of emodin (~ 20 mg/kg, 40 mg/kg, and 80 mg/kg) infused into the AIN-76A diet of male and female C57BL/6 mice (n = 5/group/sex). Body weight and composition were assessed following the 12-week feeding regime. Tissues were harvested and assessed for gross pathological changes and blood was collected for a complete blood count and evaluation of alanine transaminase (ALT), aspartate transaminase (AST) and creatinine. For the pharmacokinetic study, emodin was delivered intraperitoneally I.P. or P.O. at 20 mg/kg or 40 mg/kg doses to male and female mice (n = 4/group/sex/time-point) and circulating levels of emodin were determined at 1, 4 and 12 h following administration via liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. RESULTS: We found that 12 weeks of low (20 mg/kg), medium (40 mg/kg), or high (80 mg/kg) emodin feeding did not cause pathophysiological perturbations in major organs. We also found that glucuronidated emodin peaks at 1 h for both I.P. and P.O. administered emodin and is eliminated by 12 h. Interestingly, female mice appear to metabolize emodin at a faster rate than male mice as evidenced by greater levels of glucuronidated emodin at the 1 h time-point (40 mg/kg for both I.P. and P.O. and 20 mg/kg I.P.) and the 4-h time-point (20 mg/kg I.P.). CONCLUSIONS: In summary, our studies establish that 1) emodin is safe for use in both male and female mice when given at 20, 40, and 80 mg/kg doses for 12 weeks and 2) sex differences should be considered when establishing dosing intervals for emodin treatment.

Emodin, a natural anthraquinone, suppresses liver cancer in vitro and in vivo by regulating VEGFR2 and miR-34a.

The pharmacokinetic (PK) and potential effects of Emodin on liver cancer were systematically evaluated in this study. Both the intragastric administration (i.g.) and hypodermic injection (i.h.) of Emodin exhibited a strong absorption (absorption rate < 1 h) and elimination capacity (t1/2 ≈ 2 h). The tissue distribution of Emodin after i.h. was rapid and wide. The stability of Emodin in three species of liver microsomes wasrat >human> beagle dog. These PK data provided the basis for the subsequent animal experiments. In liver cancer patient tissues, the expression of vascular endothelial growth factor (VEGF)-induced signaling pathways, including phosphorylated VEGF receptor 2 (VEGFR2), AKT, and ERK1/2,were simultaneously elevated, but miR-34a expression was reduced and negatively correlated with SMAD2 and SMAD4. Emodin inhibited the expression of SMAD2/4 in HepG2 cells by inducing the miR-34a level. Subsequently, BALB/c nude mice received a daily subcutaneous injection of HepG2 cells with or without Emodin treatment (1 mg/kg or 10 mg/kg), and Emodin inhibited tumorigenesis and reduced the mortality rate in a dose-dependent manner. In vivo experiments showed that cell proliferation, migration, and invasion were promoted by VEGF or miR-34a signal treatment but were inhibited when combined with Emodin treatment. All these results demonstrated that Emodin inhibited tumorigenesis in liver cancer by simultaneously inhibiting the VEGFR2-AKT-ERK1/2signaling pathway and promoting a miR-34a-mediated signaling pathway.

UHPLC-MS/MS method for the quantification of aloin-A in rat plasma and its application to a pharmacokinetic study.

Aloin-A (also known as barbaloin), the main bioactive anthraquinone-C-glycoside of Aloe species, exhibits various beneficial pharmacological effects. However, the determination and pharmacokinetic study of aloin-A in rat plasma need to be improved and systematically demonstrated. In the present study, a simple, robust and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for rapid quantification of aloin-A in rat plasma was developed. Plasma preparation was conducted by a single step protein precipitation with obtusin serving as an internal standards (IS) followed by separation of the analytes using an Agilent C18 column with a gradient mobile phase comprised of acetonitrile and formic acid aqueous solution. Negative ion electrospray was used and multiple reaction monitoring transitions were m/z 417.1 → 297.0 for aloin-A and m/z 343.1 → 328.1 for IS, respectively. The developed method was validated with linear range of 1-1000 ng/mL. All validation parameters were well within the acceptance criteria based on the guidance of FDA. The validated approach was successfully applied to analyze samples from a pharmacokinetic study in healthy rats following intravenous and oral administration. Aloin-A was found to be quickly absorbed, extensively distributed and rapidly eliminated. The absolute bioavailability of aloin-A was 5.79%.

Nine components pharmacokinetic study of rat plasma after oral administration raw and prepared Semen Cassiae in normal and acute liver injury rats.

In China, Semen Cassiae has long been used to protect liver, brighten eyes, and relieve constipation. Prepared Semen Cassiae is produced from raw Semen Cassiae by processing, the two forms of Semen Cassiae have different clinical applications. Pathological state is an important factor affecting the efficacy of drugs, the pharmacokinetic behavior of drugs could be significantly changed when people or animal were under different pathological state. To clarify the effect of processing mechanism and pathological state for pharmacokinetic behavior, the pharmacokinetics of nine components of raw and prepared Semen Cassiae under normal and acute liver injury rats were examined. The results showed that the bimodal phenomenon appeared on the plasma concentration-time profiles of obtusin, emodin, chrysophanol, aloe emodin and rhein. The Tmax of aurantio-obtusin, obtusin, chrysoobtusin, emodin, chrysophanol, aloe emodin, physcion in normal groups administrated prepared Semen Cassiae were shorter than those administrated raw Semen Cassiae. For the AUC0-t , aurantio-obtusin, obtusin, chrysoobtusin, chrysophanol, aloe emodin and physcione in model groups administrated prepared Semen Cassiae were significantly higher than other groups, unlike above components, rhein had poor absorption in model groups. The study would be useful for further studies on pharmacokinetics and clinical application of raw and prepared Semen Cassiae.

Simultaneous determination of wogonin, oroxylin a, schisandrin, paeoniflorin and emodin in rat serum by HPLC-MS/MS and application to pharmacokinetic studies.

Wogonin and oroxylin A in Scutellariae Radix, schisandrin in Chinensis Fructus, paeoniflorin in Moutan Cortex and emodin in Polygoni Cuspidate Rhizome et Radix are anti-inflammatory active compounds. A method for simultaneous determination of the five compounds in rat was developed and validated using high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). The separation was performed on a Symmetry C18 column (4.6 × 50 mm, 3.5 µm) with acetonitrile and 0.1% formic acid aqueous solution as the mobile phases. The detection was performed using multiple-reaction monitoring with electrospray ionization source in positive-negative ion mode. The calibration curves showed good linearity (r ≥ 0.9955). The lower limit of quantification (LLOQ) was 5 ng/mL for wogonin and schisandrin, 10 ng/mL for oroxylin A and emodin, and 15 ng/mL for paeoniflorin, respectively. The relative standard deviations of intraday and interday precisions were <11.49 and 14.28%, respectively. The extraction recoveries and matrix effects were acceptable. The analytes were stable under the experiment conditions. The validated method has been successfully applied to pharmacokinetic studies of the five compounds in rats after oral administration of Hu-gan-kan-kang-yuan capsule. This paper would be a valuable reference for pharmacokinetic studies of Chinese medicine preparations containing the five compounds.

Emodin, a compound with putative antidiabetic potential, deteriorates glucose tolerance in rodents.

Emodin is found in remedies from Traditional Chinese Medicine. Since antihyperglycaemic action was observed in rodents, non-scientific sources advertise emodin intake as a natural cure for diabetes. Emodin was admixed to high fat-food of obese mice at two doses (2 and 5g/kg; daily emodin uptake 103 and 229mg/kg). Comparison was made to ad libitum fed and to food restricted control groups, the latter showing the same weight gain as the corresponding emodin-treated groups. Emodin blunted food intake by 6% and 20% for the low and high dose, which was accompanied by proportionate reductions in weight gain. Emodin reduced blood glucose relative to freely feeding controls, but comparison to weight-matched controls unmasked deterioration, rather than improvement, of basal glycaemia (mmol/l: fed ad libitum, 9.5±0.4; low emodin, 9.4±0.3, weight-matched, 8.2±0.3; high emodin, 7.2±0.4, weight-matched, 6.1±0.3; P<0.01, emodin vs weight-matched) and glucose tolerance (area under the curve, min*mol/l: fed ad libitum, 2.01±0.08; low emodin, 1.97±0.12, weight-matched, 1.75±0.03; high emodin, 1.89±0.07, weight-matched, 1.65±0.05; P<0.0002, emodin vs weight-matched). An insulin tolerance test suggested insulin desensitisation by prolonged emodin treatment. Furthermore, a single oral emodin dose did not affect glucose tolerance in obese mice, whereas intravenous injection in rats suggested a potential of emodin to acutely impair insulin release. Our results show that the antihyperglycaemic action of emodin as well as associated biochemical alterations could be the mere consequences of a spoilt appetite. Published claims of antidiabetic potential via other mechanisms evoke the danger of misuse of natural remedies by diabetic patients.

Metabolite identification of seven active components of Huan-Nao-Yi-Cong-Fang in rat plasma using high-performance liquid chromatography combined with hybrid ion trap/time-of-flight mass spectrometry.

Huan-Nao-Yi-Cong-Fang (HNYCF) is a potential prescription in treating Alzheimer's disease. Seven constituents [ferulic acid (FA), 2,3,5,4'-tetrahydroxystilbene-2-O-ß-d-glucoside (THSG), berberine hydrochloride (BHCl), emodin, ginsenoside Rg1 (Rg1), ginsenoside Re (Re) and ginsenoside Rb1 (Rb1)] have been used as quality chemical markers of HNYCF owing to their biological significance and high contents in crude plant materials. This study explored the metabolites of the seven bioactive components in rat plasma to give useful data for further study of the action mechanism of HNYCF. LC/MS-IT-TOF was used to simultaneously characterize the metabolites of the seven components. Using the combination of MetID Solution 1.0 software and accurate mass measurements, the metabolites of HNYCF were reliably characterized. Their structures were elucidated based on the accurate MS(2) spectra and comparisons of their changes in accurate molecular masses and fragment ions with those of parent compounds. A total of five parent active compounds (BHCl, emodin, Rg1, Rb1 and Re) and 10 metabolites were found from the rat plasma 2 h after oral administration of HNYCF dosage, of which two metabolites of emodin were observed for the first time. The proposed metabolic pathways of the bioactive components in the rat plasma are helpful for further studies on the pharmacokinetics and real active compound forms of this drug.

Synergistic effects of rhubarb-gardenia herb pair in cholestatic rats at pharmacodynamic and pharmacokinetic levels.

ETHNOPHARMACOLOGICAL RELEVANCE: Herb pair serves as the basic building block of a traditional Chinese medicine (TCM) formula. The rhubarb-gardenia herb pair (RGHP), composed of rhubarb and gardenia, has meaningful clinical effects to cure cholestasis diseases. This study was designed to confirm the expected synergistic effects of RGHP at pharmacodynamic and pharmacokinetic levels. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were divided into control, model and drug-treated groups. After intragastrically administrated with α-naphthylisothiocyanate (ANIT) to induce cholestasis, rats were treated with rhubarb, gardenia or RGHP. For pharmacodynamic study, biochemical and histopathological tests were performed to assess the hepatoprotective effects. While for pharmacokinetic study, a LC-MS method was developed for determination of five main chemical markers, namely genipin, rhein, aloe emodin, emodin and chrysophanol in rat plasma. RESULTS: The biochemical and histopathological tests suggested that RGHP exerted enhanced hepatoprotective effects against the ANIT-induced cholestasis compared with single herbs. The pharmacokinetic study indicated RGHP could significantly elevate systemic exposure level and prolong retention time of five markers in comparison with rhubarb or gardenia alone. CONCLUSIONS: The present study demonstrated the synergistic effects of RGHP in ANIT-induced cholestatic rats at pharmacodynamic and pharmacokinetic levels, and has significant enlightenments for the rational use of the related TCM formulas containing RGHP.

Effect of piperine on the bioavailability and pharmacokinetics of emodin in rats.

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) has been widely used as a traditional medicine and was shown to possess a multitude of health-promoting properties in pre-clinical studies, but its bioavailability was low due to the extensive glucuronidation in liver and intestine, hindering the development of emodin as a feasible chemopreventive agent. In this study, piperine, as a bioenhancer, was used to enhance the bioavailability of emodin by inhibiting its glucuronidation. The pharmacokinetic profiles of emodin after oral administration of emodin (20mg/kg) alone and in combination with piperine (20mg/kg) to rats were investigated via a validated LC/MS/MS method. As the in vivo pharmacokinetic studies had indicated, the AUC and Cmax of emodin were increased significantly after piperine treatment, and the glucuronidation of emodin was markedly inhibited. Our study demonstrated that piperine significantly improved the in vivo bioavailability of emodin and the influence of piperine on the pharmacokinetics of emodin may be attributed to the inhibition of glucuronidation of emodin. Further research is needed to investigate the detailed mechanism of improved bioavailability of emodin via its combination with piperine.

Hepatotoxic assessment of Polygoni Multiflori Radix extract and toxicokinetic study of stilbene glucoside and anthraquinones in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Polygoni Multiflori Radix (PMR) has been traditionally used as a tonic and an anti-aging remedy for centuries; however, hepatic lesions linked to PMR have been frequently reported. AIM OF THE STUDY: This work attempted to investigate the hepatotoxic potential of PMR extract and the toxicokinetics of stilbene glucoside and anthraquinones in PMR extract following repeated administration. MATERIALS AND METHODS: Histopathological and biochemical tests were performed to assess the hepatotoxicity of PMR extract. A rapid and sensitive liquid chromatography-mass spectrometry (LC-MS) assay was developed for toxicokinetic analysis of the main constituents of PMR extract, including 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside (TSG), emodin-8-O-ß-D-glucoside and emodin. RESULTS: The histopathological and biochemical tests indicated that repeated administration of high-dose PMR extract (20 g/kg) for 3 weeks could cause hepatic lesions, while the low-dose treatment (1 g/kg) was safe. Necrosis and steatosis of hepatic cells, inflammatory cell infiltration and mild fibrosis were the main toxicity symptoms caused by high-dose PMR extract in rat liver. The aspartate aminotransferase (AST) levels increased by approximately 17%, from 110.80±0.84 to 129.75±10.83 IU/L, in the high-dose group compared with the control group. The proposed LC-MS method was proven to be suitable for the simultaneous quantification of these three constituents by affording desirable linearity (r(2)>0.998) and satisfactory precision (error less than 10%). The toxicokinetic study showed that emodin could not be detected in the low-dose group, but the AUC and Cmax of emodin displayed a gradual increase with repeated treatments in the high-dose group. The toxicokinetics of TSG in the low- and high-dose groups exhibited similar trends after repeated administration. CONCLUSIONS: Consideration needs to be given to the rational application of PMR in the clinic to balance its benefits and risks. The increased emodin exposure in vivo provided a putative explanation for the observed hepatic lesions induced by PMR extract, although further studies to confirm the potentially causal link between emodin exposure and hepatic lesions are still necessary.

Simultaneous quantification of chrysophanol and physcion in rat plasma by ultra fast liquid chromatography-tandem mass spectrometry and application of the technique to comparative pharmacokinetic studies of Radix et Rhei Rhizoma extract alone and Dahuang Fuzi Decoction.

Most herbal medicines are prescribed in combination based on the theory of TCM to obtain synergistic effects or diminish the possible adverse reactions. Compatibility refers to the combination of two or more herbs based on the clinical settings and the properties of herbs. Chrysophanol and physcion are the main effective compounds in Radix et Rhizoma Rhei and Dahuang Fuzi Decoction which is the combination of Radix et Rhizoma Rhei, Radix Aconiti Lateralis Praeparata and Radix et Rhizoma Asari. However, chrysophanol and physcion are difficult to detect in vivo because of their low concentration and interference from endogenous compounds. The aim of this study is to develop a rapid, specific and sensitive ultra high performance liquid chromatography-triple quadrupole tandem mass method to simultaneously quantify chrysophanol and physcion in rat plasma, in order to better understand the pharmacokinetics and compatibility mechanism of Dahuang Fuzi Decoction for the first time. Multiple reaction monitoring (MRM) mode was applied for the quantitation at [M-H](-)m/z 253.0→m/z 225.1 for chrysophanol, [M-H](-) for m/z 283.1→m/z 240.0 physcion and [M-H](-)m/z 239.0→m/z 211.0 for IS. The analytes were separated on an Agilent Eclipse plus C18 column (100mm×2.1mm, 1.8µm) column within a total running time of 6.5min using a mixture of 3mM ammonium acetate in water and methanol (95:5, v/v) with a time program flow gradient according to the "plus gradient chromatography" theory. The inclusion of the ammonium acetate in the UFLC mobile phase dramatically improved the detection limit of the tested compounds and decreased the interference by matrix effects, which have been referred to as "LC-electrolyte effects". Finally, we demonstrated the application of a validated method in a comparative pharmacokinetic study of rats receiving an oral dose of Dahuang Fuzi Decoction or Radix et Rhei Rhizoma, the monarch drug in the prescription. Pharmacokinetic parameters showed significant difference between the two groups. The achieved comparative pharmacokinetic results were helpful to clarify the combination mechanism of Dahuang Fuzi Decoction.

A rapid UFLC-MS/MS method for simultaneous determination of formononetin, cryptotanshinone, tanshinone IIA and emodin in rat plasma and its application to a pharmacokinetic study of Bu Shen Huo Xue formula.

Bu Shen Huo Xue formula (BSHX) is a traditional Chinese medicine prescription used for clinical treatment of chronic kidney diseases. A rapid and selective Ultra fast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous determination of four bioactive components of BSHX including formononetin, cryptotanshinone, tanshinone IIA, and emodin in control and unilateral ureteral obstruction (UUO) model rat plasma for the first time. Atorvastatin was used as the internal standard (IS). Plasma samples were extracted by liquid-liquid extraction with ethyl acetate. The chromatographic separation was carried out on a Shim-pack XR-ODS III column with a gradient mobile phase consisting of acetonitrile and 0.1% formic acid. The detection was performed on a triple-quad tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with positive ionization mode for formononetin, cryptotanshinone, tanshinone IIA, and negative mode for emodin. The method was linear for four analytes over the range of investigated concentration with all coefficients of determination (R(2)) greater than 0.9938. The lower limits of quantification (LLOQ) for formononetin, cryptotanshinone, tanshinone IIA, and emodin were defined as 0.3, 0.5, 1.5, and 0.3ng/mL, respectively. The rapid and sensitive method was fully validated and successfully applied to the pharmacokinetic study of formononetin, cryptotanshinone, tanshinone IIA and emodin in rats following oral administration of Bu Shen Huo Xue formula.

Influence of processing on pharmacokinetic of typical constituents in radix polygoni multiflori after oral administration by LC-ESI-MS/MS.

ETHNOPHARMACOLOGICAL RELEVANCE: The processed radix polygoni multiflori (P-RPM) are produced from the raw radix polygoni multiflori (R-RPM) steamed with black bean juice, but the two traditional Chinese medicines are used to treat the different diseases in clinic. In order to clarify the influence of processing on pharmacological properties of radix polygoni multiflori, an investigation was carried out to compare the pharmacokinetics of typical constituents after oral administration of P-RPM and R-RPM extracts MATERIALS AND METHODS: A simple, rapid and sensitive high performance liquid chromatography-tandem mass spectroscopy (LC-MS/MS) was developed and validated for the simultaneous determination of gallic acid, polydatin, 2,3,5,4'-tetrahydroxystilbene-2-O-ß-d-glucoside (PM-SG), resveratrol, and emodin in rat plasma. Male Sprague-Dawley rats were orally administered the two extracts with approximately the same dosage. RESULTS: It was found that gallic acid was distributed as opened one-compartment model while polydatin, PM-SG and emodin were fitted to an open two-compartment model after oral administration of raw and processed radix polygoni multiflori extract. Cmax and AUC of gallic acid were increased (P<0.01), but Cmax and AUC of PM-SG were descreased (P<0.05). AUC of polydatin and emodin were similar with that of PM-SG. However, resveratrol was not detected in plasma collected at certain intervals following oral administration of the two extracts. CONCLUSIONS: These results indicate that influence of the processing could improve the bioavailability of gallic acid and reduce the absorption of PM-SG, polydatin and emodin in rats. The LC-MS/MS method could be used to evaluate the effect of processing on pharmacokinetic of typical constituents in radix polygoni multiflori after oral administration.

Stilbene glucoside inhibits the glucuronidation of emodin in rats through the down-regulation of UDP-glucuronosyltransferases 1A8: application to a drug-drug interaction study in Radix Polygoni Multiflori.

ETHNOPHARMACOLOGICAL RELEVANCE: The integrated effects of herbal medicines were the outcome of all of the inherent components. Currently, few studies have focused on the multicomponent interactions in an herbal medicine to elucidate its pharmacological and/or toxicological effects. In this study, an attempt was made to investigate the interaction between stilbene glucosides and the anthraquinones contained in Radix Polygoni Multiflori (RPM) and to explore the interaction's mechanism from the perspective of UDP-glucuronosyltransferase (UGT) regulation. MATERIALS AND METHODS: The extract of RPM was separated into a stilbene glucoside fraction and a emodin fraction. A rapid high-performance liquid chromatography-mass spectrometry method was developed and validated to disclose the influence of stilbene glucoside on the pharmacokinetics of emodin in rats. Drug and Statistics 2.0 was used for the estimation of the pharmacokinetic parameters. Gene expression analysis in liver and intestinal tissues was performed by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. RESULTS: The analytical method appeared to be suitable for the analysis of emodin with desirable linearity, accuracy, precision and stability, and the total analysis time was less than 2 min on a short column. Glucuronide of emodin, which is the major metabolite of emodin, was determined after ß-glucuronidase hydrolysis. As the in vivo pharmacokinetic studies had indicated, the AUC, Cmax and T1/2 of emodin were increased after the stilbene glucoside treatment, and the glucuronidation of emodin was significantly inhibited. The mRNA levels from UGT1A8 and UGT1A2 were decreased by stilbene glucoside treatment. In contrast, the expression of UGT1A1, UGT1A6 and UGT1A9 mRNA was increased in the liver following treatment. CONCLUSIONS: The influence of stilbene glucoside on the pharmacokinetics of emodin may be attributed to the inhibition of UGT1A8 mRNA expression. Thus, it is important to extend this research to deepen our understanding of the pharmacological and/or toxicological effects of RPM.

Comparative pharmacokinetics study of three anthraquinones in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang by high performance liquid chromatography-mass spectrometry.

A specific and sensitive high performance liquid chromatography-mass spectrometric (HPLC-MS) method has been developed and validated for simultaneous determination of three anthraquinones of rhein, aloe-emodin and emodin in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang. The analytes were separated on a Kromaisl(®) C(18) column within a total running time of 12min with a mobile phase of methanol:ammonium acetate (3mM) (75:25, v/v). The calibration curves for all the anthraquinones showed good linearity in the measured range with correlation coefficient (r) higher than 0.9978. The precision, accuracy, recovery and stability were deemed acceptable. The method was successfully applied to the comparative pharmacokinetics study of the anthraquinones in rat plasma after oral administration of Radix et Rhei Rhizoma extract and Dahuang Fuzi Tang.

Effect of formula compatibility on the pharmacokinetics of components from Dachengqi Decoction [See Text] in rats.

OBJECTIVE: To investigate the effect of prescription compatibility on the pharmacokinetics of components from Dachengqi Decoction (DCQD, ) in rats. METHODS: Twenty-four male rats were randomly and equally divided into the DCQD group, Dahuang (Radix et Rhizoma Rhei, Polygonaceae) group, Houpo (Magnolia officinalis Rehd., Magnoliaceae) group, and Zhishi (Fructus Aurantii Immaturus, Rutaceae) group. The blood samples were collected before dosing and subsequently at 10, 15, 20, 30, 45 min, 1, 2, 4, 8, and 12 h following gavage. The levels of aloe-emodin, rhein, emodin, chrysophanol, honokiol, magnolol, hesperidin, and naringin in rat serum were quantified using a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for pharmacokinetic study. RESULTS: The area under the curve (AUC), mean retention time (MRT), the peak concentration (C(max)) of aloe-emodin, rhein, emodin, and chrysophanol in the DCQD group were significantly different compared with the Dahuang group (P <0.05, respectively). The mean plasma concentration, C(max), and the absorption of Dahuang's component in the DCQD group were obviously lower at each time point than those in the Dahuang group, while the elimination process of Dahuang's component was obviously delayed (P <0.05). Half-lives of aloe-emodin, chrysophanol, and rhein were also extended in the DCQD group (P <0.05, respectively). In the DCQD group, the mean plasma concentration, AUC, C(max) and absorption of honokiol, and magnolol were significantly lower (P <0.01, respectively) at each time point than those in the Houpo group, while the drug distribution half-life time (T(1/2α)), the drug eliminated half-life time (T(1/2ß)), MRT, and time of peak concentration (T(max)) were significantly delayed (P <0.05, respectively). Pharmacokinetic parameters of hesperidin and naringin in the Zhishi group were not significantly different as compared with the DCQD group (P >0.05, respectively), while the MRT of naringin was significantly longer. CONCLUSIONS: The compatibility in Chinese medicine could affect the drug's pharmacokinetics in DCQD, which proves that the prescription compatibility principle of Chinese medicine formulations has its own pharmacokinetic basis.

[Analysis of emodin and its metabolites based on hollow fiber liquid phase microextraction].

Hollow fiber liquid phase microextraction (HFLPME) coupled with high performance liquid chromatography (HPLC) has been developed to analyze the emodin and its metabolites in plasma and urine samples. The abilities of the absorption and metabolism for the active components in traditional Chinese medicines between the male and female rats were compared, and the biological metabolism and transmutation of the analyte were detailed discussed. Emodin and its metabolites in plasma and urine samples were extracted into n-octanol (acceptor) in hollow fiber. The acceptor phase was dried and dissolved by 50 microL methanol and then analyzed by HPLC. Under the optimal conditions, the linearities of the analytes were all very good in biological samples (r > 0.9960), the detection limits of the analytes were within the ranges of 0.1-3.0 microg/L. The enrichment factors were 12.2 to 26.3. The relative standard deviations for intra-day and inter-day precision were lower than 11.0%. The average recoveries of the analytes in plasma and urine samples were all in the range of 97.9% to 103%. HFLPME-HPLC can eliminate interference from complex biological samples, improve the sensitivity and reduce the detection limit, thus this method is suitable for the determination of trace compounds in complex sample.

A novel UPLC-MS/MS method for simultaneous quantification of rhein, emodin, berberine and baicalin in rat plasma and its application in a pharmacokinetic study.

BACKGROUND: Dahuang Huanglian Xiexin Decoction (DHXD) is a classical formula in traditional Chinese medicines. In this study, a novel UPLC-MS/MS method was developed for the simultaneous quantification of rhein, emodin, berberine and baicalin, the major bioactive compounds of DHXD in rat plasma. RESULTS: The method possessed high sensitivity and ultrashort analysis time (7 min). Linearity, accuracy, precision and extraction recovery of four analytes were all satisfactory. The method was then successfully applied in a pharmacokinetic study of four bioactive components after a single oral administration of DHXD extract to rats. CONCLUSION: The method was applicable for simultaneous bioanalysis of rhein, emodin, berberine and baicalin.

Sensitive and robust UPLC-MS/MS method to determine the gender-dependent pharmacokinetics in rats of emodin and its glucuronide.

In this study, a sensitive and robust ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed, validated, and applied to determine gender-dependent pharmacokinetics of total emodin (aglycone+glucuronide) in male and female Sprague-Dawley rats. The lower limit of quantification for emodin and emodin glucuronide in rat plasma was 39 and 78 ng/ml, with signal-to-noise ratio of ≥ 10. Precision and accuracy studies showed emodin and emodin glucuronide plasma concentrations well within the 10% range in all studies. Plasma recovery of emodin and emodin glucuronide was always above 86% for low (emodin: 39 ng/ml; glucuronide: 78 ng/ml), 92% for medium (625 ng/ml), and 97% for high (10000 ng/ml) concentrations. Furthermore, emodin showed more than 95% plasma stability under short-term and long-term storage conditions, as well as after three freeze-thaw cycles in the experiments. The developed and validated analytical method was successfully applied to study the gender-dependent 10-fold higher oral bioavailability of total emodin in male than female rats. The oral bioavailability of emodin and emodin glucuronide was also measured separately and showed a statistically significant gender difference in oral bioavailability of emodin and emodin glucuronide in rats.