Simultaneous determination of aurantio‐obtusin,chrysoobtusin, obtusin and 1‐desmethylobtusin in rat plasma by UHPLC‐MS/MS

A sensitive and reliable ultra‐high‐performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UHPLC‐MS/MS) method was developed and validated for the simultaneous determination of four active components of Semen Cassiae extract (aurantio‐obtusin, chrysoobtusin, obtusin and 1‐desmethylobtusin) in rat plasma after oral administration. Chromatographic separation was achieved on an Agilent Poroshell 120 C₁₈ column with gradient elution using a mobile phase that consisted of acetonitrile‐ammonium acetate in water (30 mm ) at a flow rate of 0.4 mL/min. Detection was performed by a triple‐quadrupole tandem mass spectrometer in multiple reaction monitoring mode. The calibration curve was linear over a range of 3.24–1296 ng/mL for aurantio‐obtusin, 0.77–618 ng/mL for chrysoobtusin, 34.55–1818 ng/mL for obtusin and 1.86–1485 ng/mL for 1‐desmethylobtusin. Inter‐ and intra‐day assay variation was <15%. All analytes were shown to be stable during all sample storage and analysis procedures. Copyright © 2013 John Wiley & Sons, Ltd.     

Plasma pharmacochemistry combined with pharmacokinetics and pattern recognition analysis to screen potentially bioactive components from Daming capsule using ultra high performance liquid chromatography with electrospray ionization quadrupole time‐of‐flight mass spectrometry

Daming capsule is a traditional Chinese medicine for hyperlipidemia treatment. However, the vague understanding of the bioactive components of Daming capsule hampers its modernization and internationalization. This work first developed a high‐throughput, high‐resolution, and high‐sensitivity ultra high performance liquid chromatography with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry method for identifying the absorbed compounds and monitoring the pharmacokinetics of Daming capsule. A high‐throughput strategy integrating plasma pharmacochemistry, pharmacokinetics, and pattern recognition analysis was also established for screening the bioactive components of Daming capsule in vivo. The established strategy based on ultra high performance liquid chromatography with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry was successfully applied to screen the bioactive components of Daming capsule. Up to 53 absorbed compounds were identified. Six anthraquinones with fast and high absorption, namely, emodin‐O‐glucoside, aurantio‐obtusin, aloe‐emodin, rhein, emodin, and chrysophanol, were screened as potentially bioactive components of Daming capsule. The plasma pharmacochemistry and pharmacokinetics of Daming capsule were reported for the first time. Notably, the high‐throughput and reliable strategy facilitated the screening and identification of bioactive components of traditional Chinese medicine, thereby providing novel insights into the research and development of new drugs.     

Pharmacokinetics of anthraquinones in rat plasma after oral administration of a rhubarb extract

A sensitive and specific LC‐MS/MS method was developed for simultaneous determination of aloe‐emodin, rhein, emodin, chrysophanol and physcion and their conjugates in rat plasma. The lower limit of quantitation of each anthraquinone was 0.020–0.040 µm . Intra‐day and inter‐day accuracies were 90.1–114.3% and the precisions were <14.6%. The matrix effects were 104.0–113.2%. The method was successfully applied to a pharmacokinetic study in rats receiving a rhubarb extract orally. The area under the concentration–time curve (AUC_0–t) and peak concentration (C_max) of free aloe‐emodin and emodin in rat plasma were much lower than those of rhein. The amounts of chrysophanol and physcion were too low to be continuously detected. After treating the plasma samples with β‐glucuronidases, each anthraquinone was detectable throughout the experimental period (36 h) and showed much higher plasma concentrations and AUC_0–t. The free/total ratios of aloe‐emodin, rhein and emodin were 6.5, 49.0 and 1.7% for C_max and 3.7, 32.5 and 1.1% for AUC_0–t, respectively. The dose‐normalized AUC_0–t and C_max of the total of each anthraquinone were in the same descending order: rhein > emodin > chrysophanol > physcion > aloe‐emodin. These findings reveal phase II conjugates as the dominant in vivo existing forms of rhubarb antharquinones and warrant a further study to evaluate their contribution to the herbal activity. Copyright © 2013 John Wiley & Sons, Ltd.     

Analysis of the pharmacokinetics and metabolism of aloe‐emodin following intravenous and oral administrations in rats

Aloe‐emodin, a natural polyphenolic anthraquinone, has shown various beneficial bioactivities in vitro. The aim of this study was to investigate the pharmacokinetics and metabolism of aloe‐emodin. Aloe‐emodin was intravenously and orally administered to rats. The concentrations of aloe‐emodin and rhein, a metabolite of aloe‐emodin, were determined by HPLC method prior to and after hydrolysis with β‐glucuronidase and sulfatase/β‐glucuronidase. The results showed that the systemic exposures of aloe‐emodin and its metabolites were ranked as aloe‐emodin glucuronides (G) > rhein sulfates (S) > aloe‐emodin > rhein and rhein G when aloe‐emodin was given intravenously. In contrast, when aloe‐emodin was administered orally, the parent form of aloe‐emodin was not absorbed per se, and the systemic exposures of its metabolites were ranked as aloe‐emodin G > rhein G > rhein. In conclusion, the metabolites of aloe‐emodin are more important than the parent form for the bioactivities in vivo. Copyright © 2016 John Wiley & Sons, Ltd.     

UHPLC–MS/MS method for the simultaneous quantitation of five anthraquinones and gallic acid in rat plasma after oral administration of prepared rhubarb decoction and its application to a pharmacokinetic study in normal and acute blood stasis rats

Prepared rhubarb, as one of the main processed products of rhubarb, has a good effect on promoting blood circulation. In this paper we describe a rapid, sensitive, and selective ultra‐fast liquid chromatography with tandem mass spectrometry method for simultaneous quantification of five anthraquinones (rhein, aloe‐emodin, chrysophanol, emodin, and physcion) and gallic acid in plasma. Chromatographic separation was performed on an Extend C₁₈ column at the temperature of 30°C using a mobile phase that consisted of 0.1% aqueous formic acid and acetonitrile. Satisfactory linearity, precision, accuracy, extraction recovery, and matrix effect have been achieved. Then, the validated method was successfully applied to a comparative pharmacokinetic study. The results might be helpful for guiding clinical application of prepared rhubarb in the future.     

pH‐zone‐refining elution–extrusion countercurrent chromatography: Separation of hydroxyanthraquinones from Cassiae semen

Seven hydroxyanthraquinones were successfully separated from the traditional Chinese medicinal herb Cassiae semen by conventional and pH‐zone‐refining countercurrent chromatography with an environmentally friendly biphasic solvent system, in which elution–extrusion mode was investigated for pH‐zone‐refining countercurrent chromatography for the first time. A two‐phase solvent system composed of n‐hexane/ethyl acetate/ethanol/water (5:3:4:4, v/v/v/v) was used for the conventional countercurrent chromatography while the same system with a different volume ratio n‐hexane/ethyl acetate/ethanol/water (3:5:2:6, v/v/v/v) was used for pH‐zone‐refining countercurrent chromatography, in which 20 mmol/L of trifluoroacetic acid was added in the organic phase as a retainer and 15 mmol/L of ammonia was added to the aqueous phase as an eluter. A 400 mg crude sample could be well separated by pH‐zone‐refining countercurrent chromatography, yielding 53 mg of aurantio‐obtusin, 40 mg of chryso‐obtusin, 18 mg of obtusin, 24 mg of obtusifolin, 10 mg of emodin, and 105 mg of the mixture of chrysophanol and physcion with a purity of over 95.8, 95.7, 96.9, 93.5, 97.4, 77.1, and 19.8%, as determined by high‐performance liquid chromatography. Furthermore, the difference in elution sequence between conventional and pH‐zone‐refining mode was observed and discussed.     

Simultaneous determination and pharmacokinetic studies of aloe emodin and chrysophanol in rats after oral administration of Da-Cheng-Qi decoction by high-performance liquid chromatography

A validated high-performance liquid chromatography (HPLC) method was developed for simultaneous determination and pharmacokinetic study of aloe emodin and chrysophanol in rats. It was performed on a reverse-phase C(18) column and a mobile phase made up of methanol and 0.2% acetic acid (83:17, v/v). The ultraviolet detection was 254 nm. 1,8-dihydroxyanthraquinone was used as the internal standard. The assay was linear over the range 28-2800 ng/mL (r(2) = 0.9993) for aloe emodin and 25.6-2560 ng/mL (r(2) = 0.9991) for chrysophanol. The average percentage recoveries of three spiked plasmas were 98.8-104.8% and 97.7-103.2% for aloe emodin and chrysophanol, respectively. Their RSD of intra-day and inter-day precision at concentrations of 56, 280 and 1400 ng/mL for aloe emodin and 51.6, 258 and 1290 ng/mL for chrysophanol were less than 3.5%. This method was applied for the first time to simultaneously determinate aloe emodin and chrysophanol in rats following oral administration of traditional Chinese medicine of Da-Cheng-Qi decoction. The pharmacokinetic parameters showed that chrysophanol was better absorbed with higher concentrations in plasma than aloe emodin did. They both eliminated slowly in male rats. The assay is suitable for identifying the plasma and tissue levels of aloe emodin and chrysophanol in preclinical investigations.     

Qualitative analysis of multiple compounds in raw and prepared Semen Cassiae coupled with multiple statistical strategies

In China, Semen Cassiae is used clinically to improve eyesight, relieve constipation, and to treat headache and dizziness. Prepared Semen Cassiae is obtained by stir‐frying raw Semen Cassiae until it turned dark brown, micro dilatancy, and overflow aroma. After processing, the therapeutic effects change—the purgation effect is alleviated and the hepatoprotective effect is enhanced. To explore the changes in chemical compositions of Semen Cassiae after processing and clarify the material basis of the changed therapeutic effects, an ultra‐high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry coupled with automated data analysis software and statistical strategy was developed. As a result, 53 compounds in raw Semen Cassiae and 43 compounds in prepared Semen Cassiae were found, a total of 55 chemical compounds were identified. Principle component analysis and t‐test were processed by Markerview 1.2.1 software. Finally, 39 peaks were found to be the main contributors to the significant difference (p  < 0.05) between raw and prepared Semen Cassiae. Compared with raw Semen Cassiae, 19 peaks showed a higher intensity in prepared Semen Cassiae, while the contents of 20 compounds in prepared Semen Cassiae were lower, most of which belonged to naphthopyrones glycosides and anthraquinone glycosides.     

Structure elucidation of a sodium salified anthraquinone from the seeds of Cassia obtusifolia by NMR technique assisted with acid–alkali titration

A new sodium salt of anthraquinone named sodium emodin‐1‐O‐β‐gentiobioside, together with nine known compounds, viz. rubrofusarin‐6‐O‐β‐D ‐gentiobioside, chrysophanol‐1‐O‐β‐D ‐glucopyranosyl‐(1–3)‐β‐D ‐glucopyranosyl‐(1–6)‐β‐D ‐glucopyranoside, obtusifolin‐2‐O‐β‐D ‐glucopyranoside, aurantio‐obtusin‐6‐O‐β‐D ‐glucopyranoside, physcion‐8‐O‐β‐D ‐glucopyranoside, 1‐hydroxyl‐2‐acetyl‐3,8‐dimethoxy‐6‐O‐β‐D ‐apiofuranosyl‐(1–2)‐β‐D ‐glucosylnaphthalene, toralactone‐9‐O‐β‐D ‐gentiobioside, aurantio‐obtusin, rubrofusarin‐6‐O‐β‐D ‐apiofuranosyl‐(1–6)‐O‐β‐D ‐glucopyranoside, was isolated from the seeds of Cassia obtusifolia and its structure was elucidated by ¹H and ¹³C NMR technique assisted with acid–alkali titration. The change of chemical shifts of sodium emodin‐1‐O‐β‐gentiobioside before and after acid–alkali titration was also characterized. Copyright © 2011 John Wiley & Sons, Ltd.     

化学计量学用于决明子色谱指纹图谱峰纯度的鉴别

应用化学计量学方法鉴别色谱指纹图谱的峰纯度。对背景进行扣除后,用对照组分光谱构建正交投影矩阵对目标色谱峰的光谱进行投影,以目标色谱峰投影后的残余光谱与投影前的原始光谱的夹角余弦为判据鉴别目标色谱峰的峰纯度：用该方法对决明子药材色谱指纹图谱的峰纯度进行识别,鉴别出大黄素、大黄酚和大黄素甲醚三个纯色谱峰。此方法用于色谱指纹图谱峰纯度的鉴别,结果可靠。     

A DFT study on the radical scavenging activity of hydroxyanthraquinone derivatives in rhubarb

The structural and electronic properties of hydroxyanthraquinone derivatives in rhubarb, namely, chrysophanol, emodin, physcion, aloe‐emodin, rhein, and their radicals were investigated at density functional level. The bifurcated hydrogen bond property of the studied structures was investigated using the atoms in molecules theory. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bonds formation and favors hydrogen atom abstraction. Bond dissociation energy and ionization potential were also determined to know if the radical scavenging activity of these compounds proceeds via an H‐atom or an electron‐transfer mechanism. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Thin-layer chromatography of hydroxyanthraquinones in plant extracts

Summary Existing thin-layer chromatographic (TLC) methods for the separation of hydroxyanthraquinones in plant materials were found to have limited applications. This initiated the development of some new TLC systems to separate the five principal hydroxyanthraquinones: chrysophanol, physcion, emodin, rhein and aloe emodin normally present together in plant materials, on a single chromatogram and usually with a single solvent system.     

Simultaneous quantification of five anthraquinones in rat plasma by high-performance liquid chromatography with fluorescence detection

A sensitive high-performance liquid chromatographic method with fluorescence detection (excitation 435 and emission 515 nm) was established and validated for quantification of five anthraquinones (aloe-emodin, rhein, emodin, chrysophanol and physcion) in rat plasma. Following a single-step liquid-liquid extraction, the analytes and internal standard (1,8-dihydroxyanthraquinone) were separated on a reversed-phase C(18) column with water-phosphoric acid-methanol as mobile phase at a flow rate of 1 mL/min. The linear ranges of the calibration curves were 6.5-1300 ng/mL for aloe-emodin, 20-4000 ng/mL for rhein, 40-8000 ng/mL for emodin, 15-3000 ng/mL for chrysophanol and 13-2600 ng/mL for physcion. The lower limit of quantification was 6.5 ng/mL for aloe-emodin, 20 ng/mL for rhein, 40 ng/mL for emodin, 15 ng/mL for chrysophanol and 13 ng/mL for physcion. The mean accuracy was 94.3-105.1% for aloe-emodin, 90.3-108.8% for rhein, 92.6-106.7% for emodin, 95.8-103.8% for chrysophanol and 98.7-101.2% for physcion. The within-batch and between-batch precisions were < or = 5.5% and < or = 13.4%, respectively. This method is suitable for determining the five anthraquinones in plasma simultaneously and thus investigating the pharmacokinetics of anthraquinones from Xiexin decoction in rats.     

大黄蒽醌衍生物在杯[8]芳烃键合固定相上色谱行为的研究

研究了药用掌叶大黄中5种蒽醌衍生物在对-叔丁基杯[8]芳烃硅胶键合固定相上的高效液相色谱行为,并与ODS固定相进行了比较。研究发现这类化合物与杯[8]芳烃固定相之间存在多种相互作用,除疏水作用外,分离过程中还存在与ODS不同的色谱分离机制。杯芳烃键合相与溶质之间的氢键作用、包容络合作用改变了杯芳烃固定相对它们的选择性。     

Application of an efficient strategy based on liquid–liquid extraction,high‐speed counter‐current chromatography,and preparative HPLC for the rapid enrichment,separation, and purification of four anthraquinones from Rheum tanguticum

This study presents an efficient strategy based on liquid–liquid extraction, high‐speed counter‐current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum. A new solvent system composed of petroleum ether/ethyl acetate/water (4:2:1, v/v/v) was developed for the liquid–liquid extraction of the crude extract from R. tanguticum. As a result, emodin, aloe‐emodin, physcion, and chrysophanol were greatly enriched in the organic layer. In addition, an efficient method was successfully established to separate and purify the above anthraquinones by high‐speed counter‐current chromatography and preparative HPLC. This study supplies a new alternative method for the rapid enrichment, separation, and purification of emodin, aloe‐emodin, physcione, and chrysophanol.     

Identification and determination of active anthraquinones in Chinese teas by micellar electrokinetic capillary chromatography

The simultaneous determination of emodin, aloe-emodin and rhein, in Semen Cassiae, Qinghai Wild Dahuang tea, Ningxia Juemingzi tea, Lanzhou Juemingzi tea and Surong Juemingzi tea, has been investigated by micellar electrokinetic capillary chromatography for the fi rst time. With an electrolyte containing 15 mm borax, 30 mm SDS, 10% (v/v) ethanol, at pH 9.60 and 20 kV applied voltage, the three analytes were completely separated within 12 min. The effects of the concentration of borax, electrolyte pH, the concentrations of SDS and organic modifier and the applied voltage on electropheoretic behavior and separation were studied. The linear calibration range was 4-120 micro g/mL (r = 0.9921) for emodin, 10-200 micro g/mL (r = 0.9970) for aloe-emodin and 2-100 micro g/mL (r = 0.9971) for rhein, respectively. Under the optimum conditions, the relative standard deviation (RSD) values (n = 6) of the migration time and the peak area of each peak was 0.59-0.80% and 1.30-3.22%, respectively. The contents of the analytes in Rheum, Qinghai Wild Dahuang tea, Semen Cassiae and three other kinds of teas were easily determined with recoveries ranging from 95.3 to 104.4%.     

Simultaneous quantification of twelve active components in Yiqing granule by ultra-performance liquid chromatography: application to quality control study

An ultra‐performance liquid chromatography (UPLC) method coupled with photodiode array (PDA) detection has been developed and validated for simultaneous quantification of 12 active components (berberine, palmatine, jatrorrhizine, aloe‐emodin, rhein, emodin, chrysophanol, physcion, baicalin, baicalein, wogonoside and wogonin) in Yiqing granule. Optimum separation were achieved on a C₁₈ column (50 × 2.1 mm i.d., 1.7 µm particle) through a 7.5 min gradient delivery of a mixture of A (acetonitrile) and B (0.1% aqueous phosphoric acid containing 1.8 mmol/L sodium dodecyl sulfonate and 10% acetonitrile, v/v) at a flow rate of 0.3 mL/min at 30°C. Because of the different UV characteristics of these components, three detection wavelengths were used for quantitative analysis. All of the analytes showed good linearity (r of >0.999). The method was validated for repeatability, precision, stability, accuracy and selectivity. The validated method was applied to quality control of Yiqing granule from different production batches. Copyright © 2010 John Wiley & Sons, Ltd.     

中药大黄中羟基蒽醌类成分的分离

依据正交试验设计方法，研究了用乙醇和乙醚等溶剂分离中药大黄中羟基蒽醌类成分（蒽甙及游离羟基蒽醌类成分）及游离羟基蒽醌类成分的最佳分离条件，试验表明，乙醇的用量及回流次数对提取产率有很大影响，而回流时间的影响相对较小，100g大黄干粉的最佳分离条件是：用90mL95%乙醇浸润，再用150－175ml乙醇回流，回流3次，每次30－40min，即可较充分发将羟基蒽醌类成分总量的84％及游离羟基蒽醌类成分总量的82％提取出来。     

Novel strategy for quality consistency evaluation of Chinese medicine “YIQING” tablet that combines the simultaneous quantification and screening of ten bioactive constituents

The UV characteristics for different categories compounds in complex traditional Chinese medicines and herbal preparations usually vary. Thus, to achieve the integral analysis of multiwavelength fingerprint characteristics, we introduced a novel strategy of multiwavelength total fusion profiling. The simultaneous separation and quantification of multiple components by reversed‐phase high‐performance liquid chromatography coupled with diode array detection was developed in an effective, accurate, and reliable way. Furthermore, a 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) scavenging assay was set up to detect and screen the bioactivity of similar‐structure constituents (aloe‐emodin, rhein, emodin, chrysophanol, baicalein, wogonin, baicalin, wogonoside, berberine hydrochloride, and jatrorrhizine hydrochloride). Moreover, the high‐performance liquid chromatography DPPH assay was developed to monitor the relationship between the biological activity and the spatial structure, the number of hydroxyl groups, the concentration of the analytes in samples. The result of qualitative classification for 15 batches of “YIQING” tablets using principle component analysis was consistent with the quantitative fingerprint assessment using the average linear quantitative fingerprint method. Therefore, chemometrics, multiwavelength total fusion profiling in conjunction with average linear quantitative fingerprint method and antioxidant activity can control the quality of traditional Chinese medicines/herbal preparations comprehensively and practically.     

Evaluation of the influence of mirabilite on the absorption and pharmacokinetics of the ingredients in Dahuang‐mudan decoction by a validated UPLC/QTOF–MS/MS method

Dahuang‐mudan decoction (DMD) has been widely used for disease treatment in China for 1700 years. The formula consists of Rhubarb, moutan bark, Prunus persica, wax gourd kernel and mirabilite, which have been well studied by multidisciplinary approaches. However, the role of the mineral mirabilite in DMD is unclear. The objective of this study was to investigate the effects of mirabilite on the absorption and pharmacokinetics of the ingredients in DMD. The constituents were identified in DMD extract and the plasma of mirabilite–DMD (MDMD, 50 g kg^?1) treated rats and nonmirabilite–DMD (NMDMD, 50 g kg^?1) treated rats. The plasma was also used to investigate the effects of mirabilite on the pharmacokinetics of active ingredients in DMD using a new validated UPLC–MS/MS method. The results showed that 63 compounds were identified in the extract of DMD, 27 and 22 of which were found in the plasmas of MDMD‐ and NMDMD‐treated rats, respectively. Furthermore, the results of a pharmacokinetic study suggested that mirabilite influenced the absorption of the five constituents by decreasing the absorption of emodin and rhein while increasing the absorption of aloe‐emodin, paeoniflorin and amygdalin; the pharmacokinetic parameters, including the T_max, C_max, AUC_0–t, MRT_0–t, CLz and t_1/2 of five constituents, significantly changed in MDMD‐treated rats compared with the NMDMD. The method validation for selectivity, precision, accuracy, matrix effect, recovery and stability met the acceptance criteria. These findings uncover the roles of mirabilite in DMD and demonstrate the application of scientific principles to the study of DMD in human health care.