Simultaneous determination of the bioactive components in rat plasma by UPLC‐MS/MS and application in pharmacokinetic studies after oral administration of radix Scutellariae extract

A highly sensitive and rapid ultraperformance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS) method has been developed and validated for simultaneous quantification of the four main bioactive compounds, i.e. baicalin, baicalein, wogonoside and wogonin, in rat plasma after oral administration of Radix Scutellariae extract. Clarithromycin was used as an internal standard (IS). Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C₁₈ column (100 × 2.1 mm, 1.7 μm) at a flow rate of 0.4 mL/min, using 0.1% formic acid–acetonitrile as mobile phase. The MS/MS ion transit ions monitored were 447.5 → 270.1 for baicalin, 270.1 → 168.1 for baicalein, 461.2 → 284.0 for wogonoside, 284.2 → 168.1 for wogonin and 748.5 → 158.1 for IS. Method validation was performed according to US Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantification (LLOQ) achieved was 1.13 ng/mL for baicalin, 1.23 ng/mL for baicalein, 0.82 ng/mL for wogonoside and 0.36 ng/mL for wogonin. The calibration curves obtained were linear (r > 0.99) over the concentration range ~ 1–1000 ng/mL. The intra‐ and inter‐day precision was <15% and the accuracy was within ±14.7%. After validation, this method was successfully applied to a pharmacokinetic study of Radix Scutellariae extract.     

Development and validation of a UHPLC–MS/MS method for the simultaneous determination of five bioactive flavonoids in rat plasma and comparative pharmacokinetic study after oral administration of Xiaochaihu Tang and three compatibilities

An accurate, rapid, and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of baicalin, wogonoside, baicalein, wogonin, and oroxylin A in rat plasma. Then, the stability of baicalin and baicalein in the preparation of plasma sample was systematically investigated. The Waters BEH C₁₈ column was used with a gradient mobile phase system of acetonitrile and water containing 0.1% formic acid. The analytes were detected in the multiple reaction monitoring mode with positive electrospray ionization. 100 μL fresh plasma was added with 50 μL antioxidant reagent (1 mol/L HCl containing 0.5% Vitamin C), and liquid–liquid extraction with ethyl acetate was used to extract the analytes from plasma. Lower limits of quantification of baicalin, wogonoside, baicalein, wogonin, and oroxylin A were 21.9, 4.80, 1.20, 0.848, and 0.800 ng/mL, respectively. The mean extract recoveries of five flavonoids were 69.1∼89.2%, and the precision and accuracy were within the acceptable limits. This method was further successfully applied to the comparative pharmacokinetic study of these five flavonoids in rats after oral administration of Xiaochaihutang and three compatibilities. The obtained results may be helpful to reveal the mechanism of Xiaochaihutang formula compatibility.     

Simultaneous quantification of multiple active components from Xiexin decoction in rat plasma by LC‐ESI‐MS/MS: application in pharmacokinetics

A sensitive and specific liquid chromatography–electrospray ionization–tandem mass spectrometric (LC‐ESI‐MS/MS) method was developed and validated to simultaneously quantify 11 active compounds (coptisine, jatrorrhizine, berberine, palmatine, baicalin, baicalein, wogonoside, wogonin, rhein, emodin and aloeemodin) from Xiexin decoction (XXD) in rat plasma. Plasma samples extracted by a single‐step protein precipitation procedure were separated using the gradient mode on a Dikma ODS‐C₁₈ column. Selected reaction monitoring scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. Calibration curves offered satisfactory linearity (r > 0.995) at linear range of 0.47–60 ng/mL for coptisine, jatrorrhizine, berberine and palmatine, 15–1930 ng/mL for baicalin, 20–2560 ng/mL for baicalein, 14–1790 ng/mL for wogonoside, 0.57–72.8 ng/mL for wogonin, 10–1280 ng/mL for rhein, 0.6–76.8 ng/mL for emodin and 3.0–384 ng/mL for aloeemodin. The intra‐ and interday precisions were less than 10.2% in terms of relative standard deviation (RSD), and the accuracies were within ±10.84% in terms of relative error (RE). It was successfully applied to the evaluation of pharmacokinetics after single oral doses of XXD were administered to rats. Copyright © 2010 John Wiley & Sons, Ltd.     

HPLC Determination of Flavonoids in Hairy-Root Cultures of <Emphasis Type="Italic">Scutellaria baicalensis</Emphasis> Georgi

A simple and sensitive liquid chromatographic method has been established for determination of the main flavonoid components of Scutellaria baicalensis Georgi (Lamiaceae) roots and hairy-root cultures. Wogon, the dried root of the plant, is used in traditional Chinese medicine for treatment of bronchitis, hepatitis, tumors, and inflammatory diseases. Lyophilized hairy roots were extracted with methanol. The crude extracts were purified by SPE on Supelco LC-8 cartridges. HPLC separations were performed on a Eurospher 100-C₈ reversed-phase column. The mobile phase was a gradient prepared from mixtures of acetonitrile and 0.1% trifluoroacetic acid. Peaks were identified by addition of standards and/or by diode-array detection. Baicalein 7-O-glucuronide (baicalin), wogonin 7-O-glucuronide (wogonoside), baicalein, wogonin, and acteoside were determined by the external standard method at 280 nm. We found that the aglycon (baicalein and wogonin) content of the transformed roots was consistently higher than that of the intact root from Siberia.     

Discrimination of Ganoderma lucidum according to geographical origin with near infrared diffuse reflectance spectroscopy and pattern recognition techniques

A rapid and nondestructive near infrared (NIR) method combined with chemometrics was used to discriminate Ganoderma lucidum according to cultivation area. Raw, first, and second derivative NIR spectra were compared to develop a robust classification rule. The chemical properties of G. lucidum samples were also investigated to find out the difference between samples from six varied origins. It could be found that the amount of polysaccharides and triterpenoid saponins in G. lucidum samples was considerably different based on cultivation area. These differences make NIR spectroscopic method viable. Principal component analysis (PCA), discriminant partial least-squares (DPLS) and discriminant analysis (DA) were applied to classify the geographical origins of those samples. The results showed that excellent classification could be obtained after optimizing spectral pre-treatment. For the discriminating of samples from three different provinces, DPLS provided 100% correct classifications. Moreover, for samples from six different locations, the correct classifications of the calibration as well as the validation data set were 96.6% using the DA method after the SNV first derivative spectral pre-treatment. Overall, NIR diffuse reflectance spectroscopy using pattern recognition was shown to have significant potential as a rapid and accurate method for the identification of herbal medicines.     

Antiradical and antioxidant activity of flavones from Scutellariae baicalensis radix

We evaluated the antioxidant properties of four main flavones from Scutellaria baicalensis: baicalein, wogonin and their glucuronides – baicalin and wogonoside. We used three in vitro assays: free radical scavenging with 2,2′-diphenylpicrylhydrazyl radical, transition metal ions reducing power by phosphomolybdenum assay and inhibition of the hydroxyl radical-induced peroxidation of linoleic acid assay. All flavones have antioxidant capacity, which differs depending on the structure and mechanisms of activity. In all tests, only baicalein – the aglycone with three adjacent hydroxyl groups – exhibited consistent antioxidant effect. Wogonin protected linoleic acid against oxidation. Baicalin displayed less potent antioxidant properties whereas wogonoside did not have significant antioxidant activity.     

Discrimination of Rhizoma Corydalis from two sources by near-infrared spectroscopy supported by the wavelet transform and least-squares support vector machine methods

Near-infrared spectroscopy (NIRS) was applied for direct and rapid collection of characteristic spectra from Rhizoma Corydalis, a common traditional Chinese medicine (TCM), with the aim of developing a method for the classification of such substances according to their geographical origin. The powdered form of the TCM was collected from two such different sources, and their NIR spectra were pretreated by the wavelet transform (WT) method. A training set of such Rhizoma Corydalis spectral objects was modeled with the use of the least-squares support vector machines (LS-SVM), radial basis function artificial neural networks (RBF-ANN), partial least-squares discriminant analysis (PLS-DA) and K-nearest neighbors (KNN) methods. All the four chemometrics models performed reasonably on the basis of spectral recognition and prediction criteria, and the LS-SVM method performed best with over 95% success on both criteria. Generally, there are no statistically significant differences in all these four methods. Thus, the NIR spectroscopic method supported by all the four chemometrics models, especially the LS-SVM, are recommended for application to classify TCM, Rhizoma Corydalis, samples according to their geographical origin.     

Simultaneous determination of baicalin,baicalein, wogonoside,wogonin, scutellarin,berberine, coptisine,ginsenoside Rb1 and ginsenoside Re of Banxia xiexin decoction in rat plasma by LC–MS/MS and its application to a pharmacokinetic study

A rapid and high‐sensitivity liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for simultaneous determination of nine active constituents (baicalin, baicalein, wogonoside, wogonin, scutellarin, berberine, coptisine, ginsenoside Rb1 and ginsenoside Re) in rat plasma after oral administration of Banxia xiexin decoction (BXD). Biological samples were processed wtih acetone–ethyl acetate (4:1, v/v). The mobile phase consisted of methanol and water (containing 0.1% formic acid) with gradient elution at a flow rate of 0.3 mL/min. Detection was performed on a triple quadrupole mass spectrometer using positive ion and negative ESI in the multiple reaction monitoring mode. The calibration curves for all analytes had good linearity (r > 0.9933). The mean recovery of all the nine active ingredients was >75.2%, and the intra‐ and inter‐day precisions were within 12.0%; the accuracy was between 87.4 and 110.4%. This method was successfully applied to a pharmacokinetic study after administration of BXD. The results of the pharmacokinetic study might be helpful for BXD reasonable clinical application and further studies on mechanism.     

Simultaneous Determination of Ten Active Components in Chinese Medicine “Huang-Lian-Shang-Qing” Tablets by High-Performance Liquid Chromatography Coupled with Photodiode Array Detection

A simple and sensitive high-performance liquid chromatography coupled with a photodiode array detection (HPLC-PAD) method was investigated for the simultaneous determination of ten components (rutin, berberine, palmatine, baicalin, wogonoside, baicalein, wogonin, emodin, chrysophanol, and physcion) in “Huang-Lian-Shang-Qing” (HLSQ) tablets. The method was optimized and the mobile phase composed of methanol (A)-3% phosphoric acid (B) was used to elute the targets in a gradient elution mode. All the calibration curves, precisions, and recoveries were good. Then, this method was successfully used to determine the ten compounds in 33 batches of HLSQ tablets for quality control of this medicinal product.     

Discovery of conversion driven by β-glucuronidase from flavone glycoside to aglycone and application in identifying the raw Scutellariae Radix

Scutellariae Radix (SR), the dried root of Scutellaria baicalensis Georgia, is a famous Chinese materia medica that has been widely employed. Raw Scutellariae Radix (RSR), steamed Scutellariae Radix (SSR), and wine Scutellariae Radix (WSR) are adopted for use in clinical practice. Because of their easily confused appearance, they are always misused. Aiming at this problem, an ultra performance liquid chromatography coupled with photodiode array detector (UPLC-PDA) method was established to survey misuse of the RSR and the processed SR (SSR and WSR) in the market by employing baicalin (BC), wogonoside (WS), baicalein (BN), and wogonin (WN) as quality indicators. Fortunately, β-glucuronidase, which mediates conversion from flavone glycoside to aglycone, was identified in the RSR samples by the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The significant production of BN and WN was witnessed in the RSR samples, which did not occur in the SSR and WSR samples in virtue of the inactivated β-glucuronidase. Besides, the different capacities of β-glucuronidase were evaluated in the tested samples. In general, we provided the first evidence to scientifically identify RSR from SSR and WSR.     

Evaluation of phenyldimethylethoxysilane treated high-performance thin-layer chromatographic plates. Application to analysis of flavonoids inScutellariae radix

Summary The retention and selectivity of flavonoids (baicalin, baicalein, wogonin, oroxylin A) inScutellariae radix have been studies by high-performance thin-layer chromatography on phenyldimethylethoxysilane-treated silica plates. The silica plates treated with phenyl groups were used for physical and chemical analysis. From elemental carbon analysis, the maximum number of bonded phenyl surface groups per gram was calculated to be 0.467×10²¹ (Oginal silica plate: Merck Art. 15109, Silica gel 100 F₂₅₄). With methanol-1/15 M phosphate buffer (pH 6.2) mixtures as mobile phase, baicalin, baicalein, wogonin, and oroxylin A inScutellariae radix were separated. It has been shown that phenyl-treated plates are more suitable for selective separation of baicalin, baicalein, wogonin, and oroxylin A than octadecyl-treated plates.     

On-line continuous flow ultrasonic extraction coupled with high performance liquid chromatographic separation for determination of the flavonoids from root of Scutellaria baicalensis Georgi

An on-line method, based on coupling dynamic ultrasonic extraction (DUE), continuously sampling the suspension of sample and solvent, high performance liquid chromatographic separation with diode array detection, has been developed for the determination of the flavonoids, including baicalin, baicalein and wogonin, from the root of Scutellaria baicalensis Georgi. Variables influencing the DUE were evaluated by orthogonal test. The extraction yields of baicalin, baicalein and wogonin in the roots of S. baicalensis Georgi obtained from five different cultivated areas are 73.8–131.5 μg mg⁻¹ (RSD ≤ 6.24%), 6.8–15.9 μg mg⁻¹ (RSD ≤ 5.36%) and 4.4–14.3 μg mg⁻¹ (RSD ≤ 5.30%), respectively. The limits of detection for baicalin, baicalein and wogonin are 0.30, 0.37 and 0.41 μg mL⁻¹, respectively. Linearity is from 0.55 to 109 μg mL⁻¹ for baicalin, from 0.51 to 105 μg mL⁻¹ for baicalein and from 0.53 to 102 μg mL⁻¹ for wogonin. Compared with off-line continuous flow-DUE, the proposed method would be more convenient for the determination of the analytes and the rapid optimization of the extraction process. The extraction yields of flavonoids obtained by the proposed method are comparable with those obtained by dynamic microwave assisted extraction, static ultrasonic extraction and reflux extraction. The result indicated that the proposed method is suitable to determine the active components in Chinese herbal medicine.     

Treating NIR data with orthogonal discrete wavelet transform: Predicting concentrations of a multi-component system through a small-scale calibration set

Through randomly arranging samples of a calibration set, treating their NIR spectra with orthogonal discrete wavelet transform, and selecting suitable variables in terms of correlation coefficient test (r-test), it is possible to extract features of each component in a multi-component system respectively and partial least squares (PLS) models based on these features are capable of predicting the concentration of every component. What is perhaps more important, with the proposed strategy, the predictive ability of the model is at least not impaired while the size of the calibration set can be obviously reduced. Therefore, it provides a more economical, rapid, as well as convenient approach of NIR quantitative analysis for multi-component system. In addition, all important factors and parameters related to the proposed strategy are discussed in detail.     

Rapid quality assessment of Gentianae Macrophyllae Radix based on near-infrared spectroscopy and capillary electrophoresis

The aim of this study was to establish a rapid quality assessment method for Gentianae Macrophyllae Radix (RGM) using near-infrared (NIR) spectra combined with chemometric analysis. The NIR spectra were acquired using an integrating sphere diffuse reflectance module, using air as the reference. Capillary electrophoresis (CE) analyses were performed on a model P/ACE MDQ Plus system. Partial least squares-discriminant analysis qualitative model was developed to distinguish different species of RGM samples, and the prediction accuracy for all samples was 91%. The CE response values at each retention time were predicted by building a partial least squares regression (PLSR) calibration model with the CE data set as the Y matrix and the NIR spectra data set as the X matrix. The converted CE fingerprints basically match the real ones, and the six main peaks can be accurately predicted. Transforming NIR spectra fingerprints into the form of CE fingerprints increases its interpretability and more intuitively demonstrates the components that cause diversity among samples of different species and origins. Loganic acid, gentiopicroside, and roburic acid were considered quality indicators of RGM and calibration models were built using PLSR algorithm. The developed models gave root mean square error of prediction of 0.2592% for loganic acid, 0.5341% for gentiopicroside, and 0.0846% for roburic acid. The overall results demonstrate that the rapid quality assessment system can be used for quality control of RGM.     

Quantitative analysis of two adulterants in Cynanchum stauntonii by near-infrared spectroscopy combined with multi-variate calibrations

Authentication of traditional Chinese medicines (TCMs) has become important because they can be adulterated with relatively cheap herbal medicines similar in appearance. Detection of such adulterated samples is needed because their presence is likely to reduce the pharmacological potency of the original TCM and, in the worst cases, the samples may be harmful. The aim of this study was to develop a rapid near-infrared spectroscopy (NIRS) analytical method which was supported by multi-variate calibration, e.g. partial least squares regression (PLSR) and radial basis function artificial neural networks (RBF-ANN), in order to quantify the TCM and the adulterants. In this work, Cynanchum stauntonii (CS), a commonly used TCM, in mixtures with one or two adulterants ?? two morphological types of TCM, Cynanchum atrati (CA) and Cynanchum paniculati (CP), were determined using NIR reflectance spectroscopy. The three sample sets, CS adulterated with CA or CP, and CS with both CA and CP, were measured in the range of 800?C2500 nm. Both PLSR and RBF-ANN calibration models provided satisfactory results, even at an adulteration level of 5 mass %, but the RBF-ANN models with better root mean square error of prediction (RMSEP) values for CS, CA, and CP arguably performed better. Consequently, this work demonstrates that the NIR method of sampling complex mixtures of similar substances such as CS adulterated by CA and/or CP is capable of producing data suitable for the quantitative analysis of mixtures consisting of the original TCM adulterated by one or two similar substances, provided the spectral data are interrogated by multi-variate methods of data analysis such as PLS or RBF-ANN.     

Determination of effective wavelengths for discrimination of fruit vinegars using near infrared spectroscopy and multivariate analysis

Near infrared (NIR) spectroscopy based on effective wavelengths (EWs) and chemometrics was proposed to discriminate the varieties of fruit vinegars including aloe, apple, lemon and peach vinegars. One hundred eighty samples (45 for each variety) were selected randomly for the calibration set, and 60 samples (15 for each variety) for the validation set, whereas 24 samples (6 for each variety) for the independent set. Partial least squares discriminant analysis (PLS-DA) and least squares-support vector machine (LS-SVM) were implemented for calibration models. Different input data matrices of LS-SVM were determined by latent variables (LVs) selected by explained variance, and EWs selected by x-loading weights, regression coefficients, modeling power and independent component analysis (ICA). Then the LS-SVM models were developed with a grid search technique and RBF kernel function. All LS-SVM models outperformed PLS-DA model, and the optimal LS-SVM model was achieved with EWs (4021, 4058, 4264, 4400, 4853, 5070 and 5273 cm⁻¹) selected by regression coefficients. The determination coefficient (R²), RMSEP and total recognition ratio with cutoff value ±0.1 in validation set were 1.000, 0.025 and 100%, respectively. The overall results indicted that the regression coefficients was an effective way for the selection of effective wavelengths. NIR spectroscopy combined with LS-SVM models had the capability to discriminate the varieties of fruit vinegars with high accuracy.     

Multiple compounds determination and fingerprint analysis of Lidanpaishi tablet and keli by high-performance liquid chromatography

The objective of this paper was to establish an efficient method for quality control of Lidanpaishi (LDPS) tablet and keli, two famous traditional Chinese medicines. A simple and reliable high-performance liquid chromatography (HPLC) coupled with photodiode array detector (DAD) method was developed both for fingerprint analysis (FA) and quantitative determination. In quantitative analysis, linear regressions, limit of detection (LOD) and quantification (LOQ), intra-day and inter-day precisions, recovery, repeatability and stability were all tested and good results were obtained to simultaneously determine the 15 marker compounds, namely chlorogenic acid, rhaponticin, 6,7-dimethoxycoumarin, naringin, hesperidin, neohesperidin, baicalin, wogonoside, baicalein, wogonin, chrysin, honokiol, magnolol, emodin, and chrysophanol in the herbal drugs. In fingerprint analysis, 34 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from different pharmaceutical companies in China according to the State Food and Drug Administration (SFDA) requirements, and two kinds of data, relative retention time (RRT) and relative peak area (RPA) were used to identify the common peaks in 15 samples for investigation. Furthermore, hierarchical cluster analysis (HCA) was also performed to evaluate the variation of the herbal drugs. The present approach, i.e. HPLC coupled with multiple compounds determination (MCD) and FA is a powerful and meaningful tool to comprehensively conduct the quality control of traditional Chinese medicines.     

Differential distribution of phytochemicals in Scutellariae Radix and Scutellariae Amoenae Radix using microscopic mass spectrometry imaging

Scutellariae Radix, the root of Scutellaria baicalensis Georgi, is widely applied in China for the treatment of fever, ulcer, bronchitis, hepatitis and inflammatory symptoms. Sctuellariae Amoenae Radix, the root of Scutellaria amoena C.H. Wright, is often prescribed as the substitute for Scutellariae Radix. Up to now, no attempt has been made to unveil and compare the localization of phytochemicals in Scutellariae Radix and its succedaneum. This investigation succeeded to look into the differential distribution of natural compounds in Scutellariae Radix and Scutellariae Amoenae Radix using microscopic mass spectrometry imaging. Compounds presenting different distribution modes in two kinds of roots were sorted out, then a quick method for the differentiation between Scutellariae Radix and Scutellariae Amoenae Radix was established. Accumulation sites of baicalein, baicalin, wogonin and wogonoside in Scutellariae Radix were also uncovered using microscopic mass spectrometry imaging. Moreover, the application of matrix assisted laser desorption ionization-quadrupole-time of flight mass spectrometry allowed the on-tissue dissociation of major flavonoids. Overall, the utilization of microscopic mass spectrometry imaging and matrix assisted laser desorption ionization-quadrupole-time of flight mass spectrometry provided a novel perspective for the discovery of natural compounds within medicinal plants.     

Simultaneous determination of eight bioactive components in rat plasma after oral administration of Yan‐Ke‐Ning‐Tablet by liquid chromatography coupled with Q‐Exactive Orbitrap tandem mass spectrometry

A rapid, sensitive and reliable quantitative method based on ultra‐high performance liquid chromatography coupled with Q‐Exactive Orbitrap tandem mass spectrometry was developed for simultaneous determination of berberine, berberrubine, palmatine, jatrorrhizine, columbamine, baicalin, baicalein and wogonin in rat plasma after oral administration with Yan‐Ke‐Ning‐Tablet (YKNT). After precipitation with acetonitrile, the plasma samples were separated on a reverse‐phase C₁₈ column with 1 mm ammonium acetate containing 0.2% acetic acid–acetonitrile as mobile phase. Calibration curves showed good linearity (r > 0.9983) over the tested concentration ranges of 0.5–200 ng/mL for berberine, berberrubine, palmatine, jatrorrhizine and columbamine, and 1–300 ng/mL for baicalin, baicalein and wogonin. The precision (relative standard deviation) at three different concentration levels was <12.15% and the accuracy (relative error) ranged from ?8.24 to 10.85%. No matrix effects were observed with matrix effect value ranging from 89.23 to 107.68%. The extraction recovery was in the range of 82.34–92.31%. The validated assay was further successfully applied to the pharmacokinetic study of these components after oral administration of YKNT. The present study provides the pharmacokinetic profiles of major bioactive components found in YKNT, and provides valuable information regarding the chemical components that were absorbed into plasma, which will be helpful for understanding the therapeutic effects of YKNT.