- [Show abstract] [Hide abstract] ABSTRACT: A simple, reliable and high sensitive method for the simultaneous determination of aflatoxin B1, B2, G1, G2 in Fructus Bruceae was developed using high-performance liquid chromatography coupled to online post-column photochemical derivatization and fluorescence detection. Aflatoxins were first extracted by a methanol/water mixture and then cleaned up with an AflaTestTM immunoaffinity column. Different clean-up and derivatization methods were compared and optimized. The established method was extensively validated to show satisfactory performance of linearity (R2≥0.9997), recovery (74.3–100.8%) and precision (RSDs≤2.8%) for the investigated aflatoxins. This proposed method was also applied to 11 Fructus Bruceae samples. and the results showed that 10 out of 11 were contaminated with aflatoxins ranging from 0.26 to 27.52 μg kg−1 and the occurrence of aflatoxin B1, the most toxic one, was as high as 91% in all the samples, highlighting the severe contamination and the necessity to set legal limits for aflatoxins in Fructus Bruceae.This article is protected by copyright. All rights reserved
- [Show abstract] [Hide abstract] ABSTRACT: Introduction Glycyrrhizae species are popular ingredients of herbal medicine in most traditional Chinese medicine prescriptions, and they mainly contain flavonoids and triterpene saponins. The contents of these bioactive compounds may vary in different batches and affect the therapeutic effects. Thus comprehensive quality control and monitoring of their herbal formulation are of paramount concern. Objective To establish a rapid, effective pressurised liquid extraction (PLE) and ultra-performance liquid chromatography coupled with photodiode array (UPLC-PDA) method to evaluate the quality of Glycyrrhizae species. Methods Radix Glycyrrhizae was extracted by PLE using 70% ethanol at 100°C for 15 min during three static extraction cycles. Separation was performed using an UPLC system to quantify five bioactive compounds, namely liquiritin apioside, liquiritin, liquiritigenin, glycyrrhizic acid and glycyrrhetinic acid, in 12 batches of samples of different origins in China. Furthermore, the samples were analysed using an ultra-performance liquid chromatography coupled with electrospray ionisation and time-of-flight mass spectrometry (UPLC/ESI-QTOF-MS) system to confirm the results. Results The calibration curves of all five analytes showed good linearity (R2 > 0.9997). Accuracy, precision and repeatability were all within required limits. The mean recoveries measured at the three concentrations were higher than 93.7% with RSDs lower than < 3.33% for the targets. Conclusion The established PLE and UPLC-PDA method could serve as a rapid and effective method for quality evaluation of Radix Glycyrrhizae. The UPLC technique can be considered as an attractive alternative to HPLC in routine quality control of Chinese medicine, especially in situations where high sample throughput and fast analytical speed are required.
- [Show abstract] [Hide abstract] ABSTRACT: Traditional Chinese medicines (TCM) infected with toxigenic fungi have become an increasingly outstanding problem for human health. The existing reports mainly focused on the detection methods of mycotoxins in TCMs, however, the effect of mycotoxin production on the inherent quality of TCMs has not been investigated and elucidated so far. In this study, sterilized Glycyrrhiza uralensis was inoculated and incubated with Aspergillus carbonarius for some days to investigate the effect of ochratoxin A (OTA) accumulation on the inherent quality of G. uralensis by determining the content changes of OTA and five active components (liquiritin apioside, liquiritin, liquiritigenin, glycyrrhizic acid, and glycyrrhetinic acid). The results showed that consecutive incubation of G. uralensis with A. carbonarius within 30 days led to the production and accumulation of OTA, and the content reduction of five active components. A negative correlation was illustrated between the contents of OTA and active components.
- [Show abstract] [Hide abstract] ABSTRACT: Ginger, one of the most commonly used spices and additives, is also widely used to prevent and treat human disease as a traditional medicine. However, ginger is prone to contamination by ochratoxin A (OTA), which is toxic, carcinogenic and thermostable. Here, a simple, reliable and low-cost method based on molecularly imprinted polymer (MIP) as selective sorbent of solid-phase extraction (SPE) was proposed for the determination of OTA in ginger by ultra-performance liquid chromatography coupled with fluorescence detection (UPLC-FLR). The samples were firstly extracted and then cleaned up with an AFFINIMIP® SPE OTA column for UPLC-FLR analysis. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) for OTA were 0.09 and 0.30 ng mL−1, respectively. The recoveries of OTA from ginger spiked at 5, 15 and 25 μg kg−1 ranged from 87.6 to 94.5%. In addition, after a simple regenerated procedure, the MIP-based SPE column could be reused at least forty-one times to obtain more than 80% recoveries of OTA for ginger samples. The developed method was applied to the detection of twenty batches of ginger and six samples were contaminated by OTA with levels below the newest legal limits.
- [Show abstract] [Hide abstract] ABSTRACT: A simple, reliable, and low-cost method based on molecularly imprinted polymer as a selective sorbent of SPE was proposed for the determination of ochratoxin A (OTA) in beer, red wine, and grape juice by HPLC coupled with fluorescence detection (HPLC-FLD). Samples were diluted with water and cleaned up with an AFFINIMIP® SPE OTA column. After washing and eluting, the analyte was analyzed by HPLC-FLD. Under the optimized conditions, LOD and LOQ for OTA were 0.025 and 0.08 ng/mL, respectively. The recoveries of OTA from beer, red wine, and grape spiked at 0.1, 2, and 5 ng/mL ranged from 91.6 to 101.7%. Furthermore, after a simple regenerated procedure, the molecularly imprinted polymer based SPE column could be reused at least 14 times to achieve more than 80% recoveries of OTA in real samples. The developed method was applied to the detection of 30 beer, red wine, and grape juice samples and only four samples were contaminated by OTA with levels below the legal limits.
- [Show abstract] [Hide abstract] ABSTRACT: This study firstly describes the development of an accurate and sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the quantification of Taiwanin E methyl ether (TEME) in rat plasma. The assay involved a simple liquid-liquid extraction step with ethyl acetate and a gradient elution using a mobile phase consisting of water containing 0.1% formic acid and acetonitrile containing 0.1% formic acid. Chromatographic separation was successfully achieved on an Agilent Zorbax-C(18) column (2.1 × 50 mm, 3.5 µm) with a flow rate of 0.40 mL/min. The multiple reaction monitoring was based on the transitions of m/z = 379.1 → 320.1 for TEME and 386.1 → 122.0 for buspirone (internal standard). The assay was validated to demonstrate the specificity, linearity, recovery, accuracy, precision and stability. The lower limit of quantification was 0.50 ng/mL in 50 μL of rat plasma. The developed and validated method was successfully applied to the quantification and pharmacokinetic study of TEME in rats after intravenous and oral administration of 1.45 mg/kg TEME. The oral absolute bioavailability of TEME was estimated to be 5.85 ± 1.41% with an elimination half-life value of 2.61 ± 0.55 h, suggesting its poor absorption and/or strong metabolism in vivo. Copyright © 2012 John Wiley & Sons, Ltd.
- [Show abstract] [Hide abstract] ABSTRACT: Fructus aurantii, the dried, immature fruit of Citrus aurantium L. and its cultivated varieties (Family Rutaceae), is one of the commonly used Chinese medicinal herbs in which flavonoids are considered as the major bioactive constituent. In this study, reverse phase ultra-performance liquid chromatography coupled with photo diode array detector (UPLC–PDA) method was developed for the simultaneous quantification of six flavonoids, namely narirutin, naringin, hesperidin, neohesperidin, nobiletin, and tangeretin in Fructus aurantii. The analysis was performed on a Waters Acquity UPLC BEH C18 column (50 mm × 2.1 mm, 1.7 μm) with 1% aqueous acetic acid-acetonitrile gradient elution. The runtime was as short as 8 min. The method was validated in terms of linearity, sensitivity, precision, stability, and accuracy. It was found that all calibration curves showed good linearity (r2 > 0.9991) within the test ranges. The limits of detection (LOD) and limits of quantification (LOQ) were all lower than 35 and 107 ng mL−1. The overall relative standard deviations (RSDs) for intra- and inter-day repeatability were less than 2.94% and 2.74%, respectively. The sample was stable for at least 48 h. The recoveries were 95.33–103.78%. The newly proposed method was found to be simple, rapid, and reproducible for quantitative analysis of six flavonoids in ten samples from different origins. In addition, the samples were also analyzed on an ultra-performance liquid chromatography-electrospray ionization-time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS) system to confirm the identification results.
- [Show abstract] [Hide abstract] ABSTRACT: Chinensinaphthol methyl ether (CME) is a potential pharmacologically active ingredient isolated from the dried plants of Justicia procumbens L. (Acanthaceae). A sensitive and specific LC-MS/MS method was developed and validated for the analysis of CME in rat plasma using buspirone as the internal standard (IS). The analyte was extracted with ethyl acetate and chromatographed on a reverse-phase Agilent Zorbax-C18 110 Å column (50 mm × 2.1mm, 3.5 μm). Elution was achieved with a gradient mobile phase consisting of water and acetonitrile both containing 0.1% formic acid at a flow rate of 0.40 mL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 394.5→346.0 and 386.1→122.0 for CME and IS, respectively. The assay was shown to be linear over the range of 0.50-500 ng/mL, with a lower limit of quantification of 0.50 ng/mL. The method was shown to be reproducible and reliable with the inter- and intra-day accuracy and precision were within ±15%. The assay has been successfully used for pharmacokinetic evaluation of CME after intravenous and oral administration of 1.80 mg/kg CME in rats. The oral absolute bioavailability (F) of CME was estimated to be 3.2±0.2% with an elimination half-life (t½) value of 2.4±0.8h, suggesting its poor absorption and/or strong metabolism in vivo.
- [Show abstract] [Hide abstract] ABSTRACT: A sensitive and accurate LC-ESI-MS/MS method was developed and validated of for the determination of 6'-hydroxy justicidin A (HJA), a potential antitumor active component isolated from Justicia procumbens in rat plasma using a simple liquid-liquid extraction (LLE) method for sample preparation. Chromatographic separation was achieved on an Agilent Zorbax-C(18) column (2.1mm×50mm, 3.5μm) using a step gradient program with the mobile phase of 0.1% formic acid aqueous solution and acetonitrile with 0.1% formic acid. HJA and IS (buspirone) were detected using electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. This method demonstrated good linearity and did not show any endogenous interference with the active compound and IS peaks. The lower limit of quantification (LLOQ) of HJA was 0.50ng/ml in 50μl rat plasma. The developed and validated method has been successfully applied to the quantification and pharmacokinetic study of HJA in rats after intravenous and oral administration of 0.25mg/kg HJA. The oral bioavailability (F) of HJA was estimated to be 36.0±13.4% with an elimination half-life (t(1/2)) value of 1.04±0.20h.