Daoquan Tang

Development of a novel method combining HPLC fingerprint and multi-ingredients quantitative analysis for quality evaluation of traditional chinese medicine preparation

A novel method combining high performance liquid chromatography (HPLC) fingerprint and simultaneous quantitative analysis of multiple active components was developed and validated for quality evaluation of one type of traditional Chinese medicine preparations: Shuang-huang-lian (SHL) oral liquid formulation. For fingerprint analysis, 45 peaks were selected as the common peaks to evaluate the similarities among several different SHL oral liquid preparations collected from manufacturers. Additionally, simultaneous quantification of eleven markers, including chlorogenic acid, caffeic acid, rutin, forsythiaside, scutellarin, baicalin, forsythin, luteoloside, apigenin, baicalein and wogonin, was performed. Statistical analysis of the obtained data demonstrated that our method has achieved desired linearity, precision and accuracy. Finally, concentrations of these eleven markers in SHL oral liquid prepared by different manufacturers in China were determined. These results demonstrated that the combination of HPLC chromatographic fingerprint and simultaneous quantification of multi-ingredients offers an efficient and reliable approach for quality evaluation of SHL oral liquid preparations.

Preventive effects of rutin on the development of experimental diabetic nephropathy in rats.

AIMS Diabetic nephropathy (DN) is an important microvascular complication and one of the main causes of end-stage renal disease. In this study, the preventive effect and mechanism of rutin on the development of DN in streptozotocin (STZ)-induced diabetic rats were investigated. MAIN METHODS After an early DN model was induced by STZ, rats were orally administered rutin at 3 doses for 10 weeks. Fasting blood glucose, creatinine (Cr), blood urea nitrogen (BUN), urine protein, kidney index, antioxidase, advanced glycosylation end products (AGEs), extracellular matrix (ECM) including collagen IV and laminin, connective tissue growth factor (CTGF), phosphorylated Smad 2/3 (p-Smad 2/3) and Smad 7 (p-Smad 7), and transforming growth factor-β(1) (TGF-β(1)) were determined by different methods, respectively. The ultrastructural morphology was observed by a transmission electron microscope. KEY FINDINGS Compared with the DN group, rutin decreased the levels of fasting blood glucose, Cr, BUN, urine protein, the intensity of oxidative stress and p-Smad 7 significantly. The expression of AGEs, collagen IV and laminin, TGF-β(1), p-Smad 2/3 and CTGF was inhibited by rutin significantly. Moreover, rutin was observed to inhibit proliferation of mesangial cells and decrease thickness of glomerular basement membrane (GBM) by electron microscopy. SIGNIFICANCE The preventive effect of rutin on the development of DN is closely related to oxidative stress and the TGF-β(1)/Smad/ECM and TGF-β(1)/CTGF/ECM signaling pathways. Those results suggest that rutin can prevent the development of experimental DN in rats.

A novel signal-on electrochemical DNA sensor based on target catalyzed hairpin assembly strategy.

We describe a novel signal-on electrochemical DNA (E-DNA) sensing platform based on target-catalyzed hairpin assembly. The thiolated modified molecular beacon 1 (MB1) was first immobilized onto the Au electrode (GE) surface and then target DNA hybridized to the MB1, the opened MB1 assembled with the ferrocene (Fc)-labeled molecular beacon 2 to displace the target DNA, which became available for the next cycle of MB1-target hybridization. Moreover, Fc was confined close to the GE surface for efficient electron transfer, resulting in a current signal. Eventually, each target strand went through many cycles, resulting in numerous Fcs confining close to the GE, which leaded to the current of Fc dramatically increase. The observed signal gain was sufficient to achieve a demonstrated detection limit of 0.74 fM, with a wide linear dynamic range from 10(-15) to 10(-10)M and discriminated mismatched DNA from perfect matched target DNA with a high selectivity. Thus, the proposed E-DNA sensor would have a wide range of sensor applications because it is enzyme-free and simple to perform.

A sensitive sandwich-type electrochemical aptasensor for thrombin detection based on platinum nanoparticles decorated carbon nanocages as signal labels

In this work, a novel and sensitive sandwich-type electrochemical aptasensor has been developed for thrombin detection based on platinum nanoparticles (Pt NPs) decorated carbon nanocages (CNCs) as signal tags. The morphological and compositional of the Pt NPs/CNCs were examined using transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The results showed that the Pt NPs with about 3-5nm in diameter were well dispersed on the surface of CNCs. The thiolated aptamer was firstly immobilized on the gold electrode to capture the thrombin molecules, and then aptamer functionalized Pt NPs/CNCs nanocomposites were used to fabricate a sandwich sensing platform. Then, the high-content Pt NPs on carbon nanocages acting as hydrogen peroxide-mimicking enzyme catalyzed the reduction of H2O2, resulting in significant electrochemical signal amplification. Differential pulse voltammetry is employed to detect thrombin with different concentrations. Under optimized conditions, the approach provided a good linear response range from 0.05 pM to 20nM with a low detection limit of 10fM. This Pt NPs/CNCs-based aptasensor shows good precision, acceptable stability and reproducibility, which provided a promising strategy for electrochemical aptamer-based detection of other biomolecules.

Ginkgo biloba extract suppresses hypertrophy and extracellular matrix accumulation in rat mesangial cells

AbstractAim:To observe the effects of Ginkgo biloba extract (EGb) on the hypertrophy of mesangial cells and the accumulation of extracellular matrix (ECM) in mesangial cells.Methods:Cultured mesangial cells were allotted into 7 groups: normal group, solvent control group, high glucose group, low dose of EGb group, moderate dose of EGb group, high dose of EGb group, and captopril group. Activities of cell antioxidases, S phase percentage and G0/G1 phase percentage, collagen IV and laminin, Smad2/3 and Smad7, TGF-β1 mRNA were measured by different methods.Results:For EGb-treated groups, when compared with high glucose group, the cell percentage of S phase was raised and the percentage of G0/G1 was lowered. The intensity of oxidative stress was weakened. The expression of Smad2/3 was greatly decreased and Smad7 was increased. Collagen IV, laminin and TGF-β1 mRNA were also reduced.Conclusion:EGb can suppress cell hypertrophy and the accumulation of ECM in rat mesangial cells, which means it could play a vital role in the delay of glomerulosclerosis in diabetic nephropathy.

Two-dimensional liquid chromatography and its application in traditional Chinese medicine analysis and metabonomic investigation

Two-dimensional liquid chromatography has become an attractive analytical tool for the separation of complex samples due to its enhanced selectivity, peak capacity, and resolution compared with one-dimensional liquid chromatography. Recently, more attention has been drawn on the application of this separation technique in studies concerning traditional Chinese medicines, metabonomes, proteomes, and other complex mixtures. In this review, we aim to examine the application of two-dimensional liquid chromatography in traditional Chinese medicine analysis and metabonomic investigation. The classification and evaluation indexes were first introduced. Then, various switching methods were summarized when used in an on-line two-dimensional liquid chromatography system. Finally, the applications of this separation technique in traditional Chinese medicine analysis and metabonomic investigation were discussed on the basis of specific studies.

Retracted: Protective Effects of Rutin on Rat Glomerular Mesangial Cells Cultured in High Glucose Conditions

The protective effect of rutin on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells was investigated. The cultured mesangial cells were divided into eight groups: normal, solvent control, high glucose, low dose of rutin, moderate dose of rutin, high dose of rutin, captopril and Ginkgo biloba extract. The cell cycles, type IV collagen and laminin in cytoplasm, TGF‐β1 mRNA of mesangial cells, Smad 2/3 and Smad 7, and the activities of four antioxidant indexes including T‐SOD, MDA, CAT and GSH‐Px were measured by flow cytometry, radioimmunoassay, RT‐PCR, western blotting and visible spectrophotometry, respectively. Compared with the high glucose group, rutin decreased the cell percentages of the G0/G1 phase and inhibited the expression of Smad 2/3, laminin and type IV collagen, and TGF‐β1 mRNA level, significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression were significantly increased by rutin. These results suggest that rutin is a potent protective agent against glomerulosclerosis in DN. Copyright

Fingerprint analysis and multi-ingredient quantitative analysis for quality evaluation of Xiaoyanlidan tablets by ultra high performance liquid chromatography with diode array detection

A rapid and sensitive ultra high performance liquid chromatography method with diode array detection was developed for the fingerprint analysis and simultaneous determination of seven active compounds in Xiaoyanlidan (XYLD) tablets. The chromatographic separations were obtained on an Agilent Eclipse plus C18 column (50 × 2.1 mm id, 1.8 μm) using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. Within 63 min, 36 peaks could be selected as the common peaks for fingerprint analysis to evaluate the similarities among several samples of XYLD tablets collected from different manufacturers. In quantitative analysis, seven compounds showed good regression (R > 0.9990) within test ranges and the recovery of the method was within the range of 95.9-104.3%. The method was successfully applied to the simultaneous determination of seven compounds in six batches of XYLD tablets. These results demonstrate that the combination of chromatographic fingerprint analysis and simultaneous multi-ingredient quantification using the ultra high performance liquid chromatography method with diode array detection offers a rapid, efficient, and reliable approach for quality evaluation of XYLD tablets.

Development and application of a LC–MS/MS assay for the simultaneous quantification of edaravone and taurine in beagle plasma

An LC-MS/MS method was developed and validated for the simultaneous quantification of edaravone and taurine in beagle plasma. The plasma sample was deproteinized using acetonitrile containing formic acid. Chromatographic separations were achieved on an Agilent Zorbax SB-Aq (100 × 2.1 mm, 3.5 μm) column, with a gradient of water (containing 0.03% formic acid) and methanol as the mobile phase at a flow rate of 0.3 mL/min. The analyte detection was carried out in multiple reaction monitoring mode and the optimized precursor-to-product transitions of m/z [M+H](+) 175.1 → 133.0 (edaravone), m/z [M+H](+) 189.1 → 147.0 (3-methyl-1-p-tolyl-5-pyrazolone, internal standard, IS), m/z [M-H](-) 124.1→80.0 (taurine), and m/z [M-H](-) 172.0 → 80.0 (sulfanilic acid, IS) were employed to quantify edaravone, taurine, and their corresponding ISs, respectively. The LOD and the lower LOQ were 0.01 and 0.05 μg/mL for edaravone and 0.66 and 2 μg/mL for taurine, respectively. The calibration curves of these two analytes demonstrated good linearity (r ＞ 0.99). All the validation data including the specificity, precision, recovery, and stability conformed to the acceptable requirements. This validated method has successfully been applied in the pharmacokinetic study of edaravone and taurine mixture in beagle dogs.

In vitro suppression of quercetin on hypertrophy and extracellular matrix accumulation in rat glomerular mesangial cells cultured by high glucose

Quercetins protective effects on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells were investigated. The cell cycles, type IV collagen and laminin, TGF-β(1) mRNA, Smad 2/3 and Smad 7, and activities of cell antioxidases were measured. Compared with the high glucose group, quercetin may decrease the cell percentages of G(0)/G(1) phase, Smad 2/3 expression, laminin and type IV collagen, and TGF-β(1) mRNA level significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression was significantly increased by quercetin. These results suggest that quercetin is a protective agent against glomerulosclerosis in DN.