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OBJECTIVE To establish a method for the simultaneous determination of 10 rhubarb anthraquinones in Compound gentian sodium bicarbonate tablets and the content of rhaponticin，which are the characteristic components of artifacts，and to use the method to evaluate the quality of compound preparation containing Rheum officinale. METHODS The ultra-performance liquid chromatography （UPLC） method was adopted to determine the contents of 10 rhubarb anthraquinones （aloe-emodin-8-O-glucoside， rheinic acid-8-O-β-D-glucoside，emodin-8-O-glucoside，chrysophanol-8-O-β-D-glucoside，emodin monomethyl ether-8-O-β-D-glucoside， aloe-emodin，rheinic acid，emodin，chrysophanol，emodin monomethyl ether） and rhaponticin in 40 batches of Compound gentian sodium bicarbonate tablets from 8 manufacturers. The determination was performed on the Agilent Eclipse Plus C18 column with a mobile phase consisted of acetonitrile-0.1% phosphoric acid solution （gradient elution） at a flow rate of 0.3 mL/min； the column temperature was set at 30 ℃ ，and the injection volume was 5 μL. Combining principal component analysis and cluster analysis to synthesize the results of content determination，the quality of samples from different manufacturers was evaluated. RESULTS All of above 11 components showed favorable linear relationships with peak areas in their respective mass concentration ranges （r≥0.999 3），with RSDs of precision，repeatability and stability 296261547@qq.com less than 3% （n＝6）； average sample recoveries ranged 96.82%-98.92% （RSD≤1.74%，n＝6）； their contents were 0971-8247794。E-mail：304436784@qq.com 0.011 7-0.252 0，0-0.323 3，0.131 3-1.236 6，0.081 1-1.056 2，0.015 2-0.189 8，0.001 8-0.152 3，0-0.255 2，0.001 9-0.223 4，0.054 3-0.303 0，0.022 7-0.172 2，0-2.835 9 mg/g，respectively. The cumulative variance contribution of the first three principal components was 95.533%； the 40 batches of samples can be clustered into 4 categories：samples from enterprises a and d were in a category of their own，samples from enterprises f，b，g and e were in a category，and samples from enterprises c and h were in a category. There were large differences in the content of rhubarb anthraquinone in the samples from 8 manufacturers，and rhaponticin was only detected in the sample from one enterprise. CONCLUSIONS Established UPLC method is stable and reliable； it can be used for the content determination of 10 rhubarb anthraquinones and rhaponticin in Compound gentian sodium bicarbonate tablets.
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Objective To investigate the affinity and interaction of a folate receptor targeted rhapontion(RHA)conjugate (FRHA)with human serum albumins(HSA). Method The interaction between FRHA and HSA under physiological conditions was investigated by fluorescence spectroscopy,UV-visual(vis)spectroscopy and circular dichroism(CD)spectroscopy. Great attempts were made to investigate their interaction mechanism regarding the quenching mechanism,the specific binding site,the type of inter-action force,and the effect of FRHA on the micro-environmental and conformational changes in HSA molecules. Results The forma-tion of the complex of FRHA-HSA would lead to fluorescence quenching. The corresponding values of Ka were 1.4322 × 105,1.1793 × 105,0.9334 × 105 and 0.7896 × 105 L/mol when the temperature were 298,302,306,and 310 K,respectively. The enthalpy change (ΔH)and entropy change(ΔS)were calculated to be-38.772 kJ/mol and-31.39 J/(mol·K),indicating that van der Waals force and hydrogen bonds played major roles in stabilizing the complex. Conclusion The interaction process of the formation of FRHA-HSA is spontaneous. The negative values of enthalpy change(ΔH)and entropy change(ΔS)indicate that van der Waals force and hydrogen bonds play major roles in stabilizing the complex. The conformational investigation reveals theα-helical structure is decreased and the microenvironment of HSA is changed upon the addition of FRHA. The fluorescence quenching of HSA caused by FRHA is static quenching. Furthermore,the results of site marker competitive experiment suggest that FRHA binds to the sub-domainⅡA of HSA.
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Objective To establish a simple and specific method for the determination of rhaponticin in Rhei Radix et Rhizoma. Methods A comparison of the methods of polyamide, silica gel TLC and HPLC in the determination of rhaponticin was studied to investigate the optimum way to identify authentic Rhei Radix et Rhizoma. Results The durability of polyamide and silica gel TLC method for the determination of rhaponticin in Rhei Radix et Rhizoma was poor. HPLC method was more suitable for the detection of rhaponticin. Conclusion HPLC method is accurate and reliable, and can be used for the quality control of Rhei Radix et Rhizoma and provide references for the authenticity of Rhei Radix et Rhizoma.
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The binding of rhaponticin to bovine serum albumin (BSA)-bovine lactoferrin (BLF) and the factors that affect BSA-BLF interaction have been studied by fluorescence spectroscopy and Fourier transform infrared spectroscopy. In the fluorescence experiment, RT quenched the fluorescence intensity of mixed proteome and the maximum emission wavelength of BSA, BLF and BSA-BLF proteins system. RT caused obvious red-shift fluorescence for an interaction between RT and proteome. The interaction between RT and proteome was impacted by single-component protein molecular interactions and the interaction between RT-BSA and RT-BLF, the microenvironment of solutions were the factors impacting the interactions between RT and proteome, which impacted quantitative expression of the general environment micro environmental factors. In the Fourier transform infrared spectroscopy, the secondary conformation of protein molecules of single component in the protein group were changed, and the difference of the molecules' structure was responsible for the differences in the molecular conformation changes. The molecules' interaction in the single-component protein affected secondary conformation of the proteins' molecule. The proteins' concentration ratio and the interaction were different in degree of molecular conformational change. These data demonstrates an example of combination of fluorescence spectrum experiment with Fourier transform infrared spectroscopy in the study of protein structura.
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Objective To investigate the affinity and inteaction of a folate receptor targeted rhapontion (RHA) conjugate (FRHA) with human serum albumins(HSA). Method The interaction between FRHA and HSA under physiological conditions was investigated by fluorescence spectroscopy, UV- visual (vis) spectroscopy and circular dichroism (CD) spectroscopy. Great attempts were made to investigate their interaction mechanism regarding the quenching mechanism, the specific binding site, the type of interaction force, and the effect of FRHA on the micro-environmental and conformational changes in HSA molecules. Results The formation of the complex of FRHA-HSA would lead to fluorescence quenching. The corresponding values of Ka were 1.4322×105, 1.1793× 105, 0.9334×105 and 0.7896×105 L/mol when the temperature were 298, 302, 306, and 310 K, respectively. The enthalpy change (ΔH) and entropy change (ΔS) were calculated to be -38.772 kJ/mol and -31.39 J/(mol·K), indicating that van der Waals force and hydrogen bonds played major roles in stabilizing the complex. Conclusion The interaction process of the formation of FRHA-HSA is spontaneous. The negative values of enthalpy change (ΔH) and entropy change (ΔS) indicate that van der Waals force and hydrogen bonds play major roles in stabilizing the complex. The conformational investigation reveals the α·-helical structure is decreased and the microenvironment of HSA is changed upon the addition of FRHA. The fluorescence quenching of HSA caused by FRHA is static quenching. Furthermore, the results of site marker competitive experiment suggest that FRHA binds to the sub-domain II A of HSA.
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Objective: To evaluate the content of rhaponticin and anti-oxidative activities of the ethanol extracts from both the wild plants and suspension cell cultures of Rheum franzenbachii. Methods: Quantitative analysis of rhaponticin was performed by HPLC. The anti-oxidative activities of the ethanol extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assays. Results: The content of rhaponticin in the roots of the wild plant was 4.36 mg/g, while the content was only 1.59 mg/g in the leaves. The content of rhaponticin in suspension cells cultured on Murashige and Skoog (MS) medium supplemented with 1.0 mg/L 6-benzylaminopurine (6-BAP) and 2.0 mg/L 2,4-dicholorophenoxy acetic acid (2,4-D) was 17.64 mg/g, which increased by 4.05 times compared with the content in the roots of the wild plants. The roots of wild plants displayed the strongest anti-oxidative activity, followed by the suspension cells 5 and 6, and the scavenging percent was 91.96%, 91.23%, and 89.27%, respectively, at the concentration of 100 μg/mL. The IC50 values were 2.477, 15.644, and 31.415 μg/mL, respectively. In particular, the DPPH scavenging activity of the ethanol extracts from the roots of the wild plant was generally comparable to the control of ascorbic acid (VC), and the IC50 value of the extracts was lower than that of VC (2.502 μg/mL). Conclusion: Rhaponticin production in the cell culture can be modulated and the accumulation can be increased. The roots of the wild plant display the strongest anti-oxidative activity. These results suggest that R. franzenbachii could hold a good potential source for human health. © 2014 Tianjin Press of Chinese Herbal Medicines.
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AIM:To determine the contents of berberine hydrochloride,palmatine hydrochloride and rhaponticin in Sanhuang Tablets(Radix et Rhizoma Rhei,berberine hydrochloride,extract of Radix Scutellariae) by RP-HPLC. METHODS:RP-HPLC method with Shimadzu TM column(250 mm?4.6 mm,5 ?m) was used. The gradient elution mixture mobile phase consisted of acetonitrile and 0.05% Lauryl sodium sulfate(0.1% phosphoric acid). The flow rate was 1.0 mL/min. The detection wavelength was set at 334 nm. The temperature of column was at 25 ℃. RESULTS:The calibration curves of berberine hydrochloride,palmatine hydrochloride and rhaponticin were linear within the ranges of 0.05-1.04 ?g(r=0.999 9),0.02-0.49 ?g(r=0.999 8),0.05-1.02 ?g(r=0.999 9),respectively. The average recoveries (n=6) were 98.7%,97.2%,99.3%,respectively. CONCLUSION:The method of the operation is accurate,reliable and can be used to control the quality of Sanhuang Tablets.