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Studies on the Quality Control and Metabolism of Viscum Coloratum

Author: ZhaoYunLi
Tutor: BiKaiShun
School: Shenyang Pharmaceutical University
Course: Pharmaceutical Analysis
Keywords: Viscum coloratum homoeriodictyol-7-O-β-D- glucoside quality control methods pharmacokinetics
CLC: R285
Type: PhD thesis
Year: 2007
Downloads: 82
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Abstract

The branches with leaves of Viscum coloratum is a traditional Chinese medicine, named as Hujisheng in pharmacopoeia of PRC. The chemical constituents, quality control methods and the pharmacokinetics of Viscum coloratura were investigated in detail.The chemical constituents of Viscum coloratum were systematically studied and 18 compounds were purified with silica gel, polyamide, sephadex LH-20 and ODS column chromatography. Utilizing chemical and spectroscopic methods （UV, NMR, MS）, the structures of 15 compounds were fully characterized. One of these constituents was a novel compound: 1, 7-di- （4-hydroxybenzic）- heptane-1,4- diene-3- ketone; one of them was new nature product: 5-hydroxy- 3, 7, 3’- trimethoxyflavone -4’-O-β-D- glucoside; and one of these constituents was isolated from Viscum for the first time: 5, 7, 4’- trihydroxy-3, 3’-dimethoxyflavone.The methods of HPLC and GC fingerprint analysis were established for the quality control of Viscum coloratum after investigating chromatographic and extracting condition. The samples from different origins and different hosts were analyzed with cluster analysis, and the data were used for similarity evaluation with angle cosine and correlation coefficient as measurement. There was significant difference between herb and their hosts while dependability of herb from different hosts or from different origins was high, which might be the results that effects of hosts on the fingerprints of herb were negligible. Dependability between HPLC fingerprints and GC fingerprints was small because information was different from different constituents. So these methods should be lay particular emphasis on according to clinical application during evaluating the quality of unknown samples. The quality control methods of Viscum coloratum were studies. An HPLC-UV method was developed for the simultaneous quantification of those five constituents: syringin, homoeriodictyol -7-O-β-D- apiose （1→5）-β-D- apiose （1→2）-β-D- glucoside, homoeriodictyol -7-O-β-D- apiose （1→2）-β-D- glucoside, homoeriodictyol -7-O-β-D-glucoside and homoeriodictyol, in Viscum coloratum. The samples from different original area and different hosts were detected, with the results that there were evident differences from different origins and that content in the leaves were higher than that of branches. This method for analysis was simple and accurate, and was basics of quality control for Viscum coloratum. 22 essential oil of Viscum coloratum were identified with Gas Chromatography tandem Mass Spectrum comparing with standard substances, which supply the base for advanced research on essential oil of Viscum coloratum.Homoeriodictyol -7-O-β-D- glucoside, possessing various pharmacological effects, was paid close attention to. A specific, reproducible, and accurate method was developed for the determination of homoeriodictyol =7-O-β-D- glucoside in rat plasma with vanillin as internal standard. The HPLC separation was achieved on a Diamonsil C₁₈ （200 mm×4.6 mm, I.D. 5μm） column. The mobile phase consisted of methanol - 0.5 % glacial ethanol acid solution （45:55, v/v） with a flow rate of 1.0 ml/min. The UV detection wavelength was set at 280 nm. The extraction recoveries exceeded 70.0 %. Intra-day RSD and inter-day RSD were both less than 9.7 %. Accuracy （RE） ranged from -0.8 % to 5.4 %. This method was applied to the pharmacokinetic study of it in rat plasma with the parameters: Ke 0.73 h^-1, t_1/2 1.56 h, AUC_0～t 7.16μg-h/ml, AUC_0～∞ 7.82μg.h/ml. Homoeriodictyol -7-O-β-D- glucoside was found to be metabolized into aglycone, homoeriodictyol, in rat urine after i.v. administration. So another method with HPLC-MS was developed to study the distribution and excretion of homoeriodictyol -7=O-β-D-glucoside and its active metabolite homoeriodictyol. The HPLC separation was achieved on a Luna C₁₈ （150mm×4.6mm, I.D. 5μm） column. The mobile phase was a methanol-water mixture （70:30, v/v） containing 0.1% of formic acid at a flow rate of 0.8 ml/min. Homoeriodictyol -7-O-β-D- glucoside showed a quick distribution into rat tissues with the dosage of intravenous injection of homoeriodictyol -7-O-β-D- glucoside. The contents of it in small intestine and liver were higher than others, and decrease with the prolongation of time in almost all tissues. Homoeriodictyol -7-O-β-D- glucoside was metabolized to homoeriodictyol which could be detected in most of tissues, and the content of kidney was the highest. After intravenous injection of homoeriodictyol -7-O-β-D-glucoside, 11.06 % of administration dosage as original glucoside and 5.73 % as aglycone were detected in urine.An HPLC-UV method was developed for the simultaneous quantification of those four constituents: syringin, homoeriodictyol -7-O-β-D- apiose （1→5）-β-D- apiose （1→2）-β-D- glucoside, homoeriodictyol -7-O-β-D- apiose （1→2）-β-D- glucoside, homoeriodictyol -7-O-β-D- glucoside, in rat plasma with puerarin as internal standard. The HPLC separation was achieved on a Synergi C₁₈ （250 mm×4.6 mm, I. D. 4μm, Phenonex） column. The mobile phase consisted of acetonitrile - 0.5 % glacial ethanol acid with gradient elution at a flow rate of 1.0 ml/min The UV detection wavelength was set at 280 nm. Intra-day RSD and inter-day RSD were both less than 11.6 % for these constituents. Accuracy ranged from -7.9 % to 5.6 % indicated with relative error （RE）. The extraction recoveries exceeded 70.0 %. Another four HPLC-UV methods were developed to determine these four constituents respectively and all these methods were consistent with the guide for analysis of biological samples. They were applied to pharmacokinetic research after intravenous administration of monomers, mixed liquor of four monomers and Viscum coloratum extracts. The pharmacokinetic characteristics were significantly different because of the effects of co-existing compounds and different confirmation even with the same dosages.Combining the utilization of phytochemistry, pharmaceutical analysis, pharmacognosy, pharmacology and pharmacokinetics, the constituents and quality assessment standards for Viscum coloratum were studied, and the metabolism of this medicinal herb and its active constituents were also investigated. This research provided a beneficial exploration for the modernization of traditional Chinese medcine.

Studies on the Quality Control and Metabolism of Viscum Coloratum

Abstract

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