| Objective:Based on the regulation of Coptis chinensis polysaccharide on the tight junction of intestinal epithelial cells,the mechanim of berberine intestinal absorption promoted by particles of Coptis decoction was discussed.Methods:（1）The effects of particles of Coptis decoction on intestinal absorption of berberine were studied.Coptis decoction was prepared by conventional decoction.Decoction particles are separated of by high-speed centrifugation.Particles of Coptis decoction were characterized by atomic force microscopy and laser scattering particle size instrument.The composition of decoction particles was analyzed by sulfuric acid-phenol method and Coomassie Brilliant Blue method.The predominant absorption segments of berberine were screened out by rat intestinal circulation perfusion model.The effects of decoction particles on intestinal absorption of berberine were analyzed by using berberine solution as control group.（2）Studies on Separation,identification and intestinal absorption of Berberine of Coptis chinensis polysaccharides.Coptis chinensis polysaccharides were extracted by water extraction and alcohol precipitation,protein was removed by Sevage method and the yield of polysaccharides was calculated,total glucose and glucuronic acid in Coptis chinensis polysaccharides were determined by sulfuric acid-phenol method and m-hydroxybenzene method,Pre-column derivatization high performance liquid chromatography with l-phenyl-3-methyl-5-pyrazolone method was used to analyze the monosaccharide composition of Coptis chinensis polysaccharide.The effect of absorption promoting of Coptis chinensis polysaccharide was analyzed by rat intestinal circulation perfusion experiment,berberine solution containing different concentration of polysaccharide（0,20,40,60,80μg/m L）was used as perfusion solution,berberine solution of the same concentration was used as control group.（3）The mechanism of promoting intestinal absorption of Coptis chinensis polysaccharide and Decoction particles was studied by using fluorescein as a model drug through cell bypass pathway.Intestinal tissue samples were obtained through intestinal circulation perfusion experiment in rats.The changes of tight junction structure of intestinal epithelial cells were observed by transmission electron microscopy,and the expression of tight junction-related protein ZO-1 in intestinal epithelial cells was observed by immunohistochemical staining,analyzing the intestinal absorption mechanism of berberine promoted by Coptis chinensis polysaccharide and Decoction particles.Results:（1）The effects of particles of Coptis decoction on intestinal absorption of berberine were studied.The values of Ka and Papp of berberine in jejunal segment were（4.3256±0.8479）×10-3/s,（6.1143±0.9231）×10-4 cm/s,respectively,which were significantly higher than those in other intestinal segments（P<0.05）.Particles of Coptis decoction had significant promoting effect on berberine,the values of Ka and Papp of Coptis decoction group and particle group were higher than those in other intestinal segments（P<0.01）.Irregular strip or elliptic particles of Coptis decoction were distributed widely in the range of 100～1500 nm in diameter,and the surface potential was negative.Coptis decoction particles mainly contain polysaccharide components.（2）Studies of Separation,identification and intestinal absorption of berberine of Coptis chinensis polysaccharides.Coptis chinensis polysaccharides were successfully extracted,the yield of polysaccharides was 50.72 mg/g,the total glucose content of Coptis chinensis polysaccharides was 95.26%,the content of glucuronic acid was 45.74%.The monosaccharide composition of Coptis chinensis polysaccharides was galacturonic acid,arabinose,galactose and rhamnose,the mass ratio of those monosaccharides was4.2:3.1:1.5:1.The intestinal circulation perfusion experiment showed that the berberine Ka and Papp values in the experimental groups containing polysaccharide were significantly higher than those in the control group without polysaccharide（P<0.05）,and the concentration of polysaccharide in the experimental group with 80μg/m L was the highest（P<0.01）.（3）The effect of Coptis chinensis polysaccharides on promoting drug uptake by cell bypass pathway is related to tight junction regulation.Coptis chinensis polysaccharides can also promote intestinal absorption of fluorescein,a model drug of cell bypass pathway absorption,and the effect is enhanced with the increase of polysaccharide concentration,and the intestinal absorption promoting effect of 80ug/m L polysaccharide was similar to that of Decoction particles.Transmission electron microscopy showed that the intercellular space of intestinal epithelium in polysaccharide,decoctions and particulates group was significantly higher than that in control group（P<0.05）.The results of immunohistochemical show that the expression of ZO-1 in polysaccharide,decoctions and particulates group is lower than that in blank group（P<0.05）.Conclusion:Coptis chinensis polysaccharide is the main component of the Coptis decoction particle.Coptis chinensis polysaccharide can significantly promote the intestinal absorption of berberine.Coptis chinensis polysaccharide can promote the absorption of berberine by cell-promoting bypass pathway drug absorption,and expression level of tight junction protein and the regulation of tight junction structure of intestinal epithelial cells is closely related.The research of this topic will help to clarify some common problems in the mechanism of intestinal absorption of active ingredients in traditional Chinese medicine decoction,and provide theoretical basis for the interpretation of the scientific connotation of traditional Chinese medicine decoction and the development of new formulations of traditional Chinese medicine. |
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