熊果酸抑制P-糖蛋白外排功能

目的研究女贞子中的熊果酸对P-糖蛋白（P-gp）功能的影响。方法用环孢素A作为P-糖蛋白功能抑制的阳性对照,用流式细胞术分析熊果酸对P-糖蛋白底物——罗丹明123在Caco-2细胞中外排的影响。结果当熊果酸浓度在0.01μmol.L-1时,实验组细胞内荧光与阴性对照组间无显著性差异（P〉0.05）;当熊果酸浓度在0.1～1μmol.L-1时,实验组细胞内荧光强度显著强于阴性对照组（P〈0.05）,并随熊果酸浓度的增高而增强;当熊果酸浓度为10μmol.L-1时,实验组细胞内荧光强度却表现为减弱,并且显著弱于阴性对照组（P〈0.05）,其原因有待后续实验探讨。结论在低浓度时（0.01μmol.L-1）,熊果酸对P-gp的功能没有影响;当熊果酸浓度在0.1～1μmol.L-1时,熊果酸对P-gp的功能有抑制作用。

Inhibition of the function of p-glycoprotein by ursolic acid

Objective To study the effect of ursolic acid in fructus ligustri lucidi on the function of P-glycoprotein.Methods Cyclosporine A was used as positive control of the inhibitory effect on the function of P-glycoprotein. Flowcytometry was used to study the effect of ursolic acid on the efflux of rhodamine123 which was the substrate of P-gp in Caco-2 cells.Results When the concentration was 0.01 μmol·L-1, there was no difference between ursolic acid and the negative control group in the intracellular fluorescence(P>0.05). When the concentration was 0.1～1 μmol·L-1, the intracellular fluorescence of ursolic acid group was significantly higher than that of the negative control group(P<0.05),and the concentration increased with the intracellular fluorescence of ursolic acid group. When the concentration was 10 μmol·L-1, the intracellular fluorescence of ursolic acid group was significantly lower than that of the negative control group(P<0.05),and the reason to be found out in later researches.Conclusion At low concentration (0.01 μmol·L-1), ursolic acid has no effect on the function of P-glycoprotein;while at high concentration while(0.1～1 μmol·L-1), ursolic acid inhibits the function of P-glycoprotein.