The effect of a plant sterol, beta-sitosterol (SI), and a plant stanol, sitostanol (SS), on the solubilization of cholesterol (CH) by model dietary mixed micelles was examined under in vitro conditions with the use of gas chromatography, isothermal titration calorimetry, NMR spectroscopy and cryogenic transmission electron microscopy techniques. Free SI and SS were shown to reduce the concentration of CH in dietary mixed micelles via a dynamic competition mechanism. CH, SI and SS affect the microstructure of lipid vesicles and influence the process of amphiphilic self-assembly of nutrients in the gut with the formation of dietary mixed micelles in a similar manner. Therefore, substitution of CH by phytosterols and phytostanols in the diet does not lead to the notable changes in the mechanism of dietary mixed micelle formation and does not affect the process of the intestinal transport of nutrients and drugs via the micellar diffusion mechanism. Our experimental findings demonstrate that the introduction of plant sterols and plant stanols into the diet is clearly beneficial for the reduction of the intestinal uptake of cholesterol. Due to the limited capacity of dietary mixed micelles to embody hydrophobic sterol/stanol molecules, the micellar concentration of cholesterol is reduced and hence, its transport towards the intestinal brush border membrane decreases.

中文翻译：

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植物甾醇和植物甾烷醇对膳食混合胶束增溶胆固醇的影响：一项体外研究。

在体外条件下，使用气相色谱法检测了植物固醇，β-谷甾醇（SI）和植物甾烷醇，谷甾烷醇（SS）对模型饮食混合胶束增溶胆固醇（CH）的影响，等温滴定热法，NMR光谱和低温透射电子显微镜技术。游离的SI和SS通过动态竞争机制降低了膳食混合胶束中CH的浓度。CH，SI和SS影响脂质囊泡的微结构，并通过类似的饮食混合胶束的形成影响肠道中营养物质的两亲性自组装过程。因此，日粮中的植物甾醇和植物甾烷醇替代CH不会导致饮食混合胶束形成机理的显着变化，并且不会影响通过胶束扩散机理的营养物质和药物在肠道中的运输过程。我们的实验结果表明，在饮食中引入植物甾醇和植物甾烷醇显然有利于减少肠道对胆固醇的吸收。由于膳食混合胶束体现疏水性固醇/甾烷醇分子的能力有限，胆固醇的胶束浓度降低，因此，其向肠刷缘膜的转运减少。我们的实验结果表明，在饮食中引入植物甾醇和植物甾烷醇显然有利于减少肠道对胆固醇的吸收。由于膳食混合胶束体现疏水性固醇/甾烷醇分子的能力有限，胆固醇的胶束浓度降低，因此，其向肠刷缘膜的转运减少。我们的实验结果表明，在饮食中引入植物甾醇和植物甾烷醇显然有利于减少肠道对胆固醇的吸收。由于膳食混合胶束体现疏水性固醇/甾烷醇分子的能力有限，胆固醇的胶束浓度降低，因此，其向肠刷缘膜的转运减少。