Rozner Shoshana, Aserin Abraham, Wachtel Ellen J, Garti Nissim
Casali Institute of Applied Chemistry, The Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
J Colloid Interface Sci. 2007 Oct 15;314(2):718-26. doi: 10.1016/j.jcis.2007.05.091. Epub 2007 Jun 29.
It is well documented that phytosterols inhibit the uptake of exogenic cholesterol and do not interfere with cholesterol synthesis or cause side effects. The mechanism by which phytosterols interfere with cholesterol absorption is not completely clear and there are at least three hypotheses for their beneficial activity. Among these is that of competitive solubilization of phytosterols and cholesterol in dietary mixed micelles. In the present study we investigated the competitive solubilization of phytosterols (approximately 50% beta-sitosterol) and cholesterol in a nonionic microemulsion system constructed as a model for the dietary mixed micelles. We studied the effect of the competitive solubilization of cholesterol and phytosterols on the structural transformations and physical properties of the microemulsion and evaluated the locus of the solubilizates within the nanodroplets of each sterol separately and when they are loaded together at different weight ratios along one dilution line. Our results show that chemical and structural differences between cholesterol and phytosterols significantly influence the solubilization capacity of the nonionic microemulsion. Cholesterol, being more amphiphilic, is solubilized more efficiently at the W/O microemulsion interface, while in the O/W microemulsion phytosterols are dissolved somewhat more efficiently in the droplet core.
有充分的文献记载，植物甾醇可抑制外源性胆固醇的吸收，且不干扰胆固醇的合成，也不会引起副作用。植物甾醇干扰胆固醇吸收的机制尚不完全清楚，关于其有益活性至少有三种假说。其中之一是植物甾醇与胆固醇在膳食混合微团中发生竞争性增溶作用。在本研究中，我们在构建的作为膳食混合微团模型的非离子微乳液体系中，研究了植物甾醇（约50%为β-谷甾醇）与胆固醇的竞争性增溶作用。我们研究了胆固醇和植物甾醇的竞争性增溶作用对微乳液结构转变和物理性质的影响，并分别评估了每种甾醇单独以及以不同重量比沿一条稀释线一起负载时在纳米液滴内的增溶物位置。我们的结果表明，胆固醇和植物甾醇之间的化学和结构差异显著影响非离子微乳液的增溶能力。胆固醇具有更强的两亲性，在W/O微乳液界面更有效地被增溶，而在O/W微乳液中，植物甾醇在液滴核心中的溶解效率略高。
