γ-谷维素对胆固醇生物利用度和合成的影响。

Effect of gamma-oryzanol on the bioaccessibility and synthesis of cholesterol.

机构信息

The Medical Food Research and Development Center, Department of Transfusion Medicine, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.

出版信息

Eur Rev Med Pharmacol Sci. 2012 Jan;16(1):49-56.

PMID:22338548

Abstract

BACKGROUND AND OBJECTIVES

Gamma-oryzanol (gamma-OR) is a unique mixture of triterpene alcohol and sterol ferulates present in rice bran oil. Hypocholesterolemic activity of gamma-OR has been reported in various animal and human studies. However, the mechanisms for this hypocholesterolemic activity of gamma-OR remain unclear. Therefore, the aim of this in vitro study was to examine the effect of gamma-OR on the bioaccessibility and synthesis of cholesterol.

METHODS

The effects of gamma-OR on the efficiency of incorporation of cholesterol into mixed micelles during digestion and apical uptake of cholesterol by Caco-2 human intestinal cells were determined using the coupled in vitro simulated digestion/Caco-2 human intestinal cell model. The impact of gamma-OR on the HMG-CoA reductase activity was also investigated.

RESULTS

Although incorporation of cholesterol into synthetic micelles was significantly inhibited by 15-fold molar excess of gamma-OR, efficiency of micellarization of cholesterol during simulated digestion of the rice meal was not significantly altered by the presence of as high as 20-fold molar excess of gamma-OR. Nevertheless, 20-fold molar excess of gamma-OR significantly decreased apical uptake of cholesterol into Caco-2 intestinal cells. In addition, gamma-OR inhibited 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity.

CONCLUSIONS

These findings suggest that the hypocholesterolemic activity of gamma-OR is due in part to impaired apical uptake of cholesterol into enterocytes and perhaps a decrease in HMG-CoA reductase activity.

摘要

背景与目的

γ-谷维素（γ-OR）是一种存在于米糠油中的独特的三萜醇和甾醇阿魏酸混合物。γ-OR 在各种动物和人体研究中均显示出降胆固醇活性。然而，γ-OR 降胆固醇活性的机制尚不清楚。因此，本体外研究旨在探讨 γ-OR 对胆固醇生物利用度和合成的影响。

方法

采用体外模拟消化/Caco-2 人肠细胞模型，测定 γ-OR 对胆固醇在消化过程中掺入混合胶束的效率以及 Caco-2 人肠细胞摄取胆固醇的影响。还研究了 γ-OR 对 HMG-CoA 还原酶活性的影响。

结果

尽管 15 倍摩尔过量的 γ-OR 显著抑制了胆固醇掺入合成胶束，但高达 20 倍摩尔过量的 γ-OR 存在并不显著改变米糠饭消化过程中胆固醇的胶束化效率。然而，20 倍摩尔过量的 γ-OR 显著降低了胆固醇向 Caco-2 肠细胞的顶端摄取。此外，γ-OR 抑制了 3-羟基-3-甲基戊二酰辅酶 A（HMG-CoA）还原酶的活性。