No. 44 Defining the mechanism of reduced blood cholesterol by α-cyclodextrin supplementation.
News Release (2014.7.10)
This research was reported in 29th Cyclodextrin Symposium (Hoshi Univ., Tokyo, Sep. 6~7, 2012).
α-CD supplementation - previous report -
Whereas α-CD could not bind to cholesterol, it has been reported that blood cholesterol level was reduced by α-CD supplementation in mice.
α-CD can inhibit cholesterol absorption indirectly ?
Small-intestinal absorption of lipids
It is important for lipid absorption that lipids are mixed with bile acid micelle and dissolved in intestinal juice.
Constituents of bile
|Bile acid (mM)||72.1 (68%)|
|Lecithin (phospholipids) (mM)||25.8 (23%)|
|Cholesterol (mM)||8.1 (7.6%)|
α-CD can bind only lecithin in bile constituents.
Fed α-CD binds lecithin of bile acid micelle in small-intestine.
Lipid solubilization capacity of bile acid micelle should be lower.
α-CD can inhibit cholesterol absorption indirectly.
The effects of α-CD to artificial intestinal juice
- The interaction between α-CD and lecithin
- The solubility of cholesterol to artificial intestinal juice in the presence of α-CD.
Artificial intestinal juice
Fig. 1. Turbidity of artificial intestinal juice in the presence of α-CD
Increase of turbidity was observed by the addition of α-CD to artificial intestinal juice.
Fig. 2. the interaction between α-CD and lecithin.
artificial intestinal juice in the presence of α-CD (3%)
White precipitation was formed in the case of coexistence of α-CD and lecithin.
→ α-CD can bind to lecithin selectively in artificial intestinal juice. (The precipitation was α-CD-lecithin complex.)
Fig. 3. Aqueous solubility of cholesterol in artificial intestinal juice.
Decrease of aqueous solubility of cholesterol in artificail intestinal juice was observed in the presence of α-CD.
Lecithin was precipitated from bile acid micelle by complexation with α-CD.
Therefore, aqueous solubility of cholesterol was lowered in artificial intestinal juice without lecithin.
From these results, we clarified one of the mechanisms of the reducing effect of blood cholesterol level by α-CD supplementation.