Recent research finding
No.44 Defining the mechanism of reduced blood cholesterol by α-cyclodextrin supplementation.

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News Release (2014.7.10)

*This research was reported in 29th Cyclodextrin Symposium (Hoshi Univ., Tokyo, Sep. 6~7, 2012).

αCD supplementation - previous report -

Whereas αCD could not bind to cholesterol,
it has been reported that blood cholesterol level was reduced by αCD supplementation in mice.

αCD 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.

H. Yano, et al. (2009).

Constituents of bile

  bile
Bile acid (mM) 72.1 (68%)
Lecithin (phospholipids) (mM) 25.8 (23%)
Cholesterol (mM) 8.1 (7.6%)
water (%) 84

Constituents of bile

αCD can bind only lecithin in bile constituents.

A hypothesis :
Fed αCD binds lecithin of bile acid micelle in small-intestine.

Lipid solubilization capacity of bile acid micelle should be lower.

αCD can inhibit cholesterol absorption indirectly.

< Study points >
The effects of αCD to artificial intestinal juice
- The interaction between αCD and lecithin
- The solubility of cholesterol to artificial intestinal juice in the presence of αCD.
were explored.

Artificial intestinal juice

Fasted state

Constituents mM
NaTC 3
Lecithin 0.75
NaH2PO4 28.66
NaCl 106
NaOH ~13.8
(adjusted to pH 6.5)

Fed state

Constituents mM
NaTC 15
Lecithin 3.75
Acetic acid 144
NaCl 173
NaOH ~101
(adjusted to pH 5)

M. Vertzoni, et al. (2004)

Fig1 Turbidity of artificial intestinal juice in the presence of αCD

Increase of turbidity was observed by the addition of αCD to artificial intestinal juice.

Fig2 the interaction between αCD and lecithin.

artificial intestinal juice in the presence of αCD (3%)

White precipitation was formed in the case of coexistence of αCD and lecithin.

αCD can bind to lecithin selectively in artificial intestinal juice. (The precipitation was αCD-lecithin complex.)

Fig3 Aqueous solubility of cholesterol in artificial intestinal juice.

Decrease of aqueous solubility of cholesterol in artificail intestinal juice was observed
in the presence of αCD.

Conclusion

Lecithin was precipitated from bile acid micelle by complexation with αCD.
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 αCD supplementation.