Research findings

No. 25 Influence of the Glycolytic Enzyme against Fat-soluble Substances - γ-Cyclodextrin Complexes

Summary

We previously reported the plausible mechanism for the bioavailability enhancement of Coenzyme Q10 (CoQ10) which includes the enzymatic degradation of γ-Cyclodextrin (γ-CD) out of CoQ10-γ-CD complex with the aid of sodium taurocholate (NaTC) in small intestine 1), 2), 3).
In this study, the influence of NaTC on the enzymatic degradation of non-complexed γ-CD and γ-CD out of Curcumin-γ-CD (Cur-γ-CD) complex were investigated to demonstrate the previous presumption.

1) K. Terao, et al., Nutrition Research, 2006, 26 503-508.
2) Ikeda, et al., Japan Society for Bioscience, Biotechnology, and Agrochemistry, (2009.3.27-29, Fukuoka)
3) K. Terao, et al., The Society of Cyclodextrins, Japan 26th (2009.9.8-9, Utsunomiya) 2P-1.

BIOAVAILABILITY STUDY OF CURCUMIN COMPLEX IN A RODENT MODEL *)

In vivo study on bioavailability in rats from 0 to 4 h after oral gavage with three curcumin products:
Curcumin Complex, Curcumin Extract, Brand Name Curcumin
Single dose study @ 500 mg/kg in Sprague Dawley rats
Plasma was analysed for free curcumin, curcumin sulphate and curcumin glucuronide by HPLC

Conclusion

Cavamax Curcumin demonstrated the greatest bioavailability of all products tested in the 4 h bioavailability study followed by Brand Name Curcumin and Curcumin Extract

*) single dose study @ 500 mg/kg in rats

Degradation of γ-CD

Enzymatic degradation of γ-CD with the aid of NaTC as component of the bile acids

γ-CD was decomposed by amylase.
But the results showed that γ-CD was decomposed slowly by adding NaTC.

Enzymatic degradation of γ-CD in Cur-γ-CD complex with the aid of NaTC

Cur of Cur-γ-CD complex can be replaced by NaTC.
Cur-γ-CD complex is insoluble in water, so amylase can't work.
But amylase can work efficiently to NaTC-γ-CD because of its high water solubility.

Solubilization of Curcumin in water out of Cur-γ-CD complex with the aid of NaTC

Non-complexed Curcumin could dissolve in water to some extent with NaTC, but Curcumin of Cur-γ-CD complex dissolved more.

Conclusion

Enzymatic degradation of γ-CD of Cur-γ-CD complex with the aid of NaTC was facilitated.
→ Curcumin released from Cur-γ-CD complex with the aid of NaTC.
Solubility of Curcumin in water was stimulated by use of Cur-γ-CD complex with NaTC better than Curcumin itself.

These results support the mechanism for the bioavailability enhancement of Cur-γ-CD complex and CoQ10-γ-CD complex.