Recent research finding
No.46 Improvement of aqueous solubility of Ursolic Acid with Cyclodextrin

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

Background

Ursolic acid, a pentacyclic triterpenoid carboxylic acid, is the major component of many plants including apples, prunes, basil and rosemary and has been reported to possess many biological activities. In spite of its interesting characteristics, the usage of ursolic acid as a nutritional supplement has been limited by their poor water solubility. In this study, the solubilizing effects on ursolic acid with cyclodextrin (CD) were explored.

Ursolic acid

This study

UA has some problems : low aqueous solubility low bioavailability
In this study, we explored the water solubility of UA with cyclodextrins for improvement of the its bioavailability.

This study

Research points :
Preparation of UA-CD inclusion complexes. (DSC)
Evaluation of aqueous solubility of UA-CD in the presence of bile acids. (HPLC)

Preparation of UA-CD complex

Fig 1 UA-CD powder : DSC

DSC peak of UA was not observed in the cases of UA-βCD and UA-γCD.
UA-βCD and UA-γCD were confirmed that they were inclusion complexes.

Effective solubilization of hydrophobic material from its inclusion complex with bile acid.

Fig2 Solubility of UA-CD complex in artificial intestinal juice

<Method>
1) 10 mg of UA-CD was added to 2 mL of water or 1%NaTCaq (as artificial intestinal juice).
2) Sonication for 15 mins.
3) Filtration (0.2 mm) HPLC

Conclusions

Improvement of aqueous solubility of Ursolic Acid with Cyclodextrin

UA could be included in βCD and γCD to form their inclusion complexes.
UA-γCD complex was readily solubilized to artificial intestinal juice.

γCD has a possibility to increase of the bioavailability of UA in foods.