Abstract
Propolis ethanolic extracts (PE) are rather complicated mixtures of bioactive compounds belonging to several chemical classes. The potential use of β-cyclodextrin (β-CD) cavity for the incorporation of specific PE components, aiming to increase their solubility in water, was studied in a Greek propolis, which was rich in polyphenols and terpenes. The PE/β-CD inclusion complexes were prepared by sonication of PE suspensions in aqueous solutions of β-CD, followed by filtration and freeze-drying. The aqueous solubility of PE in the presence of β-CD was studied by the construction of solubility diagrams and by determining the fraction of PE constituents that was dissolved in water. Encapsulation efficiencies were found to be higher (9.4–23.3%) for relatively small aromatic molecules like cinnamic and benzoic acid derivatives and lower for terpenic acids (5.0–6.7%), anthraquinones (3.6–8.4%) and flavonoids (4.0–10.7%). The respective in vitro solubilities in simulated gastric fluid followed an opposite trend, being lower for the relatively small aromatic molecules. It is concluded that the encapsulation in β-CD may increase the solubility of PE constituents in a manner related to their structure, while the amount of substances released will depend both on their chemical properties and on their relative abundance in the matrix.
Abbreviations | ||
β-CD | = | β-cyclodextrin |
BSTFA | = | bis-(trimethylsilyl)-trifluoroacetamide |
DSC | = | differential scanning calorimetry |
PE | = | propolis ethanolic extract |
TMS | = | trimethylsilyl ethers. |
Abbreviations | ||
β-CD | = | β-cyclodextrin |
BSTFA | = | bis-(trimethylsilyl)-trifluoroacetamide |
DSC | = | differential scanning calorimetry |
PE | = | propolis ethanolic extract |
TMS | = | trimethylsilyl ethers. |