Application of amino-based chitosan cyclodextrin derivatives for the extraction of catechins in green tea with high-performance liquid chromatography.

Chitosan derivatives have been studied widely, but poor solubility in water restricts their applications. In this study, four types of amine-based chitosan derivatives were prepared and modified further with beta-cyclodextrin. The sequential microextraction of catechins ((+)-catechin and (-)-epigallocatechin gallate) from green tea powder by an optimized solid-phase extraction method using these four derivatives was investigated. The optimal conditions for the extraction of catechins were 60°C for a 40 min extraction period. The purity and amount of each catechin were determined by high-performance liquid chromatography. The different amines strengthened the extraction capacity of chitosan. Among the four types of amines, ethylene diamine grafted chitosan beta-cyclodextrin had the highest extraction capacity to catechins. Therefore, this material was used in the extraction assay, and the standard curves of (+)-catechin and (-)-epigallocatechin gallate were linear over the concentration range, 0.25-500 µg/mL, after assaying five data points in duplicate. Solid-phase extraction with the amino-based chitosan beta-cyclodextrin system is a new application of chitosan, which has potential applications in the extraction of bioactive compounds from plant materials or the removal of different impurities from specific extracts.