Interactions between β-cyclodextrin and tea catechins, and potential anti-osteoclastogenesis activity of the
Huanhuan Xu1,2, Titi Liu1,3, Jing Xu1,3
1Key Laboratory of Pu-er Tea Science, Ministry of Education, Yunnan Agricultural University Kunming 650201 China zichengting@126.com wangxuanjun@gmail.com shengjunpuer@163.com +86-871-65226058 +86-871-65226058.
Abstract:
Galloylated catechins, the most important secondary metabolites in green tea including (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate, constitute nearly 75% of all tea catechins and have stronger health effects than non-galloylated catechins such as (-)-epigallocatechin and (-)-epicatechin. EGCG is the most abundant, active, and thoroughly investigated compound in green tea, and its bioactivity might be improved by complexing with β-cyclodextrin (β-CD). We investigated interactions between four catechins and β-CD in a PBS buffer solution of pH 6.5 at 25 °C using biolayer interferometry and isothermal titration calorimetry, and to determine whether β-CD could enhance the anti-osteoclastogenesis effect of EGCG. β-CD could directly bind galloylated catechins at a stoichiometric ratio close to 1 : 1, with high specificities and affinities, and these inclusion interactions were primarily enthalpy-driven processes. We synthesized the EGCG-β-CD complex and identified it using infrared radiation and nuclear magnetic resonance spectra. Interestingly, we revealed that the EGCG-β-CD complex could inhibit osteoclastogenesis significantly more than EGCG.
