Improved stability of (+)-catechin and (-)-epicatechin by complexing with hydroxypropyl-β-cyclodextrin: Effect of pH, temperature and configuration

Food Chem. 2016 Apr 1:196:148-54. doi: 10.1016/j.foodchem.2015.09.016. Epub 2015 Sep 8.

Abstract

The stability and bioavailability of catechins, a kind of tea polyphenols with health benefit, could be improved by complexing with cyclodextrins. The aim of this study was to investigate the complexation of two geometrical isomers, (+)-catechin and (-)-epicatechin, with hydroxypropyl-β-cyclodextrin (HP-β-CD) in tris-HCl buffer solutions at pH 6.8-8.0 using isothermal titration calorimetry, fluorescence and proton nuclear magnetic resonance spectroscopy. Experimental results showed that these inclusion interactions are primarily enthalpy-driven processes. The complexation constant (KC) of EC+HP-β-CD complex was less than that of CA+HP-β-CD at the same temperature and pH value. Temperature and pH studies showed that the KC value decreased with the rise of temperature and pH. Stability study indicated that HP-β-CD showed a stronger protection effect on CA than that on EC. The different inclusion modes between CA and EC were discussed in terms of the discrepancy in their molecular structures.

Keywords: (+)-Catechin; (+)-Catechin (PubChem CID: 9064); (−)-Epicatechin; (−)-Epicatechin (PubChem CID: 72276); Dimethyl sulfoxide-d(6) (PubChem CID: 75151); Fluorescence spectroscopy; Hydroxypropyl-β-cyclodextrin; Hydroxypropyl-β-cyclodextrin (PubChem CID: 90479739); Isothermal titration calorimetry; Stability; Tris (hydroxymethyl) aminomethane (PubChem CID: 6503).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2-Hydroxypropyl-beta-cyclodextrin
  • Catechin / chemistry*
  • Molecular Structure
  • Spectrometry, Fluorescence / methods*
  • Temperature
  • beta-Cyclodextrins / chemistry*

Substances

  • beta-Cyclodextrins
  • 2-Hydroxypropyl-beta-cyclodextrin
  • Catechin