Related Experiment Video
Updated: Mar 29, 2026

Surface Functionalization of Metal-Organic Frameworks for Improved Moisture Resistance
Published on: September 5, 2018
Improved stability of (+)-catechin and (-)-epicatechin by complexing with hydroxypropyl-β-cyclodextrin: Effect of pH,
Min Liu1, Yan Zheng2, Chunmei Wang2
1School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, China; Institute of BioPharmceutical Research, Liaocheng University, Liaocheng 252059, China.
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.
More Related Videos
10:10Transport Properties of Ibuprofen Encapsulated in Cyclodextrin Nanosponge Hydrogels: A Proton HR-MAS NMR Spectroscopy Study
Published on: August 15, 2016
14:39Semi-Targeted Ultra-High-Performance Chromatography Coupled to Mass Spectrometry Analysis of Phenolic Metabolites in Plasma of Elderly Adults
Published on: April 22, 2022
Related Concept Videos
Bioavailability Enhancement: Drug Stability Enhancement and GI Retention
Complexation Equilibria: The Chelate Effect
Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Complexation Equilibria: Factors Influencing Stability of Complexes
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
EDTA: Chemistry and Properties