Molecular interactions between (-)-epigallocatechin gallate analogs and pancreatic lipase.

Shihui Wang,Zeya Sun,Yang Liu,Shengzhao Dong,Yun Liu,Gideon Schreiber

doi:10.1371/journal.pone.0111143

Shihui Wang, Zeya Sun + Show 4 more

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https://doi.org/10.1371/journal.pone.0111143

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Journal: PloS one	Publication Date: Nov 3, 2014
Citations: 69	License type: CC BY 4.0

Affiliation: Beijing University of Chemical Technology

Abstract

The molecular interactions between pancreatic lipase (PL) and four tea polyphenols (EGCG analogs), like (−)-epigallocatechin gallate (EGCG), (−)-gallocatechin gallate (GCG), (−)-epicatechin gallate (ECG), and (−)-epigallocatechin (EC), were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent.

Highlights

Obesity, mainly resulting from the excessive intake of calorie, has rapidly become a worldwide epidemic
The molecular interactions between pancreatic lipase (PL) and four epigallocatechin gallate (EGCG) analogs, i.e., EGCG, gallocatechin gallate (GCG), epicatechin gallate (ECG), and EC were investigated by circular dichroism (CD), fluorescence spectroscopy (FS), dynamic light scattering (DLS), and differential scanning calorimetry (DSC) approaches
Results showed that the EGCG analogs showed different effect on activity, conformation, thermodynamics and kinetics of PL

Summary

Introduction

Mainly resulting from the excessive intake of calorie, has rapidly become a worldwide epidemic. Bose et al found that (2)-epigallocatechin gallate (EGCG), the major active ingredient of green tea polyphenols, could inhibit obesity, metabolic syndrome, and fatty liver disease in high-fat-fed mice [14]. Grove et al found that EGCG inhibited the PL activity with an IC50 value of 7.5 mmol/L in a non-competitive manner and reduced body weight in high-fatfed obese mice [16]. The authors found that the IC50 values of EGCG with one galloyl group, (–)-epigallocatechin 3, 5-digallate with two galloyl groups and (2)-epigallocatechin (EC) with no galloyl group were 0.349, 0.098, and 20 mmol/L, respectively [17] These results indicated that the galloyl group might be of importance for the inhibition of PL activity. The mechanisms of interaction between the gallol and hydroxyl groups of EGCG and PL are still unclear

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Conclusion