In Silico Validation for the Modulatory Effect of Tea Catechins on Erythrocyte Na+/K+-ATPase

Epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG) and epicatechin (EC) are major polyphenolic compounds isolated form tea (Camellia sinensis).The present study was carried to determine through an in silico approach the modulatory effects of catechins EC, ECG, EGC and EGCG on ouabain sensitive Na+/K+-ATPase enzyme in erythrocyte membrane of healthy human. In vitro incubation of catechins (ECG, EGCG, EGC and EC) with membrane inhibited Na+/K+-ATPase activity in the following order ECG≅EGCG>EGC≅EC at 10-5-10-6M. AutoDock3 docking simulation shows that catalytic unit α of Na+/K+-ATPase is actively involved in hydrogen bonding and hydrophobic interaction with ECG, EGC, EC and EGCG. The binding affinity at the active site has been found in the order of ECG>EGCG>EGC>EC with docking energy -9.91, -9.11, -8.40 and -7.19 kcal/mol respectively in comparison with ATP (-11.13kcal/mol). These observations corroborate the in vitro findings. The in vitro result validation using AutoDock3 simulation strongly support the interaction and modulation effects of catechins with Na+/K+-ATPase.