Effects of Standardized Green Tea Extract and Its Main Component, EGCG, on Mitochondrial Function and Contractile Performance of Healthy Rat Cardiomyocytes.

Rocchina Vilella,Federica Rizzi,Riccardo Righetti,Saverio Bettuzzi,Federico Quaini,Gianluca Sgarbi,Francesca Liuzzi,Caterina Frati,Giancarlo Solaini,Leonardo Bocchi,Monia Savi,Alessandra Baracca,Donatella Stilli,Valeria Naponelli

doi:10.3390/nu12102949

Abstract

We recently showed that the long-term in vivo administration of green tea catechin extract (GTE) resulted in hyperdynamic cardiomyocyte contractility. The present study investigates the mechanisms underlying GTE action in comparison to its major component, epigallocatechin-3-gallate (EGCG), given at the equivalent amount that would be in the entirety of GTE. Twenty-six male Wistar rats were given 40 mL/day of a tap water solution with either standardized GTE or pure EGCG for 4 weeks. Cardiomyocytes were then isolated for the study. Cellular bioenergetics was found to be significantly improved in both GTE- and EGCG-fed rats compared to that in controls as shown by measuring the maximal mitochondrial respiration rate and the cellular ATP level. Notably, the improvement of mitochondrial function was associated with increased levels of oxidative phosphorylation complexes, whereas the cellular mitochondrial mass was unchanged. However, only the GTE supplement improved cardiomyocyte mechanics and intracellular calcium dynamics, by lowering the expression of total phospholamban (PLB), which led to an increase of both the phosphorylated-PLB/PLB and the sarco-endoplasmic reticulum calcium ATPase/PLB ratios. Our findings suggest that GTE might be a valuable adjuvant tool for counteracting the occurrence and/or the progression of cardiomyopathies in which mitochondrial dysfunction and alteration of intracellular calcium dynamics constitute early pathogenic factors.

Highlights

IntroductionA water infusion of the dried leaves of Camellia sinensis is widely known as green or black tea
Tea is the second most commonly consumed beverage in the world after water [1]
How, mitochondrial function contributed toward the improvement of the energy availability in cardiomyocytes isolated from green tea catechin extract (GTE)- or EGCG-supplemented rats, we analyzed in-depth the oxygen consumption rate

Summary

Introduction

A water infusion of the dried leaves of Camellia sinensis is widely known as green or black tea. The most abundant catechins in green tea are (−)-epigallocatechin-3-gallate (EGCG),. In a typical green tea extract (GTE), EGCG is believed to be the major factor responsible for the biological effects [2,3,4,5]. Among the many biological effects attributed to green tea, catechins were found to be associated with potential anticancer activity [6,7,8], to interact with gut microbiota [9,10], and to protect against nonalcoholic steatohepatitis [11,12]. Mechanisms involving reactive oxygen species (ROS) scavenging and reduction of tissue inflammation [18,19], mitochondrial function improvement, and transcriptional control of genes involved in the adaptive response to oxidative stress [20] have been reported

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