New Trends to Treat Muscular Atrophy: A Systematic Review of Epicatechin

Abstract

Epicatechin is a polyphenol compound that promotes skeletal muscle differentiation and counteracts the pathways that participate in the degradation of proteins. Several studies present contradictory results of treatment protocols and therapeutic effects. Therefore, the objective of this systematic review was to investigate the current literature showing the molecular mechanism and clinical protocol of epicatechin in muscle atrophy in humans, animals, and myoblast cell-line. The search was conducted in Embase, PubMed/MEDLINE, Cochrane Library, and Web of Science. The qualitative analysis demonstrated that there is a commonness of epicatechin inhibitory action in myostatin expression and atrogenes MAFbx, FOXO, and MuRF1. Epicatechin showed positive effects on follistatin and on the stimulation of factors related to the myogenic actions (MyoD, Myf5, and myogenin). Furthermore, the literature also showed that epicatechin can interfere with mitochondrias' biosynthesis in muscle fibers, stimulation of the signaling pathways of AKT/mTOR protein production, and amelioration of skeletal musculature performance, particularly when combined with physical exercise. Epicatechin can, for these reasons, exhibit clinical applicability due to the beneficial results under conditions that negatively affect the skeletal musculature. However, there is no protocol standardization or enough clinical evidence to draw more specific conclusions on its therapeutic implementation.

Keywords: catechins; epicatechin; muscular atrophy; myogenic regulatory factors; skeletal muscle.

Figure 1

Main food and beverage sources, chemical structure, metabolic route, and biological properties of epicatechin. NO, nitric oxide; Nrf2, nuclear factor-like 1; HO, heme oxygenase; PGC1α, peroxisome proliferator-activated receptor γ coactivator 1-alpha; ROS, reactive oxygen species.

Figure 2

PRISMA 2020 flow diagram. Search design strategy in the databases and other sources. **: records identified in the databases but not related to this review topic.

Figure 3

An overview of epicatechin effects on skeletal muscle. Modified diagram from Li et al. [4]. Act RIIB, myostatin receptor; Smad 2/3, mothers against decapentaplegic homolog 2; FoxO, forkhead transcription factor family; MAFbx, muscle atrophy F-box; MuRF1, muscle RING-finger protein-1; IGF, insulin-like growth factor-1; PI3K, phosphatidylinositol 3 kinase 9; AKT, Protein kinase B; mTOR, The mammalian target of rapamycin.