Abstract
The present study addressed the protective effects against oxidative stress (OS) of a cocoa powder extract (CPEX) on the protein expression profile of S. cerevisiae. A proteomic analysis was performed after culture preincubation with CPEX either without stress (−OS) or under stress conditions (+OS) (5 mM of H2O2). LC-MS/MS identified 33 differentially expressed proteins (–OS: 14, +OS: 19) that were included By Gene Ontology analysis in biological processes: biosynthesis of amino acids, carbohydrate metabolism and reactive oxygen species metabolic process. In a gene-knockout strains study, eight proteins were identified as putative candidates for being involved in the protective mechanism of cocoa polyphenols against OS induced by H2O2. CPEX was able to exert its antioxidant activity in yeast mainly through the regulation of: (a) amino acids metabolism proteins by modulating the production of molecules with known antioxidant roles; (b) stress-responsive protein Yhb1, but we were unable to fully understand its down-regulation; (c) protein Prb1, which can act by clipping Histone H3 N-terminal tails that are related to cellular resistance to DNA damaging agents.
Highlights
Cocoa has been recognized as a rich source of phenolic compounds that represents between4–8% of unfermented dried cocoa beans [1]
All previous evidence indicates that cocoa and its flavanols could play a beneficial role in ageing-related diseases [3,4]
Pathways influenced by polyphenols cocoa have already been transcriptionally characterised [16], but very little is known about the mode of action in proteome terms
Summary
Cocoa has been recognized as a rich source of phenolic compounds that represents between4–8% of unfermented dried cocoa beans [1]. Different studies have shown that cocoa exerts beneficial health effects by contributing to prevent and/or slow down the initiation progression of different chronic diseases related to oxidative stress (OS), such as cancer, cardiovascular diseases and diabetes [3,4]. Beyond the free radical scavenging mechanism, additional direct and indirect mechanisms of action appear to be involved in the protective effects of polyphenols [6,7,8,9,10]. In this context, efforts to delve into the molecular mechanisms of antioxidant compounds of cocoa that are implicated in reducing oxidative damage are valuable.
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