ABSTRACT
AIMS: The aim of the study was to check whether two flavanols ((-)-epigallocatechin gallate and (+)-catechin) can ameliorate oxidative stress (OS) accompanying and contributing to the lethal effects of heating (50°C) and freezing-thawing on the yeast Saccharomyces cerevisiae. METHODS AND RESULTS: The flavanols studied increased yeast survival during heating and freezing-thawing, estimated by the colony forming assay. They improved also such indices of OS as increased production of reactive oxygen species, decrease of total antioxidant activity of yeast cell extracts and increase in the level of protein carbonyls. CONCLUSIONS: Amelioration of OS by flavanols increases the survival of the yeast subjected to high temperature and freezing-thawing. SIGNIFICANCE AND IMPACT OF THE STUDY: Flavanols may be considered as means of enhancing yeast survival under extreme temperature conditions and probably in other conditions involving OS.
Subject(s)
Flavonols/pharmacology , Protective Agents/pharmacology , Saccharomyces cerevisiae , Cold Temperature , Hot Temperature , Oxidative Stress/drug effects , Reactive Oxygen Species , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/physiologyABSTRACT
Seven nitroxides of different structures were studied for the ability to prevent glycoxidation of bovine serum albumin incubated with three monosaccharides (glucose, fructose, and ribose). Glycoxidation was estimated by fluorimetric parameters of protein modifications (formation of advanced glycation end products [AGEs], dityrosine, N'-formylkynurenine, and kynurenine) and enzyme-linked immunosorbent assay for AGEs. From among the nitroxides tested, (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), 4-carboxy-TEMPO, and 4-hydroxy-TEMPO offered significant protection against glycoxidation induced by glucose and fructose, while 3-carbamoyl-PROXYL was not protective, enhancing glycoxidation. Lower protection was observed for glycoxidation induced by ribose where only 3-carbamoyl-PROXYL and 4-amino-TEMPO showed some protection. Loss of electron spin resonance signal of the nitroxides was observed during glycoxidation indicating occurrence of free radical reactions in this process. These results suggest for the first time that nitroxides may be promising compounds for preventing glycoxidation.
Subject(s)
Antioxidants/pharmacology , Cyclic N-Oxides/pharmacology , Monosaccharides/chemistry , Protein Degradation End Products/analysis , Fructose/chemistry , Glucose/chemistry , Glycosylation/drug effects , Oxidation-Reduction/drug effects , Ribose/chemistry , Serum Albumin, Bovine/chemistryABSTRACT
Proteins are subject to various posttranslational modifications, some of them being undesired from the point of view of metabolic efficiency. Prevention of such modifications is expected to provide new means of therapy of diseases and decelerate the process of aging. In this review, modifications of proteins by reactive nitrogen species and reactive halogen species, is briefly presented and means of prevention of these modifications and their sequelae are discussed, including the denitrase activity and inhibitors of myeloperoxidase.
