P-277 - Influence of catechins on Saccharomyces cerevisiae subjected to thermal stress

Abstract

Catechins (Flavan-3-ols), the main components of tea extracts, rise increasing interest due to their biological, mainly antioxidant, effects. The present study aims to investigate the capacity of selected catechins [(−)-Epigallocatechin gallate and (+)-Catechin] to protect Saccharomyces cerevisiae (two strains: wild type BY4741 and mutant BY4741Δsod1) as an eukaryotic cell model, against thermal stress promoted by a low temperature freezing at -20°C as well as by heating at a temperature of 50 °C. Oxidative stress has been demonstrated to play an important role in cell death induced by both high and low temperature. Catechins showed no toxicity to yeast cells at concentrations of up to at least 100 µM. The catechins studied, in particular (+)-Catechin and (−)-Epigallocatechin gallate, protected cells of both strains against temperature-induced lethality, as assessed by colony forming assays. The catechins (50 µM) decreased the level of reactive oxygen species in temperature-stressed yeast cells, estimated with dihydroethidine, and increased total antioxidant capacity of yeast cell extracts and elevated the level of reduced glutathione or reduced/oxidized glutathione ratio in cells exposed to -20oC, demonstrating efficient antioxidant action of catechins in the yeast model.