Effect of bioactive compounds from Moringa oleifera leaf extract against ethanol toxicity in Saccharomyces cerevisiae

During fermentation, increased concentration of ethanol is a major stress that causes yeast celldamage and finally reduces ethanol production. Therefore, the reduction of ethanol toxicity may be akey step to improve ethanol production. Previously, the protective effect of Moringa oleifera leafextract against ethanol toxicity has been reported. This study aims to investigate the effect MOLE andits bioactive compounds on reducing ethanol toxicity in Saccharomyces cerevisiae. Since the cell wallis one of major cellular targets of ethanol, we examined the effect of MOLE on protecting yeast cellwall against ethanol by using Zymolyase sensitivity assay. However, our result showed that MOLEhas no effect on yeast cell wall during ethanol stress. Since it has been reported that the generation ofintracellular reactive oxygen species is induced during ethanol stress and MOLE is rich inantioxidants, it is possible that the major antioxidants in MOLE such as quercetin and gallic acid mayhave ability to reduce ethanol toxicity. To test this hypothesis, we determined the yeast growth underethanol stress conditions in the presence and absence of quercetin or gallic acid by using spotsusceptibility assay. Our results revealed that quercetin and gallic acid did not promote the yeastgrowth during ethanol stress. Further study is therefore needed to clarify the cellular mechanism ofMOLE on reducing ethanol toxicity.