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Yeast cells from Saccharomyces cerevisiae can increase endogenous antioxidant response when stressed to prevent cell death. YAP1 is a transcription factor responsible to activate genes that encoding antioxidant enzymes such as superoxide dismutase and catalase and can be an important key to protect these cells. Tucum-do-cerrado (Bactris setosa Mart.) is a Brazilian fruit rich in polyphenols and bioactive compounds mainly found in the peel. This study investigated cell growth and viability using S. cerevisiae wild type and yap1∆ strains exposed to tucum-do-cerrado peel aqueous extract and hydrogen peroxide (H2O2) and menadione induced oxidative stress. Yeast cells from BY4741 and yap1∆ were exposed to different concentrations of tucum extract, menadione and hydrogen peroxide separated and together in mixed groups for 20h and measured for growth curve. For colony survival yeast cells were exposed to these compounds for 72h in ágar plates and colonies were counted. Results showed that aqueous extract of tucum-do-cerrado was capable to recover BY4741 density of cells stressed with both menadione and H2O2 but not for yap1∆ strain. Besides, higher concentrations of the extract demonstrated a delay in cell growth. Colony survival showed that the exposition to tucum extract resulted in colony recover in BY4741 yeast cells but not for mutant yap1∆ strains which maintained low viability even with high extract concentration. In conclusion, despite S. cerevisiae antioxidant response to menadione and H2O2 is different, the protection afforded by tucum extract in H2O2 stressed cells, is probably through an YAP1 pathway. more...