Concentration-dependent effects of aqueous extract from R. rosea root on long-term survival and stress resistance of budding yeast Saccharomyces cerevisiae were studied. At low concentrations, R. rosea aqueous extract extended yeast chronological lifespan, enhanced oxidative stress resistance of stationary-phase cells and resistance to number stressors in exponentially growing cultures. At high concentrations, R. rosea extract sensitized yeast cells to stresses and shortened yeast lifespan. These biphasic concentration-responses describe a common hormetic phenomenon characterized by a low-dose stimulation and a high-dose inhibition. Yeast pretreatment with low doses of R. rosea extract enhanced yeast survival and prevented protein oxidation under H2O2-induced oxidative stress. Positive effect of R. rosea extract on yeast survival under heat shock exposure was not accompanied with changes in antioxidant enzyme activities and levels of oxidized proteins. The deficiency in transcriptional regulators, Msn2/Msn4 and Yap1, abolished the positive effect of low doses of R. rosea extract on yeast viability under stress challenges. Potential involvement of Msn2/Msn4 and Yap1 regulatory proteins in realization of R. rosea beneficial effects is discussed.
Bayliak, Maria M.; Burdyliuk, Nadia I.; Izers’ka, Lilia I.; and Lushchak, Volodymyr I.
"CONCENTRATION-DEPENDENT EFFECTS OF RHODIOLA ROSEA ON LONGTERM SURVIVAL AND STRESS RESISTANCE OF YEAST SACCHAROMYCES CEREVISIAE: THE INVOLVEMENT OF YAP 1 AND MSN2/4 REGULATORY PROTEINS,"
Dose-Response: An International Journal: Vol. 12
, Article 6.
Available at: http://scholarworks.umass.edu/dose_response/vol12/iss1/6