## 3 Results  
### Effect of Cornus mas L. Fruit Ethanol Extract on Cell Growth  
Optimal growth conditions for _S. pombe_ cells involve a nutrient-rich medium with 3% glucose, a growth temperature of 30 \({}^{\circ}\)C, and aerobic conditions to promote exponential yeast growth. In our analysis, we investigated the impact of different concentrations of the extract (0.1%, 0.5%, 1%, 2%) on the cell growth compared to the control cells with no added extract (Figure 1A). A notable reduction in growth intensity was observed with 2% extract after 6 and 9 h of exposure. Conversely, the 0.1% extract significantly increased growth intensity after 6 h and 9 h. The growth intensity is closely linked to the generation time, representing the time needed for cell doubling. The stress induced by the 2% extract in the growth medium led to a significantly extended doubling time for the cells, whereas the addition of 0.1% Correlian cherry extract resulted in a slightly shortened generation time (Figure 1B). Impact of Cornus mas L. Fruit Ethanol Extract on ROS Generation, MDA Content, and Respiration Activity in S. pombe  
As the 2% _Cornus mas_ L. fruit ethanol extract strongly affected the growth of _S. pombe_ cells, we investigated its ability to induce oxidative stress. The generation of ROS and the content of MDA was determined in _S. pombe_ cells subjected to the 0.5% and 2% extract for 6 h, and the effect was compared to the control group of cells exposed to 0%, 0.5%, and 2% ethanol for 6 h. Interestingly, ROS generation increased with the increasing concentration of the extract in a dose-dependent manner. Notably, the extract at a higher concentration, 2%, dramatically increased ROS formation compared to 0.5%, indicating oxidative stress. This suggests a potential prooxidant effect of the 2% ethanolic extract of _Cornus mas_ L. fruits (Figure 2A). The content of MDA, which is a marker of lipid peroxidation, also showed a concentration-dependent effect. Higher extract concentration (2%) was associated with increased MDA content, indicating oxidative damage to lipids. By contrast, the extract at 0.5% concentration did not significantly change MDA content, confirming the dose-dependent effect of the extract (Figure 2B). This suggests that to achieve the intended result of the extract, its concentration needs to be properly adjusted. Figure 1: The effect of C. _mas_ fruit ethanol extract on cell growth was assessed by monitoring OD\({}_{600}\) at 3, 6, and 9 h of incubation. The extract induced significant alterations in cell growth in a dose- and time-dependent manner (**A**). Furthermore, the generation time (gt), reflecting the doubling time of the cell population was calculated (**B**). Results are presented as the mean value \(\pm\) SD of four individual samples. Statistical significance was denoted as \(p\) < 0.05 *, and 0.001 *** and identified by [PERSON]’s post-hoc test. Identical letters above the bars indicate no significant differences, whereas distinct letters above the bars represent statistically significant differences identified by [PERSON]’s post-hoc test. Furthermore, the respiratory activity in all tested samples was determined 6 h after exposure. Cell treatment with 0.5% extract significantly affected respiratory activity; however, the 2% extract caused an even more dramatic decrease in respiration activity, suggesting an impact of the _C. mas_ ethanolic extract on the mitochondrial system (Figure 3A). Strikingly, changes in respiratory activity may indicate a disruption in mitochondrial functions. It is noteworthy that there appears to be a correlation between the rise in oxidative stress and reactive oxygen species (ROS) concentration and the decline in respiratory activity. Specifically, higher ROS generation is correlated with lower respiratory activity (Figure 3B). Figure 3: Respiration activity. (**A**) Respiration activity was determined by the conversion of yellowish tetrazolium chloride (TTC) to red formazan, which is detected at 485 nm and normalized to the protein level.