*3.6. Effects of CYP on MDA and SOD in H2O2-Stimulated IEC-6 Cells*

As two important indexes for detecting the level of oxidative cell damage, SOD is an important antioxidant enzyme in organisms, which catalyzes the dismutation of superoxide anions to produce H2O2 and O2 [43]. MDA is a natural product of lipid oxidation in living organisms; lipid oxidation occurs when oxidative stress occurs in animal or plant cells, some fatty acids are oxidized and gradually decompose into a complex series of compounds, including MDA. Incubation of IEC-6 cells with 200 μg/mL CYP before H2O2 damage was able to increase SOD activity, and CYP showed a dose-increasing trend to enhance the activity of SOD. However, the MDA content remained high (6.04 μM). With an increase in CYP concentration to 400 and 800 μg/mL, the level of MDA decreased to 4.77 and 2.54 μM compared to control (1.46 μM) (Figure 4). Pretreatment with CYP significantly inhibited H2O2-induced oxidative damage, reduced MDA levels, and increased antioxidant enzyme activity. These results suggested the potential antioxidant capacity of CYP [44].

**Figure 4.** (**A**) Effects of CYP on levels of SOD in H2O2-injured IEC-6 cells, (**B**) Effects of CYP on levels of MDA in H2O2-injured IEC-6 cells, (**C**) Effects of CYP on the ROS production in H2O2-injured IEC-6 cells. Results shown are expressed as means ± SD (*n* = 3). ## *p* < 0.01 compared with normal group, \* *p* < 0.05 compared with H2O2 group alone, \*\* *p* < 0.01 compared with H2O2 group alone.
