## 4 Discussion
Considering these studies, the significant increase in SOD-like activity and the ABTS radical scavenging capacity of ESLC in this study, in comparison to the other groups, is speculated to be due to an increase in polyphenol content by enzymatic treatment. Peptides are intermediates in the breakdown of proteins into amino acids, and enzymatic processing can generate various bioactive peptides that are present in foods [39] and have been reported to have various bioactive activities, including antioxidant activity [40; 41]. The peptides produced by enzymatic treatment in this study may be associated with the increased antioxidant effects of ESLC. Organisms obtain the energy needed to sustain life through cellular respiration, and some oxygen is converted into ROS, which damage the cells in the body [42]. ROS include hydroxyl radicals, superoxide, singlet oxygen, and H\({}_{2}\)O\({}_{2}\), which are constantly produced in the body by physical or environmental factors but are mostly removed by the body's antioxidant defense system [43]. However, ROS are highly unstable and reactive, and when overproduced, they can cause oxidative stress and damage the cells. Therefore, research is being conducted to identify antioxidants that can scavenge ROS [44; 45]. ROS accumulation activates a cascade of mechanisms that disrupt cellular homeostasis and lead to cellular destruction, and ROS-induced oxidative stress is associated with neuronal cell death [46]. In this study, treatment with ESLC at concentrations of 100-250 \(\upmu\)g/mL protected SH-SYSY cells from H\({}_{2}\)O\({}_{2}\)-induced oxidative stress and significantly restored cell viability (\(p<0.05\)). However, it is limited in that it did not compare the antioxidant activity of SLC and ESLC samples at the highest concentrations of 100 or 250 \(\upmu\)g/mL. [PERSON] and [PERSON] [47] reported that the hydrolyzate produced by enzymatic hydrolysis increased cell viability in a dose-dependent manner, elevated Nrf2 expression (an antioxidant-related gene), and exerted antioxidant effects by reducing ROS levels during H\({}_{2}\)O\({}_{2}\)-induced oxidative stress in AML12 mouse hepatocytes. Moreover, enzymatic hydrolyzates and peptides produced from silkworm proteins have been reported to protect cells from oxidative stress, either by reacting directly with ROS or indirectly affecting antioxidant systems [48], which is similar to our results. MAPK signaling pathways play important roles in metabolism, stress responses, cell proliferation, apoptosis, and the immune defense system [49; 50]. To investigate the effect of ESLC on the protein expression of MAPK enzymes, such as JNK, p38, and ERK, we identified relevant factors by Western blotting and observed that ESLC treatment remarkably decreased the phosphorylation of JNK, ERK, and p38 in SH-SYSY cells (\(p<0.05\)) in a concentration-dependent manner. These results were similar to those of [PERSON] et al. [51], who reported that an ethanol extract of _Maclura tricuspidata_ fruit decreased the levels of JNK, p38, and ERK MAPK phosphorylation by H\({}_{2}\)O\({}_{2}\). Therefore, ESLC may inhibit apoptosis and exert cytoprotective effects against oxidative stress by inhibiting phosphorylation via MAPK pathway activation. ESLC may inhibit JNK kinase, p38, and ERK phosphorylation by activating the MAPK pathway, thereby inhibiting apoptosis and exerting cytoprotective effects against oxidative stress. However, there are limitations in that the antioxidant effect and safety of ESLC were not confirmed at higher concentrations than those used in this study, and an analysis of genes associated with the antioxidant effect was not performed.