## 3 Results  
### FBCC-EP858, FBCC-EP920, and FBCC-EP1014 Exhibit Strong DPPH Radical Scavenging Activity  
To identify potent antioxidant extracts from plants, we screened 184 extracts obtained from various plants found in the Nakdong River basin in the Republic of Korea, obtained from NNIBR, for their DPPH radical scavenging activity. Approximately 32% of the extracts exhibited DPPH radical scavenging activity of 50% or more at a concentration of 50 \(\upmu\)g/mL (Supplementary Table S1), and among these, FBCC-EP858, FBCC-EP920, and FBCC-EP1014 exhibited DPPH radical scavenging capacity of over 80%. We further \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Gene (1)** & **Primer Sequence (5\({}^{\prime}\)\(\rightarrow\)3\({}^{\prime}\))** & **Size (2)** & **Gene Accession No.** \\ \hline \multirow{2}{*}{_Nfr2_} & F: 5\({}^{\prime}\)-TGGACGGCATATTGAAGGC-3\({}^{\prime}\) & 735 bp & NM\_010902.5 \\  & R: 5\({}^{\prime}\)-GCCGCTTTTCAGTAGATG-3\({}^{\prime}\) & & \\ \hline \multirow{2}{*}{_HO-1_} & F: 5\({}^{\prime}\)-TGAAGGGCCCACCAAGGG-3\({}^{\prime}\) & 375 bp & NM\_010442.2 \\  & R: 5\({}^{\prime}\)-AGAGGTCACCCGGTAGCGG-3\({}^{\prime}\) & & \\ \hline \multirow{2}{*}{_GAPDH_} & F: 5\({}^{\prime}\)-ACCACAGTCCATGCATCAC-3\({}^{\prime}\) & 450 bp & NM\_001411843.1 \\  & R: 5\({}^{\prime}\)-CACCACCCTGTGTGTGTAGC-3\({}^{\prime}\) & & \\ \hline \end{tabular} \({}^{(i)}\)_Nfr2_, nuclear factor erythroid 2-related factor 2; HO-1, heme oxygenase-1; GAPDH, glyceraldehyde 3-phosphate dehydrogenase. \({}^{(2)}\) bp, base pairs.  
\end{table} 
Table 1: Primer sequences for RT-PCR used in this study. investigated the concentration-dependent DPPH radical scavenging activity and total antioxidant activity of these three extracts in vitro. The extracts demonstrated strong DPPH radical scavenging activity in a concentration-dependent manner (Table 2), with FBCC-EP858, FBCC-EP920, and FBCC-EP1014 exhibiting IC\({}_{50}\) values of 13.75 \(\upmu\)g/mL, 14.26 \(\upmu\)g/mL, and 11.89 \(\upmu\)g/mL, respectively (Figure 1). The three extracts also exhibited strong total antioxidant capacity (Table 1), with FBCC-EP1014 exhibiting the strongest total antioxidant capacity, corresponding to 0.0003 \(\pm\) 0.0017, 0.0890 \(\pm\) 0.0010, 0.1080 \(\pm\) 0.0010, 0.1550 \(\pm\) 0.0003, 0.2270 \(\pm\) 0.0027, and 0.4300 \(\pm\) 0.0020 mM Trolox at 0, 6.25, 12.5, 25, 50, and 100 \(\upmu\)g/mL, respectively. FBCC-EP858 showed total antioxidant capacity, corresponding to 0.0523 \(\pm\) 0.0037, 0.0803 \(\pm\) 0.0007, 0.1160 \(\pm\) 0.0003, 0.1180 \(\pm\) 0.0033, 0.1830 \(\pm\) 0.0000, and 0.2850 \(\pm\) 0.0037 mM Trolox at 0, 6.25, 12.5, 25, 50, and 100 \(\upmu\)g/mL, respectively (Table 2). FBCC-EP920 increased the capacity in a concentration-dependent manner, corresponding to 0.0600 \(\pm\) 0.0010, 0.0810 \(\pm\) 0.0010, 0.0883 \(\pm\) 0.0017, 0.1540 \(\pm\) 0.0010, 0.2150 \(\pm\) 0.0003, and 0.3860 \(\pm\) 0.0013 mM Trolox. FBCC-EP1014 exhibited the strongest total antioxidant capacity; 0.0003 \(\pm\) 0.0017, 0.0890 \(\pm\) 0.0010, 0.1080 \(\pm\) 0.0010, 0.1550 \(\pm\) 0.0003, 0.2270 \(\pm\) 0.0027, and 0.4300 \(\pm\) 0.0020 mM at 0, 6.25, 12.5, 25, 50, and 100 \(\upmu\)g/mL, respectively. At a concentration of 12.5 \(\upmu\)g/mL, the three extracts had total antioxidant activity similar to that of 400 \(\upmu\)M ascorbic acid, which is equivalent to 0.1 mM Trolox. These findings suggest that FBCC-EP858, FBCC-EP920, and FBCC-EP1014 are potent plant-derived antioxidants. FBCC-EP858, FBCC-EP920, and FBCC-EP1014 Regulate the Viability of RAW 264.7 Macrophages Depending on Their Concentrations  
Prior to evaluating the cellular antioxidant activity of FBCC-EP858, FBCC-EP920, and FBCC-EP1014, the relative viability of RAW 264.7 cells was assessed using the WST-8 assay. As depicted in Figure 2, FBCC-EP858 and FBCC-1014 did not exhibit any significant effect on cell morphology or relative cell viability.