## 3 Results
### Antioxidant Activities of A. tegmentosum Extract in HepG2 Cells  
To verify the antioxidative capacity of hydrothermal _A. tegmentosum_ extract against H\({}_{2}\)O\({}_{2}\), HepG2 cells were used. HepG2 cells were pretreated in the absence (sterile water) and presence of _A. tegmentosum_ extract (0-40 ug/mL) for 1 h, and oxidative stress was induced by adding 1 mM H\({}_{2}\)O\({}_{2}\) for 24 h. Hepatic cellular viability was determined using a 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan assay. H\({}_{2}\)O\({}_{2}\) treatment significantly attenuated cellular viability (>20%); however, in the presence of hydrothermal _A. tegmentosum_ extract, the optimal extraction gradually protected against H\({}_{2}\)O\({}_{2}\)-inducible hepatic cell death in vitro (Figure 7A). Intriguingly, >20 ug/mL of hydrothermal _A. tegmentosum_ extract fully protected the hepatic cells from H\({}_{2}\)O\({}_{2}\)-inducible cell death. Therefore, we extended our research question to postulate that the optimal hydrothermal _A. tegmentosum_ extract would protect against H\({}_{2}\)O\({}_{2}\)-inducible cellular ROS production. Again, HepG2 cells were cultured, as described above, and ROS production was determined by the DCF-DA method (Figure 7B). Similar to the MTT assay results, H\({}_{2}\)O\({}_{2}\) treatment remarkably elevated cellular ROS production; however, in the presence of >10 ug/mL hydrothermal _A. tegmentosum_ extract, hepatic ROS production was decreased in a dose-dependent manner, and >20 ug/mL hydrothermal _A. tegmentosum_ extract treatment showed no difference in ROS production compared to the control group.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **RT** & **Formula** & **Score** & \
\begin{tabular}{c} **Diff (MFG,** \\ **ppm)** \\ \end{tabular} &
\begin{tabular}{c} **[M + H]\({}^{\star}\)** \\ \end{tabular} & **Name** \\ \hline
1 & 7.01 & C\({}_{10}\)H\({}_{10}\)O\({}_{3}\) & 99.93 & \(-\)0.01 & 179.07027 & p-Methoxycinnamic acid \\
2 & 8.82 & C\({}_{13}\)H\({}_{14}\)O\({}_{9}\) & 99.75 & 0 & 315.0711 & Unknown \\
3 & 10.81 & C\({}_{11}\)H\({}_{14}\)O\({}_{5}\) & 96.73 & 3.47 & 227.09065 & Genipin \\
4 & 14.53 & C\({}_{10}\)H\({}_{12}\)O\({}_{5}\) & 99.73 & 0.49 & 213.07567 & Unknown \\
5 & 15.34 & C\({}_{8}\)H\({}_{10}\)O\({}_{4}\) & 99.11 & 1.17 & 171.06496 & Unknown \\
6 & 16.28 & C\({}_{8}\)H\({}_{8}\)O\({}_{2}\) & 98.69 & 2.66 & 137.05934 & Benzyl formate \\
7 & 17.85 & C\({}_{9}\)H\({}_{10}\)O\({}_{3}\) & 99.34 & 1.63 & 167.06997 & D-(+)-3-Phenyllactic acid \\
8 & 18.48 & C\({}_{9}\)H\({}_{10}\)O\({}_{5}\) & 99.32 & 0.46 & 199.06001 & Unknown \\
9 & 19.66 & C\({}_{30}\)H\({}_{26}\)O\({}_{12}\) & 96.83 & 2.01 & 579.14845 & Procyanidin B \\
10 & 19.94 & C\({}_{20}\)H\({}_{20}\)O\({}_{14}\) & 98.18 & 1.47 & 485.09202 & 1, 6-digaloylglucose \\
11 & 21.58 & C\({}_{7}\)H\({}_{6}\)O\({}_{3}\) & 99.24 & 2.46 & 139.03862 & Tyrosol \\
12 & 22.87 & C\({}_{11}\)H\({}_{16}\)O\({}_{4}\) & 99.09 & 1.89 & 213.11171 & Dyhydrocinnaryl alcohol \\
13 & 23.40 & C\({}_{13}\)H\({}_{20}\)O\({}_{5}\) & 99.76 & \(-\)0.31 & 257.13848 & Unknown \\
14 & 23.81 & C\({}_{10}\)H\({}_{8}\)O\({}_{5}\) & 99.36 & 0.54 & 209.04434 & Fraxetin \\
15 & 24.77 & C\({}_{15}\)H\({}_{14}\)O\({}_{6}\) & 98.61 & 1.31 & 291.0859 & Epicatechin \\  & & & & & 6-(2- \\
16 & 25.50 & C\({}_{11}\)H\({}_{10}\)O\({}_{5}\) & 99.8 & \(-\)0.07 & 223.0601 & Methoxyvinyl]benzo[1,3]dioxole-5-carboxylic acid \\
17 & 25.94 & C\({}_{37}\)H\({}_{30}\)O\({}_{16}\) & 98.12 & 1 & 731.15984 & Catechin-(4\(\sim\)8)-epicatechin-3-O-gallate \\
18 & 29.56 & C\({}_{22}\)H\({}_{18}\)O\({}_{10}\) & 99.37 & 0.91 & 443.09687 & (-)-Epicatechin-3-O-gallate \\ \hline \hline \end{tabular}
\end{table}
Table 8: Analytical results of a hydrothermal extract of _A. tegmentosum_ using HPLC-Q-TOF-MS.