## 3 Results and Discussion  
### Total Phenolic and Flavonoid Contents  
In phytochemicals, phenolic compounds have the most antioxidative potential for oxidative reaction quenching by donating their electrons to the radicals [32; 33; 34]. TPC is determined by measuring the absorbance of the sample compared with gallic acid, which is commonly used as a standard compound typically [35].  
As shown in Table 1, the highest and similar TPC values were exhibited in the 10, 30, 50, and 70% ethanol extracts with 422.0, 492.7, 497.7, and 448.5 GAE mg/g extract, respectively. The next highest TPC was in the 90% ethanol extract with 384.5 GAE mg/g extract. The 100% ethanol extract showed a TPC of 273.2 GAE mg/g extract. The lowest TPC value was estimated in the 0% ethanol extract. The TPC values of the 0 to 100% ethanol extraction conditions steadily increased until the 50% ethanol condition. Then, the TPC values decreased, confirming the lowest TPC value in the 100% ethanol condition. Among the extraction conditions of _E. globulus_ leaves, the significantly polar (0% ethanol) or non-polar (100% ethanol) extractions were confirmed to have relatively low TPC values compared with the extractions using ethanol and water in comparable proportions (30, 50, and 70% ethanol).  
Flavonoids generally belonging to phenolic compounds are secondary metabolites well known for their related antioxidant abilities [21]. The TPC values differed from those of the TPC of _E. globulus_ leaf extraction conditions. The TPC values exhibited a higher aspect as the ratio of relatively non-polar solvent to ethanol increased. The order of TFC values according to the ethanol portions of 0, 10, 30, 50, 70, 90, and 100% was observed as follows; 32.5, 32.7, 40.4, 41.2, 66.5, 156.5, and 169.3 mg QE/g extract, respectively. Between  
\begin{table}
\begin{tabular}{c c c} \hline
**Extract Conditions** & **TPC** & **TFC** \\  & **(mg GAE/g Extract)** & **(mg QE/g Extract)** \\ \hline
0\% ethanol & 126.7 \(\pm\) 8.5 \({}^{\mathrm{a}}\) & 32.5 \(\pm\) 5.1 \({}^{\mathrm{a}}\) \\
10\% ethanol & 422.0 \(\pm\) 18.4 \({}^{\mathrm{b}}\) & 32.7 \(\pm\) 4.8 \({}^{\mathrm{a}}\) \\
30\% ethanol & 492.7 \(\pm\) 13.2 \({}^{\mathrm{b}}\) & 40.4 \(\pm\) 6.7 \({}^{\mathrm{b}}\) \\
50\% ethanol & 497.7 \(\pm\) 15.5 \({}^{\mathrm{b}}\) & 41.2 \(\pm\) 7.5 \({}^{\mathrm{b}}\) \\
70\% ethanol & 448.5 \(\pm\) 20.1 \({}^{\mathrm{b}}\) & 66.5 \(\pm\) 6.5 \({}^{\mathrm{b}}\) \\
90\% ethanol & 384.5 \(\pm\) 10.4 \({}^{\mathrm{b}}\) & 156.5 \(\pm\) 10.4 \({}^{\mathrm{c}}\) \\
100\% ethanol & 273.2 \(\pm\) 17.5 \({}^{\mathrm{ab}}\) & 169.3 \(\pm\) 12.2 \({}^{\mathrm{c}}\) \\ \hline \end{tabular} The different superscript letters indicate significant differences (_p_ < 0.05).  
\end{table}
Table 1: TPC and TFC of different _E. globulus_ leaf extract conditions.  
the 0 and 50% ethanol extraction conditions, TFC values ranged from 32.5 to 41.2 mg QE/g extract, with similar values. The 70% ethanol extract showed a value of 66.5 mg QE/g extract, about 1.5-fold higher than the 0, 10, 30, and 50% ethanol conditions. Moreover, the highest TFC values were confirmed at 90% and 100% ethanol conditions with 156.5 and 169.3 mg QE/g extract. Overall, the results indicated that the optimum conditions for TPC and TFC differed depending on the extract solvent; TPC optimum conditions were 10-70% ethanol conditions (422.0-497.7 mg GAE/g extract), while TFC optimum conditions were the 90 and 100% ethanol conditions (156.5 and 169.3 mg QE/g extract). The best extract conditions showed at a moderate polarity for TPC and were non-polar for TFC.