## 3 Results and Discussion
### Content of TPC Using the Folin-Ciocalteu Reagent Method
#### 3.1.4 Comparison of the Extracts Tested
Also, such small variables as the degree of sunlight on the tree, soil, or exposure to pests could significantly influence the quantitative composition of phenolic compounds in apple leaves from different v cultivars [53]. Ligol leaf extracts were characterised by the significantly highest content of epicatechin, isoquercitrin, phloridzin, and phloretin. Compared to the extracts from Gloster leaves, those from the leaves of the Ligol cultivar contained approximately 20 mg/1 g of DW more phloridzin. Extracts from the leaves of the Gloster cultivar significantly contained the least polyphenols determined with HPLC; however, they contained significantly more phloretin (1.008 mg/1 g of DW) than extracts from the leaves of the Gala cultivar (0.622 mg/1 g of DW). In the latter, the most ruin and hyperoside were determined. Other authors \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Type of** \\ **Solvent** \\ \end{tabular} } & \multicolumn{4}{c}{**Content of Phenolic Compounds in Extracts (mg/1 g of DW)**} \\ \cline{2-7}  & **Epicatechin** & **Rutin** & **Hyperoside** & **Isoquercitrin** & **Phloridzin** & **Phloretin** \\ \hline Water & 0.137 \(\pm\) 0.036 \({}^{\text{c}}\) & 0.078 \(\pm\) 0.003 \({}^{\text{b}}\) & 0.203 \(\pm\) 0.013 \({}^{\text{c}}\) & 0.868 \(\pm\) 0.196 \({}^{\text{c}}\) & 5.880 \(\pm\) 7.922 \({}^{\text{c}}\) & 0.012 \(\pm\) 0.014 \({}^{\text{c}}\) \\ Water–methanol & 0.543 \(\pm\) 0.116 \({}^{\text{a}}\) & 0.081 \(\pm\) 0.009 \({}^{\text{a}}\) & 0.297 \(\pm\) 0.022 \({}^{\text{a}}\) & 2.724 \(\pm\) 0.158 \({}^{\text{a}}\) & 86.601 \(\pm\) 14.936 \({}^{\text{a}}\) & 2.165 \(\pm\) 0.847 \({}^{\text{a}}\) \\ Water–ethanol & 0.299 \(\pm\) 0.173 \({}^{\text{b}}\) & 0.072 \(\pm\) 0.006 \({}^{\text{c}}\) & 0.285 \(\pm\) 0.011 \({}^{\text{b}}\) & 2.518 \(\pm\) 0.263 \({}^{\text{b}}\) & 37.930 \(\pm\) 12.554 \({}^{\text{b}}\) & 1.185 \(\pm\) 0.639 \({}^{\text{b}}\) \\ \hline \hline \end{tabular}  
Mean values \(\pm\) SD. Letters (a–c) indicate significant differences in the content of phenolic compounds between different types of solvents (\(p<0.05\)). Abbreviations: DW: dry weight.  
\end{table} 
Table 4: Content of phenolic compounds in extracts obtained using various solvents. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Extraction** \\ **Method** \\ \end{tabular} } & \multicolumn{4}{c}{**Content of Phenolic Compounds in Extracts (mg/1 g of DW)**} \\ \cline{2-6}  & **Epicatechin** & **Rutin** & **Hyperoside** & **Isoquercitrin** & **Phloridin** & **Phloretin** \\ \hline SSE & 0.289 \(\pm\) 0.202 \({}^{\text{c}}\) & 0.074 \(\pm\) 0.007 \({}^{\text{c}}\) & 0.258 \(\pm\) 0.041 \({}^{\text{b}}\) & 2.005 \(\pm\) 0.950 \({}^{\text{c}}\) & 39.859 \(\pm\) 37.497 \({}^{\text{c}}\) & 1.324 \(\pm\) 1.031 \({}^{\text{c}}\) \\ UAE & 0.308 \(\pm\) 0.208 \({}^{\text{b}}\) & 0.078 \(\pm\) 0.004 \({}^{\text{b}}\) & 0.253 \(\pm\) 0.046 \({}^{\text{c}}\) & 2.028 \(\pm\) 0.922 \({}^{\text{b}}\) & 41.480 \(\pm\) 39.745 \({}^{\text{b}}\) & 1.104 \(\pm\) 1.093 \({}^{\text{b}}\) \\ ASE & 0.382 \(\pm\) 0.222 \({}^{\text{a}}\) & 0.079 \(\pm\) 0.010 \({}^{\text{a}}\) & 0.274 \(\pm\) 0.051 \({}^{\text{a}}\) & 2.076 \(\pm\) 0.840 \({}^{\text{a}}\) & 49.072 \(\pm\) 33.470 \({}^{\text{a}}\) & 1.228 \(\pm\) 1.176 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}  
Mean values \(\pm\) SD. Letters (a–c) indicate significant differences in the content of phenolic compounds between different extraction methods (\(p<0.05\)). Abbreviations: DW: dry weight; SSE—Shaking Solvent Extraction; UAE—Ultrasound-Assisted Extraction; ASE—Accelerated Solvent Extraction.  
\end{table} 
Table 2: Content of phenolic compounds in apple leaf extracts obtained using various extraction methods.