## 3 Results
### Principal Component Analysis (PCA)  
To analyze correlation between the cultivars, the obtained data of the major phenolic compounds were subjected to PCA. The PC1 accounted for 94.05% of the total variance, while the PC2 explained 4.94% (Figure 4). The PCA results indicated that phenolic compound's composition was significantly dependent on the cultivar type and plant part. The variables located in the same direction are considered more closely related to each other. The PCA analysis distinctly separated the Paldong and Singhi cultivar. Except for Paldong leaves, all variables from the two cultivars were located on the negative side of the PC1. Samples extracted from the leaf of Paldong cultivars, with a higher concentration of phenolic compounds, showed a close correlation to vanillic acid, syringe acid, salicylic acid, and _p_-hydroxybenzoic acid. Variations in the phenolic compound's composition between the two cultivars can be attributed to the variation in the geographical region of cultivar origin, climatic conditions, and genetic variations. Moreover, variations in the composition of the phenolic compounds can provide useful information for distinguishing the two _S. cereale_ cultivars.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Cultvar** & **Parts** & \multicolumn{6}{c}{**Phenolic Compound Concentration (ug mL\({}^{-1}\))**} \\ \hline  & & \multicolumn{2}{c}{**Saliicylic Acid**} & \multicolumn{2}{c}{_p-Hydroxybenzoic Acid_} & \multicolumn{2}{c}{_Vanillic Acid_} & \multicolumn{2}{c}{_Spring Acid_} & \multicolumn{2}{c}{_P-Coumaric Acid_} & \multicolumn{2}{c}{_Fervlic Acid_} & \multicolumn{2}{c}{**Total**} \\ \hline Paldong & Leaf & 1492.50 \(\pm\) 12.20 \({}^{\text{d}}\) & 1286.50 \(\pm\) 12.50 \({}^{\text{d}}\) & 1354.00 \(\pm\) 15.0 \({}^{\text{d}}\) & 1506.50 \(\pm\) 10.00 \({}^{\text{d}}\) & 1392.50 \(\pm\) 15.00 \({}^{\text{d}}\) & 292.00 \(\pm\) 5.00 \({}^{\text{d}}\) & 7324.00 \(\pm\) 25.80 \({}^{\text{d}}\) \\  & Root & 383.00 \(\pm\) 5.00 \({}^{\text{b}}\) & 437.50 \(\pm\) 5.00 \({}^{\text{c}}\) & 311.50 \(\pm\) 6.90 \({}^{\text{a}}\) & 7.00 \(\pm\) 0.50 \({}^{\text{a}}\) & 752.00 \(\pm\) 8.80 \({}^{\text{a}}\) & 57.00 \(\pm\) 2.00 \({}^{\text{a}}\) & 1948.00 \(\pm\) 15.90 \({}^{\text{a}}\) \\ \hline Singhi & Leaf & 479.00 \(\pm\) 4.00 \({}^{\text{c}}\) & 278.20 \(\pm\) 4.00 \({}^{\text{a}}\) & 410.00 \(\pm\) 5.00 \({}^{\text{c}}\) & 117.90 \(\pm\) 5.00 \({}^{\text{c}}\) & 1085.50 \(\pm\) 15.00 \({}^{\text{c}}\) & 98.500 \(\pm\) 4.00 \({}^{\text{b}}\) & 2469.10 \(\pm\) 14.40 \({}^{\text{c}}\) \\  & Root & 358.50 \(\pm\) 5.00 \({}^{\text{a}}\) & 351.00 \(\pm\) 5.00 \({}^{\text{b}}\) & 403.00 \(\pm\) 4.00 \({}^{\text{b}}\) & 98.00 \(\pm\) 3.00 \({}^{\text{b}}\) & 1065.00 \(\pm\) 10.00 \({}^{\text{b}}\) & 162.00 \(\pm\) 2.50 \({}^{\text{c}}\) & 2437.50 \(\pm\) 16.50 \({}^{\text{b}}\) \\ \hline \hline \end{tabular} Experimental data are expressed as mean \(\pm\) standard deviation (\(n=3\)). Data with the same letter in a column are not significantly different, as determined by [PERSON]’s multiple range test (\(p<0.05\)).  
\end{table}
Table 3: Identification of phenolic compounds from the different tissues and cultivars of _S. cereale_.  
Figure 2: Chromatogram of standard phenolic compounds.  
Figure 3: Chromatogram of phenolic compounds identified from Paldong cultivars.