## 3 Results
#### 3.2.2 HPLC-MS-TOF Metabolites  
To summarise the obtained results from the HPLC-MS-Q-TOF of untargeted metabolites profiling, the chemometric analysis approach was applied to observe metabolite variations and similarities within samples treated with OMET and non-OMET in three Amaranth species. With the use of unsupervised principal component analysis (PCA) (Figure 5A), two main clusters were observed and separated based on the Amaranth species. In fact, samples of _A. tricolor_ grown on OMET (TR1) system showed a holistic distinctive metabolome profile from samples of _A. caudatus_ (CA1) and _A. cruentus_ (CR1), irrespective of their growth condition (OMET system). However, there was no clear clustering between samples of _A. caudatus_ and _A. cruentus_ grown on either OMET or non-OMET. Therefore, a supervised OPLS-DA plot was generated, and results obtained therein showed good model statistics with predictive ability (Q2 cum value: 62%) that was above 50% (Figure 5B). Two clear clusters were now observed to separate 1: _A. tricolor_ (TR1) and _A. caudatus_ (CA1) grown on OMET, and 2: _A. cruentus_ grown on OMET (CR1) and the other three species grown on non-OMET. The OPLS-DA model (Figure 6) was generated to demonstrate metabolites biomarker responsible to the OMET and non-OMET clusters irrespective \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Amaranth Species \& Treatment**} & **Total Phenolic** & **Total Flavonoids** & **Total Tannins** \\  & & **(mg GAE/100 g DW)** & **(mg CA/100 g DW)** & **(mg GAE/100 g DW)** \\ \hline \multirow{2}{*}{_A. caudatus_} & OMET & 210.24 \(\pm\) 0.033 d & 391.26 \(\pm\) 0.046 d & 4.09 \(\pm\) 0.042 d \\ \cline{2-5}  & non-OMET & 259.68 \(\pm\) 0.046 b & 453.34 \(\pm\) 0.036 b & 9.60 \(\pm\) 0.022 a \\ \hline \multirow{2}{*}{_A. cruentus_} & OMET & 209.65 \(\pm\) 0.035 d & 382.60 \(\pm\) 0.047 e & 3.98 \(\pm\) 0.043 d \\ \cline{2-5}  & non-OMET & 262.45 \(\pm\) 0.028 a & 473.28 \(\pm\) 0.021 a & 8.78 \(\pm\) 0.031 b \\ \hline \multirow{2}{*}{_A. tricolor_} & OMET & 207.70 \(\pm\) 0.036 e & 364.24 \(\pm\) 0.038 f & 3.61 \(\pm\) 0.038 d \\ \cline{2-5}  & non-OMET & 257.24 \(\pm\) 0.040 c & 447.59 \(\pm\) 0.042 c & 6.89 \(\pm\) 0.040 c \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The interactive effects of OMET system and Amaranth species on total phenolics, flavonoids and tannins. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & **Chl a (mg/kg)** & **Chl b (mg/kg)** & **Chl a + b (mg/kg)** \\ \hline \multirow{2}{*}{_A. caudatus_} & OMET & 0.306 \(\pm\) 0.005 a & 47.779 \(\pm\) 0.004 a & 48.085 \(\pm\) 0.005 a \\ \cline{2-5}  & non-OMET & 0.301 \(\pm\) 0.0047 b & 47.142 \(\pm\) 0.003 a & 47.443 \(\pm\) 0.007 a \\ \hline \multirow{2}{*}{_A. cruentus_} & OMET & 0.301 \(\pm\) 0.0048 b & 47.142 \(\pm\) 0.008 a & 47.443 \(\pm\) 0.008 a \\ \cline{2-5}  & non-OMET & 0.296 \(\pm\) 0.0034 c & 46.306 \(\pm\) 0.003 b & 46.603 \(\pm\) 0.004 a \\ \hline \multirow{2}{*}{_A. tricolor_} & OMET & 0.289 \(\pm\) 0.044 d & 45.253 \(\pm\) 0.048 c & 45.543 \(\pm\) 0.045 a \\ \cline{2-5}  & non-OMET & 0.197 \(\pm\) 0.036 e & 30.749 \(\pm\) 0.041 d & 30.946 \(\pm\) 0.039 b \\ \hline \hline \end{tabular} \
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{_A. cruentus_} & OMET & 0.301 \(\pm\) 0.0048 b & 47.142 \(\pm\) 0.008 a & 47.443 \(\pm\) 0.008 a \\ \cline{2-5}  & non-OMET & 0.296 \(\pm\) 0.0034 c & 46.306 \(\pm\) 0.003 b & 46.603 \(\pm\) 0.004 a \\ \hline \multirow{2}{*}{_A. tricolor_} & OMET & 0.289 \(\pm\) 0.044 d & 45.253 \(\pm\) 0.048 c & 45.543 \(\pm\) 0.045 a \\ \cline{2-5}  & non-OMET & 0.197 \(\pm\) 0.036 e & 30.749 \(\pm\) 0.041 d & 30.946 \(\pm\) 0.039 b \\ \hline \hline \end{tabular}
\begin{tabular}{c c} \hline \hline \multirow{2}{*}{_A. tricolor_} & Chl a = Chlorophyll a; Chl b = Chlorophyll b; Chl a + b = Chlorophyll a + b; different letters in the same column indicate significance difference at \(p\leq 0.05\).  
\end{table} 
Table 3: The interactive effects of OMET system and Amaranth species on chlorophyll concentration (mg/kg).