## 3 Results and Discussion
### Evaluation of the Total Antioxidant Capacity (TAC) of Hydroalcoholic Extracts
The significant contribution of hydrophilic species to the total antioxidant capacity of the extract is also supported by the higher values observed in the ABTS assay compared to those in the DPPH assay. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{3}{c}{**Type of Assay**} \\ \cline{2-4}  & **FRAP (mg TE/g Extract)** & **DPPH (mg TE/g Extract)** & **ABTS (mg TE/g Extract)** \\ \hline SM000 & 22.94 \(\pm\) 0.82 d & 15.87 \(\pm\) 0.27 \({}_{t}\) & 40.37 \(\pm\) 0.21 c \\ SM111 & 34.08 \(\pm\) 1.46 b & 27.20 \(\pm\) 1.33 c & 39.46 \(\pm\) 1.91 c \\ SM011 & 34.27 \(\pm\) 0.58 b & 29.48 \(\pm\) 0.08 b & 41.67 \(\pm\) 0.21 c \\ SM001 & 31.50 \(\pm\) 2.04 b & 23.23 \(\pm\) 0.04 d & 40.64 \(\pm\) 0.17 c \\ SM110 & 33.28 \(\pm\) 1.80 b & 26.15 \(\pm\) 0.53 b & 44.32 \(\pm\) 1.54 b \\ SM100 & 16.07 \(\pm\) 1.28 \({}_{e}\) & 9.34 \(\pm\) 3.88 \({}_{g}\) & 34.55 \(\pm\) 1.62 \({}_{d}\) \\ SM101 & **39.39 \(\pm\) 1.59 a** & **31.50 \(\pm\) 0.80 a** & **45.55 \(\pm\) 0.91 a** \\ SM010 & 27.67 \(\pm\) 0.83 c & 19.49 \(\pm\) 0.68 e & 44.20 \(\pm\) 0.08 b \\ \hline AM000 & 86.47 \(\pm\) 3.85 b & 24.64 \(\pm\) 0.43 d & 49.90 \(\pm\) 2.89 c \\ AM111 & **107.31 \(\pm\) 3.66 a** & 29.46 \(\pm\) 1.34 b & **64.74 \(\pm\) 7.80 a** \\ AM011 & 95.76 \(\pm\) 5.31 b & 26.79 \(\pm\) 2.00 dcb & 60.60 \(\pm\) 0.04 b \\ AM001 & 82.19 \(\pm\) 3.72 cd & 28.06 \(\pm\) 0.18 b & 57.85 \(\pm\) 1.23 b \\ AM110 & 71.67 \(\pm\) 0.06 e & 27.65 \(\pm\) 1.15 b & 60.09 \(\pm\) 4.16 b \\ AM100 & 88.52 \(\pm\) 5.31 b & 24.77 \(\pm\) 0.54 d & 55.92 \(\pm\) 1.27 c \\ AM101 & 75.79 \(\pm\) 3.00 cd & 27.44 \(\pm\) 0.59 cba & 60.60 \(\pm\) 2.34 b \\ AM010 & 81.04 \(\pm\) 2.43 cd & **30.02 \(\pm\) 1.41 a** & 53.85 \(\pm\) 5.07 c \\ \hline TP000 & **44.02 \(\pm\) 4.67 a** & 9.57 \(\pm\) 1.37 a & **84.11 \(\pm\) 0.67 a** \\ TP111 & 29.14 \(\pm\) 0.91 c & 7.51 \(\pm\) 0.79 b & 65.13 \(\pm\) 3.13 c \\ TP011 & 26.39 \(\pm\) 2.51 b & 6.81 \(\pm\) 0.68 b & 56.45 \(\pm\) 51.1 d \\ TP001 & 31.54 \(\pm\) 1.73 b & 8.30 \(\pm\) 1.05 b & 34.28 \(\pm\) 2.65 c \\ TP110 & 28.86 \(\pm\) 1.44 b & 6.95 \(\pm\) 0.61 b & 63.40 \(\pm\) 3.92 c \\ TP100 & 40.93 \(\pm\) 1.15 a & **9.60 \(\pm\) 1.15 a** & 73.34 \(\pm\) 6.73 b \\ TP101 & 28.93 \(\pm\) 0.38 b & 6.51 \(\pm\) 0.16 b & 52.00 \(\pm\) 2.69 d \\ TP010 & 24.83 \(\pm\) 1.59 c & 6.55 \(\pm\) 1.14 b & 37.95 \(\pm\) 3.64 e \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of the measured FRAP, DPPH, and ABTS values of the extracts of plants obtained under different cultivation conditions. SM: _Silybum marianum_; AM: _Achillea millefolium_; TP: _Trifolium pratense_. The triplets of numbers refer to the applied cultivation conditions as reported in the text (Table 1). All data are reported as the mean value of three independent measurements, along with the corresponding standard deviation. Different letters (\({}_{\text{bcdefg}}\)) indicate statistically different mean values (\(p\leq\) 0.01; ANOVA one-way, [PERSON]’s HSD tests) from highest to lowest. For each assay and plant source, the highest and lowest values are reported in bold and italics, respectively. Figure 4: Graphical summary of the antioxidant assays: FRAP, DPPH, and ABTS; values of the hydroalcoholic extract from selected species. In analogy with what has already been stated for the other two species, the three spectrophotometric assays consistently suggested the optimal cultivation conditions for _Trifolium pratense_ (TP) (condition TP000: FRAP = 44.02 \(\pm\) 4.67 mg TE/g extract; DPPH = 9.34 \(\pm\) 0.38 mg TE/g extract; ABTS = 84.11 \(\pm\) 0.67 mgTE/g extract, Table 5); for the DPPH assay, the slightly better combination was the presence of PGPR, absence of fertilization, and a restricted irrigation regime (TP100: DPPH = 9.60 \(\pm\) 1.15 mg TE/g extract; TP000: DPPH = 9.57 \(\pm\) 1.37 mg TE/g extract).