## 3 Results and Discussion
### Antioxidant Activity of Extracts from Unground and Ground Purslane  
The antioxidant activity of the extracts of unground and ground purslane was evaluated using three antioxidant methods (DPPH, ABTS, and FRAP), as shown in Figures 5-7. All methods measure the ability of a compound to scavenge free radical. As expected, the extracts of all samples showed high antioxidant activity in all methods, and this is consistent with the results of other authors [17; 43]. However, there are no studies on the influence of grinding techniques on the antioxidant activity of purslane. The influence of particle size on extraction yield and antioxidant activity is shown in studies with green tea powder or _Vaccinium bracetatum_ Thunb leaf powder [52; 53]. As shown in Figure 5, the PPK and PPB samples showed higher DPPH radical scavenging activity compared to the extract of unground purslane (control). The PPP sample showed the lowest DPPH radical scavenging activity. Figure 6 shows the ABTS radical scavenging activity of the tested samples. The ABTS radical scavenging method is considered suitable for testing phenolic compounds [52]. The results show a dose-dependent radical scavenging ability. The PPB sample showed a significantly higher radical scavenging potential than all other tested samples. Protocatheuic acid, as the dominant phenolic acid in purslane, is widely distributed in plants, and its radical scavenging ability has been demonstrated through various methods [54]. Some authors reported that the reduction in particle size of the powder of macroalgae increases the ABTS potential [55]. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Phenolic Compounds**} & \multicolumn{2}{c}{**Control**} & \multicolumn{2}{c}{**PPK**} & \multicolumn{2}{c}{**PPB**} & \multicolumn{2}{c}{**PPP**} \\ \cline{2-13}  & **UN** & **GA** & **IN** & **UN** & **GA** & **IN** & **UN** & **GA** & **IN** & **UN** & **GA** & **IN** \\  & **(\(\mathbf{\mu}\)g/g)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline Benzoic & 20.90 & 100 & 34.54 & 16.03 & 74.85 & 100 & 14.06 & 99.43 & 100 & 10.12 & 72.13 & 76.18 \\ \hline Protocatheuic & 2010.03 & 88.60 & 41.29 & 2318.08 & 74.50 & 61.10 & 2059.76 & 69.47 & 29.08 & 804.40 & 65.67 & 57.34 \\ \hline Chlorogenic & 380.20 & 100 & 80.33 & 467.55 & 65.12 & 68.71 & 365.89 & 85.44 & 72.27 & 389.15 & 95.31 & 73.53 \\ \hline Syringic & 11.57 & 71.39 & 93.17 & 40.57 & 45.00 & 14.61 & 8.77 & 57.24 & 91.67 & 7.68 & 93.88 & 32.42 \\ \hline Ferulic & 242.17 & 86.83 & 86.83 & 287.80 & 63.66 & 76.17 & 253.05 & 89.73 & 73.34 & 666.61 & 88.36 & 64.24 \\ \hline Synapic & 8.93 & 56.77 & 56.77 & 8.00 & 77.37 & 46.12 & 9.20 & 100 & 49.89 & 6.81 & 63.14 & 56.24 \\ \hline \hline \end{tabular}  
* The gastrointestinal stability (%) of phenolic acids was calculated according to the formula described in Section 2.6. UN = undigested; GA = gastric; IN = intestinal; control = freeze-dried, unground purslane; PPK = purslane powder after grinding with a knife mill; PPB = purslane powder after grinding with a ball mill; PPP = purslane powder after grinding with a planetary ball mill.  
\end{table} 
Table 2: Gastrointestinal stability of dominant phenolic compounds from unground and ground purslane. Figure 5: DPPH radical scavenging activity of extracts from unground and ground purslane. Values represent the means \(\pm\) standard deviations of three biological replicates and three technical replicates. Different letters indicate significant differences between the samples for each concentration separately (one-way ANOVA, Duncan test, \(p\leq 0.05\)). Control = freeze-dried, unground purslane; PPK = purslane powder after grinding with a knife mill; PPB = purslane powder after grinding with a ball mill; PPP = purslane powder after grinding with a planetary ball mill. Figure 6: ABTS radical scavenging activity of extracts from unground and ground purslane.