# Biosynthesis of Zinc Oxide Nanoparticles Using Seaweed: Exploring Their Therapeutic Potentials
## 3 Results
### Antimicrobial Activity of the Biosynthesisized ZnO-NPs
#### 3.3.1 Antioxidant Activity of the Biosynthesisized ZnO-NPs DPPH Radical Scavenging Activity  
The IC\({}_{50}\) value of the DPPH scavenging activity was considerably lower (12.6 \(\upmu\)g/mL) for the _U. lactuca_ ZnO-NPs than that of the ZnO-NPs synthesized using _S. moticum_ and _U. intestinalis_ extracts, which was 13.8 \(\upmu\)g/mL and 15.2 \(\upmu\)g/mL, respectively as shown \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**ZnO-NP Treatment**} & \multirow{2}{*}{**Potency (mg/mL)**} & \multicolumn{4}{c}{**Zones of Inhibition (mm)**} & \multirow{2}{*}{**f Value**} \\ \cline{3-3} \cline{5-6}  & & & _Klebsiella_ & & _Candidia_ & _Aspegillus_ \\  & & _pneumonia_ & & _albicans_ & _niger_ \\ \hline \multirow{3}{*}{_Ulla lactuca_  ZnO-NPs} & 60 & 17.8 \(\pm\) 1.54 & 20.7 \(\pm\) 2.06 & 19.3 \(\pm\) 1.42 & 21.3 \(\pm\) 2.19 & 2.861 \({}^{**}\) \\ \cline{2-6}  & 30 & 14.2 \(\pm\) 0.97 & 13.3 \(\pm\) 0.83 & 15.2 \(\pm\) 1.05 & 13.4 \(\pm\) 1.12 & 3.848 \({}^{*}\) \\ \cline{2-6}  & 15 & 11.7 \(\pm\) 0.68 & 12.6 \(\pm\) 0.76 & 11.4 \(\pm\) 0.41 & 11.2 \(\pm\) 0.3 & 5.904 \({}^{*}\) \\ \hline \multirow{3}{*}{_Sargassum_ _moticum_  ZnO-NPs} & 60 & 15.1 \(\pm\) 0.95 & 19.1 \(\pm\) 1.23 & 18.6 \(\pm\) 1.63 & 17.7 \(\pm\) 1.4 & 2.955 \({}^{**}\) \\ \cline{2-6}  & 30 & 13.3 \(\pm\) 1.11 & 12.5 \(\pm\) 0.42 & 15.7 \(\pm\) 1.7 & 14.3 \(\pm\) 0.88 & 3.871 \({}^{*}\) \\ \cline{2-6}  & 15 & 12.8 \(\pm\) 0.84 & 11.3 \(\pm\) 0.3 & 12.2 \(\pm\) 0.49 & 11 \(\pm\) 0.21 & 5.874 \({}^{*}\) \\ \hline \multirow{3}{*}{_Uliva intestinalis_  ZnO-NPs} & 60 & 17.6 \(\pm\) 1.33 & 16.9 \(\pm\) 1.61 & 15.8 \(\pm\) 0.53 & 16.2 \(\pm\) 1.09 & 3.018 \({}^{**}\) \\ \cline{2-6}  & 30 & 13.1 \(\pm\) 0.74 & 15.2 \(\pm\) 1.28 & 13.9 \(\pm\) 0.94 & 15.1 \(\pm\) 0.74 & 3.83 \({}^{*}\) \\ \cline{2-6}  & 15 & 12.8 \(\pm\) 0.95 & 12.4 \(\pm\) 0.49 & 11.1 \(\pm\) 0.22 & 12.1 \(\pm\) 0.51 & 5.812 \({}^{*}\) \\ \hline \multirow{3}{*}{Antibiotics} & \multicolumn{2}{c}{Ciprofloxacinacin} & \multirow{2}{*}{13.4 \(\pm\) 0.87} & \multirow{2}{*}{12.8 \(\pm\) 0.27} & \multirow{3}{*}{} & \multirow{3}{*}{} \\ \cline{2-6}  & \multicolumn{2}{c}{Amoxicillin 25} & \multirow{2}{*}{R} & \multirow{2}{*}{20.2 \(\pm\) 2.65} & \multirow{3}{*}{} & \multirow{3}{*}{} \\ \cline{2-6}  & \multicolumn{2}{c}{S-Adenosylmethionine} & \multicolumn{2}{c}{R} & & \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} Synthetic \\ antifungal \\ \end{tabular} } & \multicolumn{2}{c}{Fluconazole} & \multicolumn{2}{c}{R} & \multirow{2}{*}{12.3 \(\pm\) 0.56} \\ \cline{2-6}  & \multicolumn{2}{c}{Isothiocyanafcs} & & \multicolumn{2}{c}{R} & 11.7 \(\pm\) 0.63 \\ \cline{2-6}  & \multicolumn{2}{c}{Metronidazoleazole} & \multicolumn{2}{c}{R} & \multirow{2}{*}{14.2 \(\pm\) 1.12} \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Negative \\ controls \\ \end{tabular} } & \multicolumn{2}{c}{ZN Acetate} & \multicolumn{2}{c}{13.6 \(\pm\) 1.02} & \multicolumn{2}{c}{11.1 \(\pm\) 1.03} & \multicolumn{2}{c}{13.4 \(\pm\) 0.00} \\ \cline{2-6}  & \multicolumn{2}{c}{_Ulta lactuca_ _Sargassum moticum_} & \multicolumn{2}{c}{13.2 \(\pm\) 0.83} & \multicolumn{2}{c}{11.6 \(\pm\) 0.54} & \multicolumn{2}{c}{12.5 \(\pm\) 0.65} \\ \cline{2-6}  & \multicolumn{2}{c}{_Sargassum moticum_} & \multicolumn{2}{c}{13.1 \(\pm\) 0.8} & \multicolumn{2}{c}{NA} & \multicolumn{2}{c}{11.9 \(\pm\) 0.36} \\ \cline{2-6}  & \multicolumn{2}{c}{_Ulta_ _intestinalis_} & \multicolumn{2}{c}{12.6 \(\pm\) 0.24} & \multicolumn{2}{c}{11.7 \(\pm\) 0.32} & \multicolumn{2}{c}{NA} \\ \hline \hline \end{tabular}  
* Each value is the mean of three replicates \(\pm\) standard deviation. \(p\) \(>\) 0.05, nonsignificant; \(p\) \(<\) 0.05, \({}^{*}\) significant; \(p\) \(<\) 0.001, \({}^{**}\) highly significant. R = Resistance, NA = no activity.  
\end{table} 
Table 1: Inhibition zone diameters (mm) of ZnO-NPs biosynthesized using different seaweeds. in Table 2. Increasing concentrations of ZnO-NPs showed comparatively higher DPPH antioxidant activities (Table 2) compared to ascorbic acid (AA) as a standard antioxidant.