## 3 Results and Discussion
### Inhibition of Nanoparticles of Garlic Extract on the Different Bacteria
Moderate growth inhibition was observed at concentrations of garlic extract ranging from 40 to 60 mg/mL, while the concentrations of 80 to 100 mg/mL showed the strongest inhibition activity against _S. aureus_[32]. Contrary to _E. coli_ and _S. aureus_ sub. _aureus_, during our study _S. mutans_ and _P. gingivalis_ were sensitive to 20 mg/mL (Tables 1 and 2). In general, all four bacteria tested, whether gram-negative or gram-positive, were sensitive to nanoparticles of garlic extract, regardless of the concentration tested in this study. However, the growth inhibition depended on the bacterial species. These findings are consistent with previous research that looked at the antibacterial activity of south Indian spices [39], Greek garlic genotypes [33], and Chinese and Desi varieties [40] against _Aeromonas hydrophilia_, _B. cereus_, _E. coli_, _E. cloacae_, _Enterococcus faecalis_, _K. pneumoniae_, _Listeria monocytogenes_, _M. flavus_, _P. mirabilis_, _P. aeruginosa_, and _Salmonella_ species. The obtained results also show that all tested bacteria had higher inhibition zones when tested using the agar well diffusion method than when tested using the disk diffusion method. This could be due to the high absorption of garlic extract when introduced into the wells, whereas in the disk diffusion method, the disk is pressed on the agar surface and does not allow for the complete diffusion of garlic extract on the agar surface. Another \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Garlic Extract** **(40 mg/mL)**} & \multicolumn{4}{c}{**Inhibition Zone (mm)**} \\ \cline{2-5}  & _S. mutans_ & _S. aureus_ **sub. aureus** & _E. coli_ & _P. gingivalis_ \\ \hline Extract without sonication & \(18.3\pm 0.3\) d & \(14.3\pm 0.5\) d & \(13.2\pm 0.3\) d & \(17.6\pm 0.5\) d \\ \hline Sonic without centrifugation & \(20.2\pm 0.5\) c & \(16.2\pm 0.3\) c & \(14.3\pm 0.4\) c & \(19.3\pm 0.6\) c \\ \hline Sonicated supernatant & \(21.9\pm 0.3\) b & \(17.2\pm 0.4\) b & \(16.4\pm 0.6\) b & \(20.4\pm 0.7\) b \\ \hline Standard & \(34.1\pm 0.0\) a & \(27.2\pm 0.0\) a & \(25.5\pm 0.0\) a & \(35.4\pm 0.0\) a \\ \hline R-Square & \(0.9983\) & \(0.9971\) & \(0.9958\) & \(0.9961\) \\ \hline Coeff Var & \(1.32\) & \(1.75\) & \(2.21\) & \(2.36\) \\ \hline Root MSE & \(0.31\) & \(0.32\) & \(0.38\) & \(0.55\) \\ \hline \hline \end{tabular} Values are the mean \(\pm\) standard deviation (S.D.) of three replicates. According to [PERSON]’s multiple range test, S.D. within a column followed by different letters are significantly different at \(p\leq 0.05\) level. Coeff Var: coefficient of variation; Root MSE: Root-mean-square deviation.  
\end{table} 
Table 4: Antibacterial activity of 40 mg/mL garlic extracts treated in different conditions by agar well diffusion method. supporting point is that when utilizing the disk diffusion approach, some extract's active components may be held within the disk's pores and limiting their ability to reach the inoculation media, preventing the extract from performing to its full potential [41]. In the present study, the diameter of the inhibition zone increased with the concentration of garlic extract; the more the concentration increased, the more the zone of inhibition increased (Tables 1 and 2). The results of this study are in line with the findings of the research done by [PERSON] et al. [42], who investigated the antibacterial effect of garlic and _Eucalyptus_ extracts on oral cariogenic bacteria, and reported that both _Streptococcus mutans_ and _Lactobacillus acidophilus_ were sensitive to garlic extract and the association between concentration of garlic extract and the inhibition zone was proved. As the concentration increased, the diameter of the inhibition zone gradually increased [42]. The results presented in Tables 3 and 4 indicate the inhibition zones of the garlic extract on the four tested bacteria at a 40 mg/mL concentration under three different extraction conditions.