## 3 Results and Discussion
### Role of Sonication on Antibacterial Activity of Garlic Extract  
The current findings show that 40 mg/mL of the sonicated supernatant garlic extract had the greatest inhibition on _S. mutans_. The counts reduced from 1.77 \(\times\) 10\({}^{4}\) CFU/mL (control) to 0.58 \(\times\) 104 CFU/mL, whereas 40 mg/mL the sonicated garlic extract without centrifugation reduced _S. mutans_ colonies to 0.64 \(\times\) 10\({}^{4}\) CFU/mL, and garlic extract without sonication did not show significant inhibition in the sonicated extracts. It reduced the bacterial counts to 0.88 \(\times\) 10\({}^{4}\) CFU/mL. The second bacteria to be challenged with 40 mg/mL of the sonicated garlic extract were _P. gingivalis_; a decline from 2.01 \(\times\) 10\({}^{4}\) CFU/mL to 0.64 \(\times\) 10\({}^{4}\) CFU/mL was observed. The sonicated samples without centrifugation were effective against _P. gingivalis_ up to 0.7 \(\times\) 10\({}^{4}\) and the unsonicated garlic extract inhibited _P. gingivalis_ up to 1.0 \(\times\) 10\({}^{4}\) CFU/mL, _Staphylococcus aureus_ followed, showing maximum reflectivity at 40 mg/mL of the sonicated supernatant sample, bringing about a reduction in the bacterial count from 2.05 \(\times\) 10\({}^{5}\) CFU/mL to 0.67 \(\times\) 10\({}^{5}\) CFU/mL compared to 1.2 \(\times\) 10\({}^{5}\) CFU/mL of the unsonicated sample (Figure 3).  
The least susceptible bacteria (_E. coli_) when treated at concentrations of 40 mg/mL showed a reduction in counts from 2.30 \(\times\) 10\({}^{5}\) CFU/mL to 0.78 \(\times\) 10\({}^{5}\) CFU/mL against the sonicated supernatant garlic extracts. The unsonicated garlic extracts without centrifugation decreased _E. coli_ to 0.84 \(\times\) 10\({}^{5}\) CFU/mL. The sample that showed the least bacterial inhibition on _E. coli_ was garlic extract without sonication (1.4 \(\times\) 10\({}^{5}\) CFU/mL). The above findings indicate the positive influence of sonication on increasing the capacity of garlic extract to inhibit the growth of all tested bacteria through increasing extraction of active compounds, mostly allicin, the biological compound of garlic that is responsible for many biological benefits of garlic extract, including its antibacterial property [46]. This is in accordance with another investigations based on the influence of ultrasound, microwaves, and other factors on synthetic allicin and showed that allicin production during ultrasonication extraction increases with sonication, through cavitation effects caused by ultrasound on the cell material by disrupting the cell wall structure, increasing the speed of diffusion, causing cell lysis, and ultimately releasing the cell contents as well, which indicates the high release of allicin during ultrasonication of garlic during extraction [47]. Effective extraction of garlic active compounds during sonication could be explained by the mechanism of the high solubility of garlic in water when ultrasonicated [21], leading to the breaking of garlic into nanoparticles that easily interact with biological systems.  
Figure 2: Graphical presentation of antibacterial activity of nanoparticles (supernatant) of garlic extract in terms of total viable counts (CFU/mL) on tested bacteria. Values are means of determinations of three replicates, and bars represent standard deviations (S.Ds.) of the means. S.Ds. followed by different letters are significantly different at \(p\leq\) 0.05 level by [PERSON]’s multiple range test.  
Briefly, the effect of sonication on the antibacterial capacity of the garlic extract in the reduction of total viable counts when bacteria were tested against 40 mg/mL treated in different conditions was reported in Figure 3 and indicated that the sonicated supernatant garlic extract significantly reduced the total viable bacteria counts compared to other types of garlic extracts.