## 3 Results
### Biological Activities
#### 3.2.3 Mode of Action of Ethanolic Extract  
Time Kill Assays  
The speed and duration of antibacterial property of ethanolic extracts of studied plants against tested strains posted a significant difference (\(p<0.05\)). The studied strains were evaluated by analysis of lysis and kill time. Bacterial counts were plotted against time to obtain the kill time graph (Figure 2). Data were presented in terms of colony-forming units. This kill kinetics study was performed against the studied strains at a concentration equivalent to the MIC and for 24 h against the strains studied at a concentration equivalent to the MIC. \begin{table}
\begin{tabular}{l c c c} \hline \hline  & \multicolumn{2}{c}{**Inhibition Zone Diameter (mm)**} & \multirow{2}{*}{**MIC (mg/mL)**} & \multirow{2}{*}{**BMC (mg/mL)**} \\ \cline{2-2} \cline{4-4}  & & & \\ \hline \multicolumn{4}{c}{_Staphylococcus aureus_} \\ \hline _Pistacia lenticus_ & 15\({}^{\text{ c}}\) \(\pm\) 0.8 & & 12 & 25 \\ _Rosmarinus officinalis_ & 14.5 \(\pm\) 0.2 \({}^{\text{cd}}\) & & 3.84 & 12 \\ _Erica multifloma_ & 16\({}^{\text{ b}}\) \(\pm\) 0.1 & 24\({}^{\text{ a}}\)\(\pm\) 0.1 & 0.04 & 3.84 \\ _Calicotome villosa_ & 13\({}^{\text{ d}}\)\(\pm\) 0.3 & & 25 & 25 \\ _Phillyrea lafifolia_ & 16\({}^{\text{ b}}\)\(\pm\) 0.5 & & 3.84 & 12 \\ \hline \multicolumn{4}{c}{_Escherichia coli_} \\ \hline _Pistacia lenticus_ & 15\({}^{\text{ c}}\)\(\pm\) 0.7 & & 12 & 25 \\ _Rosmarinus officinalis_ & 14\({}^{\text{ d}}\)\(\pm\) 0.00 & & 3.84 & 12 \\ _Erica multifloma_ & 16\({}^{\text{ b}}\)\(\pm\) 0.3 & 25\({}^{\text{ a}}\)\(\pm\) 0.08 & 0.04 & 3.84 \\ _Calicotome villosa_ & 15\({}^{\text{ c}}\)\(\pm\) 0.5 & & 25 & 25 \\ _Phillyrea lafifolia_ & 13\({}^{\text{ e}}\)\(\pm\) 0.5 & & 3.84 & 12 \\ \hline \multicolumn{4}{c}{_Listeria monocytogenes_} \\ \hline _Pistacia lenticus_ & 13\({}^{\text{ d}}\)\(\pm\) 0.4 & & 0.04 & 3.84 \\ _Rosmarinus officinalis_ & 14\({}^{\text{ c}}\)\(\pm\) 0.5 & & 3.84 & 3.84 \\ _Erica multifloma_ & 15\({}^{\text{ b}}\)\(\pm\) 0.1 & 25\({}^{\text{ a}}\)\(\pm\) 0.1 & 3.84 & 3.84 \\ _Calicotome villosa_ & 14\({}^{\text{ c}}\)\(\pm\) 0.3 & & 3.84 & 12 \\ _Phillyrea lafifolia_ & 15\({}^{\text{ b}}\)\(\pm\) 0.5 & & 3.84 & 12 \\ \hline \multicolumn{4}{c}{_Salmonella typhimurium_} \\ \hline _Pistacia lenticus_ & 15\({}^{\text{ b}}\)\(\pm\) 0.2 & & 3.84 & 12 \\ _Rosmarinus officinalis_ & 13\({}^{\text{ c}}\)\(\pm\) 0.4 & & 12 & 25 \\ _Erica multifloma_ & 14\({}^{\text{ c}}\)\(\pm\) 0.7 & 25\({}^{\text{ a}}\)\(\pm\) 0.1 & 3.84 & 12 \\ _Calicotome villosa_ & 14\({}^{\text{ c}}\)\(\pm\) 0.2 & & 3.84 & 12 \\ _Phillyrea lafifolia_ & 14\({}^{\text{ c}}\)\(\pm\) 0.5 & & 3.84 & 12 \\ \hline \hline \end{tabular}  
* The values with different exponents in the same row (a–e) showed significant differences at \(p<0.05\).  
\end{table} 
Table 2: Qualitative and quantitative results (MIC and BMC) of the antibacterial effects of the EEs of _Pistacia lenticus_, _Rosmarinus officinalis_, _Erica multifloma_, _Calicotome villosa_, and _Phillyrea lafifolia_ on the reference strains were assayed. Figure 2: Time-kill curves of Gram-negative in the left (_Escherichia coli (S2)_ and _Salmonella typhimurium (S4)_) and Gram-positive in the right (_Listeria monocytogenes (S2)_ and _Staphylococcus aureus (S1)_) in control suspensions and the MICs of P1 (_Pistacia lentiiscus_), P2 (_Rosmarinus officinalis_), P3 (_Erica multiflona_), P4 (_Calicotone villosa_) and P5 (_Phillyrea latifolia_) ethanolic extracts. The mean of the standard deviations for three replicates is indicated by symbols. The lower detection threshold was 0 CFU/mL. The control bacterial population exhibited a classic three-phase growth curve (growth, stationary, and decline). In the presence of each extract at a concentration corresponding to the MIC, the shape of the growth curve was inverted, and the three phases disappeared. This indicated the stop of growth of the four bacterial strains after 24 h incubation at 37 \({}^{\circ}\)C with the EEs at the MIC concentration. The EE of _C. villosa, P. Ientiscus, R. officinalis_, and _E.