## 3 Results and Discussion
### The Antimicrobial Activity of Medicinal Plant Extracts
In terms of effectiveness, _P. aeruginosa_ follows, with a MIC value at 15 mg/mL concentration but with a negative evolution trend that started from 25.61% BIR at 15 mg/mL and reached 3.66% at the maximum tested concentration of 60 mg/mL. The rest of the strains tested have approximately similar trends and BIR% values, which varied between 49.56 and 68.37% in the case of the 15% tested concentration and between 60.06% and 75.36%, respectively, in the case of the 60 mg/mL concentration. The antimicrobial activity of the SO2 extract (Figure 9h) proved to be much weaker than the other extracts, but a positive evolution trend correlated with the concentration for all tested strains. _S. pyogenes_ and _P. aeruginosa_ showed negative BIR% values for the first three concentrations tested, with MIC being demonstrated only for the 60 mg/mL concentration in the case of both strains, with values of 16.99% BIR for _S. pyogenes_ and 1.83% BIR for _P. aeruginosa_. The rest of the tested strains showed approximately similar efficacy, with values varying between 38.99% and 65.78% BIR in the 60 mg/mL concentration case. The LA extract (Figure 9i) showed weaker effectiveness as measured by BIR% values than the rest of the tested extracts. _S. aureus_, _S. flexneri_, and _P. aeruginosa_ do not demonstrate sensitivity to the LA extract from the first tested concentration. _S. aureus_ and _S. flexneri_ were inhibited starting with a concentration of 30%, while _P. aeruginosa_ showed MIC only in the case of the last tested concentration. The rest of the strains show sensitivity, starting with the first concentration, with the evolution trend being positive. The recorded BIR% values varied, in the case of the last tested concentration, between 36.41% and 67.11%. Regarding the activity of the MO extract (Figure 9j), the results obtained are promising regarding the strains of _S. flexneri_, _S. aureus_, _E. coli_, _H. influenzae_, _S. typhimurium_, and _C. albicans_. The values obtained in the case of the maximum concentration tested were around 50-60% BIR. _S. pyogenes_, however, does not demonstrate MIC in the case of any of the 4 tested concentrations. The obtained values are negative, even if they have a positive evolution trend. In the case of _P. aeruginosa_, the MIC is highlighted only in the case of the 30 mg/mL concentration, the resistance being more pronounced than in the cases of other strains, a fact proven by the low value of BIR% (12.20%) expressed in the case of the maximum tested concentration. _C. paraspilsosis_ was the only strain that showed a negative evolution trend correlated with an increased tested concentration in the case of MO extract. The effectiveness was below average in the HP extract (Figure 9k), with a positive evolution trend across all strains tested. _S. pyogenes_, _S. aureus_, _S. flexneri_, and _C. paraspilsosis_ were not sensitive when the first concentration was applied, showing MIC only for the 30 mg/mL concentration. _P. aeruginosa_, on the other hand, proved to have a high resistance, with the maximum allowed concentration reaching a BIR% of \(-\)56.10%. CO extract has an antimicrobial profile similar to that of HP extract (Figure 9l), notable for an increase in inhibition capacity with the concentration of the extract but with negative BIR values for _P. aeruginosa_. The MIC values (mg/mL) for plant extracts and positive control against tested strains are presented in Table 5.  
The antimicrobial effects of medicinal plant extracts have been less studied than those of essential oils, considering the lower efficiency of the former. Previous studies showed that the gram-positive bacteria _S. aureus_ were the more susceptible bacteria, while the gram-negative bacteria _E. coli_ were unaffected by medicinal plant extracts [49]. Other authors have proven the interaction of flavonoid compounds with the cell membrane of gram-positive bacteria and the relationship between their chemical profile and antimicrobial activities [49; 55].