# Functional and Antimicrobial Properties of Propolis from Different Areas of Romania
## 3 Results
### Antimicrobial Activity and MIC  
The PEEs were evaluated for their antimicrobial activity against five Gram-positive pathogens (Table 8), five Gram-negative pathogens, and one yeast pathogen (Table 9). Among Gram-positive bacteria, for _E. faecalis_ ATCC 29212, the inhibition values ranged \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Propolis Extracts**} \\ \cline{2-5}  & **C1** & **C2** & **A** & **S** & **H** \\ \hline
**Phenolic acids** & 259.9 \(\pm\) 41.5 & 151.38 \(\pm\) 29.9 & 515.2 \(\pm\) 72.7 & 482.45 \(\pm\) 88.4 & 663.7 \(\pm\) 157.2 \\
**Flavonoids** & 688.5 \(\pm\) 120.6 & 342.37 \(\pm\) 79.3 & 406.6 \(\pm\) 79.6 & 61.18 \(\pm\) 15.3 & 15.95 \(\pm\) 3.5 \\
**Flavonoids + Phenolic acids** & 948.4 \(\pm\) 92.4 & 493.75 \(\pm\) 59.5 & 921.91 \(\pm\) 72.7 & 546.63 \(\pm\) 72.1 & 679.7 \(\pm\) 135.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total quantity of phenolics and flavonoids obtained by summing their individual quantities. Data are expressed in ug/g as the mean \(\pm\) SD (\(n=3\)). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Antioxidant** & \multicolumn{4}{c}{**Propolis Extracts**} \\ \cline{2-5}
**Assay** & **C1** & **C2** & **A** & **S** & **H** & **PC** \\ \hline FRAP & 5.4 \(\pm\) 0.1  & 4.8 \(\pm\) 0.09  & 7.4 \(\pm\) 0.2  & 5.4 \(\pm\) 0.3  & 6.2 \(\pm\) 0.2  & 58.3 \(\pm\) 1.0  \\ DPPH & 29.8 \(\pm\) 0.8  & 24.9 \(\pm\) 0.5  & 31.6 \(\pm\) 0.3  & 26.4 \(\pm\) 0.6  & 28.8 \(\pm\) 0.5  & 79.6 \(\pm\) 0.4  \\ ABTS & 34.0 \(\pm\) 0.3  & 25.2 \(\pm\) 1.90  & 33.4 \(\pm\) 0.2  & 29.2 \(\pm\) 0.3  & 31.0 \(\pm\) 0.2  & 49.5 \(\pm\) 0.7  \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Antioxidant activity of the propolisis ethanolic extracts. The data (mean \(\pm\) SD; \(n=3\)) are expressed as Trolox Eq./g. Different lowercase letters (a–e) in each row indicate significant differences (\(p<0.05\)). from 5.3 mm (A) to 10.4 mm (C1). The inhibition values for _S. aureus_ ATCC 25923 ranged from 7.3 mm (S) to 12.8 mm (C1), while for methicillin-resistant _S. aureus_ ATCC 43300, the highest inhibition value, 9.4 mm, was obtained from extract C1. Regarding _S. epidermidis_ ATCC, the lowest inhibition value was observed with extract S (6.9 mm), while the highest inhibition halos were produced by extracts A and C1 (8.8 mm and 11 mm, respectively). The lowest inhibition values for _L. monocytogenes_ ATCC 35152 were observed with sample H (6.5 mm). In the case of Gram-negative bacteria, specifically _S. enterica_ ATCC 25928, the lowest recorded inhibition was 3.8 mm (H), while inhibition values of 11.1 and 11.5 mm were observed for samples C2 and A, respectively. For Gram-positives, the inhibition levels observed with the positive control ranged from 15.3 mm (_E. faecalis_) to 20 mm (_S. epidermidis_), with significant differences between the PEEs and the control. The ethanolic extract of propolis from Salaj (S) exhibited the greatest inhibitory effect on _K. pneumoniae_ ATCC 13883, with an inhibition halo of 7.2 mm. With regard to _P. aeruginosa_ ATCC 27853, the most efficacious extracts were A (11.5 mm) and C2 (11.1 mm), whereas the least efficacious was H, which exhibited an inhibition halo of 3.8 mm. In the case of _E. coli_ ATCC 25922, the inhibition values were found to be relatively similar among the extracts, with the exception of samples S (7.1 mm) and C2 (6.1 mm). As for _A. baumannii_ ATCC 19606, the highest inhibition value was 7.9 mm for sample S, while the lowest was recorded for extract H (3.2 mm). The yeast _C. albicans_ ATCC 10231 was most inhibited by extracts C1 (12.5 mm) and A (8.9 mm), while the lowest value recorded was 7.1 mm (S). For Gram-negative pathogens, the inhibition values found with the positive control ranged from 10.0 to 20 mm, while for _C. albicans_, the antibiotic produced an inhibition halo of 28 mm. The MIC results of the five propolis extracts showed a high variability between the strains tested, with differences between Gram-positive and Gram-negative bacteria (Table 10).