## 4 Discussion  
Our investigation focused on the antibacterial effects of _T. vulgare_ extracts against bovine mastitis-causing bacteria in vitro. The results of our study showed that 70% acetone and 70% ethanol extracts had the broadest range and the best effects against tested bacteria. Flower and leaf extracts were effective against _S. aureus_ and _S. agalactiae_. The flower extracts of _T. vulgare_ were effective against all _E. coli_ strains tested. On the contrary, the leaf extracts of _T. vulgare_ showed an effect against _S. aureus_ and _Serratia liquefaciens_ but no effect against _E. coli_. However, to have adequate antibacterial effects in all cases, the concentrations of extracts had to be high. Several factors could affect the antibacterial effectiveness of extracts, such as the type of solvent, concentration, extraction process, and plant material [35]. Differing results for different extracts shown by [PERSON] et al. support the idea that the solvent polarity  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \begin{tabular}{c} **Bacteria** \\ **Sample** \\ \end{tabular}  & \multicolumn{2}{c}{_T. vulgare_ **Flower Extract, mg/mL**} & \multicolumn{2}{c}{_T. vulgare_ **Leaf Extract, mg/mL**} \\  & & **MIC** & **MBC** & **MIC** & **MBC** \\ \hline \multirow{3}{*}{_E coli_} & _ATCC_ 25922 & 53.9 & 53.9 & - & - \\  & _V25_ & 53.9 & 107.8 & - & - \\  & _V4_ & 53.9 & 107.8 & - & - \\ \hline \multirow{3}{*}{_S. aureus_} & _ATCC_ 25923 & 3.4 & 6.8 & 7.8 & 15.7 \\  & _V256_ & 3.4 & 3.4 & 15.7 & 125.9 \\ \hline _S. agalactiae_ & _V171_ & 53.9 & 53.9 & 31.4 & 62.9 \\ _S. tuberis_ & _V243_ & - & - & 62.9 & 125.9 \\ \hline _Serratia_ & _V251_ & - & - & 125.9 & 125.9 \\ \hline \multicolumn{3}{l}{_Tilgatracies_} & \multicolumn{2}{c}{_Tilgatracies_} & \multicolumn{2}{c}{_Tilgatracies_} \\ \hline \hline \multicolumn{3}{l}{MIC–Minimal Inhibitory Concentration, MBC—Minimal Bactericidal Concentration. Bacterial cultures: _Escherichia coli_ (ID. V-2019-4), _E. coli_ (ID. V-2019-252), _E. coli_ (ATCC 25922), _Streptococcus__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s__s____s__s__s__s__s____s____s__s____s__s____s____s____s____s__s____s____s__s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s____s______s____s______s__  
and the _T. vulgare_ part used could affect the amounts and effects of the extracted phenolic compounds [19]. Ethanol extracts (70%, ratio of 1:10) of _T. vulgare_ flowers grown in Transylvania showed low antibacterial effects against _S. aureus_ (10 mm inhibition zone diameter), but unlike our extracts, theirs did not show any effect against _E. coli_. These extracts had 46.8-50.1 mg GAE/g of TPC, less than our _T. vulgare_ flower ethanol extract [24]. An analysis of aerial parts of _T. vulgare_ methanol extracts reported effects against _S. aureus_, but no effect against Gram-negative bacteria--namely _E. coli_[24]. Similar results were obtained in a study from Transylvania [36]. Diverse antimicrobial activity of _T. vulgare_ parts (herb, leaf, flower, and essential oil) was noted by [PERSON] et al. [37], and here, overall methanolic extracts showed better antibacterial effects against Gram-positive bacteria (_S. aureus_, _Bacillus cereus_, and _Microoccus flavus_). Flower methanolic extracts inhibited Gram-negative bacteria such as _E. coli_ and _Enterobacter cloacae_ better than leaf extracts. These findings correspond to our results, where _T. vulgare_ flowers had antibacterial effects against _E. coli_ strains, but leaf extracts did not. Previously reported characteristics of components of _T. vulgare_ extracts showed that changing extraction solvent type and its concentration led to different extracted compositions. Additionally, _T. vulgare_ flower extracts had distinctively different main peaks in FTIR spectra from those of _T. vulgare_ leaf extracts, meaning that the chemical composition of both extracts differs [34]. Leaves and flowers of different _T.