## 4 Discussion
The extracts were further purified by column chromatography on Amberlite XAD 1600 N. Stronger anti-staphylococcal activity was observed in the extracts obtained with the use of acetone and the purified extracts. Interestingly, according to the literature data, the ethanol extracts showed a higher antimicrobial potential. [PERSON] [52] not only investigated the antimicrobial properties of _Rosa damascena_ extracts but also tried to determine the effect of the extraction solvent on the antimicrobial properties of the extracts (water, methanol, ethanol, and hexane). Their research showed that the highest anti-staphylococcal properties were obtained in the case of ethanol extracts (growth inhibition zone in the range of 27-30 mm; MIC: 62.5 ug/mL). A similar antimicrobial activity was observed in water (MIC: 62.5-125 ug/mL) and methanol (MIC: 62.5-250 ug/mL) extracts. The weakest antimicrobial property was observed in extracts prepared with the use of hexane. [PERSON] et al. [53] used many popular solvents to prepare _Rosa damascena_ flower extracts (water, hexane, and ethanol and alcoholic extracts were suspended in chloroform, butanol, and ethyl acetate). Then, the bactericidal properties of the extracts against _Streptococcus pyogenes_, _B. subtilis_, and _S. aureus_ were examined. The MIC value for the _S. aureus_ strain ranged from 0.125 to 2.0 mg/mL. Nevertheless, the methanol and acetone extracts of _Rosa damascena_ prepared by [PERSON] et al. [54] also demonstrated anti-staphylococcal properties. The antagonistic activity of the extracts at a concentration of 100 mg/mL resulted in the formation of zones of growth inhibition of _S. aureus_ isolates at the level of 11-18 mm for the methanol extract and 14-18 mm for the acetone extract. There are also reports in the literature examining the antimicrobial potential of roses as a by-product in the food industry. An example of a product that is waste from the production of fruit juices is pomace. The work investigated extracts made of frozen _Rosa rugosa_ Thunb. pseudo-fruit pomace resulting from the production of natural juices. [PERSON] et al. [55] also used an extract from _Rosa rugosa_ Thunb. var. plena Regal (by-product of production of rose tea or dried rose petals; Fragrant Rose Biological Technology Co., LTD in Pingyin) for testing antimicrobial properties. The total content of the compounds in the extract was divided into phenolics (0.31 mg/mL) and flavonoids (0.43 mg/mL). The three main components of the extract are hyperoside, kaempferol-3-O-rutoside, and rutin. _Rosa rugosa_ Thunb. var. plena Regal extract showed antimicrobial properties against _Cutiobacterium acnes_ (called _Propionibacterium acnes_ by [PERSON], et al. [55]) and _S. aureus_ (MIC: 125 ug/mL). For the remaining bacteria (e.g., _Listeria iwanovii_, _Salmonella_ Enteritidis, or _E. coli_) the MIC value of the tested extract exceeded 250 ug/mL. Lactic acid produced as a result of fermentation makes LAB bacteria antagonistic to pathogenic microorganisms that pollute not only food but also other ecological niches [56]. The selection of an appropriate carbohydrate in the medium may increase the acidifying activity. Therefore, the addition of polyphenols from _Rosa rugosa_ Thunb. pseudo-fruit pomace extracts in a concentration below 0.156 mg/mL does not affect the metabolic processes leading to acidification of the environment by the tested LAB bacteria. [PERSON] et al. [57] also proved that lowering the pH of LAB cultures is an obvious consequence of metabolic processes. The pH of _Lactobacillus casei_ (_Lacticasieiucillus casei_) cultures decreased from 5 to 3.4, while in the case of _Lactobacillus plantarum_ (_Lactiplantithacillus plantarum_) and _Lactobacillus delbruecki_ subsp. _delbruecki_, the pH of the environment decreased from 5.8 to 3.6. The tolerance of LAB to low pH levels is therefore a strain feature.