## 3 Result and Discussion
The assessment of the antimicrobial properties of silymarin solutions in DMSO was tested against microorganisms that are common etiological agents of skin infections--Gram-positive _Staphylococcus aureus_ and MRSA, Gram-negative _Escherichia coli_ and _Pseudomonas aeruginosa_, and yeasts of the genus _Candida_. The results are presented as the MIC and MBC/MFC of the compound in mg\(\cdot\)mL\({}^{-1}\) (Table 4). Silymarin is a complex of substances containing flavonoidignans, mainly sillybinin or silydianin. Sillybinin has hepatoprotective and antimicrobial activity, especially against Gram-positive bacteria, because it inhibits the synthesis of their RNA and protein [46]. In our research, however, it was shown that against Gram-positive bacteria _S. aureus_ and MRSA, a silymarin extract with a high content of silydianin and sillychristin (organic raw material) was more effective than a silymarin extract with a predominance of the sum of silyldianin (Tables 2 and 4). At the same time, silymarin did not inhibit the growth of Gram-negative bacteria--_E. coli_ and _P. aeruginosa_, which is consistent with the reports of other researchers [46; 47]. The microorganism most sensitive to its action was the methicillin-resistant strain of _S. aureus_ (MRSA), for which the MIC/MBC was determined at the level of 15.6/31.25 mg\(\cdot\)mL\({}^{-1}\) for the product from the conventional system and 7.8/15.6 mg\(\cdot\)mL\({}^{-1}\) for the organic system. The antibacterial activity of silymarin against MRSA was also tested by [PERSON] et al. [48] and the MIC of silymarin against the antibiotic-resistant strain was 500 mg/L, so it was much higher than in the present study. Such discrepancies may be the result of both different starting concentrations of silymarin and the use of bacteria that are less sensitive to the test compound. Reports in the literature on the antifungal effect of silymarin confirm the effectiveness of the compound against both yeast and mold fungi [49]. [PERSON] and [PERSON] [50] studied the effect of silymarin against _Candida albicans_, _C. glabrata_, _C. parapsilosis_, _C. tropicalis_, and _C. Krusei_, determining the MIC to be in the range from 30 to 300 \(\mu\)g/mL. In our study, silymarin was less active, its MIC value ranged from 20-255 mg\(\cdot\)mL\({}^{-1}\). One yeast species, _Candida glabrata_, was not sensitive to even the highest concentration of the preparation. The results of the present study indicate that the silymarin extract from organic milk thistle crops had a more effective antimicrobial effect than that from the conventional system. This was most clearly seen for _S. aureus_, whose development was inhibited 4 times more strongly by the organic product. The organic extract also turned out to be a more effective biocide against the MRSA strain. Two times higher anti-yeast activity of the organic extract was noticeable for _C. albicans_ and _C. tropicalis_. Differences in the effectiveness of antimicrobial activity may result from the composition of silymarin. Among the raw materials from organic farming, three genotypes represented chemotype B with a predominance of silybinin and silychristin, while in the group of raw materials from conventional farming, all genotypes represented chemotype A with silybinin as the basic component. There are mentions in the literature of silydianin having a different action than silybinin [16]. According to [PERSON] and [PERSON] [51], silydianin is an effective inhibitor of free radicals production and release and this can partly explain the therapeutic use of silydianin as an anti-inflammatory drug. However, this issue requires further research. If the above hypothesis is confirmed, it will be justified to breed and register cultivars with a high content of silydianin in silymarin, adapted to the conditions of a temperate climate.