## 3 Discussion  
This study determined the concentrations of compounds in the methanol extracts of _S. nigrum_ in the above-ground parts and the roots. In the first study examined, the total flavonoid content determined by [PERSON] et al. (2019) [33] was 16.42 mg QE/g of dry extract, while in our study, we determined total flavonoid content to be 15.73 mg QE/g of dry extract. Regarding the root portion of _S. nigrum_, there are no reliable sources in the scientific literature reporting flavonoid content. Only for plants belonging to the same family, such as wolfberry (_S. xanthocarpum_) (Schrad. And Wendl), the total content of  
Figure 4: ROS levels in NHDF cells incubated in the presence of the tested extracts (at concentrations of 25–500 ug/mL): untreated (**a**) and treated with H\({}_{2}\)O\({}_{2}\) (100 uM, 30 min) (**b**). Control value for (**a**) 79.7 RFU \(\pm\) 5.50; (**b**) 2551.0 RFU \(\pm\) 94.32. Results are presented as RFU (relative fluorescent units) of fluorescence level. Statistical significance of the differences between the results for the tested compounds compared to the control and between the tested extracts (* \(p\) < 0.05). Figure 5: Determination of cellular ROS by DCFDA assay. Representative fluorescence images were taken by an EVOS FL fluorescence microscope, ex. 482 em. 524. Microphotographs show fluorescence of 2′,7′-dichlorohydrofluorescein (DCFH-DA) in NHDF cells. (**a**) control; (**b**) incubation with root extract, (**c**) incubation with extract from aerial parts. 10\(\times\) objective magnification. flavonoids in the root was 15.83 mg QE/g of the dry extract [34]. Moreover, our extracted compounds from _S. nigrum_, both from the ground and the root parts, partially coincide with the composition published by [PERSON] et al. (2013) [35]. This study also identified naringenin, naringenin-7-O-glucoside, kaempfer-3-O-rutinoside-7-O-glucoside, cyanidin-3-O-(6\({}^{\prime\prime}\))-O-\(\alpha\)-rhamnopyranosyl)-\(\beta\)-glucopyranoside, del-finitidin-3-O-(6\({}^{\prime\prime}\)-O-\(\alpha\)-rhamnopyranosyl)-\(\beta\)-glucopyranoside, pelargonide-in-3-O-(6\({}^{\prime\prime}\)-O-\(\alpha\)-rhamnopyranosyl)-\(\beta\)-glucopyranoside or tomatin compared to studies by [PERSON] et al. (2013) [35]. All those compounds may be found in _Solanum_ plants, including _S. nigrum_[35; 36; 37]. Different plant chemotypes can cause these differences, which are well documented in the scientific literature on plant secondary metabolites [34]. Moreover, [PERSON] et al. (2013) [35] do not state whether the roots were also used for extraction in their studies of plants, which may also be the reason for the noted differences. Studies have shown the highest antimicrobial activity of compounds such as iso-quercetin and naringenin and its derivatives: rutin, demysin, solamargine, solanidine, solanine, solasodine, solasodine, solasain and tomatin, the activity of which has been repeatedly mentioned in numerous scientific reports [36; 37; 38; 39; 40; 41; 42]. All these compounds or groups to which they belong can be found in the concise review by [PERSON] et al., (2012) [37] on the therapeutic role of _S. nigrum_, especially in terms of antiviral, antimicrobial, anti-inflammatory and antitumor activity. In addition, some plant protective actions, such as cardioprotective or hepatoprotective, have also been described. A similar but more comprehensive review report by [PERSON] et al. (2011) [36] also draws attention to the mentioned actions. Additionally, it points to the important role of solanine in terms of antitumor activity in _S. nigrum_ extracts. Nevertheless, solanine and its related compounds, with a small amount of protein, are more often associated with toxic effects [39]. Despite its anti-cancer effects, the presence of solanine can cause headaches, colic, skin warming, nausea and some physical symptoms such as weakness or depression. Moreover, by focusing on the antimicrobial activity of _S. nigrum_, [PERSON] et al.