## 3 Discussion
In our previous study [3], the contents of flavonoids, phenolic acids and anthocyanins tested by RP-HPLC and HPLC methods in the extracts from the cookies with chokeberry were the most impressive among all kinds and equaled (mg\(\cdot\)100 g\({}^{-1}\) dm) (Table S1): neochlorogenic acid (919.28 \(\pm\) 4.85), protocatechuic acid (269.20 \(\pm\) 0.62), chlorogenic acid (1026.18 \(\pm\) 0.94), cinnamic acid (3.32 \(\pm\) 1.85), catechin (21.82 \(\pm\) 1.23); epicatechin (792.48 \(\pm\) 0.53); quercetin (202.66 \(\pm\) 1.71); quercetin-3-galactoside (237.19 \(\pm\) 3.17), rutin (461.74 \(\pm\) 10.92) and cyanidin-3-glucoside (78.05 \(\pm\) 0.36) [3]. The greatest amounts of polyphenols, especially chlorogenic acid, rutin and quercetin-3-galactoside together with one of the strongest antioxidant activities (\(\mu\)mol\(\cdot\)g\({}^{-1}\) dm) (Table S1): ABTS--15.22 \(\pm\) 0.05; FRAP--17.47 \(\pm\) 0.05 might be strongly linked to the low viability (mean 38%) of MCF7 human breast cells which were treated with chokeberry extracts in this study (Table 3). One more possible anticancer mechanism might be the presence of triterpen ester derivatives of ursolic acid in chokeberry fruits, namely, 3-O-trans- and -_cis-p_-coumaroyl tormite which were found to inhibit MCF7 and MDA-MB-231 human breast cancer cell proliferation and mammosphere creation through deregulation of the expression of c-Myc protein, a cancer stem cell survival factor [38]. Similarly, the aqueous acetone extract of elderberry fruits in the LoVo human colon adenocarcinoma cell line and MCF7 human breast cancer had a lower value of IC\({}_{50}\) compared to the ethyl acetate extract, and its major triterpen uracil acid exhibited the highest cytotoxic activity, with IC\({}_{50}\) values of 10.7 and 7.7 \(\mu\)g/mL on MCF-7 and LoVo cells, respectively [39]. The cytotoxic properties of ethanolic extracts from elderflowers, leaves and stems were also documented in human liver cell carcinoma, lung carcinoma and colon cancer cells [9]. The probable explanation was the synergistic actions of (poly)phenolic components, and the molecular docking study indicated that chlorogenic acid and rutin had the ability to interact with important amino acids in the Bcl-2 binding site [39]. Elderly (_Sambucus nigra_ L.) is the most common species in the family _Adoxaceae_ and the genus _Sambucus_ L. [39]. The fruits have a variety of beneficial components, mainly polyphenolic, including phenolic acids (gallic acid and gentisic acid), flavanones, flavonoids and anthocyanins (cyanidin 3-O-sambubioside and cyanidin 3-O-glucoside) together with terpenoid compounds. The major flavonoids were rutin and quercetin [40; 41]. RP-HPLC and HPLC determinations of polyphenolic compounds [3] in the extracts from elderberry cookies were as follows (mg\(\cdot\)100 g\({}^{-1}\) dm) (Table S1): protocatechuic acid (131.23 \(\pm\) 0.72); catechin (14.05 \(\pm\) 0.12); quercetin (156.04 \(\pm\) 0.23) and rutin (1083.20 \(\pm\) 1.40) [3]. No chlorogenic acid was detected in the cookies prepared from elderberry fruits, but rutin content was statistically significantly highest as evidenced by RP-HPLC determinations (Table S1). Other studies indicated that elderberry agglutinin could selectively identify ovarian carcinoma via specific recognition of \(\alpha\)-2,6-linked sialic acids and was capable of activating AKT, launching cytochrome c, provoking mitochondrial dysfunction, increasing the mitochondria oxidative phosphorylation, finally leading to cell cycle arrest at the G2/M phase and the apoptosis of ovarian cancer cells [42]. On the other hand, [PERSON] and [PERSON] [10] proved that elderberry fruit extract and its anthocyanin compound cyanidin 3-O-glucose enhanced the packing order of polar heads of membrane lipids and changed the structure of membranesas well as decreased the fluidity of human breast adenocarcinoma cells membranes [10].