## 4 Conclusions  
The valorization of phenolic compounds from black chokeberry pomace using ultrasound-assisted extraction in two solvents was employed. The highest concentration of phenolic compounds was obtained in the ethanolic extract under ultrasound exposure for 10 min at a 30% amplitude. Compared with conventional extraction, ultrasound treatment shows higher potential for the valorization of black chokeberry pomace. The chromatographic characterization revealed that black chokeberry pomace is a rich source of non-anthocyanin polyphenolic compounds with outstanding health properties, such as antimicrobial potential against _Staphylococcus aureus_ and _Escherichia coli_. These properties make black chokeberry pomace a promising candidate for the development of new ingredients with health benefits in a sustainable manner. The novelty of this study lies in combining the experimental approach with the in silico approach to ensure a better understanding of the mechanisms involved in the antibacterial activity exerted by the main phenolic compounds from the BC extract. The results of the molecular docking tests suggested that chlorogenic acid and rutin binding might interfere with the ATPase activity of _Escherichia coli_ gyrase, potentially inhibiting the DNA supercoiling activity and therefore affecting the preservation of the bacterial chromosomes in an appropriate state. All investigated ligands, namely quercetin, catechchin, chlorogenic acid and rutin, were found to interfere with the activity of tyrosyl-tRNA synthetase from _Staphylococcus aureus_ and therefore to potentially affect cell growth. Moreover, the studied phytochemicals appeared to preferentially bind to DNA gyrase clefts located in direct contact with nucleic acids, therefore preventing the enzyme from catalyzing the specific DNA topology changes that are crucial for _Staphylococcus aureus_' survival. These findings, coupled with those of the in vitro studies, might be of particular importance in drug discovery, contributing to the knowledge-based design and development of active compounds that are suitable for alternative therapeutic strategies to address drug resistance. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15137070/s1](https://www.mdpi.com/article/10.3390/app15137070/s1)]([https://www.mdpi.com/article/10.3390/app15137070/s1](https://www.mdpi.com/article/10.3390/app15137070/s1)), Figure S1: The antimicrobial activity of black chokeberry extract against _Staphylococcus aureus_ (_S. a_) and _Escherichia coli_ (_E.c_). The test was made in duplicate with two different concentrations (2 mg/mL--**AV** and 1 mg/mL--**AN**). The arrow shows the bacteria inhibition zones,; Figure S2: The colors developed in the 96-well microplate inoculated with _Staphylococcus aureus_ (_S. a_) and _Escherichia coli_ (_E.c_) together with different concentrations of black chokeberry extract (lane 1--1 mg/mL to lane 10--1.95 \(\mathrm{\SIUnitSymbolMicro m}\)/mL), after 24 h of incubation at 37 \({}^{\circ}\)C.  
**Author Contributions:** Conceptualization, L.D. and I.A. ; methodology, L.D., C.L.C., L.G.-G. and I.A. ; software, L.D. and I.A. ; validation, L.D., C.L.C., I.A. and L.G.-G.; formal analysis, L.D., C.L.C., L.G.-G. and I.A. ; investigation, L.D., C.L.C., L.G.-G. and I.A. ; resources, I.A. ; data curation, L.D. and I.A. ; writing--original draft preparation, L.D., C.L.C., L.G.-G. and I.A. ; writing--review and editing, L.D. and I.A. ; supervision, L.D. and I.A. ; project administration, I.A. ; funding acquisition, I.A. All authors have read and agreed to the published version of the manuscript. **Funding:** This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS/CCCDI-UEFISCDI, project number ERANET-M-3-SMARTGEL, within PNCDI IV. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.