## 5 Conclusions  
This study provided further insight into the diversity of OPCs present in chokeberries. A number of new substances have been characterized with the groups of cinchonains and hexosides. It was further shown that all cinchonains display B-type linkages between the monomers, and the characterized hexoside displays an A-type linkage. In order to investigate the health-promoting properties with regard to the antioxidant effect of OPCs contained in chokeberries, four subfractions enriched with lead compounds of different DP were selected and investigated with regard to their antioxidant effects. The cell-free TEAC assay showed a correlation between the degree of polymerization of OPCs and their antioxidant capacity. The higher the DP of the OPCs and thus also the number of ortho-positioned phenolic hydroxy groups, the greater the antioxidant effect. In the cell-based test system, however, antioxidant effects were only observed for the subfractions enriched with a trimer and tetramer main compound. In addition, these also showed a concentration dependence over the entire period especially after a short period of peroxide incubation. In the case of SmSCin and SmSPen, which showed no or only minimal effects, it is assumed that they are unstable under the conditions used and/or that no cellular uptake has taken place. Further investigations should therefore be carried out into the stability of the tested main substances and their cellular uptake. These results offer new opportunities to utilize the antioxidant effects of specific OPCs. For example, extracts enriched with trimeric or tetrameric OPCs could possibly be developed for new food supplements in order to utilize the antioxidant effects of this group of substances even more effectively. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14177839/s1](https://www.mdpi.com/article/10.3390/app14177839/s1)]([https://www.mdpi.com/article/10.3390/app14177839/s1](https://www.mdpi.com/article/10.3390/app14177839/s1)), Table S1: LTQ Orbitrap XL mass spectrometer with heated electrospray ionization (HESI) parameters for identification of oligomeric proanthocyanidins (OPCs) and fragmentation experiments for the characterization of OPCs from _Aronia_\(\times\)_prunifolia_ 'Nero' based on the application of LC-HRMS; Figure S1: Exemplarily HPCL-FLD chromatogram of the subfractions from TriF from Sephadex separation by using HILIC conditions. Fluorescence was measured at \(\lambda_{\text{em}}\): 316 nm and \(\lambda_{\text{ex}}\): 276 nm. The twenty-one collected fractions are numbered and marked by the dotted lines; Figure S2: Fragmentation spectrum of a prodelphinid tetramer by application of LC-HRMS. MS\({}^{2}\) spectrum of the [M-H]\({}^{-}\) ion \(m/z\) 1167.2373 is displayed; Figure S3: Fragmentation spectrum of a procyanidin hexamer by the application of LC-HRMS. MS\({}^{2}\) spectrum of the double-charged quasi-molecular ion [M-2H]\({}^{2-}\) ion \(m/z\) 864.1903 is shown; Figure S4: Fragmentation spectrum of a hexoside-procyanidin trimer by the application of LC-HRMS. MS\({}^{2}\) spectrum of the [M-H]\({}^{-}\) ion \(m/z\) 1025.2343 is shown; Figure S5: Fragmentation spectrum of a cinchonain dimer by application of LC-HRMS. MS\({}^{2}\) spectrum of the [M-H]\({}^{-}\) ion \(m/z\) 739.1654 is displayed; Figure S6: Fragmentation spectrum of a cinchonain tetramer by application of LC-HRMS. MS\({}^{2}\) spectrum of the [M-H]\({}^{-}\) ion \(m/z\) 2315.28911 is displayed; Figure S7: Fragmentation spectrum of a cinchonan pentamer by application of LC-HRMS. MS\({}^{2}\) spectrum of the double-charged quasi-molecular ion [M-2H]\({}^{2-}\) ion \(m/z\) 801.1757 is shown; Figure S8: Fragmentation spectrum of a procyanidin trimer by application of LC-HRMS. MS\({}^{2}\) spectrum of the [M-H]\({}^{-}\) ion \(m/z\) 863.1803 is displayed; Figure S9: Fragmentation spectrum of a pyrocaridin trimer by application of LC-HRMS.