Polyphenol content and antioxidant activities of Prunus padus L. and Prunus serotina L. leaves: Electrochemical and spectrophotometric approach and their antimicrobial properties

The aim of the study was to compare the content of selected phytochemicals as well as the antioxidant and antimicrobial potential of the leaves of Prunus padus L. and Prunus serotina L., as there is very little research on this subject in the literature. Therefore, it is used to deepen knowledge on this subject. In addition, an electrochemical test was also carried out, which was not yet available for the above plants. Antibacterial studies have also been deepened to include the analysis of new strains of bacteria and fungi, which has not been studied earlier. The water extracts of P. padus using the utra-performance liquid chromatography (UPLC) system showed a higher content of both phenolic acids and flavonols (651.77(b) +/- 18.12 mg/100 g dw for acids and 3.85(b) +/- 0.08 mg/100 g dw for flavonols, respectively). Ferulic and p-coumaric acids were the dominant polyphenols in leaves. Extracts from P. padus showed higher activity against DPPH radical, which was 6.62(b) +/- 0.06 mgTE/1 g dw, as well as higher antioxidant capacity, measured using 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) cation radical (37.39(b) +/- 3.81 mgTE/gdw). The higher antioxidant potential of P. padus was confirmed based on the oxidizing potentials of electroactive compounds present in them. Stronger inhibition against Enterococcus faecium and Klebsiella pneumoniae was found for P. padus, whereas P. serotina extract was more potent against Enterococcus faecium bacterium. It has been shown that P. padus can be an attractive raw material with antioxidant and antimicrobial properties that can be used on a much wider scale in food technology than its current application.