In order to assist developing a natural, safe food-preservative, aqueous ethanolic extracts of leaves and berries of eight Finnish berry plants were fractionated with Sephadex LH-20 column chromatography. For each fraction, phenolic compounds were analyzed with NMR, UPLC-DAD-ESI-MS and HPLC-DAD. The antioxidant activities of the fractions were investigated using oxygen radical absorbance capacity (ORAC) assay, and the antibacterial activities were evaluated against foodborne pathogens Staphylococcus aureus and Escherichia coli. Antioxidant activities of the fractions correlated highly with both the total concentration and structural feature of phenolic compounds, including both flavonoids and non-flavonoid phenolics. ORAC value correlated strongly with the concentration of (+)-catechin, (-)-epicatecin, quercetin glycosides, and anthocyanins. Increase in size and number of sugar moieties may reduce the antioxidative activities of quercetin glycosides. Type of sugar moieties may have a significant role in influencing peroxyl-radicals scavenging ability of quercetin glycosides with monosaccharides as a single sugar moieties. Most of the fractions inhibited the target microbes. S. aureus strains expressed a higher sensitivity to phenolic compounds than E. coli strains.
Keywords: Anti-bacteria; Antioxidant; Berry; Leaf; Phenolic compounds; Sephadex LH-20.
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