Berry phenolics: Antimicrobial properties and mechanisms of action against severe human pathogens

Liisa Nohynek, Hanna-Leena Alakomi, Marja Kähkönen, Marina Heinonen, Ilkka Helander, Kirsi-Marja Oksman-Caldentey, Riitta Puupponen-Pimiä

Research output: Contribution to journalArticleScientificpeer-review

279 Citations (Scopus)

Abstract

Abstract: Antimicrobial activity and mechanisms of phenolic extracts of 12 Nordic berries were studied against selected human pathogenic microbes. The most sensitive bacteria on berry phenolics were Helicobacter pylori and Bacillus cereus. Campylobacter jejuni and Candida albicans were inhibited only with phenolic extracts of cloudberry, raspberry, and strawberry, which all were rich in ellagitannins. Cloudberry extract gave strong microbicidic effects on the basis of plate count with all studied strains. However, fluorescence staining of liquid cultures of virulent Salmonella showed viable cells not detectable by plate count adhering to cloudberry extract, whereas Staphylococcus aureus cells adhered to berry extracts were dead on the basis of their fluorescence and plate count. Phenolic extracts of cloudberry and raspberry disintegrated the outer membrane of examined Salmonella strains as indicated by 1-N-phenylnaphthylamine (NPN) uptake increase and analysis of liberation of [14C]galactose- lipopolysaccharide. Gallic acid effectively permeabilized the tested Salmonella strains, and significant increase in the NPN uptake was recorded. The stability of berry phenolics and their antimicrobial activity in berries stored frozen for a year were examined using Escherichia coli and nonvirulent Salmonella enterica sv. Typhimurium. The amount of phenolic compounds decreased in all berries, but their antimicrobial activity was not influenced accordingly. Cloudberry, in particular, showed constantly strong antimicrobial activity during the storage.
Original languageEnglish
Pages (from-to)18-32
Number of pages15
JournalNutrition and Cancer
Volume54
Issue number1
DOIs
Publication statusPublished - 2006
MoE publication typeA1 Journal article-refereed

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