Antimicrobial effects of Finnish plant extracts containing flavonoids and other phenolic compounds

Plant phenolics, especially dietary flavonoids, are currently of growing in terest owing to their supposed functional properties in promoting human hea lth. Antimicrobial screening of 13 phenolic substances and 29 extracts prep ared from Finnish plant materials against selected microbes was conducted i n this study, The tests were carried out using diffusion methods with four to nine microbial species (Aspergillus niger, Bacillus subtilis, Candida al bicans, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Sacch nromyces cerevisiae, Staphyloccus nervous and Staphyloccus epidermidis). Fl avone, quercetin and naringenin were effective in inhibiting the growth of the organisms. The most active plant extracts were purple loosestrife (Lyth rum salicaria L.) against Candida albicans, meadowsweet (Filipendula ulmari a (L,) Maxim.), willow herb (Epilobium angustifolium L.), cloudberry (Rubus chamaemorus L.) and raspberry (Rubus idaeus L.) against bacteria, and whit e birch (Betula pubescens Ehrh.), pine (Pinus sylvestris L.) and potato (So lanum tuberosum. L.) against gram-positive Staphylococcus aureus. (C) 2000 Elsevier Science B.V. All rights reserved.