Antibacterial Activity of Spruce Bark (Picea abies L.) Extract against Escherichia coli

The increase of antibiotic resistant bacteria in lasts years resulted in limited options for treatment of bacterial diseases. Escherichia coli is one of the most common Gram-negative bacterial pathogen and a cause of both community and hospital acquired infections. Medicinal plants are alternative rich sources of useful antibacterial agents. The antimicrobial activities of the spruce (Picea abies L.) bark polyphenolic extracts were examined for their capacity to inhibit the growth of Escherichia coli. Spruce bark extract was obtained by conventional aqueous extraction and with ultrasounds. The minimum inhibitory concentration was determined by microdilution method. The antibacterial effect of both extracts was strong against Escherichia coli. The antimicrobial effect of polyphenolic extracts on Escherichia coli was expressed at a concentration of 15 mg/ml. Antimicrobial activity of spruce bark compounds suggest a possible use of spruce bark in pharmaceutical preparations.