Antibacterial Activities of Spruce Bark (Picea abies L.) Extract and Its Components Against Human Pathogens

Abstract

Spruce is a used material in the wood industry and bark is regarded as a by-product. The aim of this study was to provide information about natural bioactive compounds from spruce (Picea abies L.) bark with potential therapeutic applications such as antibacterial activity against human pathogens. Spruce bark extract was obtained by the conventional aqueous extraction (EAM), and second with ultrasounds (USM). It was determined the total polyphenols by spectrophotometric methods and individual polyphenols by high-performance liquid chromatography (HPLC). For the determination of minimum inhibitory concentration was used microdilution technique. The following strains were tested: Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The yield of extracted polyphenols in the case of spruce bark extract was of 33.8mg gallic acid/gfor EAM and 28.73 mg gallic acid/g for USM. The compounds identified in samples, by HPLC, were vanillic acid and taxifolin.It was found that both extracts have antibacterial capacity for all bacteria tested. The antibacterial effect of both extracts was stronger against Gram positive cocci compared with Gram negative bacilli.Antimicrobial spectra and activities of the fractions and pure isolated compounds from the spruce bark, can be suggested the use of spruce bark in pharmaceutical preparations and as well as a food preservative.