Advanced Research Journal of Microbiology Vol. 1 (4), pp. 067-073, December, 2013.© Advanced Scholars Journals

Full Length Research Paper

Antibacterial and antioxidant activities of bilberry (Vaccinium myrtillus L.) in vitro

Dragana M. Vučić¹*, Miroslav R. Petković¹, Branka B. Rodić-Grabovac², Olgica D. Stefanović³, Sava M. Vasić³ and Ljiljana R. Čomić³

¹Department of Microbiology, Medical Faculty, University of Banja Luka, Save Mrkalja 14,78000 Banja Luka,Bosnia and Herzegovina Republic of Srpska.

²Department of Organic Chemistry, Faculty of Technology, University of Banja Luka,Bulevar Stepe Stepanovića 73, 78000 Banja Luka, Bosnia and Herzegovina Republic of Srpska.

³Department of Biology and Ecology,Faculty of Science, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Republic of Serbia.

*Corresponding author. E-mail: [email protected].  Tel:+ 387 51 437 245.

Accepted 21 November, 2013

Abstract 

Antibacterial and antioxidant activity, total phenolic and flavonoid concentrations of water, ethanol and ethyl acetate extract of fruits and leaves of Vaccinium myrtillus L. were studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined. Testing was performed on 30 clinical isolates, including strains of Escherichia coli, Enterococcus faecalis and Proteus vulgaris. The values for MIC were in the range from 5 to 40 mg/ml. The most sensitive bacterial strain was Enterococcus faecalis MF-Ef8 strain. The ethanol extract of fruits of V. myrtillus was found the most active. The total phenolic content was determined using Folin-Ciocalteu reagent and ranged between 31.44 to 119.17 mg GAE/g. The concentration of flavonoids in extracts was determined and the highest amount was in ethyl acetate extract of leaves of V. myrtillus. Antioxidant activity was monitored spectrophotometrically using 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent. The highest capacity to neutralize DPPH radicals (94%RSA) was found in the ethanol extract from fruits and in the water extract from leaves of V. myrtillus. The results of the total phenolic content determination of the examined extracts indicate that bilberry extracts are a rich source of phenolic compounds and also possess a significant antioxidant activity and moderate antibacterial activity.

Key words: Plant extracts, phenols, flavonoids, Escherichia coli, Enterococcus faecalis, Proteus vulgaris.