Phenolic Profile, Mineral Content and Antibacterial Activity of the Methanol Extract of Vaccinium myrtillus L.

Abstract

Bilberry is considered as one of the most economically important wild berries. However, bilberry is not enough investigated, and there are only a few published works. Therefore, we performed in one place complete qualitative analysis, antimicrobial activity against different Gram-positive and Gram-negative bacteria and contents of metals. In our research, it was found that bilberry contains different active phenolic compounds, such as chlorogenic acid, delphinidin glycoside, delphinidin arabinoside, cyanidin glycoside, cyanidin arabinoside, malvidin glycoside, peonidin glycoside, and malvidin arabinoside. The content of metals was different in leaves and fruits. In our samples, the content of aluminum, boron, barium, calcium, cadmium, chromium, copper, iron, manganese, nickel, phosphorus, silicon and zinc was higher, and contents of potassium, magnesium, and sodium were lower than in bilberry samples investigated in Latvia. Antimicrobial activity of investigated extracts was evaluated against laboratory control strains from ATCC collection, Gram (+) bacteria: Staphylococcus epidermidis ATCC 12228, Staphylococcus aureus ATCC 6538, Streptococcus pyogenes ATCC 19615, Enterococcus faecalis ATCC 19433, Propionibacterium acnae ATCC 11827, and Gram (-) bacteria: Escherichia coli ATCC 9863, Pseudomonas aeruginosa ATCC 9027, Acinetobacter boumanii ATCC 196060, Proteus mirabilis ATCC 12453, Klebsiella pneumonia ATCC 10031, and against related strains isolated from human wound swabs. V. myrtillus extract was less potent against strains from wounds compared to ATCC strains as well Gram (-) bacteria compared to Gram (+) bacteria. The most sensitive strains were St. epidermidis, St. pyogenes, P. mirabilis and S. aureus.