Determination of antimicrobial activity of alcohol extractions of bark and buds of Quercus robur L.

Antimicrobial activity of alcoholic extractions from the aboveground organs like bark and buds of Quercus robur L. was studied. The determination of the minimum inhibitory concentration (MIC) was performed with the use of double serial dilution in broth. The following microorganisms were used as test cultures: Bacillus cereus, Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus. It has been revealed that alcoholic extractions of the bark of Quercus robur have the widest spectrum of antibacterial activity in relation to Pseudomonas aeruginosa, Escherichia coli and Candida albicans. Results of microbiological analysis show that alcoholic extractions from the bark and buds have an antimicrobial effect on all of these strains with a single dilution (except for antimicrobial activity against Staphylococcus aureus with 70% extractions of bark of Quercus robur). In particular, relatively high antimicrobial activity was observed in alcoholic extracts of all buds concentrations against Candida albicans at a dilution of 2, 4 and 8 times and Escherichia coli at a dilution of 4, 8 and 16 times. The greatest antimicrobial effect against Pseudomonas aeruginosa has extracts from the bark and buds in all the studied concentrations of alcohol. A significant antimicrobial effect against Escherichia coli has 40% of extractions from the buds of Quercus robur when diluted by 2, 4, 8, 16, 32 and 64 times. The results can be used as justification for the introduction of a new type of raw material that is buds of Quercus robur, as well as drugs based on it in the State Pharmacopoeia of the Russian Federation as antibacterial phytopharmaceuticals.