No abstract

In this study, we determined the concentration of total phenols, flavonoids, tannins, and proanthocyanidins in the water, diethyl ether, acetone, and ethanol extracts of Agrimonia eupatoria L. We also investigated the antioxidant activity of these extracts using two methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power] and their in vitro antimicrobial (antibacterial and antifungal) activity on some selected species of bacteria and fungi. In addition, the effects of the acetone and water extracts on the inhibition of biofilm formation of Proteus mirabilis and Pseudomonas aeruginosa were investigated using the crystal violet method. The concentration of total phenols was measured according to the Folin-Ciocalteu method and the values obtained ranged from 19.61 mgGA/g to 220.31 mgGA/g. The concentration of flavonoids was examined by the aluminum chloride method and the values obtained ranged from 20.58 mgRU/g to 97.06 mgRU/g. The total tannins concentration was measured by the polyvinylpolypyrrolidone method and the values obtained ranged from 3.06 mgGA/g to 207.27 mgGA/g. The concentration of proanthocyanidins was determined by the butanol-HCl method and the values obtained ranged from 4.15 CChE/g to 103.72 CChE/g. Among the various extracts studied, the acetone extract exhibited good antioxidant activity (97.13%, as determined by the DPPH method). The acetone extract was active in the absorbance value range from 2.2665 to 0.2495 (as determined by the reducing power method). The strongest antimicrobial activity was detected on G bacteria, especially on probiotic species, and the acetone extract demonstrated the highest activity. Biofilm inhibitory concentration required to reduce biofilm coverage by 50% values for acetone extract was 4315 μg/mL for P. mirabilis and 4469.5 μg/mL for P. aeruginosa. The results provide a basis for further research of this plant species.

ABSTRACT. The antibacterial and anti-biofilm activity of ethanolic extract from the rhizome of Zingiber officinale were evaluated. In vitro antibacterial activity was investigated by microdilution method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined. The values were in the range from 0.0024 to > 20 mg/ml. The most sensitive bacteria were Gram-positive bacteria: Staphylococcus aureus and Staphylococcus aureus ATCC 25923. Anti-biofilm activity was tested by crystal violet assay. Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis and Escherichia coli ATCC 25922 were used as the test organisms. Ethanolic extract showed the best result on Proteus mirabilis biofilm where biofilm inhibitory concentration (BIC 50 ) was 19 mg/ml.

No abstract

No abstract

Calluna vulgaris L. Hull (Ericaceae) has been used for treatment of urinary tract infections in traditional medicine. In this study we analyzed in vitro antibacterial activity of the plant extracts on different strains of Escherichia coli, Enterococcus faecalis and Proteus vulgaris, as well as the concentrations of total phenols and flavonoids in the extracts. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The concentrations of total phenols were examined by using Folin-Ciocalteu reagent and ranged between 67.55 to 142.46 mg GAE/g. The concentrations of flavonoids in extracts were determined using spectrophotometric method with aluminum chloride and the values ranged from 42.11 to 63.68 mg RUE/g. The aqueous extract of C. vulgaris showed a significant antibacterial activity. The values of MIC were in the range from 2.5 mg/ml to 20 mg/ml for this extract. Proteus vulgaris strains were found to be the most sensitive. The results obtained suggest that all tested extracts of C. vulgaris inhibit the growth of human pathogens, especially the aqueous extract.

The antioxidant and antimicrobial activities and contents of total phenolics and flavonoids of Ajuga chamaepitys (L.) Schreb. subsp. chamaepitys (Lamiaceae) were investigated. Five different extracts from aboveground flowering plant parts were obtained by extraction with water, methanol, acetone, ethyl acetate and petroleum ether. The total phenolic content was determined spectrophotometrically using the Folin-Ciocalteu reagent and expressed as the gallic acid equivalent (mg GA/g of extract). The highest value was obtained in the ethyl acetate extract (57.02 mg GA/g). The concentration of flavonoids, determined using a spectrophotometric method with aluminum chloride and expressed as the rutin equivalent (mg RU/g of extract), was highest in the ethyl acetate extract (91.76 mg RU/g). The antioxidant activity was determined in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent. The highest antioxidant activity was detected in the acetone extract (SC50 value = 330.52 ?g/mL). In vitro antimicrobial activities were determined using a microdilution method, and the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined. The most effective antimicrobial activity against Bacillus cereus was demonstrated by the acetone extract, with MIC and MMC values of 1.25 mg/mL. Based on the results of this study, A. chamaepitys subsp. chamaepitys could be considered as a valuable source of natural compounds with important biological activities. [Projekat Ministarstva nauke Republike Srbije, br. III 41010 i OI 173032]

No abstract