Štefánia Vaverková

Composition of the Oil from the Flowerheads of Anthemis tinctoria L. Cultivated in Slovak Republic

Abstract The chemical composition of the essential oil obtained from the flowerheads of Anthemis tinctoria L(Asteraceae) was analyzed by capillary GC/MS. 86 components of the oil were separated, 48 of which were identified. The major constituents were 1,8-cineole (7.9%), β-pinene (7,3%), decanoic acid (5.4%) and α-pinene (4.4%).

In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC) indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis.

Composition of the essential oil from Melissa officinalis L. cultivated in Slovak Republic

Abstract The leaf oil obtained by hydrodistillation from Melissa officinalis L. c. v. citra cultivated at Nitra locality (Slovak Republic) was analyzed by GC and GC/MS. M. officinalis oil was found to contain geranial (33.60%), neral (22.18%), citronellal (11.30%), caryophyllene oxide (8.35%), geranyl acetate (5.89%), and β-caryophyllene (4.20%) as the major components. More than 50 components were identified in the oil.

The inhibition the Tet(K) efflux pump of tetracycline resistant Staphylococcus epidermidis by essential oils from three Salvia species

The inhibition of efflux pumps is an attractive and powerful response to the emergence of bacteria resistant to antibiotics. Essential oils (EOs) from Salvia fruticosa, Salvia officinalis and Salvia sclarea reduce the minimal inhibition concentration of tetracycline, decrease efflux of antibiotic and decrease the expression of tet(K) gene in tetracycline resistant clinical isolates of Staphylococcus epidermidis. In all the cases S. fruticosa was the best one. By using checkerboard and time‐killing methods, we found synergistic interactions of EOs with tetracycline.

Morphology and anatomy of Echinacea purpurea, E. angustifolia, E. pallida and Parthenium integrifolium

The Echinacea species are native to the Atlantic drainage area of the United States of America and Canada. They have been introduced as cultivated medicinal plants in Europe. Echinacea purpurea, E. angustifolia and E. pallida are the species most often used medicinally due to their immune-stimulating properties. This review is focused on morphological and anatomical characteristics of E. purpurea, E. angustifolia, E. pallida, because various species are often misidentified and specimens are often confused in the medicinal plant market.

Synergism between antibiotics and plant extracts or essential oils with efflux pump inhibitory activity in coping with multidrug-resistant staphylococci

The alarming growth of the number of antibiotic resistant bacteria and in the same time limited possibilities to develop new antimicrobial compounds, lead to an urgent need to keep the sensitivity of bacteria against currently used antibiotics. Bacterial efflux pumps are an important mechanism of antibiotic resistance as the bacteria use efflux pumps for the extrusion of different types of antibiotics and chemicals. The knowledge about inhibitors of efflux pumps from natural sources suggests that this mechanism may be a good target for new drugs based on synergistic interactions of antibiotics with plant extracts, essential oils, or their constituents with efflux pump inhibitory activity. This review summarizes the current knowledge of staphylococcal efflux pumps and potential strategies to overcome them. Natural inhibitors of efflux pumps and their synergistic interactions with antibiotics are summarized.

Gas chromatographic method for determination of uracil herbicides in roots of Echinacea angustifolia Moench (Asteraceae).

A GC/NPD method and a rapid screening TLC method were developed for the simultaneous determination of uracil herbicide residues (bromacil, lenacil, terbacil) in the roots of Echinacea angustifolia Moench (Asteraceae). The uracil herbicide residues were extracted into acetone. After evaporation of acetone from the acetone-water extract the residue was dissolved in water-methanol (5:1 v/v). Cyclohexane was used for removal of the non-polar co-extractives in the sample matrix. After separation of the cyclohexane phase the uracil herbicide residues were extracted into chloroform. This extract was purified on a Florisil column, and residues were eluted with dichloromethane-acetone (9:1, v/v). The cleaned up extract was analysed by the GC/NPD method on a capillary column DB-1 using atrazine as internal standard. A minimum recovery of 70% was attained for contamination levels of 0.02-0.40 mg kg(-1).

Content and composition of the oil from Melissa officinalis L. after application of Ridomil 72 WP.

Abstract The essential oil obtained by hydrodistillation from dried leaves of Melissa officinalis L. cultivated at Nitra in Slovak Republic, was analyzed by GC/MS. Comparisons were made between the yield and composition of the oil distilled from plants at different ontogenetic stages, and between untreated control plants and those treated with Ridomil 72 WP.

Modulation of mecA Gene Expression by Essential Oil from Salvia sclarea and Synergism with Oxacillin in Methicillin Resistant Staphylococcus epidermidis Carrying Different Types of Staphylococcal Chromosomal Cassette mec

The essential oil (EO) from Salvia sclarea was shown to increase the susceptibility of methicillin resistant Staphylococcus epidermidis (MRSE) isolates to oxacillin. The purpose of this study was to investigate the effect of EO from S. sclarea on expression of mecA gene of MRSE carrying different types of staphylococcal chromosomal cassette (SCCmec) and to evaluate potential synergistic effect of EO with oxacillin. Using real-time PCR we found that EO alone inhibited the expression of the resistant genes mecA, mecR1, and mecI and blaZ, blaR1, and blaI. The use of the combination of EO with oxacillin resulted in significantly inhibited expression of mecA gene in all tested strains with different types of SCCmec. Using time-kill assay and checkerboard assay we confirmed synergistic effect of EO from S. sclarea and oxacillin in MRSE.