Antimicrobial activity of Satureja L. essential oils against phytopathogenic bacteria Erwinia amylovora

In this paper, antimicrobial activity of S. kitaibelii Wierzb. ex Heuff., S. montana ssp. montana L., S. adamovicii Šilić and S. fukarekii Šilić has been investigated. During the testing, two methods were used: disc-diffusion and broth micro-dilution. The results showed high sensitivity of this bacteria to all four essential oils. The essential oil of S. montana ssp. montana exhibited the largest inhibition zone (25 mm), while S. adamovicii showed the highest inhibitory and bactericidal activity (MIC=MBC=0.09 μlml-1). All investigated oils showed the same values for MIC and MBC, which means that the oils posses bactericidal effect at very low concentrations and they could be used as non-harmful source of bactericides

Antimicrobial and antioxidant potential of wild growing Silene baccifera (L.) Roth. (Caryophyllaceae) fruits juice

Silene baccifera is widespread plant species in Europe, Asia and North Africa, registered in the list of medicinal plants of India. Insufficiently known, biological activities of juice obtained from fresh fruits of this plant were investigated in this study. Antimicrobial activity of juice was tested against pathogenic gastrointestinal microbial strains, using microwell-dilution method, while antioxidant properties were evaluated employing DPPH and total phenolic and flavonoid content assays. To our knowledge, this is the first study of the juice from fruits of this plant species

Commercial Carlinae radix herbal drug: Botanical identity, chemical composition and antimicrobial properties

Context: Carlinae radix is an herbal drug, commonly used by the locals in southeastern Serbia for the treatment of respiratory and urogenital diseases and, externally, for various skin conditions. There still seems to be no detailed studies correlating the chemical composition of this drug and its ethnopharmacological uses. Objective: Chemical composition, antimicrobial activity and mode of action of C. radix essential oil, isolated from commercial samples (confirmation of whose true biological identity was also the aim of this work) were analyzed. Antimicrobial potential of decoctions (extracts prepared by boiling plant material in a given solvent), used in ethnomedicine preferentially to the pure essential oil, was also investigated. Materials and methods: The essential oil obtained by hydrodistillation was screened for antimicrobial activity by disc diffusion and broth microdilution methods. Effects of the oil on the growth of Staphylococcus aureus cells were investigated using turbidimetric measurements and visualized using scanning electron microscopy. Analyses of the chemical composition of the oils were done using gas chromatography and gas chromatography/mass spectrometry. Results and discussion: Both the essential oil and the decocts exhibited a very high antimicrobial activity against all tested strains, with S. aureus as the most sensitive one [e.g., for the oil sample the values for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were 0.02, 0.04 L/mL, respectively]. Growth curves of S. aureus demonstrated a significant decrease in turbidity (for the MIC concentration this amounted to ca. 70%) showing a concentration-dependent lysis of the cells, confirmed by scanning electron microscopy. Chemical composition, anatomical and morphological features of the sample pointed to Carlina acanthifolia L. (Asteraceae) instead of Carlina acaulis L. (Asteraceae). Conclusion: The results showed significant antimicrobial effect of the essential oil and the decoctions and support the use of this plant in ethnomedicine for the treatment of various human infections, especially those caused by S. aureus. Adulteration of the drug would not cause significant differences in its biological activity, since chemical composition of the sample showed high similarity with those containing C. acaulis roots. © 2012 Informa Healthcare USA, Inc

Antibacterial activity chemical composition relationship of the essential oils from cultivated plants from Serbia

The antibacterial effects of essential oils from Serbian cultivated plants, Thymus vulgaris L. (Lamiace) and Lavandula angustifolia L. (Lamiace) on different bacteria were investigated, with an emphasis on an antibacterial activity-chemical composition relationship. Essential oil was obtained from airdried aerial parts of the plants by hydrodistillation for 3 h using a Clevenger-type apparatus. The essential oil analyses were performed simultaneously by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) systems. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalyl acetate (38.23%) and linalool (35.01%) were main compounds in lavender oil. The antibacterial activity of the essential oils samples was tested towards 5 different bacteria: laboratory control strain obtained from the American Type Culture Collection and clinical isolates from different pathogenic media. Gram-negative bacteria were represented by Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 43895 and Salmonella enteretidis ATCC 9027 while researched Gram-positive strains were Bacillus cereus ATCC 8739 and Staphylococcus aureus ATCC 25923. A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Essential oils from thyme have been found to have antimicrobial activity against all microorganisms tested, with a range of MIC values from 0.025 to 0.10 μl/ml and MBC values from 0.05 to 0.78 μl/ml. Lavender oils demonstrated MIC values from 0.025 to 0.20 μl/ml and MBC values from 0.05 and 0.78 μl/ml. Reference antibiotic tetracycline was active in concentrations between 0.025 and 0.05 μl/ml. The Gram- -positive bacteria were more sensitive to the essential oil of thyme, while Gram- -negative bacteria were more sensitive to the essential oil of lavender. Essential oils from thyme and lavender may be used at low concentrations for prevention and treatment of infective diseases in animals and humans caused by pathogenic bacterial species