Tatjana Mihajilov-Krstev

Chemical composition and antimicrobial activity of Satureja hortensis L. essential oil

Essential oil of Satureja hortensis L. was analyzed by GC and GC/MS and tested by a broth micro-well dilution method for activity against multiresistant clinical isolates of pathogenic bacteria from 10 different genera: Klebsiella, Escherichia, Proteus, Staphylococcus, Streptococcus, Pseudomonas, Enterococcus, Enterobacter, Citrobacter and Acinetobacter. The main compounds in the oil were carvacrol (67%), γ-terpinene (15.3%) and p-cymene (6.73%). The oil showed activity against all tested strains. MIC/MBC values were in the range of 0.78-25 μl/ml, with the exception of the strain P. aeruginosa. Microbicidal concentration for this particular strain (50 μl/ml) was the highest tested concentration. The oil showed inhibitory and bactericidal effect at the same concentration (MIC=MBC) for all but three strains.

Chitosan-PLGA polymer blends as coatings for hydroxyapatite nanoparticles and their effect on antimicrobial properties, osteoconductivity and regeneration of osseous tissues.

Composite biomaterials comprising nanostructured hydroxyapatite (HAp) have an enormous potential for natural bone tissue reparation, filling and augmentation. Chitosan (Ch) as a naturally derived polymer has many physicochemical and biological properties that make it an attractive material for use in bone tissue engineering. On the other hand, poly-D,L-lactide-co-glycolide (PLGA) is a synthetic polymer with a long history of use in sustained drug delivery and tissue engineering. However, while chitosan can disrupt the cell membrane integrity and may induce blood thrombosis, PLGA releases acidic byproducts that may cause tissue inflammation and interfere with the healing process. One of the strategies to improve the biocompatibility of Ch and PLGA is to combine them with compounds that exhibit complementary properties. In this study we present the synthesis and characterization, as well as in vitro and in vivo analyses of a nanoparticulate form of HAp coated with two different polymeric systems: (a) Ch and (b) a Ch-PLGA polymer blend. Solvent/non-solvent precipitation and freeze-drying were used for synthesis and processing, respectively, whereas thermogravimetry coupled with mass spectrometry was used for phase identification purposes in the coating process. HAp/Ch composite particles exhibited the highest antimicrobial activity against all four microbial strains tested in this work, but after the reconstruction of the bone defect they also caused inflammatory reactions in the newly formed tissue where the defect had lain. Coating HAp with a polymeric blend composed of Ch and PLGA led to a decrease in the reactivity and antimicrobial activity of the composite particles, but also to an increase in the quality of the newly formed bone tissue in the reconstructed defect area.

Investigation of the chemical composition–antibacterial activity relationship of essential oils by chemometric methods

The antibacterial effects of Thymus vulgaris (Lamiaceae), Lavandula angustifolia (Lamiaceae), and Calamintha nepeta (Lamiaceae) Savi subsp. nepeta var. subisodonda (Borb.) Hayek essential oils on five different bacteria were estimated. Laboratory control strain and clinical isolates from different pathogenic media were researched by broth microdilution method, with an emphasis on a chemical composition–antibacterial activity relationship. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalool acetate (38.23%) and β-linalool (35.01%) were main compounds in lavender oil. C. nepeta essential oil was characterized by a high percentage of piperitone oxide (59.07%) and limonene (9.05%). Essential oils have been found to have antimicrobial activity against all tested microorganisms. Classification and comparison of essential oils on the basis of their chemical composition and antibacterial activity were made by utilization of appropriate chemometric methods. The chemical principal component analysis (PCA) and hierachical cluster analysis (HCA) separated essential oils into two groups and two sub-groups. Thyme essential oil forms separate chemical HCA group and exhibits highest antibacterial activity, similar to tetracycline. Essential oils of lavender and C. nepeta in the same chemical HCA group were classified in different groups, within antibacterial PCA and HCA analyses. Lavender oil exhibits higher antibacterial ability in comparison with C. nepeta essential oil, probably based on the concept of synergistic activity of essential oil components.

Antimicrobial Activity of Satureja Hortensis L. Essential Oil Against Pathogenic Microbial Strains

ABSTRACT A hydrodistilled oil of Satureja hortensis L. was investigated for its antimicrobial activity against a panel of 11 bacterial and three fungal strains. The antimicrobial activity was determined using disk-diffusion method and broth microdilution method. Essential oil of S. hortensis L. showed significant activity against wide spectrum of Gram (-) bacteria (MIC/MBC=0.025–0.78/0.05–0.78 μl/ml) and Gram (+) bacteria (MIC/MBC=0.05–0.39/0.05–0.78 μl/ml), as well as against fungal strains (MIC/MBC=0.20/0.78 μl/ml). Therefore, the present results indicate that this oil can be used in food conservation, treatment of different deseases of humans, and also for the treatment of the plants infected by phytopathogens.

Chemical profile and antioxidative and antimicrobial activity of juices and extracts of 4 black currants varieties (Ribes nigrum L.).

UNLABELLED The aim of this article was to determine the chemical composition (anthocyanin and ascorbic acid contents, total phenols, and tannins), and the antioxidative, and antimicrobial activities of the juices and methanol extracts of 4 varieties-Tenah, Triton, Ben Sarek, and Ometa. The juices were made during 2008, 2009, and 2010 from the berries grown on the same location. Statistically significant differences were found in all the tested parameters of each variety for every year. Ometa variety exhibited the best antioxidative activity. The highest ascorbic acid value had Tenah juice from 2010 (211 mg/100 g) and Ben Sarek methanol extract (656 mg/100 g). Delphinidin-3-ruthenoside was the dominant anthocyanin in Triton, Tenah, and Ben Sarek variety during all 3 y and Ometa in 2010 where Ometa in 2008 and 2009 had slightly higher content of cyanidin-3-ruthenoside. The minimum inhibitory and microbicidal concentrations ranged from MIC/MBC(MFC) = 62.5 to 500 mg/mL for juices and 0.4 to 500 mg/mL for extracts. There was no significant difference in the effect of the juices against Gram(+) and Gram(-) bacteria. All the extracts acted in lower concentrations than juices. PRACTICAL APPLICATION Data contained in this article provide an insight into the effects the weather condition has on the content of the bioactive compounds in genetically different types of black currants, during the 3-y observation period. This article is relevant to the commercial application of black currants-based dietary supplements.

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 µL/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.

Chemical composition, antimicrobial, antioxidative and anticholinesterase activity of Satureja Montana L. ssp montana essential oil

The present study investigates the chemical compositions of three Satureja montana L. ssp montana essential oils and correlates chemical variability with biological activities. GC/MS analysis showed that with an increase in altitude (100–500–800 m), a higher content of linalool, terpinen-4-ol and cis-sabinene hydrate was found, while the percentage of phenolic compounds, thymol and carvacrol decreased. Antimicrobial activity of the essential oils was tested against 7 fungal and 23 bacterial strains. The essential oil characterized by the highest content of phenols and alcohols exhibited the highest antimicrobial potential. The correlation analysis showed that the major carriers of the obtained antioxidant activity are oxygenated monoterpenes. All essential oils inhibited human serum cholinesterase activity. High antimicrobial potential, together with moderate antioxidant capacity and strong inhibition of human serum cholinesterase, classifies S. montana essential oil as a natural source of compounds that can be used in the treatment of foodborne and neurological diseases, wound and other infections, as well as for general health improvement.

Screening of antioxidant, antimicrobial and antiradical activities of twelve selected Serbian wild mushrooms

This study was undertaken to evaluate and compare the antioxidant, antimicrobial and antiradical activities of twelve wild edible mushrooms from Serbia. The antioxidant activity was evaluated by five different methods: DPPH, ABTS, total reducing power (TRP), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC). Folin–Ciocalteu total phenolic compounds (TPC) were also determined. The present study shows that the ethanol extract of Boletus regius has the highest antioxidant values (10.997 ± 0.891 mg mL−1 in DPPH; 0.771 ± 0.004 mg AAE per mg dw in TRP; 56.924 ± 0.022 mmol Fe per mg dw in FRAP; 21.738 ± 0.108 mg TE per mg dw in CUPRAC; 173.125 ± 0.475 mg GAE per mg dw in TPC). This is the first report on the evaluation of the antioxidant activity of ethanol extracts of mushrooms by the CUPRAC method. The in vitro antimicrobial activity was investigated by the microdilution method. This is the first report on the antimicrobial activity for many analyzed mushroom species. The highest antiradical activity unit (EAU515) was from Polyporus squamosus (6.349 EAU515). We determined the antioxidant capacity and the antioxidant potency composite index (ACI) was calculated. Agglomerative hierarchical clustering (AHC) was applied to investigate the similarities between the used methods for antioxidant activities. PCA was used for determining the number of variables to explain the observed variances in the antioxidant activity data of the examined wild mushroom species.

Total phenolic content, flavonoid concentration, antioxidant and antimicrobial activity of methanol extracts from three Seseli L. taxa

The present study describes the total phenolic content, concentrations of flavonoids and in vitro antioxidant and antimicrobial activity of methanol extracts from Seseli pallasii Besser, S. libanotis (L.) Koch ssp. libanotis and S. libanotis (L.) Koch ssp. intermedium (Rupr.) P. W. Ball, growing wild in Serbia. The total phenolic content in the extracts was determined using Folin-Ciocalteu reagent and their amounts ranged between 84.04 to 87.52 mg GA (gallic acid)/g. The concentrations of flavonoids in the extracts varied from 4.75 to 19.37 mg Qu (quercetin)/g. Antioxidant activity was analyzed using DPPH reagent. Antioxidant activity ranged from 0.46 to 4.63 IC50 (mg/ml) and from 1.98 to 2.19 mg VitC (vitamin C)/g when tested with the DPPH and ABTS reagents, respectively, using BHA and VitC as controls. The antimicrobial activity of the extracts was investigated using a micro-well dilution assay for the most common human gastrointestinal pathogenic bacterial strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027, Salmonella enteritidis ATCC 13076, Bacillus cereus ATCC 10876, Listeria monocytogenes ATCC15313, Staphylococcus aureus ATCC 25923 and Candida albicans ATCC 10231. This finding suggests that Seseli species may be considered as a natural source of antioxidants and antimicrobial agents.

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 l/ml and MBC values from 0.05 to 0.78 l/ml. Lavender oils demonstrated MIC values from 0.025 to 0.20 l/ml and MBC values from 0.05 and 0.78 l/ml. Reference antibiotic tetracycline was active in concentrations between 0.025 and 0.05 l/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.