Preparation of kombucha from winter savory (Satureja Montana L.) in the laboratory bioreactor

The possibility of obtaining kombucha from winter savory tea has been tested in the laboratory bioreactor by applying starter cultures and traditional way of inoculation. On the basis of the obtained results, it can be concluded that applying the inoculating method with the beverage from the previous process of biotransformation yielded kombucha beverage (capacity 15 I) from winter savory tea in the laboratory bioreactor. The application of defined starter culture from the isolate of yeast and acetic acid bacteria of local tea in the glass jar (capacity 5 I) gave 3 litres of kombucha beverage, which is acceptable according to the basic parameters and sensory characteristics. However, the application of the same starter culture in the laboratory bioreactor did not result in synchronized activity of yeast and bacteria

QSAR MODELING OF ANTIBACTERIAL ACTIVITY OF SOME BENZIMIDAZOLE DERIVATIVES

A quantitative structure-activity relationship (QSAR) study has been carried out for a training set of 12 benzimidazole derivatives to correlate and predict the antibacterial activity of studied compounds against Gram-negative bacteria Pseudomonas aeruginosa. Multiple linear regression was used to select the descriptors and to generate the best prediction model that relates the structural features to inhibitory activity. The predictivity of the model was estimated by cross-validation with the leave-one-out method. Our results suggest a QSAR model based on the following descriptors: parameter of lipophilicity (logP) and hydration energy (HE). Good agreement between experimental and predicted inhibitory values, obtained in the validation procedure, indicated the good quality of the generated QSAR model

Screening of antibacterial activity of raspberry (Rubus idaeus L.) fruit and pomace extracts

Antibacterial activity of fruit and pomace extracts (concentration 50 mg/ml) of two raspberry (Rubus idaeus L.) cultivars (Meeker and Willamette) was tested against selected Gram-positive and Gram-negative bacteria (reference and wild strains). Disc diffusion method with 15 μl of extracts and agar-well diffusion method with 50 and 100 μl were used. Antibiotic (cefotaxime/clavulanic acid) was used as a control. Both raspberry fruit extracts showed the strongest antibacterial activity against Pseudomonas aeruginosa (wild strain) and Bacillus cereus, where the largest clear zones (without growth) appeared. Escherichia coli was the most resistant strain, with only zone of reduced growth. The highest antibacterial activity of pomace extracts was against Staphylococcus aureus and Staphylococcus saprophyticus. There were no differences in the antibacterial activity between cultivars for both fruit and pomace extracts. [Projekat Ministarstva nauke Republike Srbije, br. TR 31044

Quantitative structure-activity relationship of some 1-benzylbenzimidazole derivatives as antifungal agents

In the present study, the antifungal activity of some 1-benzylbenzimidazole derivatives against yeast Saccharomyces cerevisiae was investigated. The tested benzimidazoles displayed in vitro antifungal activity and minimum inhibitory concentration (MIC) was determined for all the compounds. Quantitative structure-activity relationship (QSAR) has been used to study the relationships between the antifungal activity and lipophilicity parameter, logP, calculated by using CS Chem-Office Software version 7.0. The results are discussed on the basis of statistical data. The best QSAR model for prediction of antifungal activity of the investigated series of benzimidazoles was developed. High agreement between experimental and predicted inhibitory values was obtained. The results of this study indicate that the lipophilicity parameter has a significant effect on antifungal activity of this class of compounds, which simplify design of new biologically active molecules

Antibacterial activity of Beta vulgaris L. pomace extract

Antibacterial activity of Beta vulgaris L. (beetroot) pomace extract (concentration 100 mg/ml) was tested against five Gram positive and seven Gram negative bacterial strains (reference cultures and natural isolates). Disc diffusion method with 15 µl of extract and agar-well diffusion method with 50 and 100 µl were used. Antibiotic (cefotaxime/clavulanic acid) was used as a control sample. The tested extract showed the highest activity against Staphylococcus aureus and Bacillus cereus, where clear zones (without growth) appeared. There was no any activity against other tested Gram-positive bacteria, except for Staphylococcus epidermidis, with a small zone of reduced growth. Growth of all tested Gram-negative bacteria was inhibited usually with 100 µl of extract. The most susceptible were Citrobacter freundii and Salmonella typhymurium. The tested antibiotic gave clear, usually large zones for all tested strains except for Staphylococcus cohni spp. cohni, where only a zone of reduced growth appeared

Antioxidant and Antibacterial Activity of the Beverage Obtained by Fermentation of Sweetened Lemon Balm (Melissa offi cinalis L.) Tea with Symbiotic Consortium of Bacteria and Yeasts

Kombucha je napitak koji se tradicionalno dobiva fermentacijom zaslađenog crnog ili zelenog čaja (Camellia sinensis L.) s pomoću simbiotičke kulture bakterija i kvasaca (engl. SCOBY). U ovom je radu za pripremu napitka kombucha kao izvor dušika pri fermentaciji upotrijebljena melisa (Melissa officinalis L.). Tijekom sedmodnevne fermentacije mjereni su sljedeći parametri: pH-vrijednost, titracijska kiselost, udjeli ukupnih fenola i fenolnih spojeva, te sposobnost uklanjanja hidroksilnog (˙OH) i 1,1-difenil-2-pikrilhidrazilnog (DPPH) radikala da bi se utvrdila povezanost trajanja fermentacije s antioksidativnom i antibakterijskom aktivnošću fermentiranog napitka od melise. Određena je optimalna titracijska kiselost od 4 do 4,5 g/L, koju su potvrdili dugogodišnji konzumenti tog napitka. Ispitan je antibakterijski učinak napitaka povećane kiselosti od 8,12 g/L na jedanaest divljih bakterijskih sojeva. Rezultati pokazuju da se u proizvodnji fermentiranog napitka kombucha čaj (C. sinensis) može uspješno zamijeniti melisom. Udjel ukupnih fenola i sposobnost uklanjanja DPPH radikala bili su veći u podlozi s melisom nego u tradicionalnom napitku kombucha. Za biološku je aktivnost napitka kombucha s melisom najvjerojatnije zaslužna ružmarinska kiselina, glavni fenolni spoj u napitku. Vrijednosti EC50 pokazuju da napitak kombucha ima veću antioksidativnu vrijednost od čajnih infuzija C. sinensis L. i M. officinalis L., čemu vjerojatno pridonose metaboliti simbiotičke kulture bakterija i kvasaca. Kombucha s melisom optimalne i povećane titracijske kiselosti imala je izraženi antibakterijski učinak, ponajprije zbog prisustva octene kiseline, ali i zbog drugih sastojaka čaja te prisustva metabolita simbiotičke kulture.Kombucha is a fermented tea beverage which is traditionally prepared by fermenting sweetened black or green tea (Camellia sinensis L.) with symbiotic consortium of bacteria and yeasts (SCOBY). In this study, lemon balm (Melissa offi cinalis L.) was used as the only nitrogen source for kombucha fermentation. During the seven-day fermentation process, pH value, titratable acidity (TA), total phenolic content, phenolic compounds, and antioxidant activity against hydroxyl (˙OH) and 1,1-diphenyl-2-picrylhydrazil (DPPH) radicals were measured to detect the connection between the fermentation time and antioxidant and antibacterial activities of lemon balm kombucha. Antibacterial activity of fi nished beverages with optimum acidity (TA=4–4.5 g/L), the value which is confi rmed by long-time kombucha consumers, and enhanced acidity (TA=8.12 g/L) was tested against eleven wild bacterial strains. The results showed that lemon balm could be successfully used as an alternative to C. sinensis L. for kombucha fermentation. Total phenolic content and antioxidant activity against DPPH radicals of lemon balm fermentation broth were higher than those of traditional kombucha. Rosmarinic acid is the main phenolic compound of the lemon balm-based kombucha that probably provides biological activity of the beverage. Judging from the EC50 values, kombucha beverages exhibited higher antioxidant activities compared with C. sinensis L. and M. offi cinalis L. infusions, which can probably be ascribed to SCOBY metabolites. Lemon balm kombucha with both optimum and enhanced acidity showed antibacterial activity, which can be primarily ascribed to acetic acid, but also to some other tea components and SCOBY metabolites

Presence of Listeria species in fresh meats from retail markets in Serbia

Listeria spp. are Gram positive, short, non-sporing rods, microaerophilic. Of the six species currently recognized, Listeria monocytogenes is the most important as it causes a range of infections in humans and animals. The organism can be found in a wide variety of habitats including the soil, food processing environments and raw foods. The ability of the organism to grow at refrigeration temperatures is of major importance in food production. This study examines the presence of Listeria species in fresh meat. 29 samples (chicken, pork and beef) meat. This bacteria was found in 82.7% of analyzed samples; 7 L. innocua, 8 L. monocytogenes and 9 L. welshimeri (of all isolates). L. innocua prevailed in pork meat (40%), L. monocytogenes in chicken and pork meat (30%), and L. welshimeri in beef meat (44.4%)

An In Vitro Synergistic Interaction of Combinations of Thymus glabrescens Essential Oil and Its Main Constituents with Chloramphenicol

The chemical composition and antibacterial activity of Thymus glabrescens Willd. (Lamiaceae) essential oil were examined, as well as the association between it and chloramphenicol. The antibacterial activities of geraniol and thymol, the main constituents of T. glabrescens oil, individually and in combination with chloramphenicol, were also determined. The interactions of the essential oil, geraniol, and thymol with chloramphenicol toward five selected strains were evaluated using the microdilution checkerboard assay in combination with chemometric methods. Oxygenated monoterpenes were the most abundant compound class in the oil, with geraniol (22.33%) as the major compound. The essential oil exhibited in vitro antibacterial activity against all tested bacterial strains, but the activities were lower than those of the standard antibiotic and thymol. A combination of T. glabrescens oil and chloramphenicol produced a strong synergistic interaction (FIC indices in the range 0.21-0.87) and a substantial reduction of the MIC value of chloramphenicol, thus minimizing its adverse side effects. The combinations geraniol-chloramphenicol and thymol-chloramphenicol produced synergistic interaction to a greater extent, compared with essential oil-chloramphenicol association, which may indicate that the activity of the thyme oil could be attributed to the presence of significant concentrations of geraniol and thymol

Antioxidative responses to seasonal changes and chemiluminescence assay of Astragalus onobrychis leaves extract

The aim of this study was to research the seasonal changes of antioxidant enzyme activity and total antioxidant capacity in leaves of Astragalus onobrychis L. subsp. chlorocarpus (Griseb.) S. Kozuharov et D.K. Pavlova. Leaves of A. onobrychis were collected during the different stages of growth and analyzed for antioxidant enzyme activity: superoxide dismutase, catalase, guaiacol peroxidase, glutathione peroxidase. Quantities of malonyldialdehyde, superoxide radicals, and hydroxyl radicals were measured as well as the content of soluble proteins. Furthermore, total antioxidant capacity was determined by the inhibition of chemiluminescence activity of blood phagocytes by leaf extracts. Stages of vegetation significantly affected the accumulation of superoxide radicals, but there were no significant differences in hydroxyl radical quantity and lipid peroxidation levels during vegetation. Soluble proteins vary greatly between different stages of growth. Seasonal changes were found to have an effect on enzymatic activities. During the spring season, guaiacol peroxidase showed the highest levels. Catalase and glutathione peroxidase increased their activities in summer, while, during the autumn season, superoxide dismutase showed maximum activity. On the basis of chemiluminescence assay, it can be concluded that leaf extract of A. onobrychis possesses a significant antioxidant capacity thus protecting plants during environmental stress

LIPOPHILICITY AND ANTIFUNGAL ACTIVITY OF SOME 2-SUBSTITUTED BENZIMIDAZOLE DERIVATIVES

Available on line a