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The series of pyrazolyl-phthalazine-dione derivatives (PPDs) was subjected to evaluation of their in vitro lipoxygenase (LOX) inhibition and antimicrobial activities. Results obtained for LOX inhibition activities of PPDs showed that all compounds exhibit good to excellent activity, whereby compounds with eudesmic, syringic, vanillic or toluic moiety are the most active. Molecular modelling study was performed to investigate the possible mechanism of action and binding mode of compounds within the LOX active site. Docking results revealed that activity of the examined compounds depends on the functional group ability to create hydrogen bond accepting (HBA) and hydrophobic features (Hy) in the LOX-Ib active site. In addition, all substances were tested for their antibacterial and antifungal activities. The investigated compounds showed better antifungal than antibacterial activity. The highest antifungal activity was on Aspergillus fumigatus ATTC 204305 and Trichoderma viridae ATCC 13233.

Nine species (sixteen isolates) of lactic acid bacteria (LAB) isolated from traditionally made Serbian cheese were evaluated for their enzymatic activities in order to select indigenous strains of technical interest for the manufacture of cheese. These strains were selected based on their previously determined biochemical and physiological characteristics, as well as their antimicrobial activity, and were identified as Lactococcus lactis subsp. lactis (one isolate), Lc. lactis subsp. lactis biovar. diacetylactis (five isolates), Lactobacillus fermentum (two isolates), Lb. plantarum (one isolate), Lb. brevis (one isolate), Enterococcus faecalis (three isolates), E. faecium (one isolate), E. durans (one isolate) and E. hirae (one isolate). The enzymatic activities (acid and alkaline invertases, alkaline phosphatase, alkaline protease, a-amylase) were measured by using the spectrophotometric method. The results indicated that all Lactobacillus isolates showed protease, amylase, and alkaline phosphatase activities, while the activities of acid and alkaline invertases were not observed. The Lactococcus isolates showed protease, acid invertase and alkaline phosphatase activities, except the KGPMF50 isolate, which showed no alkaline phosphatase activity. The tested Enterococcus isolates showed weakly and strain-specific enzymatic activity. The results indicated that the enzymes produced by the investigated strains have a role in the formation of the specific flavor of cheese and that these isolates, especially Lactobacillus isolates, showed the potential for use in the dairy industry or applied biotechnology.

In this paper, the effect of different temperatures, pH, and NaCl concentration on the growth of autochthonous lactic acid bacteria isolated from traditionally made Serbian cheese (Sokobanja area) was investigated by using the spectrophotometric method. Growth of tested Lactobacillus (Lb. fermentum, Lb. plantarum, and Lb. brevis) and Lactococcus lactis subsp. lactis biovar. diacetylactis five isolates were better in acidic pH, while the growth of Enterococcus isolates (E. durans, E. faecium, and E. faecalis) was better in basic pH, at 37 °C. At 4 °C after 24 h, none of the tested bacteria showed growth. Since the autochthonous isolates were tolerant to a tested range of dairy processing conditions, further studies need to include the characterization of enzymatic activity of selected isolates, as well as the ability to use these isolates like starter cultures or food supplements in dairy or non-dairy products.

In this paper, we investigated, for the first time, the enzyme activity of enterobacteria from cheese from Southeastern Serbia (Sokobanja), which was produced in a traditional way. The tested bacteria were selected from the spring, summer, and autumn collections and grown in two different broths. The enzyme activity was investigated in the two broths and measured using spectrophotometry method. It was concluded that there were differences in the amount of extracellular enzymes depending on the broths. A statistically significant rise in the amount of enzymes was demonstrated in Tripton soy broth. Bacteria in cheese do not possess the ability to produce extracellular enzymes in large amounts. Therefore, they do not change the organoleptic characteristics of the cheese. There is a possibility that if they are found outside their natural environment (cheese), without interactions with antagonists, they may exhibit stronger enzyme activity.

The purpose of this study was the investigation of the growth ability of lactic acid bacteria (LAB), isolated from traditionally made cheese from Southeastern Serbia, in the presence of different percent of sugars and sugar substitutes (fructose, lactose, inulin, and mannitol). Dextrose was included for comparative purposes. The results indicated that fructose and lactose stimulated the growth of Lactobacillus strains, with exceptions of Lactobacillus plantarum KGPMF62 and Lb. plantarum LP 299v. Lactose showed similar effects like dextrose on the growth of Lactococcus strains, while higher growth rates of Enterococcus hirae KGPMF9, E. durans KGPMF10, E. faecium KGPMF14, and E. faecalis KGPMF47 were observed for lactose and mannitol. The results indicated the potential use of tested sugars and sugar substitutes as prebiotic compounds for the development of symbiotics with tested LAB, in medical or food industry.

This study observed the preliminary investigation of Oleum Hyperici, an original product made from Hypericum perforatum flowers, collected from Goč Mountain (Serbia). Some of the chemical properties (pH, the content of metals and metalloids - As, Cr, Pb, Cd, Ni, Hg) and the microbiological safety of the product including the total count of aerobic mesophilic bacteria, coagulase positive staphylococci, Escherichia coli, Pseudomonas aeruginosa, Proteus sp., as well as fungi: molds and yeasts) were evaluated. Antimicrobial activity of H. perforatum oil against 18 species of bacteria was determined using the disc diffusion and microdilution methods, by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The antibiofilm activity of Oleum Hyperici was evaluated using the biofilm formation assay. The results indicated that oil did not contain potentially pathogenic microorganisms. Oleum Hyperici product showed the antimicrobial activity on the most of tested bacteria (inhibition zone was in a range from 14 - 24 mm), except on Klebsiella pneumoniae ATCC 70063, K. pneumoniae, E. coli ATCC 25922, P. mirabilis, Bacillus subtilis ATCC 6633 and B. subtilis IP 5832. According to the obtained results, tested bacteria (planktonic and biofilm form) showed sensitivity up to 10-2 dilution of Oleum Hyperici. Based on the obtained preliminary results, it could be concluded that Oleum Hyperici can be used in traditional medicine for development control of some potential human pathogens.

Extracts of the aerial parts and roots of the wild-growing medicinal plant Gentiana asclepiadea were analysed for their antimicrobial, antibiofilm, and antioxidant activity with quantification of the total phenolic and total flavonoid content. Antimicrobial activity was tested against pathogenic and spoilage bacteria, yeasts, and moulds using the microdilution method. The strongest antibacterial activity was detected on Bacillus species, where minimum inhibitory concentrations (MICs) of from 0.16 mg/mL to 5 mg/mL were obtained, while antifungal activity was low to moderate, with MICs between 1.25 and 20 mg/mL. In the crystal violet assay, the extracts inhibit 50% biofilm formation in the concentration range of from 2.12 to 37.04 mg/mL. Staphylococcus aureus, S. aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853 biofilms were the most sensitive to the presence of extracts. The extracts rich in phenolic compounds showed good DPPH-scavenging activity, with EC50 values between 181.3 and 614.3 μg/mL for extracts of aerial parts and from 426.67 to >1000 μg/mL for root extracts. Even though G. asclepiadea has long been traditionally used, its biological activity is still insufficiently explored, so the obtained results are significant for contributing new knowledge about the plant's medicinal properties.

In the Western Balkans, traditional dry-cured sheep ham called Pastrma or Stelja is produced. Dry-cured sheep ham from Sjenica is produced in a very complex manner, and a prerequisite for its production is the sanitary safety of raw materials in accordance with veterinary and sanitary regulations. Isolation and preliminary identification of fungi from sheep ham were carried out in this study, as well as in vitro testing of the effects of water activity (aw) on the growth of isolated fungi. Fungi were isolated from 9 samples of dry-cured sheep meat taken from three households in the area of Sjenica in two productive years (2015 and 2016). Species of genus Penicillium were isolated as dominant in all the investigated samples. Water activity was tested on MY50GF agar from the series of malt extract yeast extract glucose fructose agar. Water activity was set to values of 0.87, 0.89, and 0.97. The results of the research showed that the growth of fungal colonies is under the direct influence of water activity. Fungi grew fastest at water activity of 0.97, and the highest growth of all tested species was recorded after 3 (A. niger), 7 (P. patulum), and 10 days (A. nidulans).

The antimicrobial and antioxidant activities, as well as the DNA-binding of four square-planar Pd(II) complexes, [Pd(terpy)Cl]+ (C1), [Pd(en)Cl2] (C2), [Pd(DMEAImiPr)Cl2] (C3) and [Pd(dach)Cl2] (C4) (terpy = 2,2′:6′,2′′- -terpyridine, en = ethylenediamine, dach = trans-1,2-diaminocyclohexane and DMEAImiPr = N2-((1,3-dihydro-1,3-diisopropyl-4,5-dimethyl)-2H-imidazol-2- ylidene)-N1,N1-dimethyl-1,2-ethanediamine are reported. The antimicrobial activities of the Pd(II) complexes with the appropriate ligands were tested using the microdilution method against 18 strains of microorganisms, whereby the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined. The antibiofilm activity of [Pd(terpy)Cl]+ and the corresponding ligand were determined on a formed biofilm. The intensity of antimicrobial activity varied depending on the type of microorganism and the tested compound. The C1 complex with the corresponding ligand demonstrated significantly greater overall antimicrobial activity than C2, C3 and C4. The antibacterial activity of the C1 complex was better than its antifungal activity that was overall greater than that of the positive control, fluconazole. The greatest sensitivity for C1 and L1 was with Penicillium italicum (MIC < 0.49 μg mL-1) among the fungi, and with Proteus mirabilis ATCC 12453 (MIC = 0.98 μg mL-1) among the tested bacteria. The tested compounds show low and moderate antibiofilm activity. The complexes showed weak antioxidant properties when tested using the DPPH (1,1-diphenyl-2- -picrylhydrazyl) method. The interaction of the metal complexes C1–C4 with calf thymus DNA (CT-DNA) was further examined by absorption (UV–Vis) and emission spectral studies (EthBr displacement studies). Overall, the investigated complexes exhibited good DNA interaction ability. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172011 and Grant no. 173032]

The impact of heavy metals, cadmium (Cd2+), zinc (Zn2+) and nickel (Ni2+) on planktonic cells and biofilm of Rhodotorula mucilaginosa and Saccharomyces boulardii was examined. The metal tolerance testing was performed by MBECTM-HTP assay. The minimum inhibitory concentration (MICp) and minimum lethal concentration (MLCp) were determined as well as the minimum biofilm eradication concentration (MBEC). Biofilm was more tolerant on the presence of heavy metals than the planktonic cells. The planktonic cells of R. mucilaginosa were tolerant to high concentrations of Cd2+, Zn2+ and Ni2+, while the planktonic cells of S. boulardii tolerated Zn2+, exclusively. The R. mucilaginosa biofilm was tolerant to all of the tested metal concentrations and the obtained results were confirmed by fluorescence microscopy. S. boulardii did not show ability of biofilm formation. Metal removal efficiency of the R. mucilaginosa planktonic cells and biofilm were also tested. The R. mucilaginosa biofilm showed higher efficiency in metals removing compared to the planktonic cells. Until now, the heavy metal tolerance and the removal efficiency (Cd2+, Zn2+ and Ni2+) analyzes were performed solely on planktonic cells of Rhodotorula species. In this study, we investigated the metal removal efficiency of R. mucilaginosa planktonic cells and biofilm and compared the obtained results.

In this study, the effects of environmental factors (different media, temperature, pH, salt and sugar concentrations) on the planktonic growth, biofilm formation and formed biofilm of Escherichia coli KGPMF 16 and Escherichia coli KGPMF 17 were investigated. Tested bacteria were isolated from traditionally made cheese produced in Southeastern Serbia (Sokobanja region). The influence on planktonic growth, biofilm formation and formed biofilm was determined using spectrophotometric method. The limiting factors for the planktonic growth and biofilm formation were temperature of 4 °C and all tested concentrations of salt. The growth of tested bacteria was higher in media enriched with lactose than in media containing glucose. TSB was more congenial media to the planktonic growth of bacteria than MHB broth. None of the tested bacteria demonstrated the ability to form biofilm at 4 °C and 44 °C. Only E. coli KGPMF 17 showed ability to form biofilm in TSB at 37 °C. Different concentrations of salt, glucose and lactose exhibited inhibitory effect on biofilm formation, but all tested concentrations of lactose showed stimulating effect on formed biofilm of E. coli KGPMF 17. These results contribute to better understanding of the effects of environmental factors on the development of E. coli in cheese.

Synergistic activity between water, acetone, ethanol and diethyl ether extract of Agrimonia eupatoria L. and commonly used antibiotic (ampicillin) were evaluated. Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa were used. Interaction between plant extracts and antibiotic were tested by checkerboard method and expressed as fractional inhibitory concentration (FIC) index showed indifferent, additive and synergistic effects. Synergism was observed against E. coli for every combination of agents. FICI values were ranged from 0.03 to 0.29. Inhibitory concentration (IC50) was evaluated for every combination of tested extracts and antibiotic and the best combinations for every tested bacteria were combination of diethyl ether extract + ampicillin and combination of acetone extract + ampicillin.

This study compares the effect of commercial industrial paints on the Escherichia coli PMFKG-F2, Proteus mirabilis PMFKG-F4 and Saccharomyces cerevisiae PMFKG-F6 planktonic cells and biofilms. A MBECTM-HTP assay and standard 96 microtiter plate assay were used to test the levels of resistance of planktonic cells and biofilms. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of the tested substances, which affects planktonic cells and biofilms, were determined and the results were confirmed by fluorescence microscopy. Results obtained for planktonic cells were compared between them and with the results obtained for biofilms. Noticeable difference in the resistance between the biofilms and the planktonic cells on paints, was observed. The E. coli PMFKG-F2 planktonic cells showed the highest resistance in the presence of the tested substance 2 (MICp 2.5 μl/ml), while the P. mirabilis PMFKG-F4 planktonic cells showed the highest resistance in the presence of the tested substance 2 (MICp 5 μl/ml). The S. cerevisiae PMFKG-F6 planktonic cells showed the same level of resistance in the presence of the tested substances 1, 2 and 5 (MICp 0.62 μl/ml). The E. coli PMFKG-F2, P. mirabilis PMFKGF4 and S. cerevisiae PMFKG-6 biofilms showed the highest resistance in the presence of the tested substance 5 (MICb 125 μl/ml, MICb 125 μl/ml and MICb 62.5 μl/ml). The obtained results suggest that the biofilm may have a potential to be used in bioremediation of wastewater contaminated with industrial paints.

The influence of 5 new Platinum(IV) (Pt(IV)) complexes with S-alkyl derivatives of thiosalicylic acid (C1-benzyl, C2-methyl, C3-ethyl, C4-propyl and C5- butyl) was studied on 16 strains of bacteria. Antibacterial activity was tested using microdilution method with resazurin while antibiofilm activity was observed by tissue culture plate method, using doxycycline as a positive control. The results were expressed as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and biofilm inhibitory concentration (BIC). The best result on Gram positive bacteria exhibited C1 and MIC was

The aim of this study was to examine heavy metal tolerance (lead (Pb2+) and mercury (Hg2+)) of single- and mixed-species biofilms, formed by yeast Rhodotorula mucilaginosa and bacteria Escherichia coli LM1. Single- and mixed-species biofilms were quantified by crystal violet test and the absorbance was measured using microplate reader (OD570). The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were determined and the results were confirmed by fluorescence microscopy. The significant difference in lead tolerance was observed between the mixed- and the single-species biofilms. The MIC of lead (Pb2+) for the examined biofilms (E. coli LM1, R. mucilaginosa and R. mucilaginosa / E. coli) was recorded at concentrations of 4000 μg/ml, 4000 μg/ml and 16000 μg/ml, respectively. The MIC of mercury (Hg2+) for the biofilms was noticed at concentrations of 31.25 μg/ml, 250 μg/ml and 250 μg/ml, respectively. Standard antibiotics (amphotericin B and tetracycline) were used as positive control. Results obtained for single-species biofilms were compared in between and with the results obtained for mixed-species biofilm. The tolerance of the mixed- species biofilm was higher in comparison to the singlespecies biofilms and the results were confirmed by a fluoresecence microscope. The obtained results suggest that the R. mucilaginosa / E. coli biofilm may have a potential to be used in bioremediation of wastewaters contaminated with lead and mercury.

This study deals with synthesis of methyl cinnamate, butyl cinnamate, and p-methoxy methyl cinnamate and testing of their in vitro antimicrobial activity. Antimicrobial activity was examined towards 29 microorganisms using microdilution method. It is shown that antimicrobial activity of methyl cinnamate and p-methoxy methyl cinnamate was better than that of butyl cinnamate. Sarcina lutea, Bacillus subtilis ATCC 6633, B. subtilis and B. subtilis IP 5832 (probiotic) were the most sensitive bacteria. It is established that p-methoxy methyl cinnamate can be a new, potential anti-Staphylococcus aureus agent with minimum inhibitory concentration of 62.5 μg/ml. Methyl cinnamate and p-methoxy methyl cinnamate inhibited the growth of Aspergillus restrictus, A. flavus and A. fumigatus in the concentration range from 62.5 μg/ml to 250 μg/ml.

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 μg/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]

This study investigated the antimicrobial activity as well as some phytochemical analysis of ethanol and diethyl ether extracts from plant species Vinca minor L. In vitro antimicrobial activity of extracts was studied on 20 strains of microorganisms (16 bacteria and four yeasts). Testing was performed by microdilution method and minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined. The strongest antimicrobial activity was detected on G+ bacteria of the genus Bacillus. Tested G- bacteria and yeasts were not sensitive to the action of the extracts or the sensitivity was insignificant. Phytochemical analysis involved determining the amount of total phenolics, flavonoids and tannins, as well as the determination of antioxidant activity monitoring capability to neutralize free radicals (DPPH) and the reductive potential. Phytochemical examination indicates that the total phenolic compounds were more in the ethanolic extract and the content of flavonoids and tannins marginally higher in the diethyl ether extract. The antioxidant activity (DPPH) of the ethanolic extract of V. minor was significantly stronger as compared to the diethyl ether extract, and the reduction potential was approximately the same.

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 (BIC50) was 19 mg/ml.

Antibacterial, antibiofilm and antioxidant activity of acetone, ethanol, ethyl acetate and diethyl ether extracts of P. nodosus Poir. were tested. 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 5 to > 5 mg/ml. Antibiofilm activity was tested by crystal violet assay. The biofilm inhibitory concentration (BIC) values were from 2.03 to > 10 mg/ml. The best results against biofilm formation had ethanol and ethyl acetate extracts. The total phenolic content was established by using Folin-Ciocalteu method. The highest total phenol content was found in the ethyl acetate extract (28.45 mg GA/g) while the lowest content in the ethanol extract (22.74 mg GA/g). The concentrations of flavonoids were determined using aluminium chloride method. The concentration of total flavonoid content was 102.09 mg RU/g for the ethyl acetate extract, while the lowest content was noticed in diethyl ether extract (32.93 mg RU/g). The antioxidant activity was determined by the DPPH free radicals assay. Antioxidative efficiency was in the range from 641.77 to 8811.63 μg/ml. The tested extracts showed weak antioxidant activity (AAI < 0.5).

In this research paper, the total phenols (TP), flavonoids (TF), and tannins (TT) content in the acetone and ethyl acetate extracts of Najas marina L. and the identification and quantification of phenolic acids and flavonoids from the ethyl acetate extract were performed. Antioxidant, antimicrobial, and antibiofilm properties of the mentioned extracts were investigated in vitro. The genotoxic potential was analyzed in cultured human peripheral blood lymphocytes (PBL). The TP and TF content was higher in the ethyl acetate extract, dominated by quercetin (172.4 µg mg−1) and ferulic acid (22.74 µg mg−1), while the TT content was slightly higher in the acetone extract. Both extracts tested showed limited antioxidant effects compared to ascorbic acid. The strongest antibacterial activity was observed with Gram-positive bacteria, particularly Staphylococcus aureus (MIC and MMC at 0.31 mg ml−1) and S. aureus ATCC 25923 (MIC at <0.02 mg ml−1), while antifungal activity was limited. Both extracts tested showed better activity on preformed biofilms. Acetone extract had no genotoxic activity but showed significant genoprotective activity against mitomycin C-induced DNA damage in cultured PBLs. Results of our research demonstrate the potential for the development of plant-based antibacterial and biofilm agents. [ABSTRACT FROM AUTHOR]