Putative application of Najas marina L. extracts as a source of bioactive compounds and their antioxidant, antimicrobial, antibiofilm, and genotoxic properties.

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.

Assessment of safety aspect and probiotic potential of autochthonous Enterococcus faecium strains isolated from spontaneous fermented sausage.

OBJECTIVE: The objectives of this research project were isolation, identification, and evaluation of the safety aspect and probiotics properties of 21 Enterococcus faecium strains isolated from sausages originated from southeastern Serbia. RESULTS: Analyzed E. faecium isolates showed tolerance to simulated gastrointestinal conditions. All the examined isolates grew well on media with 0.1% and 0.2% of phenol. None of the tested isolates were histamine-producers, while the synthesis of tyramine was observed for E. faecium sk8-1 and sk8-17. Full resistance to antibiotics was not observed for any examined isolate of E. faecium (penicillin, amoxicillin, and ofloxacin showed the effect on all tested isolates). An inhibition zone against examined pathogens was exhibited by all strains, with the largest inhibition zone against Pseudomonas spp., Proteus spp. and E. coli (12-30 mm/MIC values ranged from 0.5 to 12 mg mL-1). CONCLUSION: The results indicated that E. faecium isolates from spontaneously fermented sausage showed a potential for further investigation and possible application as probiotics.

Autochthonous lactic acid bacteria-presentation of potential probiotics application.

OBJECTIVE: The objective of this study was to evaluate the probiotic potential as well as the ability of adhesion and aggregation of natural and autochthonous lactic acid bacteria, isolated from traditionally made cheese. RESULTS: Lactic acid bacteria from natural food sources can be promising probiotic candidates and they can be used in natural food preservation or like starter cultures. Tested autochthonous isolates showed tolerance to the simulated gastrointestinal condition as well as the sensitivity to clinically relevant antibiotics, especially to ampicillin (MIC at 0.195 µg mL-1 for lactobacilli and from 0.195 to 3.125 µg mL-1 for lactococci). Among isolates, the highest percentage of adhesion was detected with chloroform, while the adhesion ability of selected isolates to pig intestinal epithelium was in the correlation with the results of adhesion ability with solvents. The auto-aggregation ability of isolates was demonstrated, while co-aggregation with Escherichia coli was strain specific. CONCLUSION: The results indicated the potential probiotic properties of the isolates and give evidence for further investigation and potential application in the dairy industry.

Heavy metal tolerance and removal potential in mixed-species biofilm.

The aim of the study was to examine heavy metal tolerance (Cd2+, Zn2+, Ni2+ and Cu2+) of single- and mixed-species biofilms (Rhodotorula mucilaginosa and Escherichia coli) and to determine metal removal efficiency (Cd2+, Zn2+, Ni2+, Cu2+, Pb2+ and Hg2+). Metal tolerance was quantified by crystal violet assay and results were confirmed by fluorescence microscopy. Metal removal efficiency was determined by batch biosorption assay. The tolerance of the mixed-species biofilm was higher than the single-species biofilms. Single- and mixed-species biofilms showed the highest sensitivity in the presence of Cu2+ (E. coli-MIC 4 mg/ml, R. mucilaginosa-MIC 8 mg/ml, R. mucilaginosa/E. coli-MIC 64 mg/ml), while the highest tolerance was observed in the presence of Zn2+ (E. coli-MIC 80 mg/ml, R. mucilaginosa-MIC 161 mg/ml, R. mucilaginosa-E. coli-MIC 322 mg/ml). The mixed-species biofilm exhibited better efficiency in removal of all tested metals than single-species biofilms. The highest efficiency in Cd2+ removal was shown by the E. coli biofilm (94.85%) and R. mucilaginosa biofilm (97.85%), individually. The highest efficiency in Cu2+ (99.88%), Zn2+ (99.26%) and Pb2+ (99.52%) removal was shown by the mixed-species biofilm. Metal removal efficiency was in the range of 81.56%-97.85% for the single- and 94.99%-99.88% for the mixed-species biofilm.

Comparative Study of Composition, Antioxidant, and Antimicrobial Activities of Essential Oils of Selected Aromatic Plants from Balkan Peninsula.

The objective of the present study to perform a comparative analysis of the chemical composition, antioxidant, and antimicrobial activities of the essential oils of plant species Hyssopus officinalis, Achillea grandifolia, Achillea crithmifolia, Tanacetum parthenium, Laserpitium latifolium, and Artemisia absinthium from Balkan Peninsula. The chemical analysis of essential oils was performed by using gas chromatography and gas chromatography-mass spectrometry. Monoterpenes were dominant among the recorded components, with camphor in T. parthenium, A. grandifolia, and A. crithmifolia (51.4, 45.4, and 25.4 %, respectively), 1,8-cineole in H. officinalis, A. grandifolia, and A. crithmifolia (49.1, 16.4, and 14.8 %, respectively), and sabinene in L. latifolium and A. absinthium (47.8 and 21.5 %). The antiradical and antioxidant activities were determined by using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging methods. The essential oil of A. grandifolia has shown the highest antioxidant activity [IC50 of 33.575 ± 0.069 mg/mL for 2,2-diphenyl-1-picrylhydrazyl and 2.510 ± 0.036 mg vitamin C/g for the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay]. The antimicrobial activity against 16 multiresistant pathogenic bacteria isolated from human source material was tested by the broth microdilution assay. The resulting minimum inhibitory concentration/minimum bactericidal concentration values ranged from 4.72 to 93.2 mg/mL. Therefore, the essential oils of the plant species included in this study may be considered to be prospective natural sources of antimicrobial substances, and may contribute as effective agents in the battle against bacterial multiresistance.

ANTIMICROBIAL AND ANTIBIOFILM EFFECTS OF EXTRACTS FROM TRAPA NATANS L., EVALUATION OF TOTAL PHENOLIC AND FLAVONOID CONTENTS AND GC-MS ANALYSIS.

Research conducted in this study shows the applied in vitro antimicrobial and antibiofilm activity of the four extracts isolated from Trapa natans L. leaves. In this study, different methods were used (microdilution, tissue culture plate, different colorimetric methods, GC-FID and GC-MS analysis). While the water extract didn't show antibacterial activity, the acetone extract showed the strongest one. The same activity in the case of Pseudomonas aeruginosa (MIC was 313 µg/mL) was better than the activity of controls and it matched with antibiofilm activity. The effect of extracts was better on G+ bacteria (MICs were <78-625 µg/mL). For ethanol and ethyl acetate extracts all BIC values were better than MICs. Extracts showed a significant effect on Aspergillus restrictus (MICs were < 78/156 µg/mL). The GC and GC-MS analysis of the ethyl acetate extract revealed the identification of 22 compounds with (all E)-squalene (20.2%), n-alkanes and norlignan hinokiresinol among the most abundant ones. This is the first time that T. natans was studied using these methods.

In vitro biological activity of secondary metabolites from Seseli rigidum Waldst. et Kit. (Apiaceae).

The antioxidant, antimicrobial activity, total phenolic content and flavonoid concentration of Seseli rigidum Waldst. et Kit. were evaluated. Five different extracts of the aboveground plant parts were obtained by extraction with distilled water, methanol, acetone, ethyl acetate and petroleum ether. Total phenols were determined using the Folin-Ciocalteu's reagent, with the highest values obtained in the acetone extract (102.13 mg GAE/g). The concentration of flavonoids, determined by using a spectrophotometric method with aluminum chloride and expressed in terms of rutin equivalent, was also highest in the acetone extracts (291.58 mg RUE/g). The antioxidant activity was determined in vitro using DPPH reagent. The greatest antioxidant activity was expressed in the aqueous extract (46.15 µg/ml). In vitro antimicrobial activities were determined using a microdilution analysis method; minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) were determined. Methanolic extract had the greatest influence on bacilli (MIC at 0.0391 mg/ml), but the best antimicrobial effect had acetone and ethyl acetate extracts considering their broad impact on bacteria. According to our research, S. rigidum can be regarded as promising candidate for natural plant source with high value of biological compounds.

Phenolic content, antibacterial and antioxidant activities of Erica herbacea L.

Antibacterial and antioxidant activity, total phenolic and flavonoid concentrations of aqueous, ethanol and ethyl acetate extracts from the leaves and flowers of Erica herbacea L. were studied. In vitro antibacterial activity of the extracts was determined by macrodilution method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) have been determined. Testing was performed on 30 clinical isolates, including different strains of Escherichia coli, Enterococcus faecalis and Proteus vulgaris. The values for MIC were in the range from 2.5 mg/mL to 40 mg/mL. The most sensitive bacterial strains were Proteus vulgaris strains. The aqueous extract from E. herbacea was found the most active. The total phenolic content was determined using Folin-Ciocalteu reagent and ranged between 14.98 and 119.88 mg GA/g. The concentration of flavonoids in extracts was determined using spectrophotometric method with aluminium chloride and obtained results varied from 16.19 to 26.90 mg RU/g. Antioxidant activity was monitored spectrophotometrically using DPPH reagent. The highest capacity to neutralize DPPH radicals was found in the aqueous extract from E. herbacea. The results of the total phenolic content determination of the examined extracts indicate that E. herbacea extracts are a rich source of phenolic compounds and also possess a significant antioxidant activity and moderate antibacterial activity.

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.

Synergistic antibacterial activity of Salvia officinalis and Cichorium intybus extracts and antibiotics.

Synergistic activity of Salvia officinalis and Cichorium intybus extracts and commonly used antibiotics, amoxicillin and chloramphenicol, were evaluated. Interactions between plant extracts and antibiotics were tested by checkerboard method and interpreted as FIC index. Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and clinical isolates Staphylococcus aureus, Bacillus subtilis, Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli and Proteus mirabilis were used. Salvia officinalis showed better synergistic capacity than Cichorium intybus. Synergistic interactions were observed between amoxicillin and acetone or ethyl acetate extract of Salvia officinalis and between chloramphenicol and ethyl acetate extract of Salvia officinalis. In the presence of sub-inhibitory concentration (1/4 MIC to 1/32 MIC) of sage extracts, the MIC values of antibiotics were decreased by 2- to 10-fold. Synergism was observed against all test bacteria, except Escherichia coli. The combinations of acetone and ethyl acetate extract from Cichorium intybus and antibiotics resulted in additive and indifferent effects against tested bacteria.

Antioxidant, antimicrobial and antiproliferative activities of five lichen species.

The antioxidative, antimicrobial and antiproliferative potentials of the methanol extracts of the lichen species Parmelia sulcata, Flavoparmelia caperata, Evernia prunastri, Hypogymnia physodes and Cladonia foliacea were evaluated. The total phenolic content of the tested extracts varied from 78.12 to 141.59 mg of gallic acid equivalent (GA)/g of extract and the total flavonoid content from 20.14 to 44.43 mg of rutin equivalent (Ru)/g of extract. The antioxidant capacities of the lichen extracts were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging. Hypogymnia physodes with the highest phenolic content showed the strongest DPPH radical scavenging effect. Further, the antimicrobial potential of the lichen extracts was determined by a microdilution method on 29 microorganisms, including 15 strains of bacteria, 10 species of filamentous fungi and 4 yeast species. A high antimicrobial activity of all the tested extracts was observed with more potent inhibitory effects on the growth of Gram (+) bacteria. The highest antimicrobial activity among lichens was demonstrated by Hypogymnia physodes and Cladonia foliacea. Finally, the antiproliferative activity of the lichen extracts was explored on the colon cancer adenocarcinoma cell line HCT-116 by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) viability assay and acridine orange/ethidium bromide staining. The methanol extracts of Hypogymnia physodes and Cladonia foliacea showed a better cytotoxic activity than the other extracts. All lichen species showed the ability to induce apoptosis of HCT-116 cells.

The hydrophobicity of enterobacteria and their co-aggregation with Enterococcus faecalis isolated from Serbian cheese.

In this paper, we investigated the hydrophobicity, ability to adhere to solvents and the pig epithelium and co-aggregation of members of family Enterobacteriaceae and Enterococcus faecalis KGPMF 49. The bacteria used in this study were isolated from traditionally made autochthonous cheese from Southeastern Serbia (Sokobanja). The percentage of adhered bacteria was different in three solvents (chloroform, ethyl acetate and xylene). The highest percentage was detected in the presence of chloroform, and the lowest percentage was detected in the presence of xylene (chloroform < ethyl acetate < xylene). A different degree of co-aggregation of enterobacteria with E. faecalis KGPMF 49 was observed. Klebsiella ornithinolytica KGPMF 8 demonstrated the highest percentage of co-aggregation with E. faecalis KGPMF49 (32.29%). Klebsiella pneumoniae KGPMF 13, K. ornithinolytica KGPMF 9 and Serratia marcescens biogp 1 KGPMF 19 were found to have the ability to adhere to the pig epithelium, whereas Escherichia coli KGPMF 22 showed no such ability. The ability to co-aggregate with other species and the ability to adhere to the pig epithelium are very important characteristics of the isolated bacteria.

Anti-quorum sensing activity, toxicity in zebrafish (Danio rerio) embryos and phytochemical characterization of Trapa natans leaf extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: Trapa natans L. (water chestnut or water caltrop) is a widespread aquatic plant, which has been cultivated for food and traditional medicine since ancient times. Pharmacological studies showed that water chestnut exhibits the wide range of biological activities, such as antimicrobial, antioxidative, analgesic, anti-inflammatory, as well as antiulcer. AIM OF THE STUDY: Evaluation of anti-virulence potential and toxicity of T. natans methanol (TnM), acetone (TnA) and ethyl acetate (TnEA) leaf extracts. MATERIALS AND METHODS: The anti-quorum sensing activity of Tn extracts was addressed by measuring their effects on biofilm formation, swarming motility and pyocyanin and elastase production in Pseudomonas aeruginosa. Specific P. aeruginosa biosensors were used to identify which of the signaling pathways were affected. The lethal and developmental toxicity of extracts were addressed in vivo using the zebrafish (Danio rerio) model system. The phenolic composition of T. natans leafs extracts was analyzed by a linear ion trap-OrbiTrap hybrid mass spectrometer (LTQ OrbiTrapMS) and UHPLC system configured with a diode array detector (DAD) hyphenated with the triple quadrupole mass spectrometer. RESULTS: Subinhibitory concentrations of Tn leaf extracts (0.2 MIC) inhibited pyocyanin and elastase production up to 50% and 60%, respectively, and reduced swarming zones, comparing to non-treated P. aeruginosa. TnA inhibited biofilm formation by 15%, TnM showed a stimulatory effect on biofilm formation up to 20%, while TnEA showed no effect. The bioactive concentrations of TnM and TnA were not toxic in the zebrafish model system. Twenty-two phenolic compounds were tentatively identified in TnM, where thirteen of them were identified in T. natans for the first time. Tn extracts, as well as their major components, ellagic and ferulic acids, demonstrated the ability to interfere with P. aeruginosa Las and PQS signaling pathways. CONCLUSIONS: This study demonstrates anti-virulence potential of Tn leaf extracts against medically important pathogen P. aeruginosa and confirms the ethnopharmacological application of this plant against microbial infections.

Low-dimensional compounds containing bioactive ligands. Part VIII: DNA interaction, antimicrobial and antitumor activities of ionic 5,7-dihalo-8-quinolinolato palladium(II) complexes with K+ and Cs+ cations.

Starting from well-defined NH2(CH3)2[PdCl2(XQ)] complexes, coordination compounds of general formula Cat[PdCl2(XQ)] have been prepared by cationic exchange of NH2(CH3)2+ and Cat cations, where XQ are biologically active halogen derivatives of quinolin-8-ol (5-chloro-7-iodo-quinolin-8-ol (CQ), 5,7-dibromo-quinolin-8-ol (dBrQ) and 5,7-dichloro-quinolin-8-ol (dClQ)) and Cat is K+ or Cs+. The cation exchange of all prepared complexes, K[PdCl2(CQ)] (1), K[PdCl2(dClQ)] (2), K[PdCl2(dBrQ)] (3), Cs[PdCl2(CQ)] (4), Cs[PdCl2(dClQ)] (5) and Cs[PdCl2(dBrQ)] (6) was approved using IR spectroscopy, their structures in DMSO solution were elucidated by one- and two-dimensional NMR experiments, whereas their stability in solution was verified by UV-VIS spectroscopy. Interaction of complexes to ctDNA was investigated using UV-VIS and fluorescence emission spectroscopy. The minimum inhibitory concentration and the minimum microbicidal concentration values were detected against 15 bacterial strains and 4 yeast strains to examine the antimicrobial activity for the complexes. The in vitro antitumor properties of the complexes were studied by testing the complexes on leukemic cell line L1210, ovarian cancer cell line A2780 and non-cancerous cell line HEK293. The majority of the prepared compounds exhibited moderate antimicrobial and very high cytotoxic activity.

Extracts of Agrimonia eupatoria L. as sources of biologically active compounds and evaluation of their antioxidant, antimicrobial, and antibiofilm activities.

In this study, we determined the concentration of total phenols, flavonoids, tannins, and proanthocyanidins in the water, diethyl ether, acetone, and ethanol extracts of Agrimonia eupatoria L. We also investigated the antioxidant activity of these extracts using two methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power] and their in vitro antimicrobial (antibacterial and antifungal) activity on some selected species of bacteria and fungi. In addition, the effects of the acetone and water extracts on the inhibition of biofilm formation of Proteus mirabilis and Pseudomonas aeruginosa were investigated using the crystal violet method. The concentration of total phenols was measured according to the Folin-Ciocalteu method and the values obtained ranged from 19.61 mgGA/g to 220.31 mgGA/g. The concentration of flavonoids was examined by the aluminum chloride method and the values obtained ranged from 20.58 mgRU/g to 97.06 mgRU/g. The total tannins concentration was measured by the polyvinylpolypyrrolidone method and the values obtained ranged from 3.06 mgGA/g to 207.27 mgGA/g. The concentration of proanthocyanidins was determined by the butanol-HCl method and the values obtained ranged from 4.15 CChE/g to 103.72 CChE/g. Among the various extracts studied, the acetone extract exhibited good antioxidant activity (97.13%, as determined by the DPPH method). The acetone extract was active in the absorbance value range from 2.2665 to 0.2495 (as determined by the reducing power method). The strongest antimicrobial activity was detected on G+ bacteria, especially on probiotic species, and the acetone extract demonstrated the highest activity. Biofilm inhibitory concentration required to reduce biofilm coverage by 50% values for acetone extract was 4315 µg/mL for P. mirabilis and 4469.5 µg/mL for P. aeruginosa. The results provide a basis for further research of this plant species.

Low-dimensional compounds containing bioactive ligands. Part VI: Synthesis, structures, in vitro DNA binding, antimicrobial and anticancer properties of first row transition metal complexes with 5-chloro-quinolin-8-ol.

A series of new 3d metal complexes with 5-chloro-quinolin-8-ol (ClQ), [Mn(ClQ)2] (1), [Fe(ClQ)3] (2), [Co(ClQ)2(H2O)2] (3), [Ni(ClQ)2(H2O)2] (4), [Cu(ClQ)2] (5), [Zn(ClQ)2(H2O)2] (6), [Mn(ClQ)3]·DMF (7) and [Co(ClQ)3]·DMF·(EtOH)0.35 (8) (DMF=N,N-dimethylformamide), has been synthesized and characterized by elemental analysis, IR spectroscopy and TG-DTA thermal analysis. X-ray structure analysis of 7 and 8 revealed that these molecular complexes contain three chelate ClQ molecules coordinated to the central atoms in a deformed octahedral geometry and free space between the complex units is filled by solvated DMF and ethanol molecules. Antimicrobial activity of 1-6 was tested by determining the minimum inhibitory concentration and minimum microbicidal concentration against 12 strains of bacteria and 5 strains of fungi. The intensity of antimicrobial action varies depending on the group of microorganism and can be sorted: 1>ClQ>6>3/4>2>5. Complexes 1-6 exhibit high cytotoxic activity against MDA-MB, HCT-116 and A549 cancer cell lines. Among them, complex 2 is significantly more cytotoxic against MDA-MB cells than cisplatin at all tested concentrations and is not cytotoxic against control mesenchymal stem cells indicating that this complex seems to be a good candidate for future pharmacological evaluation. Interaction of 1-6 with DNA was investigated using UV-VIS spectroscopy, fluorescence spectroscopy and agarose gel electrophoresis. The binding studies indicate that 1-6 can interact with CT-DNA through intercalation; complex 2 has the highest binding affinity. Moreover, complexes 1-6 inhibit the catalytic activity of topoisomerase I.

Melilotus albus and Dorycnium herbaceum extracts as source of phenolic compounds and their antimicrobial, antibiofilm, and antioxidant potentials.

Melilotus albus Medic. and Dorycnium herbaceum Vill. (Fabaceae) acetone, ethyl acetate, and ethanol extracts were investigated for their in vitro antimicrobial, antibiofilm, and antioxidant activity with quantification of phenolic compound contents. In general, D. herbaceum extracts showed better antibacterial and antioxidant activity than M. albus extracts. Bacteria Bacillus subtilis, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa, and Proteus mirabilis were the most susceptible with the minimum inhibitory concentrations (MICs), determined by microdilution method, between 1.25-10 mg/mL. Antifungal activity was lower with the detectable MICs at 10 mg/mL and 20 mg/mL. The plant extracts, using the crystal violet assay, inhibit P. aeruginosa biofilm formation in concentration range from 5 mg/mL to 20 mg/mL whereas the effect on mature bacterial biofilm was lower. The antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and reducing power model systems. The intensity of DPPH radicals scavenging activity, expressed as half maximal effective concentration (EC50) values, was from 84.33 µg/mL to >1000 µg/mL. The extracts demonstrated reduced power in a concentration-dependent manner, with ethanol extract as the most active. The total phenols, flavonoids, and proanthocyanidins were determined spectrophotometrically while total extractable tannins were obtained by precipitation method. The phenolic compounds showed differences in their total contents depending on solvents polarities and plant species. Although the plants M. albus and D. herbaceum have not yet been fully explored, these results contribute better understanding of their biotic properties and potential application as antimicrobial and antioxidant agents.

Phytomedical investigation of Najas minor All. in the view of the chemical constituents.

Plants are an abundant natural source of effective antibiotic compounds. Phytomedical investigations of certain plants haven't still been conducted. One of them is Najas minor (N. minor), an aquatic plant with confirmed allelopathy. Research conducted in this study showed the influence of water and ethyl acetate extracts of N. minor on microorganisms, in the view of chemical profiling of volatile constituents and the concentrations of total phenols, flavonoids and tannins. Antimicrobial activity was defined by determining minimum inhibitory and minimum microbicidal concentrations using microdilution method. Influence on bacterial biofilm formation was performed by tissue culture plate method. The total phenolics, flavonoids and condensed tannins were determined by Folin-Ciocalteu, aluminum chloride and butanol-HCl colorimetric methods. Chemical profiling of volatile constituents was investigated by GC and GC-MS. Water extract didn't have antimicrobial activity below 5000 µg/mL. Ethyl acetate extract has shown strong antimicrobial activity on G+ bacteria - Staphylococcus aureus PMFKGB12 and Bacillus subtilis (MIC < 78.13 µg/mL). The best antibiofilm activity was obtained on Escherichia coli ATCC25922 (BIC50 at 719 µg/mL). Water extract had higher yield. Ethyl acetate extract had a significantly greater amount of total phenolics, flavonoids and tannins. As major constituent hexahydrofarnesyl acetone was identified. The ethyl acetate extract effected only G+ bacteria, but the biofilm formation of G-bacteria was suppressed. There was a connection between those in vivo and in vitro effects against pathogenic bacterial biofilm formation. All of this points to a so far unexplored potential of N. minor.

Platismatia glaucia and Pseudevernia furfuracea lichens as sources of antioxidant, antimicrobial and antibiofilm agents.

The antioxidative, antimicrobial and antibiofilm potentials of acetone, ethyl acetate and methanol extracts of lichen species Platismatia glauca and Pseudevernia furfuracea were evaluated. The phytochemical analysis by GC, GC/MS and NMR revealed caperatic acid, atraric acid, atranorin and chloroatranorin as the predominant compounds in Platismatia glauca. Atraric acid, olivetoric acid, atranorin and chloroatranorin were the major constituents in Pseudevernia furfuracea. The strong antioxidant capacities of the Platismatia glauca and Pseudevernia furfuracea extracts were assessed by their total phenolic and flavonoid contents and DPPH scavenging activities. The methanol extracts of both species exhibited the strongest antioxidant activities with the highest IC50 value for Pseudevernia furfuracea (95.33 µg/mL). The lichen extracts demonstrated important antibacterial activities against 11 bacterial strains with detectable MIC values from 0.08 mg/mL to 2.5 mg/mL for Platismatia glauca and from 0.005 mg/mL to 2.5 mg/mL for Pseudevernia furfuracea. While the antibacterial activities of Pseudevernia furfuracea were solvent-independent, the acetone and ethyl acetate extracts of Platismatia glauca showed higher antibacterial activities compared to its methanol extract. The methanol extracts of both species demonstrated significant antifungal activities against 9 fungal strains with detectable MIC values from 0.04 mg/mL to 2.5 mg/mL. The best antifungal activities were determined against Candida species in Pseudevernia furfuracea extracts with remarkable MIC values which were lower than the MIC values of the positive contol fluconazole. The acetone and ethyl acetate extracts of Platismatia glauca showed better antibiofilm activities on Staphylococcus aureus and Proteus mirabilis with BIC value at 0.63 mg/mL then its methanol extract. On the other hand, the methanol extract of Pseudevernia furfuracea was more potent with BIC value at 1.25 mg/mL on Staphylococcus aureus and 0.63 mg/mL on Proteus mirabilis compared to other types of extracts. Our study indicates a possible use of lichens Platismatia glauca and Pseudevernia furfuracea as natural antioxidants and preservatives in food, pharmaceutical and cosmetic industry.

In vitro activity of heather [Calluna vulgaris (L.) Hull] extracts on selected urinary tract pathogens.

Calluna vulgaris L. Hull (Ericaceae) has been used for treatment of urinary tract infections in traditional medicine. In this study we analyzed in vitro antibacterial activity of the plant extracts on different strains of Escherichia coli, Enterococcus faecalis and Proteus vulgaris, as well as the concentrations of total phenols and flavonoids in the extracts. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. The concentrations of total phenols were examined by using Folin-Ciocalteu reagent and ranged between 67.55 to 142.46 mg GAE/g. The concentrations of flavonoids in extracts were determined using spectrophotometric method with aluminum chloride and the values ranged from 42.11 to 63.68 mg RUE/g. The aqueous extract of C. vulgaris showed a significant antibacterial activity. The values of MIC were in the range from 2.5 mg/ml to 20 mg/ml for this extract. Proteus vulgaris strains were found to be the most sensitive. The results obtained suggest that all tested extracts of C. vulgaris inhibit the growth of human pathogens, especially the aqueous extract.