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Sample records for activity antimicrobial activity

  1. Antimicrobial Activity.

    PubMed

    2016-01-01

    Natural products of higher plants may possess a new source of antimicrobial agents with possibly novel mechanisms of action. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with conventional antimicrobials. A method using scanning electron microscope (SEM) to study the morphology of the bacterial and fungal microbes and thus determining antimicrobial activity is presented in the chapter.

  2. Antimicrobial activity of spices.

    PubMed

    Arora, D S; Kaur, J

    1999-08-01

    Spices have been shown to possess medicinal value, in particular, antimicrobial activity. This study compares the sensitivity of some human pathogenic bacteria and yeasts to various spice extracts and commonly employed chemotherapeutic substances. Of the different spices tested only garlic and clove were found to possess antimicrobial activity. The bactericidal effect of garlic extract was apparent within 1 h of incubation and 93% killing of Staphylococcus epidermidis and Salmonella typhi was achieved within 3 h. Yeasts were totally killed in 1 h by garlic extract but in 5 h with clove. Some bacteria showing resistance to certain antibiotics were sensitive to extracts of both garlic and clove. Greater anti-candidal activity was shown by garlic than by nystatin. Spices might have a great potential to be used as antimicrobial agents.

  3. Antimicrobial activity of flavonoids.

    PubMed

    Cushnie, T P Tim; Lamb, Andrew J

    2005-11-01

    Flavonoids are ubiquitous in photosynthesising cells and are commonly found in fruit, vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries, preparations containing these compounds as the principal physiologically active constituents have been used to treat human diseases. Increasingly, this class of natural products is becoming the subject of anti-infective research, and many groups have isolated and identified the structures of flavonoids possessing antifungal, antiviral and antibacterial activity. Moreover, several groups have demonstrated synergy between active flavonoids as well as between flavonoids and existing chemotherapeutics. Reports of activity in the field of antibacterial flavonoid research are widely conflicting, probably owing to inter- and intra-assay variation in susceptibility testing. However, several high-quality investigations have examined the relationship between flavonoid structure and antibacterial activity and these are in close agreement. In addition, numerous research groups have sought to elucidate the antibacterial mechanisms of action of selected flavonoids. The activity of quercetin, for example, has been at least partially attributed to inhibition of DNA gyrase. It has also been proposed that sophoraflavone G and (-)-epigallocatechin gallate inhibit cytoplasmic membrane function, and that licochalcones A and C inhibit energy metabolism. Other flavonoids whose mechanisms of action have been investigated include robinetin, myricetin, apigenin, rutin, galangin, 2,4,2'-trihydroxy-5'-methylchalcone and lonchocarpol A. These compounds represent novel leads, and future studies may allow the development of a pharmacologically acceptable antimicrobial agent or class of agents.

  4. Automation of antimicrobial activity screening.

    PubMed

    Forry, Samuel P; Madonna, Megan C; López-Pérez, Daneli; Lin, Nancy J; Pasco, Madeleine D

    2016-03-01

    Manual and automated methods were compared for routine screening of compounds for antimicrobial activity. Automation generally accelerated assays and required less user intervention while producing comparable results. Automated protocols were validated for planktonic, biofilm, and agar cultures of the oral microbe Streptococcus mutans that is commonly associated with tooth decay. Toxicity assays for the known antimicrobial compound cetylpyridinium chloride (CPC) were validated against planktonic, biofilm forming, and 24 h biofilm culture conditions, and several commonly reported toxicity/antimicrobial activity measures were evaluated: the 50 % inhibitory concentration (IC50), the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC). Using automated methods, three halide salts of cetylpyridinium (CPC, CPB, CPI) were rapidly screened with no detectable effect of the counter ion on antimicrobial activity.

  5. Antimicrobial activity of Securidaca longipedunculata.

    PubMed

    Ajali, U; Chukwurah, B K C

    2004-11-01

    The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods.

  6. Antimicrobial activity of Bryum argenteum.

    PubMed

    Sabovljevic, Aneta; Sokovic, Marina; Sabovljevic, Marko; Grubisic, Dragoljub

    2006-02-01

    The antimicrobial activity of Bryum argenteum ethanol extracts was evaluated by microdilution method against four bacterial (Escherichia coli, Bacillus subtilis, Micrococcus luteus and Staphilococcus aureus) and four fungal species (Aspergillus niger, Penicillium ochrochloron, Candida albicans and Trichophyton mentagrophyes). All the investigated ethanol extracts have been proved to be active against all bacteria and fungi tested.

  7. Antimicrobial Activity of Commercial Nanoparticles

    NASA Astrophysics Data System (ADS)

    Gajjar, Priyanka; Pettee, Brian; Britt, David W.; Huang, Wenjie; Johnson, William P.; Anderson, Anne J.

    2009-07-01

    Engineered nanoparticles are finding increased use in applications ranging from biosensors to prophylactic antimicrobials embedded in socks. The release of heavy metal-containing nanoparticles (NP) into the environment may be harmful to the efficacy of beneficial microbes that function in element cycling, pollutant degradation, and plant growth. Antimicrobial activity of commercial NP of Ag, CuO, and ZnO is demonstrated here against the beneficial soil microbe, Pseudomonas putida KT2440, which was modified to serve as a bioluminescent sentinel organism. "As manufactured" preparations of nano- Ag, -CuO, and -ZnO caused rapid, dose dependent loss of light output in the biosensor. Bulk equivalents of these products showed no inhibitory activity, indicating that particle size was determinant in activity.

  8. Antimicrobial activity of Gymnema sylvestre leaf extract.

    PubMed

    Satdive, R K; Abhilash, P; Fulzele, Devanand P

    2003-12-01

    The ethanolic extract of Gymnema sylvestre leaves demonstrated antimicrobial activity against Bacillus pumilis, B. subtilis, Pseudomonas aeruginosa and Staphylococcus aureus and inactivity against Proteus vulgaris and Escherichia coli.

  9. [Antimicrobial activity of Calendula L. plants].

    PubMed

    Radioza, S A; Iurchak, L D

    2007-01-01

    The sap of different organs of genus Calendula plant species has been studied for antimicrobial activity. The sap of racemes demonstrated the most expressed antimicrobial effect while that of the roots - the least one. Calendula species inhibited all tested pathogenic microorganisms, especially Pseudomonas syringae, P. fluorescens, Xanthomonas campestris, Agrobacterium tumefaciens. Calendula suffruticosa was the most active to all investigated microorganisms.

  10. [Antimicrobial activity exerted by sodium dichloroisocyanurate].

    PubMed

    D'Auria, F D; Simonetti, G; Strippoli, V

    1989-01-01

    Sodium dichloroisocyanurate is a chlorinated cleaner. It was used for swimming pool sanitation and for the sterilisation of linen. Not recently ago sodium dichloroisocyanurate has substituted hypochlorite for the sterilisation of infant feeding bottles and teats. Sodium dichloroisocyanurate is soluble in water; this condition causes the hydrolysis of sodium dichloroisocyanurate in hypochlorous acid, that is the active agent, isocyanurate and isocyanurate chlorine. These compounds form a chlorine protein that carry out microbicidal activity. In a toxicology study has been shown that no severe changes in the normal metabolic function occurred, furthermore sodium dichloroisocyanurate has not shown teratogenic effects at the concentration of 200 mg/kg. The antimicrobial activity of sodium dichloroisocyanurate was evaluated against Gram negative bacteria such as E. coli or Salmonella typhimurium and against some fungi. This study illustrates a rapid antimicrobial activity using concentrations. Our study concentrated on the antimicrobial activity of sodium dichloroisocyanurate in some experimental conditions. We tested 66 strains of fungi, 28 Gram positive bacteria and 29 Gram negative bacteria. We also evaluated the antimicrobial activity of sodium dichloroisocyanurate against protozoa such as Trichomonas vaginalis. The antimicrobial activity was evaluated in cultural conditions and non cultural conditions; in these experiments we observed similar action in both the commercial product and pure substance. In cultural conditions sodium dichloroisocyanurate shows a good activity against fungi and bacteria, moreover it can be observed that the serum didn't interfere with its activity. In a non cultural condition the Candida was killed rapidly by the sodium dichloroisocyanurate but this activity is influenced by the growth phase of the yeast. Against mycelial form such as Penicillium and Aspergillus the sodium dichloroisocyanurate needs a longer contact time than yeast form

  11. The antimicrobial efficiency of silver activated sorbents

    NASA Astrophysics Data System (ADS)

    Đolić, Maja B.; Rajaković-Ognjanović, Vladana N.; Štrbac, Svetlana B.; Rakočević, Zlatko Lj.; Veljović, Đorđe N.; Dimitrijević, Suzana I.; Rajaković, Ljubinka V.

    2015-12-01

    This study is focused on the surface modifications of the materials that are used for antimicrobial water treatment. Sorbents of different origin were activated by Ag+-ions. The selection of the most appropriate materials and the most effective activation agents was done according to the results of the sorption and desorption kinetic studies. Sorption capacities of selected sorbents: granulated activated carbon (GAC), zeolite (Z), and titanium dioxide (T), activated by Ag+-ions were following: 42.06, 13.51 and 17.53 mg/g, respectively. The antimicrobial activity of Ag/Z, Ag/GAC and Ag/T sorbents were tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. After 15 min of exposure period, the highest cell removal was obtained using Ag/Z against S. aureus and E. coli, 98.8 and 93.5%, respectively. Yeast cell inactivation was unsatisfactory for all three activated sorbents. The antimicrobial pathway of the activated sorbents has been examined by two separate tests - Ag+-ions desorbed from the activated surface to the aqueous phase and microbial cell removal caused by the Ag+-ions from the solid phase (activated surface sites). The results indicated that disinfection process significantly depended on the microbial-activated sites interactions on the modified surface. The chemical state of the activating agent had crucial impact to the inhibition rate. The characterization of the native and modified sorbents was performed by X-ray diffraction technique, X-ray photoelectron spectroscopy and scanning electron microscope. The concentration of adsorbed and released ions was determined by inductively coupled plasma optical emission spectroscopy and mass spectrometry. The antimicrobial efficiency of activated sorbents was related not only to the concentration of the activating agent, but moreover on the surface characteristics of the material, which affects the distribution and the accessibility of the activating agent.

  12. Antimicrobial activity of chemically modified dextran derivatives.

    PubMed

    Tuchilus, Cristina G; Nichifor, Marieta; Mocanu, Georgeta; Stanciu, Magdalena C

    2017-04-01

    Cationic amphiphilic dextran derivatives with a long alkyl group attached to the reductive end of the polysaccharide chain and quaternary ammonium groups attached as pendent groups to the main dextran backbone were synthesized and tested for their antimicrobial properties against several bacteria and fungi strains. Dependence of antimicrobial activity on both polymer chemical composition (dextran molar mass, length of end alkyl group and chemical structure of ammonium groups) and type of microbes was highlighted by disc-diffusion method (diameter of inhibition zone) and broth microdilution method (minimum inhibitory concentrations). Polymers had antimicrobial activity for all strains studied, except for Pseudomonas aeruginosa ATCC 27853. The best activity against Staphylococcus aureus (Minimun Inhibitory Concentration 60μg/mL) was provided by polymers obtained from dextran with lower molecular mass (Mn=4500), C12H25 or C18H37 end groups, and N,N-dimethyl-N-benzylammonium pendent groups.

  13. The Antimicrobial Activity of Porphyrin Attached Polymers

    NASA Astrophysics Data System (ADS)

    Thompson, Lesley

    2008-03-01

    We are interested in testing the antimicrobial activity of a porphyrin that is attached to a polymer. The porphyrin (5-(4-carboxyphenyl)-10,15,20-tris-(4-pryridyl)) was synthesized from methyl 4-formyl benzoate, 4-pyridinecarboxaldehyde, and pyrrole and attached to a copolymer of polystyrene/poly(vinyl benzyl chloride), which was synthesized by free radical polymerization. The antimicrobial activity of the polymer-attached porphyrin was then determined for gram-negative E. Coli grown to 0.80 OD. In this procedure, glass slides were coated with polymer-attached porphyrin via dip-coating, and the E. Coli bacteria were plated in Luria Broth media. The plates were subsequently exposed to light overnight before they were incubated as porphyrins act as photo-sensitizers when irradiated with light. The polymer-attached porphyrin did exhibit antimicrobial activity and parameters that affect its efficiency will be discussed.

  14. Antimicrobial Activity of Indigofera suffruticosa

    PubMed Central

    Leite, Sônia Pereira; Vieira, Jeymesson Raphael Cardoso; de Medeiros, Paloma Lys; Leite, Roberta Maria Pereira; de Menezes Lima, Vera Lúcia; Xavier, Haroudo Satiro; de Oliveira Lima, Edeltrudes

    2006-01-01

    Various organic and aqueous extracts of leaves of Indigofera suffruticosa Mill (Fabaceae) obtained by infusion and maceration were screened for their antibacterial and antifungal activities. The extracts were tested against 5 different species of human pathogenic bacteria and 17 fungal strains by the agar-solid diffusion method. Most of the extracts were devoid of antifungal and antibacterial activities, except the aqueous extract of leaves of I. suffruticosa obtained by infusion, which showed strong inhibitory activity against the Gram-positive bacteria Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 5000 µg ml−1. The MIC values to dermatophyte strains were 2500 µg ml−1 against Trichophyton rubrum (LM-09, LM-13) and Microsporum canis. This study suggests that aqueous extracts of leaves of I. suffruticosa obtained by infusion can be used in the treatment of skin diseases caused by dermatophytes. PMID:16786057

  15. Antimicrobial activity of Aspilia latissima (Asteraceae).

    PubMed

    Souza, Jeana M E; Chang, Marilene R; Brito, Daniela Z; Farias, Katyuce S; Damasceno-Junior, Geraldo A; Turatti, Izabel C C; Lopes, Norberto P; Santos, Edson A; Carollo, Carlos A

    2015-01-01

    We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MIC of 500 μg/mL. This fraction was submitted to bioautographic assays to characterize the activity of the compounds. Two bands from the leaves (L-A and L-B) and three bands from the roots (R-C, R-D and R-E) were bioactive. Within the root-derived bands, the terpene derivatives stigmasterol, kaurenoic acid and kaura-9(11), 16-dien-18-oic acid were identified. Antibiotic activity of A. latissima is reported for the first time.

  16. Antimicrobial Activity of Carbon-Based Nanoparticles

    PubMed Central

    Maleki Dizaj, Solmaz; Mennati, Afsaneh; Jafari, Samira; Khezri, Khadejeh; Adibkia, Khosro

    2015-01-01

    Due to the vast and inappropriate use of the antibiotics, microorganisms have begun to develop resistance to the commonly used antimicrobial agents. So therefore, development of the new and effective antimicrobial agents seems to be necessary. According to some recent reports, carbon-based nanomaterials such as fullerenes, carbon nanotubes (CNTs) (especially single-walled carbon nanotubes (SWCNTs)) and graphene oxide (GO) nanoparticles show potent antimicrobial properties. In present review, we have briefly summarized the antimicrobial activity of carbon-based nanoparticles together with their mechanism of action. Reviewed literature show that the size of carbon nanoparticles plays an important role in the inactivation of the microorganisms. As major mechanism, direct contact of microorganisms with carbon nanostructures seriously affects their cellular membrane integrity, metabolic processes and morphology. The antimicrobial activity of carbon-based nanostructures may interestingly be investigated in the near future owing to their high surface/volume ratio, large inner volume and other unique chemical and physical properties. In addition, application of functionalized carbon nanomaterials as carriers for the ordinary antibiotics possibly will decrease the associated resistance, enhance their bioavailability and provide their targeted delivery. PMID:25789215

  17. ANTIMICROBIAL ACTIVITY OF EXTRACTS FROM ECUADORIAN LICHENS.

    PubMed

    Matvieieva, N A; Pasichnyk, L A; Zhytkevych, N V; Jacinto, Pabón Garcés Galo; Pidgorskyi, V S

    2015-01-01

    Antimicrobial activity of the ethanolic, isopropanolic, acetone, DMSO and aqueous extracts of the two lichen species from Ecuadorian highland, Usnea sp. and Stereocaulon sp. were explored in vitro against bacteria Bacillus subtilis, Escherichia coli and Staphylococcus aureus by the disc-diffusion method. Also the minimal inhibitory concentration (MIC) was determined. The strongest antimicrobial activity was found in DMSO extract of Usnea sp. compared to antibacterial activity of ciprfloxacin and cefazolin antibiotics. The inhibition zone was 28 mm, 30 mm, 31mm (DMSO extract, ciprfloxacin and cefazolin respectively) in case of B. subtilis usage as the test bacteria. MIC value for Usnea sp. and Stereocaulon sp. DMSO extracts was 0.4 mg/ml. E. coli was resistant to all kinds of extracts. The S. aureus sensitivity to lichen DMSO extracts was comparable to sensitivity of these microorganisms to tetracycline and vancomycin. Thereby, most kinds of extracts (ethanol, isopropanol, hexane, DMSO and acetone solvents) from Ecuadorian lichens Usnea sp. and Stereocaulon sp. with the exception of aqueous Stereocaulon sp. extracts possessed antibacterial activity against B. subtilis. DMSO lichen extracts had also antimicrobial activity against S. aureus. At the same time the extracts studied didn't demonstrate antibacterial activity against the representatives of the most common and harmful phytopathogenic bacteria tested. Further investigations of Ecuadorian lichens especially study of plants collected from extremal highland biotops can be very important in study of possibility of treatment of numerous diseases caused by pathogenic microorganisms.

  18. Antimicrobial activity of preparation Bioaron C.

    PubMed

    Gawron-Gzella, Anne; Michalak, Anna; Kędzia, Anna

    2014-01-01

    The antimicrobial activity of sirupus Bioaron C, a preparation, whose main ingredient is an extract from the leaves of Aloe arborescens, was tested against different microorganisms isolated from patients with upper respiratory tract infections. The experiments were performed on 40 strains: 20 strains of anaerobic bacteria, 13 strains of aerobic bacteria and 7 strains of yeast-like fungi from the genus Candida and on 18 reference strains (ATCC). The antimicrobial activity of Bioaron C (MBC and MFC) was determined at undiluted concentration. Bioaron C proved to be very effective against the microorganisms causing infections. At the concentration recommended by the producer, the preparation showed biocidal activity (MBC, MFC) against the strains of the pathogenic microorganisms, which cause respiratory infections most frequently, including, among others, Peptostreptococcus anaerobius, Parvimonas micra, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus anginosus, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa and Candida albicans, already after 15 min. The MIC of Bioaron C against most of the tested microorganisms was 5 to 100 times lower than the usually applied concentration. The great antimicrobial activity means that the preparation may be used in the prevention and treatment of infections of the upper respiratory tract. Bioaron C may be an alternative or complement to classical therapy, especially in children.

  19. Magnesium Based Materials and their Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Robinson, Duane Allan

    The overall goals of this body of work were to characterize the antimicrobial properties of magnesium (Mg) metal and nano-magnesium oxide (nMgO) in vitro, to evaluate the in vitro cytotoxicity of Mg metal, and to incorporate MgO nanoparticles into a polymeric implant coating and evaluate its in vitro antimicrobial properties. In the course of this work it was found that Mg metal, Mg-mesh, and nMgO have in vitro antimicrobial properties that are similar to a bactericidal antibiotic. For Mg metal, the mechanism of this activity appears to be related to an increase in pH (i.e. a more alkaline environment) and not an increase in Mg2+. Given that Mg-mesh is a Mg metal powder, the assumption is that it has the same mechanism of activity as Mg metal. The mechanism of activity for nMgO remains to be elucidated and may be related to a combination of interaction of the nanoparticles with the bacteria and the alkaline pH. It was further demonstrated that supernatants from suspensions of Mg-mesh and nMgO had the same antimicrobial effect as was noted when the particles were used. The supernatant from Mg-mesh and nMgO was also noted to prevent biofilm formation for two Staphylococcus strains. Finally, poly-epsilon-caprolactone (PCL) composites of Mg-mesh (PCL+Mg-mesh) and nMgO (PCL+nMgO) were produced. Coatings applied to screws inhibited growth of Escherichia coli and Pseudomonas aeruginosa and in thin disc format inhibited the growth of Staphylococcus aureus in addition to the E. coli and P. aeruginosa. Pure Mg metal was noted to have some cytotoxic effect on murine fibroblast and osteoblast cell lines, although this effect needs to be characterized further. To address the need for an in vivo model for evaluating implant associated infections, a new closed fracture osteomyelitis model in the femur of the rat was developed. Magnesium, a readily available and inexpensive metal was shown to have antimicrobial properties that appear to be related to its corrosion products and

  20. Antimicrobial activity of naphthoquinones from fusaria.

    PubMed

    Baker, R A; Tatum, J H; Nemec, S

    1990-07-01

    Twenty-two naphthoquinone compounds isolated or derived synthetically from culture extracts of Fusarium solani and F. oxysporum were examined for antimicrobial activity. Fifteen exhibited antibiotic activity against Staphylococcus aureus, and 12 were active against Streptococcus pyogenes, but none were active at the highest rate of 128 micrograms/ml against Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Serratia marcescens, or Pseudomonas aeruginosa. Of 8 plant pathogenic bacteria tested against 11 naphthoquinones, Corynebacterium poinsettiae was inhibited by 6 compounds, and Pseudomonas viridiflava was weakly inhibited by one. Only one of a group of 6 fluorescent soil pseudomonads was inhibited by one naphthoquinone. Antifungal activity of 10 compounds against 8 fungal plant pathogens was limited to inhibition of Phytophthora parasitica by one naphthopyran.

  1. Kombucha fermentation and its antimicrobial activity.

    PubMed

    Sreeramulu, G; Zhu, Y; Knol, W

    2000-06-01

    Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the "tea fungus" and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacterpylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha.

  2. Assessing the antimicrobial activities of Ocins

    PubMed Central

    Choyam, Shilja; Lokesh, Dhanashree; Kempaiah, Bettadaiah Bheemakere; Kammara, Rajagopal

    2015-01-01

    The generation of a zone of inhibition on a solid substrate indicates the bioactivity of antimicrobial peptides such as bacteriocin and enterocin. The indicator strain plays a significant role in bacteriocin assays. Other characteristics of bacteriocins, such as their dispersal ability and the different zymogram components, also affect bacteriocin assays. However, universal well diffusion assays for antimicrobials, irrespective of their ability to diffuse (bacteriocin and enterocin), do not exist. The ability of different zymography components to generate non-specific activities have rarely been explored in the literature. The purpose of the present work was to evaluate the impact of major factors (diffusion and rate of diffusion) in a solid substrate bioassay, and to document the adverse effects of sodium dodecyl sulfate in zymograms used to estimate the approximate molecular weight of bacteriocins. PMID:26441952

  3. Antimicrobial Activity against Intraosteoblastic Staphylococcus aureus

    PubMed Central

    Trouillet-Assant, Sophie; Riffard, Natacha; Tasse, Jason; Flammier, Sacha; Rasigade, Jean-Philippe; Chidiac, Christian; Vandenesch, François; Ferry, Tristan; Laurent, Frédéric

    2015-01-01

    Although Staphylococcus aureus persistence in osteoblasts, partly as small-colony variants (SCVs), can contribute to bone and joint infection (BJI) relapses, the intracellular activity of antimicrobials is not currently considered in the choice of treatment strategies for BJI. Here, antistaphylococcal antimicrobials were evaluated for their intraosteoblastic activity and their impact on the intracellular emergence of SCVs in an ex vivo osteoblast infection model. Osteoblastic MG63 cells were infected for 2 h with HG001 S. aureus. After killing the remaining extracellular bacteria with lysostaphin, infected cells were incubated for 24 h with antimicrobials at the intraosseous concentrations reached with standard therapeutic doses. Intracellular bacteria and SCVs were then quantified by plating cell lysates. A bactericidal effect was observed with fosfomycin, linezolid, tigecycline, oxacillin, rifampin, ofloxacin, and clindamycin, with reductions in the intracellular inocula of −2.5, −3.1, −3.9, −4.2, −4.9, −4.9, and −5.2 log10 CFU/100,000 cells, respectively (P < 10−4). Conversely, a bacteriostatic effect was observed with ceftaroline and teicoplanin, whereas vancomycin and daptomycin had no significant impact on intracellular bacterial growth. Ofloxacin, daptomycin, and vancomycin significantly limited intracellular SCV emergence. Overall, ofloxacin was the only molecule to combine an excellent intracellular activity while limiting the emergence of SCVs. These data provide a basis for refining the choice of antibiotics to prioritise in the management of BJI, justifying the combination of a fluoroquinolone for its intracellular activity with an anti-biofilm molecule, such as rifampin. PMID:25605365

  4. Antiendotoxin activity of cationic peptide antimicrobial agents.

    PubMed

    Gough, M; Hancock, R E; Kelly, N M

    1996-12-01

    The endotoxin from gram-negative bacteria consists of a molecule lipopolysaccharide (LPS) which can be shed by bacteria during antimicrobial therapy. A resulting syndrome, endotoxic shock, is a leading cause of death in the developed world. Thus, there is great interest in the development of antimicrobial agents which can reverse rather than promote sepsis, especially given the recent disappointing clinical performance of antiendotoxin therapies. We describe here two small cationic peptides, MBI-27 and MBI-28, which have both antiendotoxic and antibacterial activities in vitro and in vivo in animal models. We had previously demonstrated that these peptides bind to LPS with an affinity equivalent to that of polymyxin B. Consistent with this, the peptides blocked the ability of LPS and intact cells to induce the endotoxic shock mediator, tumor necrosis factor (TNF), upon incubation with the RAW 264.7 murine macrophage cell line. MBI-28 was equivalent to polymyxin B in its ability to block LPS induction of TNF by this cell line, even when added 60 min after the TNF stimulus. Furthermore, MBI-28 offered significant protection in a galactosamine-sensitized mouse model of lethal endotoxic shock. This protection correlated with the ability of MBI-28 to reduce LPS-induced circulating TNF by nearly 90% in this mouse model. Both MBI-27 and MBI-28 demonstrated antibacterial activity against gram-negative bacteria in vitro and in vivo against Pseudomonas aeruginosa infections in neutropenic mice.

  5. Antiendotoxin activity of cationic peptide antimicrobial agents.

    PubMed Central

    Gough, M; Hancock, R E; Kelly, N M

    1996-01-01

    The endotoxin from gram-negative bacteria consists of a molecule lipopolysaccharide (LPS) which can be shed by bacteria during antimicrobial therapy. A resulting syndrome, endotoxic shock, is a leading cause of death in the developed world. Thus, there is great interest in the development of antimicrobial agents which can reverse rather than promote sepsis, especially given the recent disappointing clinical performance of antiendotoxin therapies. We describe here two small cationic peptides, MBI-27 and MBI-28, which have both antiendotoxic and antibacterial activities in vitro and in vivo in animal models. We had previously demonstrated that these peptides bind to LPS with an affinity equivalent to that of polymyxin B. Consistent with this, the peptides blocked the ability of LPS and intact cells to induce the endotoxic shock mediator, tumor necrosis factor (TNF), upon incubation with the RAW 264.7 murine macrophage cell line. MBI-28 was equivalent to polymyxin B in its ability to block LPS induction of TNF by this cell line, even when added 60 min after the TNF stimulus. Furthermore, MBI-28 offered significant protection in a galactosamine-sensitized mouse model of lethal endotoxic shock. This protection correlated with the ability of MBI-28 to reduce LPS-induced circulating TNF by nearly 90% in this mouse model. Both MBI-27 and MBI-28 demonstrated antibacterial activity against gram-negative bacteria in vitro and in vivo against Pseudomonas aeruginosa infections in neutropenic mice. PMID:8945527

  6. Antimicrobial activity of two essential oils.

    PubMed

    Mickienė, Rūta; Bakutis, Bronius; Baliukonienė, Violeta

    2011-01-01

    The aim of the study was to evaluate the antimicrobial activity of essential oils in vitro for possible application to reduce the content of microorganisms in the air of animal houses. The essential oils of Cymbopogon citrarus L. and Malaleuca alternifolia L. were screened against bacteria Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis and yeast Candida albicans. The minimal inhibitory concentration of the active essential oils was tested using broth dilution assay. The essential oils concentrations ranged from 0.1-50.0%. The combined effects of essential oils were tested for Malaleuca alternifolia L. and Cymbopogon citrarus L. concentrations ranged from 0.005-50.0%. The oils showed a wide spectrum of antibacterial activity. Concentrations of 0.1-0.5% of Cymbopogon citrarus L. and Malaleuca alternifolia L. reduced total microorganisms count of Proteus mirabilis and Candida albicans. High antibacterial activity was also revealed for Cymbopogon citrarus L. with bactericidal concentrations of 0.8% for Escherichia coli, 5.0% for Enterococcus faecium, 5.0% for Pseudomonas aeruginosa and 8.0% for Staphylococcus aureus. Bactericidal concentrations of Malaleuca alternifolia L. were 5.0% for Pseudomonas aeruginosa and Enterococcus faecium, and 8.0% for Staphylococcus aureus. The essential oils of Cymbopogon citrarus and Malaleuca alternifolia may be a promising alternative of air disinfection in animal houses.

  7. Impact of interspecific interactions on antimicrobial activity among soil bacteria.

    PubMed

    Tyc, Olaf; van den Berg, Marlies; Gerards, Saskia; van Veen, Johannes A; Raaijmakers, Jos M; de Boer, Wietse; Garbeva, Paolina

    2014-01-01

    Certain bacterial species produce antimicrobial compounds only in the presence of a competing species. However, little is known on the frequency of interaction-mediated induction of antibiotic compound production in natural communities of soil bacteria. Here we developed a high-throughput method to screen for the production of antimicrobial activity by monocultures and pair-wise combinations of 146 phylogenetically different bacteria isolated from similar soil habitats. Growth responses of two human pathogenic model organisms, Escherichia coli WA321 and Staphylococcus aureus 533R4, were used to monitor antimicrobial activity. From all isolates, 33% showed antimicrobial activity only in monoculture and 42% showed activity only when tested in interactions. More bacterial isolates were active against S. aureus than against E. coli. The frequency of interaction-mediated induction of antimicrobial activity was 6% (154 interactions out of 2798) indicating that only a limited set of species combinations showed such activity. The screening revealed also interaction-mediated suppression of antimicrobial activity for 22% of all combinations tested. Whereas all patterns of antimicrobial activity (non-induced production, induced production and suppression) were seen for various bacterial classes, interaction-mediated induction of antimicrobial activity was more frequent for combinations of Flavobacteria and alpha- Proteobacteria. The results of our study give a first indication on the frequency of interference competitive interactions in natural soil bacterial communities which may forms a basis for selection of bacterial groups that are promising for the discovery of novel, cryptic antibiotics.

  8. Biologically Active and Antimicrobial Peptides from Plants

    PubMed Central

    Salas, Carlos E.; Badillo-Corona, Jesus A.; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application. PMID:25815307

  9. [Evaluation of antimicrobial activity of indol alkaloids].

    PubMed

    Rojas Hernández, N M

    1979-01-01

    In pursuing the study of the antimicrobial properties of alkaloids prepared from Cuban plants the activity of 10 indol alkaloids and 4 semisynthetic variables obtained from three plants--Catharanthus roseus G. Don., Vallesia antillana Wood and Ervatamia coronaria Staph, of the family Apocynaceae--growing in Cuba was assessed in vitro. The alkaloids and the variables used were catharantine, vindoline, vindolinine, perivine, reserpine, tabernaemontanine, tetrahydroalstonine, aparicine, vindolinic acid, reserpic acid and vindolininol. These were faced to 40 bacterial strains from the genera Salmonella, Shigella, Proteus, Escherichia, Pseudomonas, Staphylococcus and Corynebacterium as well as to fungi and yeasts from the genera Aspergillus, kCunnighamella, kCandida and Saccharomyces. The method involving cylindric sections in a double agar layer was applied and lectures were obtained at 24-48 hours of incubation at 25 degrees C for fungi and yeasts and 37 degrees C for bacteria. Inhibition zones are reported in millimeters.

  10. Biologically active and antimicrobial peptides from plants.

    PubMed

    Salas, Carlos E; Badillo-Corona, Jesus A; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

    2015-01-01

    Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application.

  11. Peptides with Dual Antimicrobial and Anticancer Activities

    PubMed Central

    Felício, Mário R.; Silva, Osmar N.; Gonçalves, Sônia; Santos, Nuno C.; Franco, Octávio L.

    2017-01-01

    In recent years, the number of people suffering from cancer and multi-resistant infections has increased, such that both diseases are already seen as current and future major causes of death. Moreover, chronic infections are one of the main causes of cancer, due to the instability in the immune system that allows cancer cells to proliferate. Likewise, the physical debility associated with cancer or with anticancer therapy itself often paves the way for opportunistic infections. It is urgent to develop new therapeutic methods, with higher efficiency and lower side effects. Antimicrobial peptides (AMPs) are found in the innate immune system of a wide range of organisms. Identified as the most promising alternative to conventional molecules used nowadays against infections, some of them have been shown to have dual activity, both as antimicrobial and anticancer peptides (ACPs). Highly cationic and amphipathic, they have demonstrated efficacy against both conditions, with the number of nature-driven or synthetically designed peptides increasing year by year. With similar properties, AMPs that can also act as ACPs are viewed as future chemotherapeutic drugs, with the advantage of low propensity to resistance, which started this paradigm in the pharmaceutical market. These peptides have already been described as molecules presenting killing mechanisms at the membrane level, but also acting toward intracellular targets, which increases their success compartively to one-target specific drugs. This review will approach the desirable characteristics of small peptides that demonstrated dual activity against microbial infections and cancer, as well as the peptides engaged in clinical trials. PMID:28271058

  12. Cationic Hydrophobic Peptides with Antimicrobial Activity

    PubMed Central

    Stark, Margareta; Liu, Li-Ping; Deber, Charles M.

    2002-01-01

    The MICs of cationic, hydrophobic peptides of the prototypic sequence KKAAAXAAAAAXAAWAAXAAAKKKK-amide (where X is one of the 20 commonly occurring amino acids) are in a low micromolar range for a panel of gram-negative and gram-positive bacteria, with no or low hemolytic activity against human and rabbit erythrocytes. The peptides are active only when the average segmental hydrophobicity of the 19-residue core is above an experimentally determined threshold value (where X is Phe, Trp, Leu, Ile, Met, Val, Cys, or Ala). Antimicrobial activity could be increased by using peptides that were truncated from the prototype length to 11 core residues, with X being Phe and with 6 Lys residues grouped at the N terminus. We propose a mechanism for the interaction between these peptides and bacterial membranes similar to the “carpet model,” wherein the Lys residues interact with the anionic phospholipid head groups in the bacterial membrane surface and the hydrophobic core portion of the peptide is then able to interact with the lipid bilayer, causing disruption of the bacterial membrane. PMID:12384369

  13. Antimicrobial activity of alcohols from Musca domestica.

    PubMed

    Gołębiowski, Marek; Dawgul, Małgorzata; Kamysz, Wojciech; Boguś, Mieczysława I; Wieloch, Wioletta; Włóka, Emilia; Paszkiewicz, Monika; Przybysz, Elżbieta; Stepnowski, Piotr

    2012-10-01

    Information on the stimulatory and inhibitory effects of cuticular alcohols on growth and virulence of insecticidal fungi is unavailable. Therefore, we set out to describe the content of cuticular and internal alcohols in the body of housefly larvae, pupae, males and females. The total cuticular alcohols in larvae, males and females of Musca domestica were detected in comparable amounts (4.59, 3.95 and 4.03 μg g(-1) insect body, respectively), but occurred in smaller quantities in pupae (2.16 μg g(-1)). The major free alcohol in M. domestica larvae was C(12:0) (70.4%). Internal alcohols of M. domestica larvae were not found. Among cuticular pupae alcohols, C(12:0) (31.0%) was the most abundant. In the internal lipids of pupae, only five alcohols were identified in trace amounts. The most abundant alcohol in males was C(24:0) (57.5%). The percentage content of cuticular C(24:0) in males and females (57.5 and 36.5%, respectively) was significantly higher than that of cuticular lipids in larvae and pupae (0.9 and 5.6%, respectively). Only two alcohols were present in the internal lipids of males in trace amounts (C(18:0) and C(20:0)). The most abundant cuticular alcohols in females were C(24:0) (36.5%) and C(12:0) (26.8%); only two alcohols (C(18:0) and C(20:0)) were detected in comparable amounts in internal lipids (3.61±0.32 and 5.01±0.42 μg g(-1), respectively). For isolated alcohols, antimicrobial activity against 10 reference strains of bacteria and fungi was determined. Individual alcohols showed approximately equal activity against fungal strains. C(14:0) was effective against gram-positive bacteria, whereas gram-negative bacteria were resistant to all tested alcohols. Mixtures of alcohols found in cuticular lipids of larvae, pupae, males and females of M. domestica generally presented higher antimicrobial activity than individual alcohols. In contrast, crude extracts containing both cuticular and internal lipids showed no antifungal activity against the

  14. Antimicrobial activity of selected herbal extracts.

    PubMed

    Gowthamarajan, K; Kulkarni, T Giriraj; Mahadevan, N; Santhi, K; Suresh, B

    2002-01-01

    METHANOLIC EXTRACT OF OLEORESINS OF ARAUCARIA BIDWILLI HOOK: and aerial parts of Cytisus scoparius Linn. Were screened for antimicrobial activity against two bacterial strains-Bacillus subtilis (Gram Positive) and Escherichia coli (Gem negative), and two fungal strains - Candida albicans and crytococcus neoformans by two-fold serial dilution technique. The results showed that all the microorganisms used were sensitive to the extracts. The minimum inhibitory concentrations (MIC) for A. bidwilli were found to be 31.25 μg/ml for Bacillus subtilis and 500 μg/ml for all other organisms used in the study. In case of C. Scoparius, the MIC values were 250 μg/ml for B. Subtilis and 500 μg/ml for allthe other strains used. However, in comparison the ampicillin (MIC: 62.5 μg/ml), and Amphotericin-B (MIC: 125 μg/ml ), the activities of both the extracts were less except A. bidwilli against B.Subtilis.

  15. Antimicrobial resistance and the activities of the Codex Alimentarius Commission.

    PubMed

    Bruno, A V; Mackay, Carolissen

    2012-04-01

    The Codex Alimentarius Commission has been working on the subject of antimicrobial resistance, mainly through the activities of the Committee on Residues of Veterinary Drugs in Foods and the ad hoc Intergovernmental Task Force on Antimicrobial Resistance. Principal texts developed by Codex include the 'Code of Practice to Minimize and Contain Antimicrobial Resistance (CAC/RCP 61-2005) and 'Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance' (CAC/GL 77-2011). The successful containment of antimicrobial resistance requires the collaboration of a wide range of stakeholders, working together to protect consumer health by ensuring the safety of food products of animal origin.

  16. Antimicrobial activity of human islet amyloid polypeptides: an insight into amyloid peptides' connection with antimicrobial peptides.

    PubMed

    Wang, Lan; Liu, Qian; Chen, Jin-Chun; Cui, Yi-Xian; Zhou, Bing; Chen, Yong-Xiang; Zhao, Yu-Fen; Li, Yan-Mei

    2012-07-01

    Human islet amyloid polypeptide (hIAPP) shows an antimicrobial activity towards two types of clinically relevant bacteria. The potency of hIAPP varies with its aggregation states. Circular dichroism was employed to determine the interaction between hIAPP and bacteria lipid membrane mimic. The antimicrobial activity of each aggregate species is associated with their ability to induce membrane disruption. Our findings provide new evidence revealing the antimicrobial activity of amyloid peptide, which suggest a possible connection between amyloid peptides and antimicrobial peptides.

  17. Cytotoxicity and Antimicrobial Activity of Oral Rinses In Vitro

    PubMed Central

    Müller, Heinz-Dieter; Moritz, Andreas; Lussi, Adrian

    2017-01-01

    While oral rinses used for cosmetic purposes only do not necessarily have to be antiseptic, antimicrobial activity is required for medical indications, including oral and periodontal surgery. So the question arises—is the antimicrobial activity of oral rinses associated with any destructive changes in cell viability in vitro? To answer this question, we examined twelve oral rinses with respect to their antimicrobial and cytotoxic activity. Antimicrobial activity was screened against five bacterial strains using disc diffusion. Cytotoxicity was determined by mitochondrial reductase activity with primary gingival fibroblasts, L929 cells, and HSC-2 epithelial cells. Phase contrast microscopy and trypan blue staining were then performed to reveal cell morphology. Cells remained vital after exposure to oral rinses that were only used for cosmetic purposes. Moderate cytotoxic effects were observed for oral rinses containing 0.05% chlorhexidine, ethanol, or pegylated hydrogenated castor oil and sodium dodecyl sulfate. Other oral rinses containing 0.2% chlorhexidine and cocamidopropyl betaine exhibited strong cytotoxic and antimicrobial activity. Strong cytotoxic but moderate antimicrobial activity was observed in oral rinses containing cetylpyridinium chloride. The in vitro data show that oral rinses are heterogeneous with respect to their cytotoxic and antimicrobial effects. Based on their respective properties, oral rinses can be selected either to reduce the microbial load or for cosmetic purposes.

  18. Antimicrobial activity of extracts of Terminalia catappa root.

    PubMed

    Pawar, S P; Pal, S C

    2002-06-01

    The effect against bacteria of petroleum ether (60-80 degrees C), chloroform and methanolic extract of dried root of Terminalia catappa Linn. (combrataceae) was employed by cup plate agar diffusion method. The chloroform extract showed prominent antimicrobial activity against S. aureus and E. coli as compared to other tested microorganisms, while petroleum ether extract was devoid of antimicrobial activity. The methanolic: extract exhibited MIC of 0.065 mg/ml against E. coli. and chloroform extract exhibited MIC of 0.4 mg/ml against S. aureus The chloroform has well as methanolic extracts showed good antimicrobial activity against Gram positive and Gram negative microorganisms.

  19. Hydrocarbon-stapled lipopeptides exhibit selective antimicrobial activity.

    PubMed

    Jenner, Zachary B; Crittenden, Christopher M; Gonzalez, Martín; Brodbelt, Jennifer S; Bruns, Kerry A

    2017-01-10

    Antimicrobial peptides (AMPs) occur widely in nature and have been studied for their therapeutic potential. AMPs are of interest due to the large number of possible chemical structural combinations using natural and unnatural amino acids, with varying effects on their biological activities. Using physicochemical properties from known naturally occurring amphipathic cationic AMPs, several hydrocarbon-stapled lipopeptides (HSLPs) were designed, synthesized, and tested for antimicrobial properties. Peptides were chemically modified by N-terminal acylation, C-terminal amidation, and some were hydrocarbon stapled by intramolecular olefin metathesis. The effects of peptide length, amphipathic character, and stapling on antimicrobial activity were tested against Escherichia coli, three species of Gram-positive bacteria (Staphylococcus aureus, Bacillus megaterium, and Enterococcus faecalis), and two strains of Candida albicans. Peptides were shown to disrupt liposomes of different phospholipid composition, as measured by leakage of a fluorescent compound from vesicles. Peptides with (S)-2-(4'-pentenyl)-alanine substituted for L-alanine in a reference peptide showed a marked increase in antimicrobial activity, hemolysis, and membrane disruption. Stapled peptides exhibited slightly higher antimicrobial potency; those with greatest hydrophobic character showed the greatest hemolysis and liposome leakage, but lower antimicrobial activity. The results support a model of HSLPs as membrane-disruptive AMPs with potent antimicrobial activity and relatively low hemolytic potential at biologically active peptide concentrations. This article is protected by copyright. All rights reserved.

  20. DBAASP: database of antimicrobial activity and structure of peptides.

    PubMed

    Gogoladze, Giorgi; Grigolava, Maia; Vishnepolsky, Boris; Chubinidze, Mindia; Duroux, Patrice; Lefranc, Marie-Paule; Pirtskhalava, Malak

    2014-08-01

    The Database of Antimicrobial Activity and Structure of Peptides (DBAASP) is a manually curated database for those peptides for which antimicrobial activity against particular targets has been evaluated experimentally. The database is a depository of complete information on: the chemical structure of peptides; target species; target object of cell; peptide antimicrobial/haemolytic/cytotoxic activities; and experimental conditions at which activities were estimated. The DBAASP search page allows the user to search peptides according to their structural characteristics, complexity type (monomer, dimer and two-peptide), source, synthesis type (ribosomal, nonribosomal and synthetic) and target species. The database prediction algorithm provides a tool for rational design of new antimicrobial peptides. DBAASP is accessible at http://www.biomedicine.org.ge/dbaasp/.

  1. Fatty acid conjugation enhances the activities of antimicrobial peptides.

    PubMed

    Li, Zhining; Yuan, Penghui; Xing, Meng; He, Zhumei; Dong, Chuanfu; Cao, Yongchang; Liu, Qiuyun

    2013-04-01

    Antimicrobial peptides are small molecules that play a crucial role in innate immunity in multi-cellular organisms, and usually expressed and secreted constantly at basal levels to prevent infection, but local production can be augmented upon an infection. The clock is ticking as rising antibiotic abuse has led to the emergence of many drug resistance bacteria. Due to their broad spectrum antibiotic and antifungal activities as well as anti-viral and anti-tumor activities, efforts are being made to develop antimicrobial peptides into future microbial agents. This article describes some of the recent patents on antimicrobial peptides with fatty acid conjugation. Potency and selectivity of antimicrobial peptide can be modulated with fatty acid tails of variable length. Interaction between membranes and antimicrobial peptides was affected by fatty acid conjugation. At concentrations above the critical miscelle concentration (CMC), propensity of solution selfassembly hampered binding of the peptide to cell membranes. Overall, fatty acid conjugation has enhanced the activities of antimicrobial peptides, and occasionally it rendered inactive antimicrobial peptides to be bioactive. Antimicrobial peptides can not only be used as medicine but also as food additives.

  2. Antimicrobial activity and phytochemical characterization of Carya illinoensis.

    PubMed

    Bottari, Nathieli Bianchin; Lopes, Leonardo Quintana Soares; Pizzuti, Kauana; Filippi Dos Santos Alves, Camilla; Corrêa, Marcos Saldanha; Bolzan, Leandro Perger; Zago, Adriana; de Almeida Vaucher, Rodrigo; Boligon, Aline Augusti; Giongo, Janice Luehring; Baldissera, Matheus Dellaméa; Santos, Roberto Christ Vianna

    2017-03-01

    Carya illinoensis is a widespread species, belonging to the Juglandaceae family, commonly known as Pecan. Popularly, the leaves have been used in the treatment of smoking as a hypoglycemic, cleansing, astringent, keratolytic, antioxidant, and antimicrobial agent. The following research aimed to identify for the first time the phytochemical compounds present in the leaves of C. illinoensis and carry out the determination of antimicrobial activity of aqueous and ethanolic extracts. The antimicrobial activity was tested against 20 microorganisms by determining the minimum inhibitory concentration (MIC). Phenolic acids (gallic acid and ellagic acid), flavonoids (rutin), and tannins (catechins and epicatechins) were identified by HPLC-DAD and may be partially responsible for the antimicrobial activity against Gram-positive, Gram-negative, and yeast. The results showed MIC values between 25 mg/mL and 0.78 mg/mL. The extracts were also able to inhibit the production of germ tubes by Candida albicans.

  3. Endophytic Fungi Isolated from Coleus amboinicus Lour Exhibited Antimicrobial Activity

    PubMed Central

    Astuti, Puji; Sudarsono, Sudarsono; Nisak, Khoirun; Nugroho, Giri Wisnu

    2014-01-01

    Purpose: Coleus amboinicus is a medicinal plant traditionally used to treat various diseases such as throat infection, cough and fever, diarrhea, nasal congestion and digestive problems. The plant was explored for endophytic fungi producing antimicrobial agents. Methods: Screening for endophytic fungi producing antimicrobial agents was conducted using agar plug method and antimicrobial activity of promising ethyl acetate extracts was determined by disc diffusion assay. Thin layer chromatography (TLC) - bioautography was performed to localize the bioactive components within the extract. TLC visualization detection reagents were used to preliminary analyze phytochemical groups of the bioactive compounds. Results: Three endophytic fungi were obtained, two of them showed promising potential. Agar diffusion method showed that endophytic fungi CAL-2 exhibited antimicrobial activity against P. aeruginosa, B. subtilis, S. aureus and S. thypi, whilst CAS-1 inhibited the growth of B. subtilis. TLC bioautography of ethyl acetate extract of CAL-2 revealed at least three bands exhibited antimicrobial activity and at least two bands showed inhibition of B. subtilis growth. Preliminary analysis of the crude extracts suggests that bioactive compounds within CAL-2 extract are terpenoids, phenolics and phenyl propanoid compounds whilst the antimicrobial agents within CAS-1 extract are terpenoids, propylpropanoids, alkaloids or heterocyclic nitrogen compounds. Conclusion: These data suggest the potential of endophytic fungi of C. amboinicus as source for antimicrobial agents. PMID:25671195

  4. Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

    PubMed

    Guzman, Juan David

    2014-11-25

    Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.

  5. Quaternized Chitosan as an Antimicrobial Agent: Antimicrobial Activity, Mechanism of Action and Biomedical Applications in Orthopedics

    PubMed Central

    Tan, Honglue; Ma, Rui; Lin, Chucheng; Liu, Ziwei; Tang, Tingting

    2013-01-01

    Chitosan (CS) is a linear polysaccharide with good biodegradability, biocompatibility and antimicrobial activity, which makes it potentially useful for biomedical applications, including an antimicrobial agent either alone or blended with other polymers. However, the poor solubility of CS in most solvents at neutral or high pH substantially limits its use. Quaternary ammonium CS, which was prepared by introducing a quaternary ammonium group on a dissociative hydroxyl group or amino group of the CS, exhibited improved water solubility and stronger antibacterial activity relative to CS over an entire range of pH values; thus, this quaternary modification increases the potential biomedical applications of CS in the field of anti-infection. This review discusses the current findings on the antimicrobial properties of quaternized CS synthesized using different methods and the mechanisms of its antimicrobial actions. The potential antimicrobial applications in the orthopedic field and perspectives regarding future studies in this field are also considered. PMID:23325051

  6. Lipid selectivity in novel antimicrobial peptides: Implication on antimicrobial and hemolytic activity.

    PubMed

    Maturana, P; Martinez, M; Noguera, M E; Santos, N C; Disalvo, E A; Semorile, L; Maffia, P C; Hollmann, A

    2017-05-01

    Antimicrobial peptides (AMPs) are small cationic molecules that display antimicrobial activity against a wide range of bacteria, fungi and viruses. For an AMP to be considered as a therapeutic option, it must have not only potent antibacterial properties but also low hemolytic and cytotoxic activities [1]. Even though many studies have been conducted in order to correlate the antimicrobial activity with affinity toward model lipid membranes, the use of these membranes to explain cytotoxic effects (especially hemolysis) has been less explored. In this context, we studied lipid selectivity in two related novel AMPs, peptide 6 (P6) and peptide 6.2 (P6.2). Each peptide was designed from a previously reported AMP, and specific amino acid replacements were performed in an attempt to shift their hydrophobic moment or net charge. P6 showed no antimicrobial activity and high hemolytic activity, and P6.2 exhibited good antibacterial and low hemolytic activity. Using both peptides as a model we correlated the affinity toward membranes of different lipid composition and the antimicrobial and hemolytic activities. Our results from surface pressure and zeta potential assays showed that P6.2 exhibited a higher affinity and faster binding kinetic toward PG-containing membranes, while P6 showed this behavior for pure PC membranes. The final position and structure of P6.2 into the membrane showed an alpha-helix conversion, resulting in a parallel alignment with the Trps inserted into the membrane. On the other hand, the inability of P6 to adopt an amphipathic structure, plus its lower affinity toward PG-containing membranes seem to explain its poor antimicrobial activity. Regarding erythrocyte interactions, P6 showed the highest affinity toward erythrocyte membranes, resulting in an increased hemolytic activity. Overall, our data led us to conclude that affinity toward negatively charged lipids instead of zwitterionic ones seems to be a key factor that drives from hemolytic to

  7. Antimicrobial activity in the common seawhip, Leptogorgia virgulata (Cnidaria: Gorgonaceae).

    PubMed

    Shapo, Jacqueline L; Moeller, Peter D; Galloway, Sylvia B

    2007-09-01

    Antimicrobial activity was examined in the gorgonian Leptogorgia virgulata (common seawhip) from South Carolina waters. Extraction and assay protocols were developed to identify antimicrobial activity in crude extracts of L. virgulata. Detection was determined by liquid growth inhibition assays using Escherichia coli BL21, Vibrio harveyii, Micrococcus luteus, and a Bacillus sp. isolate. This represents the first report of antimicrobial activity in L. virgulata, a temperate/sub-tropical coral of the western Atlantic Ocean. Results from growth inhibition assays guided a fractionation scheme to identify active compounds. Reverse-phase HPLC, HPLC-mass spectrometry, and 1H and 13C NMR spectroscopy were used to isolate, purify, and characterize metabolites in antimicrobial fractions of L. virgulata. Corroborative HPLC-MS/NMR evidence validated the presence of homarine and a homarine analog, well-known emetic metabolites previously isolated from L. virgulata, in coral extracts. In subsequent assays, partially-purified L. virgulata fractions collected from HPLC-MS fractionation were shown to contain antimicrobial activity using M. luteus and V. harveyii. This study provides evidence that homarine is an active constituent of the innate immune system in L. virgulata. We speculate it may act synergistically with cofactors and/or congeners in this octocoral to mount a response to microbial invasion and disease.

  8. Antimicrobial activity of essences from labiates.

    PubMed

    Larrondo, J V; Agut, M; Calvo-Torras, M A

    1995-01-01

    Bacteria, filamentous fungi and yeasts were subjected to the action of Lavandula officinalis, Melissa officinalis and Rosmarinus officinalis essences in a steam phase, using a microatmospheric technique. Due to the methodology employed, L. officinalis essence was more active in filamentous fungi than the other essential oils studied. All three essences possessed a similar degree of activity against the micro-organisms tested, though a relatively higher activity was seen in the case of M. officinalis.

  9. Antimicrobial activity of antiseptic-coated orthopaedic devices.

    PubMed

    Darouiche, R O; Green, G; Mansouri, M D

    1998-04-01

    Antimicrobial coating of medical devices, including fracture fixation devices, has evolved as a potentially effective method for preventing device-related infections. We examined the in vitro antimicrobial activity of titanium cylinders coated with the antiseptic combination of chlorhexidine and chloroxylenol. The coated devices provided zones of inhibition against Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans, at baseline and up to 8 weeks after incubation of the coated cylinders in human serum at 37 degrees C. This durable antimicrobial activity was attributed to the relatively slow leaching of chlorhexidine and chloroxylenol from the coated cylinders as measured by high-performance liquid chromatography. These results suggest that antiseptic-coated orthopaedic devices may provide broad-spectrum and durable antimicrobial protection against device-related infection.

  10. Activities of Antimicrobial Agents against Intracellular Pneumococci

    PubMed Central

    Mandell, Gerald L.; Coleman, Elizabeth J.

    2000-01-01

    Pneumococci can enter and survive inside human lung alveolar carcinoma cells. We examined the activity of azithromycin, gentamicin, levofloxacin, moxifloxacin, penicillin G, rifampin, telithromycin, and trovafloxacin against pneumococci inside and outside cells. We found that moxifloxacin, trovafloxacin, and telithromycin were the most active, but only telithromycin killed all intracellular organisms. PMID:10952618

  11. Synergistic antimicrobial activities of natural essential oils with chitosan films.

    PubMed

    Wang, Lina; Liu, Fei; Jiang, Yanfeng; Chai, Zhi; Li, Pinglan; Cheng, Yongqiang; Jing, Hao; Leng, Xiaojing

    2011-12-14

    The synergistic antimicrobial activities of three natural essential oils (i.e., clove bud oil, cinnamon oil, and star anise oil) with chitosan films were investigated. Cinnamon oil had the best antimicrobial activity among three oils against Escherichia coli , Staphylococcus aureus , Aspergillus oryzae , and Penicillium digitatum . The chitosan solution exhibited good inhibitory effects on the above bacteria except the fungi, whereas chitosan film had no remarkable antimicrobial activity. The cinnamon oil-chitosan film exhibited a synergetic effect by enhancing the antimicrobial activities of the oil, which might be related to the constant release of the oil. The cinnamon oil-chitosan film had also better antimicrobial activity than the clove bud oil-chitosan film. The results also showed that the compatibility of cinnamon oil with chitosan in film formation was better than that of the clove bud oil with chitosan. However, the incorporated oils modified the mechanical strengths, water vapor transmission rate, moisture content, and solubility of the chitosan film. Furthermore, chemical reaction took place between cinnamon oil and chitosan, whereas phase separation occurred between clove bud oil and chitosan.

  12. Activity of 10 antimicrobial agents against intracellular Rhodococcus equi.

    PubMed

    Giguère, Steeve; Berghaus, Londa J; Lee, Elise A

    2015-08-05

    Studies with facultative intracellular bacterial pathogens have shown that evaluation of the bactericidal activity of antimicrobial agents against intracellular bacteria is more closely associated with in vivo efficacy than traditional in vitro susceptibility testing. The objective of this study was to determine the relative activity of 10 antimicrobial agents against intracellular Rhodococcus equi. Equine monocyte-derived macrophages were infected with virulent R. equi and exposed to erythromycin, clarithromycin, azithromycin, rifampin, ceftiofur, gentamicin, enrofloxacin, vancomycin, imipenem, or doxycycline at concentrations achievable in plasma at clinically recommended dosages in foals. The number of intracellular R. equi was determined 48h after infection by counting colony forming units (CFUs). The number of R. equi CFUs in untreated control wells were significantly higher than those of monolayers treated with antimicrobial agents. Numbers of R. equi were significantly lower in monolayers treated with enrofloxacin followed by those treated with gentamicin, and vancomycin, when compared to monolayers treated with other antimicrobial agents. Numbers of R. equi in monolayers treated with doxycycline were significantly higher than those of monolayers treated with other antimicrobial agents. Differences in R. equi CFUs between monolayers treated with other antimicrobial agents were not statistically significant. Enrofloxacin, gentamicin, and vancomycin are the most active drugs in equine monocyte-derived macrophages infected with R. equi. Additional studies will be needed to determine if these findings correlate with in vivo efficacy.

  13. Mechanical properties that influence antimicrobial peptide activity in lipid membranes.

    PubMed

    Marín-Medina, Nathaly; Ramírez, Diego Alejandro; Trier, Steve; Leidy, Chad

    2016-12-01

    Antimicrobial peptides are small amphiphilic proteins found in animals and plants as essential components of the innate immune system and whose function is to control bacterial infectious activity. In order to accomplish their function, antimicrobial peptides use different mechanisms of action which have been deeply studied in view of their potential exploitation to treat antibiotic-resistant bacterial infections. One of the main mechanisms of action of these peptides is the disruption of the bacterial membrane through pore formation, which, in some cases, takes place via a monomer to oligomer cooperative transition. Previous studies have shown that lipid composition, and the presence of exogenous components, such as cholesterol in model membranes or carotenoids in bacteria, can affect the potency of distinct antimicrobial peptides. At the same time, considering the membrane as a two-dimensional material, it has been shown that membrane composition defines its mechanical properties which might be relevant in many membrane-related processes. Nevertheless, the correlation between the mechanical properties of the membrane and antimicrobial peptide potency has not been considered according to the importance it deserves. The relevance of these mechanical properties in membrane deformation due to peptide insertion is reviewed here for different types of pores in order to elucidate if indeed membrane composition affects antimicrobial peptide activity by modulation of the mechanical properties of the membrane. This would also provide a better understanding of the mechanisms used by bacteria to overcome antimicrobial peptide activity.

  14. Comparison of antimicrobial activities of naphthoquinones from Impatiens balsamina.

    PubMed

    Sakunphueak, Athip; Panichayupakaranant, Pharkphoom

    2012-01-01

    Lawsone (1), lawsone methyl ether (2), and methylene-3,3'-bilawsone (3) are the main naphthoquinones in the leaf extracts of Impatiens balsamina L. (Balsaminaceae). Antimicrobial activities of these three naphthoquinones against dermatophyte fungi, yeast, aerobic bacteria and facultative anaerobic and anaerobic bacteria were evaluated by determination of minimal inhibitory concentrations (MICs) and minimal bactericidal or fungicidal concentrations (MBCs or MFCs) using a modified agar dilution method. Compound 2 showed the highest antimicrobial activity. It showed antifungal activity against dermatophyte fungi and Candida albicans with the MICs and MFCs in the ranges of 3.9-23.4 and 7.8-23.4 µg mL(-1), respectively, and also had some antibacterial activity against aerobic, facultative anaerobic and anaerobic bacteria with MICs in the range of 23.4-93.8, 31.2-62.5 and 125 µg mL(-1), respectively. Compound 1 showed only moderate antimicrobial activity against dermatophytes (MICs and MFCs in the ranges of 62.5-250 and 125-250 µg mL(-1), respectively), but had low potency against aerobic bacteria, and was not active against C. albicans and facultative anaerobic bacteria. In contrast, 3 showed significant antimicrobial activity only against Staphylococus epidermidis and Bacillus subtilis (MIC and MBC of 46.9 and 93.8 µg mL(-1), respectively).

  15. Synthesis and antimicrobial activity of cysteine-free coprisin nonapeptides.

    PubMed

    Lee, Jaeho; Lee, Daeun; Choi, Hyemin; Kim, Ha Hyung; Kim, Ho; Hwang, Jae Sam; Lee, Dong Gun; Kim, Jae Il

    2014-01-10

    Coprisin is a 43-mer defensin-like peptide from the dung beetle, Copris tripartitus. CopA3 (LLCIALRKK-NH₂), a 9-mer peptide containing a single free cysteine residue at position 3 of its sequence, was derived from the α-helical region of coprisin and exhibits potent antibacterial and anti-inflammatory activities. The single cysteine implies a tendency for dimerization; however, it remains unknown whether this cysteine residue is indispensible for CopA3's antimicrobial activity. To address this issue, in the present study we synthesized eight cysteine-substituted monomeric CopA3 analogs and two dimeric analogs, CopA3 (Dimer) and CopIK (Dimer), and evaluated their antimicrobial effects against bacteria and fungi, as well as their hemolytic activity toward human erythrocytes. Under physiological conditions, CopA3 (Mono) exhibits a 6/4 (monomer/dimer) molar ratio in HPLC area percent, indicating that its effects on bacterial strains likely reflect a CopA3 (Mono)/CopA3 (Dimer) mixture. We also report the identification of CopW, a new cysteine-free nonapeptide derived from CopA3 that has potent antimicrobial activity with virtually no hemolytic activity. Apparently, the cysteine residue in CopA3 is not essential for its antimicrobial function. Notably, CopW also exhibited significant synergistic activity with ampicillin and showed more potent antifungal activity than either wild-type coprisin or melittin.

  16. Photo-activated DNA binding and antimicrobial activities of furoquinoline and pyranoquinolone alkaloids from rutaceae.

    PubMed

    Hanawa, Fujinori; Fokialakis, Nikolas; Skaltsounis, Alexios-Leandros

    2004-06-01

    To find novel photo-active compounds of potential use in photochemotherapy from higher plants, photo-activated antimicrobial and DNA binding activities of the furoquinolines, skimmianine, kokusaginine, and haplopine, and a pyranoquinolone, flindersine, from two species of Rutaceae plants were investigated. TLC overlay assays against a methichillin-resistant strain of Staphylococcus aureus and Candida albicans were employed to test antimicrobial properties. All of the tested compounds showed photo-activated antimicrobial activity against S. aureus in the order of kokusaginine > haplopine, flindersine > skimmianine. Weaker activity was found for C. albicans. Photo-activated DNA binding activity of these compounds was investigated by a method using restriction enzymes and a specially designed 1.5 kb DNA fragment. Kokusaginine showed inhibition against all of the 16 restriction enzymes. Haplopine showed a similar inhibition pattern but the binding activity against Asc I and Sma I with restriction sequences consisting only of G and C was very weak. Skimmianine showed binding activity against Xba I, BciV I, Sal I, Pst I, Sph I and Hind III, but very weak or no activity was found for the other restriction enzymes. A pyranoquinolone, flindersine, showed no activity against any of the restriction enzymes. Photo-activated DNA binding activity of furoquinolines was therefore in the order of kokusaginine > haplopine > skimmianine, which was the same order as their photo-activated antimicrobial activity against S. aureus. Therefore, it was concluded that DNA is one of the cellular targets for the furoquinolines to exert their biological activities, similar to psoralens. However, because flindersine showed photo-activated antimicrobial activity against S. aureus but did not show photo-activated DNA binding activity, it is clear that there are other cellular target components for this compound to exert photo-toxic activity.

  17. The antimicrobial activity, toxicity and antimicrobial mechanism of a new type of tris(alkylphenyl)sulfonium.

    PubMed

    Hirayama, Michiasa

    2012-03-01

    The antimicrobial activity, toxicity and antimicrobial mechanism of a new type of tris(4-alkylphenyl)sulfonium which has sterically bulky alkyl substituents (bTAPS), were estimated and compared with those of other sulfoniums which we reported previously. Concerning tris {4-(iso-propyl)phenyl}sulfonium (bTAPS-iso3) and tris{4-(tert-butyl)phenyl}sulfonium (bTAPS-tert4), the antimicrobial activity of these compounds tended to be lower than both tri(n-alkyl)sulfoniums (TASs) and tris{4-(n-alkylphenyl)}sulfoniums (TAPSs) at similar ClogP values. However, the activities of tris{4-(cyclohexyl)phenyl}sulfonium (bTAPS-cyclo6) were clearly higher than those of TAS and were almost similar to those of TAPS at similar ClogP values. The mutagenicities of tested bTAPSs were judged to be all negative. Both the acute oral toxicity strength and the acute skin irritation/corrosion toxicity strength tended to follow the order of TAPSs > bTAPSs > TASs. However, only the acute skin irritation/corrosion toxicity strength of bTAPS-cyclo6 was almost as low as that of TAS which has a similar ClogP value to bTAPS-cyclo6. Because bTAPS-cyclo6 has both high antimicrobial activity and low toxicity, this compound might become to be an alternative antimicrobial compound to relatively hazardous antimicrobials which have been widely used in many fields.

  18. Radical scavenging, antioxidant and antimicrobial activities of halophytic species.

    PubMed

    Meot-Duros, Laetitia; Le Floch, Gaëtan; Magné, Christian

    2008-03-05

    For the first time, both antioxidant and antimicrobial activities are simultaneously reported in halophytic plants, particularly on polar fractions. Chloroformic and methanolic extracts of the halophytes Eryngium maritimum L., Crithmum maritimum L. and Cakile maritima Scop. were tested for their antimicrobial activities against 12 bacterial and yeast strains. In addition, radical scavenging and antioxidant activities were assessed, as well as total phenol contents. Only one bacterial strain (Listeria monocytogenes) was not inhibited by plants extracts, and apolar (chloroformic) fractions were generally more active than polar (methanolic) ones. Eryngium maritimum presented the weakest radical scavenging activity (ABTS IC(50)=0.28 mg ml(-1)), as well as the lowest total phenol content (16.4 mg GAE g(-1) DW). However, the three halophytic species had relatively strong total antioxidant activities (from 32.7 to 48.6 mg ascorbate equivalents g (-1) DW). Consequences on the potential use of these plants in food or cosmetic industry are discussed.

  19. Phytochemical screening and antimicrobial activity of Coccinia cordifolia L. plant.

    PubMed

    Khatun, Shahanaz; Pervin, Farzana; Karim, Mohammad Rezaul; Ashraduzzaman, Mohammad; Rosma, Ahmad

    2012-10-01

    The medicinal plant, Coccinia cordifolia L. was analyzed for its chemical composition. The antimicrobial activities of the methanol, water, ethanol and ethyl acetate extracts of Coccinia cordifolia L. plant were evaluated against some Gram positive bacteria (Sarcina lutea, Bacillus subtilis and Staphylococcus aureus), Gram negative bacteria (Salmonella typhi, Shigella dysenteriae and Escherichia coli) and fungi (Candida albicans, Aspergillus niger and Penicillium notatum). Chemical analysis showed that the plant is rich in nutrients, especially antioxidant compounds such as total phenol, vitamin C and β-carotene. Phytochemical screening showed that the methanolic extract contains the bioactive constituents such as tannins, saponins, phenols, flavonoids and terpenoids. In the methanolic extract of the plant, promising antimicrobial potential was observed against the tested microorganism. Methanolic extract showed highest activity against Shigella dysenteriae, Escherichia coli, Staphylococcus aureus, and Candida albicans compared to the other extracts. Water extract showed less antimicrobial activity as compared to other extractants.

  20. Synthesis and Antimicrobial Activity of Silver-Doped Hydroxyapatite Nanoparticles

    PubMed Central

    Ciobanu, Carmen Steluta; Iconaru, Simona Liliana; Chifiriuc, Mariana Carmen; Costescu, Adrian; Le Coustumer, Philippe; Predoi, Daniela

    2013-01-01

    The synthesis of nanosized particles of Ag-doped hydroxyapatite with antibacterial properties is of great interest for the development of new biomedical applications. The aim of this study was the evaluation of Ca10−xAgx(PO4)6(OH)2 nanoparticles (Ag:HAp-NPs) for their antibacterial and antifungal activity. Resistance to antimicrobial agents by pathogenic bacteria has emerged in the recent years and became a major health problem. Here, we report a method for synthesizing Ag doped nanocrystalline hydroxyapatite. A silver-doped nanocrystalline hydroxyapatite was synthesized at 100°C in deionised water. Also, in this paper Ag:HAp-NPs are evaluated for their antimicrobial activity against Gram-positive and Gram-negative bacteria and fungal strains. The specific antimicrobial activity revealed by the qualitative assay is demonstrating that our compounds are interacting differently with the microbial targets, probably due to the differences in the microbial wall structures. PMID:23509801

  1. Chemical composition and antimicrobial activity of Polish herbhoneys.

    PubMed

    Isidorov, V A; Bagan, R; Bakier, S; Swiecicka, I

    2015-03-15

    The present study focuses on samples of Polish herbhoneys (HHs), their chemical composition and antimicrobial activity. A gas chromatography-mass spectrometry (GC-MS) method was used to analyse eight samples of herbal honeys and three samples of nectar honeys. Their antimicrobial activities were tested on selected Gram-positive (Bacillus cereus, Staphylococcus aureus, Staphylococcus schleiferi) and Gram-negative (Escherichia coli) bacteria, as well as on pathogenic fungi Candida albicans. Ether extracts of HHs showed significant differences in composition but the principal groups found in the extracts were phenolics and aliphatic hydroxy acids typical of royal jelly and unsaturated dicarboxylic acids. In spite of the differences in chemical composition, antimicrobial activity of the extracts of HHs against all the tested microorganisms except E. coli was observed.

  2. Bacillus clausii probiotic strains: antimicrobial and immunomodulatory activities.

    PubMed

    Urdaci, Maria C; Bressollier, Philippe; Pinchuk, Irina

    2004-07-01

    The clinical benefits observed with probiotic use are mainly attributed to the antimicrobial substances produced by probiotic strains and to their immunomodulatory effects. Currently, the best-documented probiotic bacteria used in human therapy are lactic acid bacteria. In contrast, studies aiming to characterize the mechanisms responsible for the probiotic beneficial effects of Bacillus are rare. The current work seeks to contribute to such characterization by evaluating the antimicrobial and immunomodulatory activities of probiotic B. clausii strains. B. clausii strains release antimicrobial substances in the medium. Moreover, the release of these antimicrobial substances was observed during stationary growth phase and coincided with sporulation. These substances were active against Gram-positive bacteria, in particular against Staphylococcus aureus, Enterococcus faecium, and Clostridium difficile. The antimicrobial activity was resistant to subtilisin, proteinase K, and chymotrypsin treatment, whereas it was sensitive to pronase treatment. The evaluation of the immunomodulatory properties of probiotic B. clausii strains was performed in vitro on Swiss and C57 Bl/6j murine cells. The authors demonstrate that these strains, in their vegetative forms, are able to induce NOS II synthetase activity, IFN-gamma production, and CD4 T-cell proliferation.

  3. Poisson Parameters of Antimicrobial Activity: A Quantitative Structure-Activity Approach

    PubMed Central

    Sestraş, Radu E.; Jäntschi, Lorentz; Bolboacă, Sorana D.

    2012-01-01

    A contingency of observed antimicrobial activities measured for several compounds vs. a series of bacteria was analyzed. A factor analysis revealed the existence of a certain probability distribution function of the antimicrobial activity. A quantitative structure-activity relationship analysis for the overall antimicrobial ability was conducted using the population statistics associated with identified probability distribution function. The antimicrobial activity proved to follow the Poisson distribution if just one factor varies (such as chemical compound or bacteria). The Poisson parameter estimating antimicrobial effect, giving both mean and variance of the antimicrobial activity, was used to develop structure-activity models describing the effect of compounds on bacteria and fungi species. Two approaches were employed to obtain the models, and for every approach, a model was selected, further investigated and found to be statistically significant. The best predictive model for antimicrobial effect on bacteria and fungi species was identified using graphical representation of observed vs. calculated values as well as several predictive power parameters. PMID:22606039

  4. Antimicrobial Activity and Stability of Electron Beam Irradiated Dental Irrigants

    PubMed Central

    Geethashri, A; Palaksha, K.J.; Sridhar, K. R.; Sanjeev, Ganesh

    2014-01-01

    Background: The electron beam (e-beam) radiation is considered as an effective means of sterilization of healthcare products as well as to induce the structural changes in the pharmaceutical agents/drug molecules. In addition to structural changes of pharmaceutical it also induces the formation of low molecular weight compounds with altered microbiological, physicochemical and toxicological properties. Among the several known medicaments, sodium hypochlorite (NaOCl) and chlorhexidine digluconate (CHX) are used as irrigants in dentistry to kill the pathogenic microorganisms like Enterococcus faecalis, Staphylococcus aureus, Streptococcus mutans and Candida albicans inhabiting the oral cavity. Objectives: The aim of this study was to evaluate the antimicrobial activity and stability of e-beam irradiated dental irrigants, NaOCl and CHX. Materials and Methods: Two dental irrigants NaOCl (1.25% and 2.5%) and CHX (1% and 2%) were exposed to various doses of e-beam radiation. The antimicrobial activities of e-beam irradiated irrigants were compared with the non-irradiated (control) irrigants against E. faecalis, S. aureus, S. mutans and C. albicans by disc diffusion method. Following the storage, physico-chemical properties of the irrigants were recorded and the cytotoxic effect was evaluated on human gingival fibroblast cells. Result: The irrigants, 1.25% NaOCl and 1% CHX showed significantly increased antimicrobial activity against both E. faecalis, (16+0.0) and S. aureus (25+0.0) after irradiation with 1 kGy e-beam. Whereas, 2.5% NaOCl and 2% CHX showed slightly increased antimicrobial activity only against S. aureus (28+0.0). The significant difference was noticed in the antimicrobial activity and cytotoxicity of irradiated and non-irradiated irrigants following the storage for 180 d at 40C. Conclusion: The e-beam irradiation increased the antimicrobial activity of irrigants without altering the biocompatibility. PMID:25584220

  5. The antimicrobial activities of the cinnamaldehyde adducts with amino acids.

    PubMed

    Wei, Qing-Yi; Xiong, Jia-Jun; Jiang, Hong; Zhang, Chao; Wen Ye

    2011-11-01

    Cinnamaldehyde is a well-established natural antimicrobial compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff base adduct in real food system. In this paper, 9 such kind of adducts were prepared by the direct reaction of amino acids with cinnamaldehyde at room temperature. Their antimicrobial activities against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae were evaluated with benzoic acid as a reference. The adducts showed a dose-dependent activities against the three microbial strains. Both cinnamaldehyde and their adducts were more active against B. subtilis than on E. coli, and their antimicrobial activities were higher at lower pH. Both cinnamaldehyde and its adducts were more active than benzoic acid at the same conditions. The adduct compound A was non-toxic by primary oral acute toxicity study in mice. However, in situ effect of the adduct compound A against E. coli was a little lower than cinnamaldehyde in fish meat. This paper for the first time showed that the cinnamaldehyde adducts with amino acids had similar strong antimicrobial activities as cinnamaldehyde, which may provide alternatives to cinnamaldehyde in food to avoid the strong unacceptable odor of cinnamaldehyde.

  6. [Isolation and antimicrobial activities of actinomycetes from vermicompost].

    PubMed

    Wang, Xue-jun; Yan, Shuang-lin; Min, Chang-li; Yang, Yan

    2015-02-01

    In this paper, actinomycetes were isolated from vermicompost by tablet coating method. Antimicrobial activities of actinomycetes were measured by the agar block method. Strains with high activity were identified based on morphology and biochemical characteristics, as well as 16S rDNA gene sequence analysis. The results showed that 26 strains of actinomycetes were isolated, 16 of them had antimicrobial activities to the test strains which accounts for 61.54% of all strains. Among the 16 strains, the strain QYF12 and QYF22 had higher antimicrobial activity to Micrococcus luteus, with a formed inhibition zone of 27 mm and 31 mm, respectively. While the strain QYF26 had higher antimicrobial activity to Bacillus subtilis, and the inhibition zone diameter was 21 mm. Based on the identification of strains with high activity, the strain QYF12 was identified as Streptomyces chartreusis, the strain QYF22 was S. ossamyceticus and the strain QYF26 was S. gancidicus. This study provided a theoretical basis for further separate antibacterial product used for biological control.

  7. Design of novel analogues of short antimicrobial peptide anoplin with improved antimicrobial activity.

    PubMed

    Wang, Yang; Chen, Jianbo; Zheng, Xin; Yang, Xiaoli; Ma, Panpan; Cai, Ying; Zhang, Bangzhi; Chen, Yuan

    2014-12-01

    Currently, novel antibiotics are urgently required to combat the emergence of drug-resistant bacteria. Antimicrobial peptides with membrane-lytic mechanism of action have attracted considerable interest. Anoplin, a natural α-helical amphiphilic antimicrobial peptide, is an ideal research template because of its short sequence. In this study, we designed and synthesized a group of analogues of anoplin. Among these analogues, anoplin-4 composed of D-amino acids displayed the highest antimicrobial activity due to increased charge, hydrophobicity and amphiphilicity. Gratifyingly, anoplin-4 showed low toxicity to host cells, indicating high bacterial selectivity. Furthermore, the mortality rate of mice infected with Escherichia coli was significantly reduced by anoplin-4 treatment relative to anoplin. In conclusion, anoplin-4 is a novel anoplin analogue with high antimicrobial activity and enzymatic stability, which may represent a potent agent for the treatment of infection.

  8. Antimicrobial activity of organically modified nano-clays.

    PubMed

    Hong, Seek-In; Rhim, Jong-Whan

    2008-11-01

    Antimicrobial activity of three kinds of commercially available montmorillonite nano-clays including a naturally occurring one (Cloisite Na+) and two organically modified ones (Cloisite 20A and Cloisite 30B) against four representative pathogenic bacteria (two Gram-positive ones such as Staphylococcus aureus and Listeria monocytogenes, and two Gram-negative ones such as Salmonella typhimurium and E. coli O157:H7) was investigated. Antimicrobial activity was found to be dependent on the type of nano-clay and microorganisms tested. Among the nano-clays tested, Cloisite 30B showed the highest antibacterial activity followed by Cloisite 20A, however, the unmodified montmorillonite (Cloisite Na+) did not show any antibacterial activity. Especially, Cloisite 30B inactivated Gram-positive bacteria completely within an hour of incubation and inactivated Gram-negative bacteria by more than 2-3 log cycles after 8 hours incubation. SEM and TEM images of cell structure indicated that the organically modified nano-clay caused rupture of cell membrane and inactivation of the bacteria. This finding of antimicrobial activity of the organo-clay would open a new opportunity to develop polymer nanocomposites with additional functionality, i.e., antimicrobial function.

  9. Antimicrobial activity of nerolidol and its derivatives against airborne microbes and further biological activities.

    PubMed

    Krist, Sabine; Banovac, Daniel; Tabanca, Nurhayat; Wedge, David E; Gochev, Velizar K; Wanner, Jürgen; Schmidt, Erich; Jirovetz, Leopold

    2015-01-01

    Nerolidol and its derivatives, namely cis-nerolidol, O-methyl-nerolidol, O-ethyl-nerolidol, (-)-α-bisabolol, trans,trans-farnesol and its main natural source cabreuva essential oil, were tested for their antimicrobial activity against airborne microbes and antifungal properties against plant pathogens. Among the tested compounds, α-bisabolol was the most effective antimicrobial agent and trans,trans-farnesol showed the best antifungal activity.

  10. In vitro antimicrobial activity of Achyranthes coynei Sant.

    PubMed Central

    Ankad, Gireesh; Upadhya, Vinayak; Pai, Sandeep R.; Hegde, Harsha V.; Roy, Subarna

    2013-01-01

    Objective To validate the traditional use of Achyranthes coynei (A. coynei) Sant. as an antimicrobial in treatment of various infectious diseases. Methods Leaf extracts of A. coynei obtained through successive solvent extraction using petroleum ether, dichrloromethane, chloroform and methanol were used to screen the antimicrobial activity on five Gram positive, five Gram negative bacteria and two fungi. Minimum inhibitory concentration (MIC) was determined by two fold tube-dilution method. Results Methanolic leaf extract was more effective than other three extracts on the tested bacteria. Methanolic extract was efficient on Staphylococcus epidermis, Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa with MIC values (0.62±0.00) mg/mL. The fungal organisms were less susceptible against extracts tested. Conclusions These results support the traditional use of leaf extracts of A. coynei as they have antimicrobial potential. Further studies are needed for establishing safety, toxicity and pharmacological activity with phytochemical investigation.

  11. A Novel Teaching Tool Combined With Active-Learning to Teach Antimicrobial Spectrum Activity

    PubMed Central

    2017-01-01

    Objective. To design instructional methods that would promote long-term retention of knowledge of antimicrobial pharmacology, particularly the spectrum of activity for antimicrobial agents, in pharmacy students. Design. An active-learning approach was used to teach selected sessions in a required antimicrobial pharmacology course. Students were expected to review key concepts from the course reader prior to the in-class sessions. During class, brief concept reviews were followed by active-learning exercises, including a novel schematic method for learning antimicrobial spectrum of activity (“flower diagrams”). Assessment. At the beginning of the next quarter (approximately 10 weeks after the in-class sessions), 360 students (three yearly cohorts) completed a low-stakes multiple-choice examination on the concepts in antimicrobial spectrum of activity. When data for students was pooled across years, the mean number of correct items was 75.3% for the items that tested content delivered with the active-learning method vs 70.4% for items that tested content delivered via traditional lecture (mean difference 4.9%). Instructor ratings on student evaluations of the active-learning approach were high (mean scores 4.5-4.8 on a 5-point scale) and student comments were positive about the active-learning approach and flower diagrams. Conclusion. An active-learning approach led to modestly higher scores in a test of long-term retention of pharmacology knowledge and was well-received by students. PMID:28381885

  12. Synthesis and biological activity of lipophilic analogs of the cationic antimicrobial active peptide anoplin.

    PubMed

    Chionis, Kostas; Krikorian, Dimitrios; Koukkou, Anna-Irini; Sakarellos-Daitsiotis, Maria; Panou-Pomonis, Eugenia

    2016-11-01

    Anoplin is a short natural cationic antimicrobial peptide which is derived from the venom sac of the solitary wasp, Anoplius samariensis. Due to its short sequence G(1) LLKR(5) IKT(8) LL-NH2 , it is ideal for research tests. In this study, novel analogs of anoplin were prepared and examined for their antimicrobial, hemolytic activity, and proteolytic stability. Specific substitutions were introduced in amino acids Gly(1) , Arg(5) , and Thr(8) and lipophilic groups with different lengths in the N-terminus in order to investigate how these modifications affect their antimicrobial activity. These cationic analogs exhibited higher antimicrobial activity than the native peptide; they are also nontoxic at their minimum inhibitory concentration (MIC) values and resistant to enzymatic degradation. The substituted peptide GLLKF(5) IKK(8) LL-NH2 exhibited high activity against Gram-negative bacterium Zymomonas mobilis (MIC = 7 µg/ml), and the insertion of octanoic, decanoic, and dodecanoic acid residues in its N-terminus increased the antimicrobial activity against Gram-positive and Gram-negative bacteria (MIC = 5 µg/ml). The conformational characteristics of the peptide analogs were studied by circular dichroism. Structure activity studies revealed that the substitution of specific amino acids and the incorporation of lipophilic groups enhanced the amphipathic α-helical conformation inducing better antimicrobial effects. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  13. Motualevic Acids and Analogs: Synthesis and Antimicrobial Structure Activity Relationships

    PubMed Central

    Cheruku, Pradeep; Keffer, Jessica L.; Dogo-Isonagie, Cajetan; Bewley, Carole A.

    2010-01-01

    Synthesis of the marine natural products motualevic acids A, E, and analogs in which modifications have been made to the ω-brominated lipid (E)-14,14-dibromotetra-deca-2,13-dienoic acid or amino acid unit are reported, together with antimicrobial activities against Staphylococcus aureus, methicillin-resistant S. aureus, Enterococcus faecium, and vancomycin-resistant Enterococcus. PMID:20538459

  14. Antioxidant, antimicrobial and antiproliferative activities of five lichen species.

    PubMed

    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Comić, Ljiljana; Dačić, Dragana; Curčić, Milena; Marković, Snežana

    2011-01-01

    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.

  15. The Antimicrobial Activity of Liposomal Lauric Acids Against Propionibacterium acnes

    PubMed Central

    Yang, Darren; Pornpattananangkul, Dissaya; Nakatsuji, Teruaki; Chan, Michael; Carson, Dennis; Huang, Chun-Ming; Zhang, Liangfang

    2009-01-01

    This study evaluated the antimicrobial activity of lauric acid (LA) and its liposomal derivatives against Propionibacterium acnes (P. acnes), the bacterium that promotes inflammatory acne. First, the antimicrobial study of three free fatty acids (lauric acid, palmitic acid and oleic acid) demonstrated that LA gives the strongest bactericidal activity against P. acnes. However, a setback of using LA as a potential treatment for inflammatory acne is its poor water solubility. Then the LA was incorporated into a liposome formulation to aid its delivery to P. acnes. It's demonstrated that the antimicrobial activity of LA was not only well maintained in its liposomal derivatives but also enhanced at low LA concentration. In addition, the antimicrobial activity of LA-loaded liposomes (LipoLA) mainly depended on the LA loading concentration per single liposomes. Further study found that the LipoLA could fuse with the membranes of P. acnes and release the carried LA directly into the bacterial membranes, thereby killing the bacteria effectively. Since LA is a natural compound that is the main acid in coconut oil and also resides in human breast milk and liposomes have been successfully and widely applied as a drug delivery vehicle in the clinic, the LipoLA developed in this work holds great potential of becoming an innate, safe and effective therapeutic medication for acne vulgaris and other P. acnes associated diseases. PMID:19665786

  16. Antioxidant, Antimicrobial and Antiproliferative Activities of Five Lichen Species

    PubMed Central

    Mitrović, Tatjana; Stamenković, Slaviša; Cvetković, Vladimir; Tošić, Svetlana; Stanković, Milan; Radojević, Ivana; Stefanović, Olgica; Čomić, Ljiljana; Đačić, Dragana; Ćurčić, Milena; Marković, Snežana

    2011-01-01

    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. PMID:21954369

  17. Repurposing the Antihistamine Terfenadine for Antimicrobial Activity against Staphylococcus aureus

    PubMed Central

    2015-01-01

    Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure–activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics. PMID:25238555

  18. Repurposing the antihistamine terfenadine for antimicrobial activity against Staphylococcus aureus.

    PubMed

    Perlmutter, Jessamyn I; Forbes, Lauren T; Krysan, Damian J; Ebsworth-Mojica, Katherine; Colquhoun, Jennifer M; Wang, Jenna L; Dunman, Paul M; Flaherty, Daniel P

    2014-10-23

    Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.

  19. Chemical reactivity and antimicrobial activity of N-substituted maleimides.

    PubMed

    Salewska, Natalia; Boros-Majewska, Joanna; Lącka, Izabela; Chylińska, Katarzyna; Sabisz, Michał; Milewski, Sławomir; Milewska, Maria J

    2012-02-01

    Several N-substituted maleimides containing substituents of varying bulkiness and polarity were synthesised and tested for antimicrobial and cytostatic activity. Neutral maleimides displayed relatively strong antifungal effect minimum inhibitory concentrations (MICs in the 0.5-4 µg ml(-1) range); their antibacterial activity was structure dependent and all were highly cytostatic, with IC(50) values below 0.1 µg ml(-1). Low antimicrobial but high cytostatic activity was noted for basic maleimides containing tertiary aminoalkyl substituents. Chemical reactivity and lipophilicity influenced antibacterial activity of neutral maleimides but had little if any effect on their antifungal and cytostatic action. N-substituted maleimides affected biosynthesis of chitin and β(1,3)glucan, components of the fungal cell wall. The membrane enzyme, β(1,3)glucan synthase has been proposed as a putative primary target of N-ethylmaleimide and some of its analogues in Candida albicans cells.

  20. Influence of abiotic factors on the antimicrobial activity of chitosan.

    PubMed

    Tavaria, Freni K; Costa, Eduardo M; Gens, Eduardo J; Malcata, Francisco Xavier; Pintado, Manuela E

    2013-12-01

    In an effort to bypass the adverse secondary effects attributed to the traditional therapeutic approaches used to treat skin disorders (such as atopic dermatitis), alternative antimicrobials have recently been suggested. One such antimicrobial is chitosan, owing to the already proved biological properties associated with its use. However, the influence of abiotic factors on such activities warrants evaluation. This research effort assessed the antimicrobial activity of chitosan upon skin microorganisms (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) in vitro when subject to a combination of different abiotic factors such as pH, ionic strength, organic acids and free fatty acids. Free fatty acids, ionic strength and pH significantly affected chitosan's capability of reducing the viable numbers of S. aureus. This antimicrobial action was potentiated in the presence of palmitic acid and a lower ionic strength (0.2% NaCl), while a higher ionic strength (0.4% NaCl) favored chitosan's action upon the reduction of viable numbers of S. epidermidis and E. coli. Although further studies are needed, these preliminary results advocate that chitosan can in the future be potentially considered as an antimicrobial of choice when handling symptoms associated with atopic dermatitis.

  1. Antimicrobial activity of the Anseriform outer eggshell and cuticle.

    PubMed

    Wellman-Labadie, Olivier; Picman, Jaroslav; Hincke, Maxwell T

    2008-04-01

    The avian eggshell is a complex, multifunctional biomineral composed of a calcium carbonate mineral phase and an organic phase of lipids and proteins. The outermost layer of the eggshell, the eggshell cuticle, is an organic layer of variable thickness composed of polysaccharides, hydroxyapatite crystals, lipids and glycoprotein. In addition to regulating gas exchanges, the eggshell cuticle may contain antimicrobial elements. In this study, we investigated the antimicrobial activity of eggshell cuticle and outer eggshell protein extracts from four Anseriform species: wood duck (Aix sponsa), hooded merganser (Lophodytes cucullatus), Canada goose (Branta canadensis) and mute swan (Cygnus olor). Cuticle and outer eggshell protein was extracted by urea or HCl treatment of eggs. C-type lysozyme, ovotransferrin and an ovocalyxin-32-like protein were detected in all extracts. Cuticle and outer eggshell protein extracts inhibited the growth of Staphylococcus aureus, Escherichia coli D31, Pseudomonas aeruginosa and Bacillus subtilis. The presence of active antimicrobial proteins within the avian cuticle and outer eggshell suggests a role in antimicrobial defense. Protein extracts from the cavity nesting hooded merganser were especially potent. The unique environmental pressures exerted on cavity-nesting species may have led to the evolution of potent antimicrobial defenses.

  2. Antimicrobial and antiproliferative activity of Peucedanum nebrodense (Guss.) Strohl.

    PubMed

    Schillaci, D; Venturella, F; Venuti, F; Plescia, F

    2003-07-01

    Acetone extract of Peucedanum nebrodense (Guss.) Strohl., a rare endemic species from the Madonie mountains (Sicily), was tested in vitro for its antimicrobial activity against bacterial reference strains and antiproliferative activity against K562 (human chronic myelogenous leukemia), HL-60 (human leukemia) and L1210 (murine leukemia) cell lines. The acetone extract showed antiproliferative IC50 values in the range of 14-0.27 microg/ml.

  3. In Vitro Antimicrobial and Antiproliferative Activity of Amphipterygium adstringens

    PubMed Central

    Rodriguez-Garcia, A.; Peixoto, I. T. A.; Verde-Star, M. J.; De la Torre-Zavala, S.; Aviles-Arnaut, H.; Ruiz, A. L. T. G.

    2015-01-01

    Amphipterygium adstringens is a plant widely used in Mexican traditional medicine for its known anti-inflammatory and antiulcer properties. In this work, we evaluated the in vitro antimicrobial and antiproliferative activities of the methanolic extract of A. adstringens against oral pathogens such as Streptococcus mutans, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Candida albicans, and Candida dubliniensis, using microdilution (MIC) and agar diffusion methods (MBC), and the antiproliferative activity evaluating total growth inhibition (TGI) by staining the protein content with sulforhodamine B (SRB), using nine human cancer cell lines. Crude extract (CE) of A. adstringens showed some degree of activity against one or more of the strains with a MIC from 0.125 mg/mL to 63 mg/mL and MBC from 1.6 to 6.3 mg/mL and cytotoxic activity, particularly against NCI-ADR/RES, an ovarian cell line expressing multiple resistance drugs phenotype. The CE is a complex mixture of possible multitarget metabolites that could be responsible for both antimicrobial and antiproliferative activities, and further investigation is required to elucidate the identity of active compounds. Nevertheless the CE itself is useful in the development of new antimicrobial treatment based on natural products to prevent oral diseases and as alternative natural source for cancer treatment and prevention. PMID:26451151

  4. Antioxidant, Antimicrobial Activity and Toxicity Test of Pilea microphylla

    PubMed Central

    Modarresi Chahardehi, Amir; Ibrahim, Darah; Fariza Sulaiman, Shaida

    2010-01-01

    A total of 9 plant extracts were tested, using two different kinds of extracting methods to evaluate the antioxidant and antimicrobial activities from Pilea microphylla (Urticaceae family) and including toxicity test. Antioxidant activity were tested by using DPPH free radical scavenging, also total phenolic contents and total flavonoid contents were determined. Toxicity assay carried out by using brine shrimps. Methanol extract of method I (ME I) showed the highest antioxidant activity at 69.51 ± 1.03. Chloroform extract of method I (CE I) showed the highest total phenolic contents at 72.10 ± 0.71 and chloroform extract of method II (CE II) showed the highest total flavonoid contents at 60.14 ± 0.33. The antimicrobial activity of Pilea microphylla extract was tested in vitro by using disc diffusion method and minimum inhibitory concentration (MIC). The Pilea microphylla extract showed antibacterial activity against some Gram negative and positive bacteria. The extracts did not exhibit antifungal and antiyeast activity. The hexane extract of method I (HE I) was not toxic against brine shrimp (LC50 value was 3880 μg/ml). Therefore, the extracts could be suitable as antimicrobial and antioxidative agents in food industry. PMID:20652052

  5. Antimicrobial Activity of Bacteriocins and Their Applications

    NASA Astrophysics Data System (ADS)

    Drosinos, Eleftherios H.; Mataragas, Marios; Paramithiotis, Spiros

    Bacteriocins are peptides or proteins that exert an antimicrobial action against a range of microorganisms. Their production can be related to the antagonism within a certain ecological niche, as the producer strain, being itself immune to its action, generally gains a competitive advantage. Many Gram-positive and Gram-negative microorganisms have been found to produce bacteriocins. The former, and especially the ones produced by lactic acid bacteria, has been the field of intensive research during the last decades mainly due to their properties that account for their suitability in food preservation and the benefits arising from that, and secondarily due to the broader inhibitory spectrum compared to the ones produced by Gramnegative microorganisms.

  6. Antimicrobial Activity of Basil, Oregano, and Thyme Essential Oils.

    PubMed

    Sakkas, Hercules; Papadopoulou, Chrissanthy

    2017-03-28

    For centuries, plants have been used for a wide variety of purposes, from treating infectious diseases to food preservation and perfume production. Presently, the increasing resistance of microorganisms to currently used antimicrobials in combination with the appearance of emerging diseases requires the urgent development of new, more effective drugs. Plants, due to the large biological and structural diversity of their components, constitute a unique and renewable source for the discovery of new antibacterial, antifungal, and antiparasitic compounds. In the present paper, the history, composition, and antimicrobial activities of the basil, oregano, and thyme essential oils are reviewed.

  7. Antioxidant, antimicrobial, and anticancer activity of 3 Umbilicaria species.

    PubMed

    Kosanić, Marijana; Ranković, Branislav; Stanojković, Tatjana

    2012-01-01

    The aim of this study is to investigate in vitro antioxidant, antimicrobial, and anticancer activity of the acetone extracts of the lichens Umbilicaria crustulosa, U. cylindrica, and U. polyphylla. Antioxidant activity was evaluated by 5 separate methods: free radical scavenging, superoxide anion radical scavenging, reducing power, determination of total phenolic compounds, and determination of total flavonoid content. Of the lichens tested, U. polyphylla had largest free radical scavenging activity (72.79% inhibition at a concentration of 1 mg/mL), which was similar as standard antioxidants in the same concentration. Moreover, the tested extracts had effective reducing power and superoxide anion radical scavenging. Total content of phenol and flavonoid in extracts was determined as pyrocatechol equivalent, and as rutin equivalent, respectively. The strong relationships between total phenolic and flavonoid contents and the antioxidant effect of tested extracts were observed. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was extract of U. polyphylla with minimum inhibitory concentration values ranging from 1.56 to 12.5 mg/mL. Anticancer activity was tested against FemX (human melanoma) and LS174 (human colon carcinoma) cell lines using MTT method. All extracts were found to be strong anticancer activity toward both cell lines with IC₅₀ values ranging from 28.45 to 97.82 μg/mL. The present study shows that tested lichen extracts demonstrated a strong antioxidant, antimicrobial, and anticancer effects. That suggests that lichens may be used as possible natural antioxidant, antimicrobial, and anticancer agents.

  8. In-vitro Antimicrobial Activities of Some Iranian Conifers

    PubMed Central

    Afsharzadeh, Maryam; Naderinasab, Mahboobe; Tayarani Najaran, Zahra; Barzin, Mohammad; Emami, Seyed Ahmad

    2013-01-01

    Male and female leaves and fruits of eleven different taxons of Iranian conifers (Cupressus sempervirens var. horizontalis, C. sempervirens var. sempervirens, C. sempervirens cv. Cereifeormis, Juniperus communis subsp. hemisphaerica, J. excelsa subsp. excelsa, J. excelsa subsp. polycarpos, J. foetidissima, J. oblonga, J. sabina, Platycladus orientalis and Taxus baccata) were collected from different localities of Iran, dried and extracted with methanol. The extracts were tested for their antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans. The extracts were screened qualitatively using four different methods, the disc diffusion, hole plate, cylinder agar diffusion and agar dilution methods, whereas the minimum inhibitory concentrations (MIC) of each extract were determined by the agar dilution method. The best result was obtained by means of hole plate method in qualitative determination of antimicrobial activities of extracts and the greatest activity was found against S. aureus in all tested methods. PMID:24250573

  9. In-vitro Antimicrobial Activities of Some Iranian Conifers.

    PubMed

    Afsharzadeh, Maryam; Naderinasab, Mahboobe; Tayarani Najaran, Zahra; Barzin, Mohammad; Emami, Seyed Ahmad

    2013-01-01

    Male and female leaves and fruits of eleven different taxons of Iranian conifers (Cupressus sempervirens var. horizontalis, C. sempervirens var. sempervirens, C. sempervirens cv. Cereifeormis, Juniperus communis subsp. hemisphaerica, J. excelsa subsp. excelsa, J. excelsa subsp. polycarpos, J. foetidissima, J. oblonga, J. sabina, Platycladus orientalis and Taxus baccata) were collected from different localities of Iran, dried and extracted with methanol. The extracts were tested for their antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Candida albicans. The extracts were screened qualitatively using four different methods, the disc diffusion, hole plate, cylinder agar diffusion and agar dilution methods, whereas the minimum inhibitory concentrations (MIC) of each extract were determined by the agar dilution method. The best result was obtained by means of hole plate method in qualitative determination of antimicrobial activities of extracts and the greatest activity was found against S. aureus in all tested methods.

  10. Thymus vulgaris essential oil: chemical composition and antimicrobial activity.

    PubMed

    Borugă, O; Jianu, C; Mişcă, C; Goleţ, I; Gruia, A T; Horhat, F G

    2014-01-01

    The study was designed to determine the chemical composition and antimicrobial properties of the essential oil of Thymus vulgaris cultivated in Romania. The essential oil was isolated in a yield of 1.25% by steam distillation from the aerial part of the plant and subsequently analyzed by GC-MS. The major components were p-cymene (8.41%), γ-terpinene (30.90%) and thymol (47.59%). Its antimicrobial activity was evaluated on 7 common food-related bacteria and fungus by using the disk diffusion method. The results demonstrate that the Thymus vulgaris essential oil tested possesses strong antimicrobial properties, and may in the future represent a new source of natural antiseptics with applications in the pharmaceutical and food industry.

  11. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    PubMed Central

    Shalavi, S; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

  12. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

    PubMed Central

    Ebbensgaard, Anna; Mordhorst, Hanne; Overgaard, Michael Toft; Nielsen, Claus Gyrup; Aarestrup, Frank Møller; Hansen, Egon Bech

    2015-01-01

    Analysis of a Selected Set of Antimicrobial Peptides The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram-negative bacteria. We compared the potency of Cap18, Cap11, Cap11-1-18m2, Cecropin P1, Cecropin B, Bac2A, Bac2A-NH2, Sub5-NH2, Indolicidin, Melittin, Myxinidin, Myxinidin-NH2, Pyrrhocoricin, Apidaecin and Metalnikowin I towards Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia coli, Aeromonas salmonicida, Listeria monocytogenes, Campylobacter jejuni, Flavobacterium psychrophilum, Salmonella typhimurium and Yersinia ruckeri by minimal inhibitory concentration (MIC) determinations. Additional characteristics such as cytotoxicity, thermo and protease stability were measured and compared among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants. Cap18 Shows a High Broad Spectrum Antimicrobial Activity Of all the tested AMPs, Cap18 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria. In addition, Cap18 is highly thermostable and showed no cytotoxic effect in a hemolytic assay, measured at the concentration used. However, Cap18 is, as most of the tested AMPs, sensitive to proteolytic digestion in vitro. Thus, Cap18 is an excellent candidate for further development into practical use; however, modifications that should reduce the protease sensitivity would be needed. In addition, our

  13. Study of the nanomaterials and their antimicrobial activities

    NASA Astrophysics Data System (ADS)

    Ramadi, Muntaha

    In the last decade, the world faced huge problems associated with the spread of antimicrobial resistant infections that are essentially untreatable such as methicillin resistant Staphylococcus aureus (MRSA) infection. These infections have begun to occur in both hospital and community environments. Developing new antimicrobial surface coatings can hold a great promise to minimize and control various problems that associated with the spreading of infections and biofilms formation, these coatings can be used in medicine where medical devices associated with severe infections, in construction industry and the in food packaging industry. It has been established that single-walled CNTs exhibit a strong antimicrobial activity and can pierce bacterial cell walls. Recently, nanomaterial structures that made from pure carbon such as CNTs have been seen as promising candidates for many potential applications in Biotechnology and bioscience due to the combination of their extraordinary properties that arise from surface area, light weight, strength, flexibility, unique electrical conductivity and many more novel physical and chemical properties at nanoscale level. CNTs have been used widely in biomedical field including drug delivery, gene therapy and creating new biomedical devices with novel properties. Researchers have now made a first step to add carbon nanotubes to antimicrobial agents list. There are two types of CNTs have been used in biomedical research. The first one is a single-walled carbon nanotube (SWNT) and the second is a multi-walled carbon nanotube (MWNT). Recent in vitro studies suggest that carbon nanotubes have antimicrobial activity and coating CNTs with nickel nanoparticle could enhance the antimicrobial activity of cabon nanotubes. In order to test this hypothesis, nickel nanoparticles were deposited on carbon nanotubes (CNTs) by electrochemical deposition. The carbon nanotubes used in this study were XD-CNTs, SWNTs and Ni-coated CNTs. The structure and

  14. Selected Antimicrobial Activity of Topical Ophthalmic Anesthetics

    PubMed Central

    Reynolds, Margaret M.; Greenwood-Quaintance, Kerryl E.; Patel, Robin; Pulido, Jose S.

    2016-01-01

    Purpose Endophthalmitis is a rare complication of intravitreal injection (IVI). It is recommended that povidone-iodine be the last agent applied before IVI. Patients have reported povidone-iodine application to be the most bothersome part of IVIs. Topical anesthetics have been demonstrated to have antibacterial effects. This study compared the minimum inhibitory concentration (MIC) of topical anesthetic eye drops (proparacaine 0.5%, tetracaine 0.5%, lidocaine 2.0%) and the antiseptic, 5.0% povidone-iodine, against two organisms causing endophthalmitis after IVI. Methods Minimum inhibitory concentration values of topical anesthetics, povidone-iodine, preservative benzalkonium chloride (0.01%), and saline control were determined using five isolates of each Staphylococcus epidermidis and viridans group Streptococcus species (VGS). A broth microdilution technique was used with serial dilutions. Results Lidocaine (8.53 × 10−5mol/mL) had MICs of 4.27 to 8.53 × 10−5 mol/mL, and tetracaine (1.89 × 10−5 mol/mL) had MICs of 9.45 × 10−6 mol/mL for all isolates. Proparacaine (1.7 × 10−5 mol/mL) had MICs of 1.32 to 5.3 × 10−7 and 4.25 × 10−6 mol/mL for S. epidermidis and VGS, respectively). Benzalkonium chloride (3.52 × 10−7 mol/mL) had MICs of 1.86 × 10−9 to 1.1 × 10−8 and 4.40 × 10−8 mol/mL for S. epidermidis and VGS, respectively. Povidone-iodine (1.37 × 10−4 mol/mL) had MICs of 2.14 to 4.28 × 10−6 and 8.56 × 10−6 mol/mL for S. epidermidis and VGS, respectively. Conclusion Proparacaine was the anesthetic with the lowest MICs, lower than that of povidone-iodine. Benzalkonium chloride had lower MICs than proparacaine. All tested anesthetics and povidone-iodine inhibited growth of S. epidermidis and VGS at commercially available concentrations. Translational Relevance For certain patients, it could be possible to use topical anesthetic after povidone-iodine for comfort without inhibiting and perhaps contributing additional antimicrobial

  15. Antimicrobial activity of bone cements embedded with organic nanoparticles.

    PubMed

    Perni, Stefano; Thenault, Victorien; Abdo, Pauline; Margulis, Katrin; Magdassi, Shlomo; Prokopovich, Polina

    2015-01-01

    Infections after orthopedic surgery are a very unwelcome outcome; despite the widespread use of antibiotics, their incidence can be as high as 10%. This risk is likely to increase as antibiotics are gradually losing efficacy as a result of bacterial resistance; therefore, novel antimicrobial approaches are required. Parabens are a class of compounds whose antimicrobial activity is employed in many cosmetic and pharmaceutical products. We developed propylparaben nanoparticles that are hydrophilic, thus expanding the applicability of parabens to aqueous systems. In this paper we assess the possibility of employing paraben nanoparticles as antimicrobial compound in bone cements. The nanoparticles were embedded in various types of bone cement (poly(methyl methacrylate) [PMMA], hydroxyapatite, and brushite) and the antimicrobial activity was determined against common causes of postorthopedic surgery infections such as: Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, and Acinetobacter baumannii. Nanoparticles at concentrations as low as 1% w/w in brushite bone cement were capable of preventing pathogens growth, 5% w/w was needed for hydroxyapatite bone cement, while 7% w/w was required for PMMA bone cement. No detrimental effect was determined by the addition of paraben nanoparticles on bone cement compression strength and cytocompatibility. Our results demonstrate that paraben nanoparticles can be encapsulated in bone cement, providing concentration-dependent antimicrobial activity; furthermore, lower concentrations are needed in calcium phosphate (brushite and hydroxyapatite) than in acrylic (PMMA) bone cements. These nanoparticles are effective against a wide spectrum of bacteria, including those already resistant to the antibiotics routinely employed in orthopedic applications, such as gentamicin.

  16. Antimicrobial activity of bone cements embedded with organic nanoparticles

    PubMed Central

    Perni, Stefano; Thenault, Victorien; Abdo, Pauline; Margulis, Katrin; Magdassi, Shlomo; Prokopovich, Polina

    2015-01-01

    Infections after orthopedic surgery are a very unwelcome outcome; despite the widespread use of antibiotics, their incidence can be as high as 10%. This risk is likely to increase as antibiotics are gradually losing efficacy as a result of bacterial resistance; therefore, novel antimicrobial approaches are required. Parabens are a class of compounds whose antimicrobial activity is employed in many cosmetic and pharmaceutical products. We developed propylparaben nanoparticles that are hydrophilic, thus expanding the applicability of parabens to aqueous systems. In this paper we assess the possibility of employing paraben nanoparticles as antimicrobial compound in bone cements. The nanoparticles were embedded in various types of bone cement (poly(methyl methacrylate) [PMMA], hydroxyapatite, and brushite) and the antimicrobial activity was determined against common causes of postorthopedic surgery infections such as: Staphylococcus aureus, methicillin-resistant S. aureus, Staphylococcus epidermidis, and Acinetobacter baumannii. Nanoparticles at concentrations as low as 1% w/w in brushite bone cement were capable of preventing pathogens growth, 5% w/w was needed for hydroxyapatite bone cement, while 7% w/w was required for PMMA bone cement. No detrimental effect was determined by the addition of paraben nanoparticles on bone cement compression strength and cytocompatibility. Our results demonstrate that paraben nanoparticles can be encapsulated in bone cement, providing concentration-dependent antimicrobial activity; furthermore, lower concentrations are needed in calcium phosphate (brushite and hydroxyapatite) than in acrylic (PMMA) bone cements. These nanoparticles are effective against a wide spectrum of bacteria, including those already resistant to the antibiotics routinely employed in orthopedic applications, such as gentamicin. PMID:26487803

  17. Antimicrobial activity of Lactobacillus against microbial flora of cervicovaginal infections

    PubMed Central

    Dasari, Subramanyam; Shouri, Raju Naidu Devanaboyaina; Wudayagiri, Rajendra; Valluru, Lokanatha

    2014-01-01

    Objective To assess the probiotic nature of Lactobacillus in preventing cervical pathogens by studying the effectiveness of antimicrobial activity against vaginal pathogens. Methods Lactobacilli were isolated from healthy vaginal swabs on selective media and different pathogenic bacteria were isolated by using different selective media. The Lactobacillus strains were tested for the production of hydrogen peroxide and antimicrobial compounds along with probiotic properties. Results Of the 10 isolated Lactobacillus strains, strain 1, 3 and 6 are high hydrogen peroxide producers and the rest were low producers. Results of pH and amines tests indicated that pH increased with fishy odour in the vaginal fluids of cervicovaginal infection patients when compared with vaginal fluids of healthy persons. The isolates were found to be facultative anaerobic, Gram-positive, non-spore-forming, non-capsule forming and catalase-negative bacilli. The results of antimicrobial activity of compounds indicated that 280 and 140 µg/mL was the minimum concentration to inhibit the growth of both pathogens and test organisms respectively. Conclusions The results demonstrated that Lactobacillus producing antimicrobial compounds inhibits the growth of cervical pathogens, revealing that the hypothesis of preventing vaginal infection by administering probiotic organisms has a great appeal to patients, which colonize the vagina to help, restore and maintain healthy vagina.

  18. Antimicrobial activity of poly(acrylic acid) block copolymers.

    PubMed

    Gratzl, Günther; Paulik, Christian; Hild, Sabine; Guggenbichler, Josef P; Lackner, Maximilian

    2014-05-01

    The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid-base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure.

  19. Antimicrobial activity of the metals and metal oxide nanoparticles.

    PubMed

    Dizaj, Solmaz Maleki; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad Hossein; Adibkia, Khosro

    2014-11-01

    The ever increasing resistance of pathogens towards antibiotics has caused serious health problems in the recent years. It has been shown that by combining modern technologies such as nanotechnology and material science with intrinsic antimicrobial activity of the metals, novel applications for these substances could be identified. According to the reports, metal and metal oxide nanoparticles represent a group of materials which were investigated in respect to their antimicrobial effects. In the present review, we focused on the recent research works concerning antimicrobial activity of metal and metal oxide nanoparticles together with their mechanism of action. Reviewed literature indicated that the particle size was the essential parameter which determined the antimicrobial effectiveness of the metal nanoparticles. Combination therapy with the metal nanoparticles might be one of the possible strategies to overcome the current bacterial resistance to the antibacterial agents. However, further studies should be performed to minimize the toxicity of metal and metal oxide nanoparticles to apply as proper alternatives for antibiotics and disinfectants especially in biomedical applications.

  20. [Antimicrobial activity of Actinomycetale isolated from the lagoon in Algeria].

    PubMed

    Alliouch-Kerboua, Chérifa; Gacemi Kirane, Djamila; La Scola, Bernard

    2015-01-01

    In the aim of the study of the taxonomy and the antimicrobial activity, a strain of actinomycete SM2/2GF which was isolated from sediment of the lagoon El-Mellah which is situated in the city of El-Kala in the Northeast of Algeria, was tested against diverse pathogenic microorganisms and against a Gram-negative bacterium Pseudomonas alcaliphila which was isolated from water of the lagoon El-Mellah. The phenotypic and the molecular characteristics show that the isolate SM2/2GF belongs to the kind Streptomyces. This strain showed an antimicrobial activity against a Gram-negative bacterium Pseudomonas alcaliphila and the positive-Gram bacteria as Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Enterococcus faecalis, as well as the yeast Candida albicans. It has no activity against Pseudomonas aeruginosa. The interesting antimicrobial activity of the strain SM2/2GF against the pathogenic microorganisms could encourage further researches on one or several bioactive molecules which it secretes.

  1. Trigona laeviceps propolis from Thailand: antimicrobial, antiproliferative and cytotoxic activities.

    PubMed

    Umthong, Supawadee; Puthong, Songchan; Chanchao, Chanpen

    2009-01-01

    Propolis is one of the natural bee products which has long been used as a crude preventative and prophylactic medicine, and has been reported to possess antibacterial, antiviral, anti-inflammatory, antioxidative and anticancer properties. Propolis of the stingless bee, Trigona laeviceps, was extracted by water or methanol at 35% (w/v) yielding a crude water or a methanolic extract at 60 and 80 mg/ml, respectively, which is 17.1 and 22.9% (w/w) of the total propolis, respectively. The antimicrobial activity of both crude extracts was assayed on four selected pathogenic microbes by using the agar well diffusion method. The results suggested that both water and methanolic crude extracts have some antimicrobial activities, water extract has greater antimicrobial activity than methanolic extract. The relative order of sensitivity of the four microbes were, however, the same between the two extracts from the most to least sensitive, S. aureus > E. coli > C. albicans > A. niger, with indeed no observed growth inhibition of A. niger at all. Antiproliferative and cytotoxic affects were tested on the colon carcinoma cell line, SW620, using the three parameters: (1) MTT assay; (2) cell morphology; and (3) the fragmentation of genomic DNA. The water extract of propolis showed a higher antiproliferative activity than that of methanolic extract to SW620 cells, additionally both appeared to cause cell death by necrosis.

  2. Peptide consensus sequence determination for the enhancement of the antimicrobial activity and selectivity of antimicrobial peptides

    PubMed Central

    Almaaytah, Ammar; Ajingi, Ya’u; Abualhaijaa, Ahmad; Tarazi, Shadi; Alshar’i, Nizar; Al-Balas, Qosay

    2017-01-01

    The rise of multidrug-resistant bacteria is causing a serious threat to the world’s human population. Recent reports have identified bacterial strains displaying pan drug resistance against antibiotics and generating fears among medical health specialists that humanity is on the dawn of entering a post-antibiotics era. Global research is currently focused on expanding the lifetime of current antibiotics and the development of new antimicrobial agents to tackle the problem of antimicrobial resistance. In the present study, we designed a novel consensus peptide named “Pepcon” through peptide consensus sequence determination among members of a highly homologous group of scorpion antimicrobial peptides. Members of this group were found to possess moderate antimicrobial activity with significant toxicity against mammalian cells. The aim of our design method was to generate a novel peptide with an enhanced antimicrobial potency and selectivity against microbial rather than mammalian cells. The results of our study revealed that the consensus peptide displayed potent antibacterial activities against a broad range of Gram-positive and Gram-negative bacteria. Our membrane permeation studies displayed that the peptide efficiently induced membrane damage and consequently led to cell death through the process of cell lysis. The microbial DNA binding assay of the peptide was found to be very weak suggesting that the peptide is not targeting the microbial DNA. Pepcon induced minimal cytotoxicity at the antimicrobial concentrations as the hemolytic activity was found to be zero at the minimal inhibitory concentrations (MICs). The results of our study demonstrate that the consensus peptide design strategy is efficient in generating peptides. PMID:28096686

  3. Antimicrobial peptides: a review of how peptide structure impacts antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Soares, Jason W.; Mello, Charlene M.

    2004-03-01

    Antimicrobial peptides (AMPs) have been discovered in insects, mammals, reptiles, and plants to protect against microbial infection. Many of these peptides have been isolated and studied exhaustively to decipher the molecular mechanisms that impart protection against infectious bacteria, fungi, and viruses. Unfortunately, the molecular mechanisms are still being debated within the scientific community but valuable clues have been obtained through structure/function relationship studies1. Biophysical studies have revealed that cecropins, isolated from insects and pigs, exhibit random structure in solution but undergo a conformational change to an amphipathic α-helix upon interaction with a membrane surface2. The lack of secondary structure in solution results in an extremely durable peptide able to survive exposure to high temperatures, organic solvents and incorporation into fibers and films without compromising antibacterial activity. Studies to better understand the antimicrobial action of cecropins and other AMPs have provided insight into the importance of peptide sequence and structure in antimicrobial activities. Therefore, enhancing our knowledge of how peptide structure imparts function may result in customized peptide sequences tailored for specific applications such as targeted cell delivery systems, novel antibiotics and food preservation additives. This review will summarize the current state of knowledge with respect to cell binding and antimicrobial activity of AMPs focusing primarily upon cecropins.

  4. Screening antimicrobial activity of various extracts of Urtica dioica.

    PubMed

    Modarresi-Chahardehi, Amir; Ibrahim, Darah; Fariza-Sulaiman, Shaida; Mousavi, Leila

    2012-12-01

    Urtica dioica or stinging nettle is traditionally used as an herbal medicine in Western Asia. The current study represents the investigation of antimicrobial activity of U. dioica from nine crude extracts that were prepared using different organic solvents, obtained from two extraction methods: the Soxhlet extractor (Method I), which included the use of four solvents with ethyl acetate and hexane, or the sequential partitions (Method II) with a five solvent system (butanol). The antibacterial and antifungal activities of crude extracts were tested against 28 bacteria, three yeast strains and seven fungal isolates by the disc diffusion and broth dilution methods. Amoxicillin was used as positive control for bacteria strains, vancomycin for Streptococcus sp., miconazole nitrate (30 microg/mL) as positive control for fungi and yeast, and pure methanol (v/v) as negative control. The disc diffusion assay was used to determine the sensitivity of the samples, whilst the broth dilution method was used for the determination of the minimal inhibition concentration (MIC). The ethyl acetate and hexane extract from extraction method I (EA I and HE I) exhibited highest inhibition against some pathogenic bacteria such as Bacillus cereus, MRSA and Vibrio parahaemolyticus. A selection of extracts that showed some activity was further tested for the MIC and minimal bactericidal concentrations (MBC). MIC values of Bacillus subtilis and Methicillin-resistant Staphylococcus aureus (MRSA) using butanol extract of extraction method II (BE II) were 8.33 and 16.33mg/mL, respectively; while the MIC value using ethyl acetate extract of extraction method II (EAE II) for Vibrio parahaemolyticus was 0.13mg/mL. Our study showed that 47.06% of extracts inhibited Gram-negative (8 out of 17), and 63.63% of extracts also inhibited Gram-positive bacteria (7 out of 11); besides, statistically the frequency of antimicrobial activity was 13.45% (35 out of 342) which in this among 21.71% belongs to

  5. Novel Cationic Lipids with Enhanced Gene Delivery and Antimicrobial Activity

    PubMed Central

    Fein, David E.; Bucki, Robert; Byfield, Fitzroy; Leszczynska, Katarzyna; Janmey, Paul A.

    2010-01-01

    Cationic lipids facilitate plasmid delivery, and some cationic sterol-based compounds have antimicrobial activity because of their amphiphilic character. These dual functions are relevant in the context of local ongoing infection during intrapulmonary gene transfer for cystic fibrosis. The transfection activities of two cationic lipids, dexamethasone spermine (DS) and disubstituted spermine (D2S), were tested as individual components and mixtures in bovine aortic endothelial cells and A549 cells. The results showed a 3- to 7-fold improvement in transgene expression for mixtures of DS with 20 to 40 mol% D2S. D2S and coformulations with DS, dioleoyl phosphatidylethanolamine, and DNA exhibited potent bactericidal activity against Escherichia coli MG1655, Bacillus subtilis, and Pseudomonas aeruginosa PAO1, which was maintained in bronchoalveolar lavage fluid. Complete bacterial killing was demonstrated at ∼5 μM, including gene delivery formulations, with 2 orders of magnitude higher tolerance before eukaryotic membrane disruption (erythrocyte hemolysis). D2S also exhibited lipopolysaccharide (LPS) scavenging activity resulting in significant inhibition of LPS-mediated activation of human neutrophils with 85 and 65% lower interleukin-8 released at 12 and 24 h, respectively. Mixtures of DS and D2S can improve transfection activity over common lipofection reagents, and D2S has strong antimicrobial action suited for the suppression of bacterial-mediated inflammation. PMID:20573781

  6. Composition and Antimicrobial Activity of Euphrasia rostkoviana Hayne Essential Oil

    PubMed Central

    Novy, Pavel; Davidova, Hana; Serrano-Rojero, Cecilia Suqued; Rondevaldova, Johana; Pulkrabek, Josef

    2015-01-01

    Eyebright, Euphrasia rostkoviana Hayne (Scrophulariaceae), is a medicinal plant traditionally used in Europe for the treatment of various health disorders, especially as eyewash to treat eye ailments such as conjunctivitis and blepharitis that can be associated with bacterial infections. Some Euphrasia species have been previously reported to contain essential oil. However, the composition and bioactivity of E. rostkoviana oil are unknown. Therefore, in this study, we investigated the chemical composition and antimicrobial activity of the eyebright essential oil against some organisms associated with eye infections: Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, and Candida albicans. GC-MS analysis revealed more than 70 constituents, with n-hexadecanoic acid (18.47%) as the main constituent followed by thymol (7.97%), myristic acid (4.71%), linalool (4.65%), and anethole (4.09%). The essential oil showed antimicrobial effect against all organisms tested with the exception of P. aeruginosa. The best activity was observed against all Gram-positive bacteria tested with the minimum inhibitory concentrations of 512 µg/mL. This is the first report on the chemical composition of E. rostkoviana essential oil and its antimicrobial activity. PMID:26000025

  7. Biocompatible cellulose-based superabsorbent hydrogels with antimicrobial activity.

    PubMed

    Peng, Na; Wang, Yanfeng; Ye, Qifa; Liang, Lei; An, Yuxing; Li, Qiwei; Chang, Chunyu

    2016-02-10

    Current superabsorbent hydrogels commercially applied in the disposable diapers have disadvantages such as weak mechanical strength, poor biocompatibility, and lack of antimicrobial activity, which may induce skin allergy of body. To overcome these hassles, we have developed novel cellulose based hydrogels via simple chemical cross-linking of quaternized cellulose (QC) and native cellulose in NaOH/urea aqueous solution. The prepared hydrogel showed superabsorbent property, high mechanical strength, good biocompatibility, and excellent antimicrobial efficacy against Saccharomyces cerevisiae. The presence of QC in the hydrogel networks not only improved their swelling ratio via electrostatic repulsion of quaternary ammonium groups, but also endowed their antimicrobial activity by attraction of sections of anionic microbial membrane into internal pores of poly cationic hydrogel leading to the disruption of microbial membrane. Moreover, the swelling properties, mechanical strength, and antibacterial activity of hydrogels strongly depended on the contents of quaternary ammonium groups in hydrogel networks. The obtained data encouraged the use of these hydrogels for hygienic application such as disposable diapers.

  8. Activity of an antimicrobial hydrocephalus shunt catheter against Propionibacterium acnes.

    PubMed

    Bayston, Roger; Vera, Litza; Ashraf, Waheed

    2010-12-01

    Shunt infection is a major complication affecting approximately 10% of procedures. Propionibacterium acnes, an anaerobic skin bacterium, is increasingly recognized as a shunt pathogen, causing up to 14% of infections. Though susceptible to penicillin and cephalosporins, P. acnes shunt infections are not preventable by means of perioperative prophylaxis, due to poor cerebrospinal fluid penetration. Antimicrobial shunts with activity against staphylococci are available, but their activity against P. acnes is unknown, and the study was designed to determine this. Three methods of evaluation were used in order to determine the emergence of resistance when exposure is to high inocula for long periods, the time taken to kill 100% of the bacteria attached to the shunt, and the duration of activity under constant flow conditions with repeated bacterial challenge. Despite repeated exposure to high bacterial inocula over 70 days, no resistance was seen. The time taken to kill all attached bacteria, 96 h, was twice that taken to kill attached staphylococci. Nevertheless, under constant flow conditions with repeated challenges, the antimicrobial catheters resisted colonization by P. acnes for 56 days. Using tests that were designed to be clinically predictive when done together, the results suggest that the antimicrobial catheters will be able to prevent colonization of hydrocephalus shunts by P. acnes.

  9. Sparse Neural Network Models of Antimicrobial Peptide-Activity Relationships.

    PubMed

    Müller, Alex T; Kaymaz, Aral C; Gabernet, Gisela; Posselt, Gernot; Wessler, Silja; Hiss, Jan A; Schneider, Gisbert

    2016-12-01

    We present an adaptive neural network model for chemical data classification. The method uses an evolutionary algorithm for optimizing the network structure by seeking sparsely connected architectures. The number of hidden layers, the number of neurons in each layer and their connectivity are free variables of the system. We used the method for predicting antimicrobial peptide activity from the amino acid sequence. Visualization of the evolved sparse network structures suggested a high charge density and a low aggregation potential in solution as beneficial for antimicrobial activity. However, different training data sets and peptide representations resulted in greatly varying network structures. Overall, the sparse network models turned out to be less accurate than fully-connected networks. In a prospective application, we synthesized and tested 10 de novo generated peptides that were predicted to either possess antimicrobial activity, or to be inactive. Two of the predicted antibacterial peptides showed cosiderable bacteriostatic effects against both Staphylococcus aureus and Escherichia coli. None of the predicted inactive peptides possessed antibacterial properties. Molecular dynamics simulations of selected peptide structures in water and TFE suggest a pronounced peptide helicity in a hydrophobic environment. The results of this study underscore the applicability of neural networks for guiding the computer-assisted design of new peptides with desired properties.

  10. Antimicrobial activity of silver/starch/polyacrylamide nanocomposite.

    PubMed

    Abdel-Halim, E S; Al-Deyab, Salem S

    2014-07-01

    A novel silver/starch/polyacrylamide nanocomposite hydrogel was prepared by grafting acrylamide onto starch in presence of silver nitrate by use of ammonium persulphate as an initiator and N,N-methylene-bisacrylamide as a crosslinking agent, then reducing the silver ions enclosed in the hydrogel structure to silver nanoparticles by treating the hydrogel with sodium hydroxide solution. All factors which affect the grafting/crosslinking reaction were optimized and the concentration of silver ion was changed from 0ppm to 50ppm. The produced nanocomposite hydrogel was characterized for its nanosilver content and the UV-spectra showed similar absorption spectra at wavelength 405nm for all AgNO3 concentrations but the plasmon showed increase in the intensity of the absorption peak as AgNO3 concentration incorporated to the hydrogel structure increases. The nanocomposite hydrogel was also characterized for its antimicrobial activity toward two types of bacteria and two types of fungi. The results showed that the hydrogel with 0ppm silver content has no antimicrobial activity, and that the antimicrobial activity expressed as inhibition zone increases as the silver content increases from 5ppm to 50ppm.

  11. Silver activation on thin films of Ag-ZrCN coatings for antimicrobial activity.

    PubMed

    Ferreri, I; Calderon V, S; Escobar Galindo, R; Palacio, C; Henriques, M; Piedade, A P; Carvalho, S

    2015-10-01

    Nowadays, with the increase of elderly population and related health problems, knee and hip joint prosthesis are being widely used worldwide. However, failure of these invasive devices occurs in a high percentage thus demanding the revision of the chirurgical procedure. Within the reasons of failure, microbial infections, either hospital or subsequently-acquired, contribute in high number to the statistics. Staphylococcus epidermidis (S. epidermidis) has emerged as one of the major nosocomial pathogens associated with these infections. Silver has a historic performance in medicine due to its potent antimicrobial activity, with a broad-spectrum on the activity of different types of microorganisms. Consequently, the main goal of this work was to produce Ag-ZrCN coatings with antimicrobial activity, for the surface modification of hip prostheses. Thin films of ZrCN with several silver concentrations were deposited onto stainless steel 316 L, by DC reactive magnetron sputtering, using two targets, Zr and Zr with silver pellets (Zr+Ag target), in an atmosphere containing Ar, C2H2 and N2. The antimicrobial activity of the modified surfaces was tested against S. epidermidis and the influence of an activation step of silver was assessed by testing samples after immersion in a 5% (w/v) NaClO solution for 5 min. The activation procedure revealed to be essential for the antimicrobial activity, as observed by the presence of an inhibition halo on the surface with 11 at.% of Ag. The morphology analysis of the surface before and after the activation procedure revealed differences in silver distribution indicating segregation/diffusion of the metallic element to the film's surface. Thus, the results indicate that the silver activation step is responsible for an antimicrobial effect of the coatings, due to silver oxidation and silver ion release.

  12. Antimicrobial activity of some Salvia species essential oils from Iran.

    PubMed

    Yousefzadi, Morteza; Sonboli, Ali; Karimic, Farah; Ebrahimi, Samad Nejad; Asghari, Behvar; Zeinalia, Amineh

    2007-01-01

    The aerial parts of Salvia multicaulis, S. sclarea and S. verticillata were collected at full flowering stage. The essential oils were isolated by hydrodistillation and analyzed by combination of capillary GC and GC-MS. The in vitro antimicrobial activity of the essential oils were studied against eight Gram-positive and Gram-negative bacteria (Bacillus subtilis, Bacillus pumulis, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) and three fungi (Candida albicans, Saccharomyces cerevisiae and Aspergillus niger). The results of antibacterial activity tests of the essential oils according to the disc diffusion method and MIC values indicated that all the samples have moderate to high inhibitory activity against the tested bacteria except for P. aeruginosa which was totally resistant. In contrast to antibacterial activity, the oils exhibited no or slight antifungal property, in which only the oil of S. multicaulis showed weak activity against two tested yeasts, C. albicans and S. cerevisiae.

  13. The Activity of Antimicrobial Surfaces Varies by Testing Protocol Utilized

    PubMed Central

    Campos, Matias D.; Zucchi, Paola C.; Phung, Ann; Leonard, Steven N.; Hirsch, Elizabeth B.

    2016-01-01

    Background Contaminated hospital surfaces are an important source of nosocomial infections. A major obstacle in marketing antimicrobial surfaces is a lack of efficacy data based on standardized testing protocols. Aim We compared the efficacy of multiple testing protocols against several “antimicrobial” film surfaces. Methods Four clinical isolates were used: one Escherichia coli, one Klebsiella pneumoniae, and two Staphylococcus aureus strains. Two industry methods (modified ISO 22196 and ASTM E2149), a “dried droplet”, and a “transfer” method were tested against two commercially available antimicrobial films, one film in development, an untreated control, and a positive (silver) control film. At 2 (only ISO) and 24 hours following inoculation, bacteria were collected from film surfaces and enumerated. Results Compared to untreated films in all protocols, there were no significant differences in recovery on either commercial brand at 2 or 24 hours after inoculation. The silver surface demonstrated significant microbicidal activity (mean loss 4.9 Log10 CFU/ml) in all methods and time points with the exception of 2 hours in the ISO protocol and the transfer method. Using our novel droplet method, no differences between placebo and active surfaces were detected. The surface in development demonstrated variable activity depending on method, organism, and time point. The ISO demonstrated minimal activity at 2 hours but significant activity at 24 hours (mean 4.5 Log10 CFU/ml difference versus placebo). The ASTEM protocol exhibited significant differences in recovery of staphylococci (mean 5 Log10 CFU/ml) but not Gram-negative isolates (10 fold decrease). Minimal activity was observed with this film in the transfer method. Conclusions Varying results between protocols suggested that efficacy of antimicrobial surfaces cannot be easily and reproducibly compared. Clinical use should be considered and further development of representative methods is needed. PMID

  14. Antimicrobial activity of endemic Digitalis lamarckii Ivan from Turkey.

    PubMed

    Benli, Mehlika; Yiğit, Nazife; Geven, Fatmagü; Güney, Kerim; Bingöl, Umit

    2009-03-01

    Antimicrobial activity of the methanolic extracts of leaves and flowers of D. lamarckii Ivan, (Scophulariaceae), an endemic plant species of Turkey, was tested on ten bacterial and four yeast strains. Effective antibacterial activity was observed in four bacterial strains. Minimum inhibitory concentration (MIC) was calculated by use of liquid culture tests and in all the four effective bacterial strains, the MIC was found to be > or = 199.5 mg/ml. The minimum bactericidal concentration (MBC) of B. subtilis, S. aureus, and L. monocytogenes was calculated to be > or = 199.5 mg/ml, and MBC value for Shigella was calculated as > or = 399 mg/ml.

  15. Antimicrobial activity of fermented Theobroma cacao pod husk extract.

    PubMed

    Santos, R X; Oliveira, D A; Sodré, G A; Gosmann, G; Brendel, M; Pungartnik, C

    2014-09-26

    Theobroma cacao L. contains more than 500 different chemical compounds some of which have been traditionally used for their antioxidant, anti-carcinogenic, immunomodulatory, vasodilatory, analgesic, and antimicrobial activities. Spontaneous aerobic fermentation of cacao husks yields a crude husk extract (CHE) with antimicrobial activity. CHE was fractioned by solvent partition with polar solvent extraction or by silica gel chromatography and a total of 12 sub-fractions were analyzed for chemical composition and bioactivity. CHE was effective against the yeast Saccharomyces cerevisiae and the basidiomycete Moniliophthora perniciosa. Antibacterial activity was determined using 6 strains: Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella choleraesuis (Gram-negative). At doses up to 10 mg/mL, CHE was not effective against the Gram-positive bacteria tested but against medically important P. aeruginosa and S. choleraesuis with a minimum inhibitory concentration (MIC) of 5.0 mg/mL. Sub-fractions varied widely in activity and strongest antibacterial activity was seen with CHE8 against S. choleraesuis (MIC of 1.0 mg/mL) and CHE9 against S. epidermidis (MIC of 2.5 mg/mL). All bioactive CHE fractions contained phenols, steroids, or terpenes, but no saponins. Fraction CHE9 contained flavonoids, phenolics, steroids, and terpenes, amino acids, and alkaloids, while CHE12 had the same compounds but lacked flavonoids.

  16. Distinct antimicrobial activities in aphid galls on Pistacia atlantica

    PubMed Central

    Yoram, Gerchman; Inbar, Moseh

    2011-01-01

    Gall-formers are parasitic organisms that manipulate plant traits for their own benefit. Galls have been shown to protect their inhabitants from natural enemies such as predators and parasitoids by various chemical and mechanical means. Much less attention, however, has been given to the possibility of defense against microbial pathogens in the humid and nutrient-rich gall environment. We found that the large, cauliflower-shaped, galls induced by the aphid Slavum wertheimae on buds of Pistacia atlantica trees express antibacterial and antifungal activities distinct from those found in leaves. Antibacterial activity was especially profound against Bacillus spp (a genus of many known insect pathogen) and against Pseudomonas aeruginosa (a known plant pathogen). Antifungal activity was also demonstrated against multiple filamentous fungi. Our results provide evidence for the protective antimicrobial role of galls. This remarkable antibacterial and antifungal activity in the galls of S. wertheimae may be of agricultural and pharmaceutical value. PMID:22105034

  17. Isolation, identification and antimicrobial activity of propolis-associated fungi.

    PubMed

    de Souza, Giovanni Gontijo; Pfenning, Ludwig Heinrich; de Moura, Fabiana; Salgado, Mírian; Takahashi, Jacqueline Aparecida

    2013-01-01

    Propolis is a natural product widely known for its medicinal properties. In this work, fungi present on propolis samples were isolated, identified and tested for the production of antimicrobial metabolites. Twenty-two fungal isolates were obtained, some of which were identified as Alternaria alternata, Aspergillus flavus, Bipolaris hawaiiensis, Fusarium merismoides, Lasiodiplodia theobromae, Penicillium citrinum, Penicillium crustosum, Penicillium janthinellum, Penicillium purpurogenum, Pestalotiopsis palustris, Tetracoccosporium paxianum and Trichoderma koningii. These fungi were grown in liquid media to obtain crude extracts that were evaluated for their antibiotic activity against pathogenic bacteria, yeast and Cladosporium cladosporioides and A. flavus. The most active extract was obtained from L. theobromae (minimum inhibitory concentration = 64 μg/mL against Listeria monocitogenes). Some extracts showed to be more active than the positive control in the inhibition of Staphylococcus aureus and L. monocitogenes. Therefore, propolis is a promising source of fungi, which produces active agents against relevant food poisoning bacteria and crop-associated fungi.

  18. Synthesis and antimicrobial activity of some new diphenylamine derivatives

    PubMed Central

    Kumar, Arvind; Mishra, Arun K.

    2015-01-01

    In search of new leads toward potent antimicrobial agent, an array of novel derivatives of 2-hydrazinyl–N-N, diphenyl acetamide has been synthesized from the chloroacetylation reaction of diphenylamine (DPA). For this, a series of DPA derivatives were prepared by replacing chlorine with hydrazine hydrate in alcoholic medium and 2-hydrazino-N, N-diphenylacetamide was synthesized. The 2-hydrazino-N, N-diphenylacetamide was further subjected to reaction with various aromatic aldehydes in presence of glacial acetic acid in methanol. The synthesized compounds were characterized by their IR, 1HNMR spectral data and elemental analysis. The compounds were screened for antibacterial and antifungal activity by cup plate method. 2-(2-Benzylidenehydrazinyl)-N, N-diphenylacetamide (A1); 2-(2-(3-methylbenzylidene) hydrazinyl)-N, N-diphenyl-acetamide (A5) and 2-(2-(2-nitrobenzylidine) hydrazinyl)-N, N-diphenyl-acetamide compounds (A7) showed significant antimicrobial as well as antifungal activity. Diphenylamine compounds may be explored as potent antimicrobial and antifungal compounds. PMID:25709343

  19. Characterization and antimicrobial activity of a pharmaceutical microemulsion.

    PubMed

    Zhang, Hui; Cui, Yinan; Zhu, Songming; Feng, Fengqin; Zheng, Xiaodong

    2010-08-16

    The characterization of a pharmaceutical microemulsion system with glycerol monolaurate as oil, ethanol as cosurfactant, Tween 40 as surfactant, sodium diacetate and water, and the antimicrobial activities against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Aspergillus niger and Penicillium expansum have been studied. The influence of ethanol and sodium diacetate on oil solubilization capability was clearly reflected in the phase behavior of these systems. One microemulsion formulation was obtained and remained stable by physical stability studies. The antimicrobial assay using solid medium diffusion method showed that the prepared microemulsion was comparable to the commonly used antimicrobials as positive controls. The kinetics of killing experiments demonstrated that the microemulsion caused a complete loss of viability of bacterial cells (E. coli, S. aureus and B. subtilis) in 1 min, killed over 99% A. niger and P. expansum spores and 99.9% C. albicans cells rapidly within 2 min and resulted in a complete loss of fungal viability in 5 min. The fast killing kinetics of the microemulsion was in good agreement with the transmission electron microscopy observations, indicating the antimembrane activity of the microemulsion on bacterial and fungal cells due to the disruption and dysfunction of biological membranes and cell walls.

  20. Multilayer hydrogel coatings to combine hemocompatibility and antimicrobial activity.

    PubMed

    Fischer, Marion; Vahdatzadeh, Maryam; Konradi, Rupert; Friedrichs, Jens; Maitz, Manfred F; Freudenberg, Uwe; Werner, Carsten

    2015-07-01

    While silver-loaded catheters are widely used to prevent early-onset catheter-related infections [1], long term antimicrobial protection of indwelling catheters remains to be achieved [2] and antiseptic functionalization of coatings often impairs their hemocompatibility characteristics. Therefore, this work aimed to capitalize on the antimicrobial properties of silver nanoparticles, incorporated in anticoagulant poly(ethylene glycol) (PEG)-heparin hydrogel coatings [3] on thermoplastic polyurethane materials. For prolonged antimicrobial activity, the silver-containing starPEG-heparin hydrogel layers were shielded with silver-free hydrogel layers of otherwise similar composition. The resulting multi-layered gel coatings showed long term antiseptic efficacy against Escherichia coli and Staphylococcus epidermidis strains in vitro, and similarly performed well when incubated with freshly drawn human whole blood with respect to hemolysis, platelet activation and plasmatic coagulation. The introduced hydrogel multilayer system thus offers a promising combination of hemocompatibility and long-term antiseptic capacity to meet an important clinical need.

  1. Antimicrobial activity of toothpastes containing natural extracts, chlorhexidine or triclosan.

    PubMed

    De Rossi, Andiara; Ferreira, Danielly Cunha Araújo; da Silva, Raquel Assed Bezerra; de Queiroz, Alexandra Mussolino; da Silva, Léa Assed Bezerra; Nelson-Filho, Paulo

    2014-01-01

    The objective of this in vitro study was to evaluate the antimicrobial effect of toothpastes containing natural extracts, chlorhexidine or triclosan. The effectiveness of toothpastes containing natural extracts (Parodontax®), 0.12% chlorhexidine (Cariax®), 0.3% triclosan (Sanogil®) or fluoride (Sorriso®, control) was evaluated against yeasts, Gram-positive and Gram-negative bacteria using the disk diffusion method. Water was used as a control. Disks impregnated with the toothpastes were placed in Petri dishes containing culture media inoculated with 23 indicative microorganisms by the pour plate method. After incubation, the inhibition growth halos were measured and statistical analyses (α=0.05) were performed. The results indicated that all formulations, except for conventional toothpaste (Sorriso®), showed antimicrobial activity against Gram-positive bacteria and yeasts. The toothpaste containing natural extracts (Parodontax®) was the only product able to inhibit the growth of Pseudomonas aeruginosa. The toothpastes containing chlorhexidine, triclosan or natural extracts presented antimicrobial activity against Gram-positive bacteria and yeasts.

  2. Structure--Antimicrobial Activity Relationship Comparing a New Class of Antimicrobials, Silanols, to Alcohols and Phenols

    DTIC Science & Technology

    2006-04-01

    Hoekman D, Leo A, Zhang LT, Li P, "The Expanding Role of Quantitative Structure–Activity Relationships ( QSAR ) in Toxicology ." Toxicol Lett 1995; 79: 45...partition coefficients (log P) and H-bond acidities (Continued on p. ii) Antimicrobial, Bacteria, Gram-negative, Gram-positive, QSAR , silanol U U U UU...Med Chem 1968; 11: 430–441. [9] Kubinyi H, QSAR : Hansch Analysis and Related Approaches. New York: VCH Publishers, 1993. [10] Kim Y, Farrah S

  3. Antimicrobial activity of grapefruit seed and pulp ethanolic extract.

    PubMed

    Cvetnić, Zdenka; Vladimir-Knezević, Sanda

    2004-09-01

    Antibacterial and antifungal activity of ethanolic extract of grapefruit (Citrus paradisi Macf., Rutaceae) seed and pulp was examined against 20 bacterial and 10 yeast strains. The level of antimicrobial effects was established using an in vitro agar assay and standard broth dilution susceptibility test. The contents of 3.92% of total polyphenols and 0.11% of flavonoids were determined spectrometrically in crude ethanolic extract. The presence of flavanones naringin and hesperidin in the extract was confirmed by TLC analysis. Ethanolic extract exibited the strongest antimicrobial effect against Salmonella enteritidis (MIC 2.06%, m/V). Other tested bacteria and yeasts were sensitive to extract concentrations ranging from 4.13% to 16.50% (m/V).

  4. Bis-chalcones and flavones: synthesis and antimicrobial activity.

    PubMed

    Husain, Asif; Rashid, Mohd; Mishra, Ravinesh; Kumar, Deepak

    2013-01-01

    A series of bis-chalcones (3a-g) and their flavones derivatives (4a-g) were synthesized and evaluated for their antimicrobial activity. Bis-chalcones were prepared by condensing 1,1'-(4,6-dihydroxy-1,3-phenylene)diethanone (2) with appropriate aryl aldehydes following Claisen-Schmidt reaction conditions. Oxidative cyclization of bis-chalcones (3a-g) in DMSO in the presence of iodine furnished flavones (4a-g). The synthesized compounds were evaluated for their antibacterial and antifungal actions against some selected microbes. The results of antimicrobial evaluation showed that some of the synthesized compounds were good in their antibacterial and antifungal actions.

  5. Antimicrobial activity of silver nanoparticles impregnated wound dressing

    NASA Astrophysics Data System (ADS)

    Shinde, V. V.; Jadhav, P. R.; Patil, P. S.

    2013-06-01

    In this work, silver nanoparticles were synthesized by simple wet chemical reduction method. The silver nitrate was reduced by Sodium borohydride used as reducing agent and Poly (vinyl pyrrolidone) (PVP) as stabilizing agent. The formation of silver nanoparticles was evaluated by UV-visible spectroscope and transmission electron microscope (TEM). Absorption spectrum consist two plasmon peaks at 410 and 668 nm revels the formation of anisotropic nanoparticles confirmed by TEM. The formation of silver nanoparticles was also evidenced by dynamic light scattering (DLS) study. DLS showed polydisperse silver nanoparticles with hydrodynamic size 32 nm. Protecting mechanism of PVP was manifested by FT-Raman study. Silver nanoparticles were impregnated into wound dressing by sonochemical method. The Kirby-Bauer disc diffusion methods were used for antimicrobial susceptibility testing. The antimicrobial activity of the samples has been tested against gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus.

  6. Antimicrobial Activity of Xanthohumol and Its Selected Structural Analogues.

    PubMed

    Stompor, Monika; Żarowska, Barbara

    2016-05-11

    The objective of this study was to evaluate the antimicrobial activity of structural analogues of xanthohumol 1, a flavonoid compound found in hops (Humulus lupulus). The agar-diffusion method using filter paper disks was applied. Biological tests performed for selected strains of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria, fungi (Alternaria sp.), and yeasts (Rhodotorula rubra, Candida albicans) revealed that compounds with at least one hydroxyl group-all of them have it at the C-4 position-demonstrated good activity. Our research showed that the strain S. aureus was more sensitive to chalcones than to the isomers in which the heterocyclic ring C is closed (flavanones). The strain R. rubra was moderately sensitive to only one compound: 4-hydroxy-4'-methoxychalcone 8. Loss of the hydroxyl group in the B-ring of 4'-methoxychalcones or its replacement by a halogen atom (-Cl, -Br), nitro group (-NO₂), ethoxy group (-OCH₂CH₃), or aliphatic substituent (-CH₃, -CH₂CH₃) resulted in the loss of antimicrobial activity towards both R. rubra yeast and S. aureus bacteria. Xanthohumol 1, naringenin 5, and chalconaringenin 7 inhibited growth of S. aureus, whereas 4-hydroxy-4'-methoxychalcone 8 was active towards two strains: S. aureus and R. rubra.

  7. Essential oil from Artemisia phaeolepis: chemical composition and antimicrobial activities.

    PubMed

    Ben Hsouna, Anis; Ben Halima, Nihed; Abdelkafi, Slim; Hamdi, Naceur

    2013-01-01

    Artemisia phaeolepis, a perennial herb with a strong volatile odor, grows on the grasslands of Mediterranean region. Essential oil obtained from Artemisia phaeolepis was analyzed by gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. A total of 79 components representing 98.19% of the total oil were identified, and the main compounds in the oil were found to be eucalyptol (11.30%), camphor (8.21%), terpine-4-ol (7.32%), germacrene D (6.39), caryophyllene oxide (6.34%), and caryophyllene (5.37%). The essential oil showed definite inhibitory activity against 10 strains of test microorganisms. Eucalyptol, camphor, terpine-4-ol, caryophyllene, germacrene D and caryophyllene oxide were also examined as the major components of the oil. Camphor showed the strongest antimicrobial activity; terpine-4-ol, eucalyptol, caryophyllene and germacrene D were moderately active and caryophyllene oxide was weakly active. The study revealed that the antimicrobial properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components.

  8. Antimicrobial activity of Willowherb (Epilobium angustifolium L.) leaves and flowers.

    PubMed

    Kosalec, Ivan; Kopjar, Nevenka; Kremer, Dario

    2013-08-01

    Since the aetiology of benign prostatic hyperplasia (BHP) is still unknown, the use of medicinal herb extracts and products prepared thereof are recommended due to their antimicrobial activity, especially during early stages of BHP. A comparison was performed of the in vitro antimicrobial activity (using broth microdilution assay) of flowers and leaves of willowherb (Epilobium angustifolium L., Onagraceae) from Mt. Velebit (Croatia). The strains (standard ATCC and clinical isolates) of Staphylococcus aureus (including MRSA), Bacillus subtilis, Escherichia coli (including p-fimbriae positive strain), Pseudomonas aeruginosa, Proteus mirabilis, Candida albicans, C. tropicalis, C. dubliniensis and Saccharomyces cerevisiae were susceptible with MIC values between 4.6±0.2 and 18.2±0.8 mg/mL. The results of in vitro studies showed that no differences were found in the antimicrobial activity between the ethanol extracts of leaves and flowers of E. angustifolium. Using the quantitative fluorescent assay with ethidium bromide and acridine orange, the viability of C. albicans ATCC 10231 was assessed after in vitro exposure to E. angustifolium leaf and flower ethanol extracts. Apoptosis of C. albicans blastospores dominated over necrosis in all treated samples after short-term exposure with 6 to 12 mg/mL of extracts. In addition to the valuable biological activity of E. angustifolium extracts, the data obtained from the in vitro diffusion, the dilution assay and antifungal viability fluorescent assay suggest that leaf and flower ethanol extracts of E. angustifolium L. are a promising complementary herbal therapy of conditions such as BHP.

  9. Synthesis and Antimicrobial Activity of 1,2-Benzothiazine Derivatives.

    PubMed

    Patel, Chandani; Bassin, Jatinder P; Scott, Mark; Flye, Jenna; Hunter, Ann P; Martin, Lee; Goyal, Madhu

    2016-06-30

    A number of 1,2-benzothiazines have been synthesized in a three-step process. Nine chalcones 1-9 bearing methyl, fluoro, chloro and bromo substituents were chlorosulfonated with chlorosulfonic acid to generate the chalcone sulfonyl chlorides 10-18. These were converted to the dibromo compounds 19-27 through reaction with bromine in glacial acetic acid. Compounds 19-27 were reacted with ammonia, methylamine, ethylamine, aniline and benzylamine to generate a library of 45 1,2-benzothiazines 28-72. Compounds 28-72 were evaluated for their antimicrobial activity using broth microdilution techniques against two Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and two Gram-negative bacteria (Proteus vulgaris and Salmonella typhimurium). The results demonstrated that none of the compounds showed any activity against Gram-negative bacteria P. vulgaris and S. typhimurium; however, compounds 31, 33, 38, 43, 45, 50, 53, 55, 58, 60, 63 and 68 showed activity against Gram-positive bacteria Bacillus subtilis and Staphylococcous aureus. The range of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was 25-600 µg/mL, though some of the MIC and MBC concentrations were high, indicating weak activity. Structure activity relationship studies revealed that the compounds with a hydrogen atom or an ethyl group on the nitrogen of the thiazine ring exerted antibacterial activity against Gram-positive bacteria. The results also showed that the compounds where the benzene ring of the benzoyl moiety contained a methyl group or a chlorine or bromine atom in the para position showed higher antimicrobial activity. Similar influences were identified where either a bromine or chlorine atom was in the meta position.

  10. Antimicrobial activity of Nerolidol and its derivatives against airborne microbes and further biological activities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nerolidol and its derivatives, namely cis-nerolidol, O-methyl-nerolidol, O-ethyl-nerolidol, (-)-alpha-bisabolol, trans,trans-farnesol and its main natural source Cabreuva essential oil, were tested for their antimicrobial activity against airborne microbes and antifungal properties against plant pat...

  11. Comparative Study of Surface-Active Properties and Antimicrobial Activities of Disaccharide Monoesters

    PubMed Central

    Zhang, Xi; Song, Fei; Taxipalati, Maierhaba; Wei, Wei; Feng, Fengqin

    2014-01-01

    The objective of this research was to determine the effect of sugar or fatty acid in sugar ester compounds on the surface-active properties and antimicrobial activities of these compounds. Disaccharides of medium-chain fatty acid monoesters were synthesized through transesterifications by immobilized lipase (Lipozyme TLIM) to yield nine monoesters for subsequent study. Their antimicrobial activities were investigated using three pathogenic microorganisms: Staphylococcus aureus, Escherichia coli O157:H7 and Candida albicans. Their surface-active properties including air–water surface tension, critical micelle concentration, and foaming and emulsion power and stability were also studied. The results showed that all of the tested monoesters were more effective against Staphylococcus aureus (Gram-positive bacterium) than against Escherichia coli O157:H7 (Gram-negative bacterium). The results demonstrated that the carbon chain length was the most important factor influencing the surface properties, whereas degree of esterification and hydrophilic groups showed little effect. PMID:25531369

  12. Synthesis, surface-active properties, and antimicrobial activities of new double-chain gemini surfactants.

    PubMed

    Murguía, Marcelo C; Vaillard, Victoria A; Sánchez, Victoria G; Conza, José Di; Grau, Ricardo J

    2008-01-01

    A novel series of neutral and cationic dimeric surfactants were prepared involving ketalization reaction, Williamson etherification, and regioselective oxirane ring opening with primary and tertiary alkyl amines. The critical micelle concentration (CMC), effectiveness of surface tension reduction (gamma(CMC)), surface excess concentration (Gamma), and area per molecule at the interface (A) were determined and values indicate that the cationic series is characterized by good surface-active and self-aggregation properties. For the first time, we reported the antimicrobial activities against representative bacteria and fungi for dimeric compounds. The antimicrobial activity was found to be dependent on the target microorganism (Gram-positive bacteria > fungi > Gram-negative bacteria), as well as both the neutral or ionic nature (cationic > neutral) and alkyl chain length (di-C(12) > di-C(18) > di-C(8)) of the compounds. The cationic di-C(12) derivative was found to have equipotent activity to that of benzalkonium chloride (BAC) used as standard.

  13. Structure-Activity Relationship of Benzophenanthridine Alkaloids from Zanthoxylum rhoifolium Having Antimicrobial Activity

    PubMed Central

    Tavares, Luciana de C.; Zanon, Graciane; Weber, Andréia D.; Neto, Alexandre T.; Mostardeiro, Clarice P.; Da Cruz, Ivana B. M.; Oliveira, Raul M.; Ilha, Vinicius; Dalcol, Ionara I.; Morel, Ademir F.

    2014-01-01

    Zanthoxylum rhoifolium (Rutaceae) is a plant alkaloid that grows in South America and has been used in Brazilian traditional medicine for the treatment of different health problems. The present study was designed to evaluate the antimicrobial activity of the steam bark crude methanol extract, fractions, and pure alkaloids of Z. rhoifolium. Its stem bark extracts exhibited a broad spectrum of antimicrobial activity, ranging from 12.5 to 100 µg/mL using bioautography method, and from 125 to 500 µg/mL in the microdilution bioassay. From the dichloromethane basic fraction, three furoquinoline alkaloids (1–3), and nine benzophenanthridine alkaloids (4–12) were isolated and the antimicrobial activity of the benzophenanthridine alkaloids is discussed in terms of structure-activity relationships. The alkaloid with the widest spectrum of activity was chelerythrine (10), followed by avicine (12) and dihydrochelerythrine (4). The minimal inhibitory concentrations of chelerythrine, of 1.50 µg/mL for all bacteria tested, and between 3.12 and 6.25 µg/mL for the yeast tested, show this compound to be a more powerful antimicrobial agent when compared with the other active alkaloids isolated from Z. rhoifolium. To verify the potential importance of the methylenedioxy group (ring A) of these alkaloids, chelerythrine was selected to represent the remainder of the benzophenanthridine alkaloids isolated in this work and was subjected to a demethylation reaction giving derivative 14. Compared to chelerythrine, the derivative (14) was less active against the tested bacteria and fungi. Kinetic measurements of the bacteriolytic activities of chelerythrine against the bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) were determined by optical density based on real time assay, suggesting that its mechanism of action is not bacteriolytic. The present study did not detect hemolytic effects of chelerythrine on erythrocytes and found a protective effect

  14. In vitro antimicrobial activity of pistachio (Pistacia vera L.) polyphenols.

    PubMed

    Bisignano, Carlo; Filocamo, Angela; Faulks, Richard M; Mandalari, Giuseppina

    2013-04-01

    We investigated the antimicrobial properties of polyphenol-rich fractions derived from raw shelled and roasted salted pistachios. American Type Culture Collection (ATCC), food and clinical isolates, of Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Pseudomonas mirabilis), Gram-positive bacteria (Listeria monocytogenes, Enterococcus hirae, Enterococcus faecium, Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus), the yeasts Candida albicans and Candida parapsilosis and the fungus Aspergillus niger were used. Pistachio extracts were active against Gram-positive bacteria with a bactericidal effect observed against L. monocytogenes (ATCC strains and food isolates), S. aureus and MRSA clinical isolates. Extracts from raw shelled pistachios were more active than those from roasted salted pistachios. The bactericidal activity of pistachio extracts could be used to help control the growth of some microorganisms in foods to improve safety and may find application as a topical treatment for S. aureus.

  15. Antioedematogenic activity, acetylcholinesterase inhibition and antimicrobial properties of Jacaranda oxyphylla.

    PubMed

    Pereira, V V; Silva, R R; Dos Santos, M H; Dias, D F; Moreira, M E C; Takahashi, J A

    2016-09-01

    Jacaranda oxyphylla Cham. (Bignoniaceae) is a shrub found in the Brazilian cerrado and used in folk medicine to treat microbial infections. The aim of this study was to carry out a phytochemical screening and evaluate antioedematogenic, antimicrobial and antiacetylcholinesterase properties of J. oxyphylla crude extracts. All extracts analysed showed presence of terpenoids, which are potentially active chemical substances. A high AChE inhibitory activity for hexane extract from leaves and for the extracts from twigs was found. Ethanol extract from leaves of J. oxyphylla showed activity against Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Escherichia coli) bacteria. This extract was also effective in inhibiting the stages of inflammation evaluated. Biological investigation and phytochemical screening of J. oxyphylla extracts provided additional evidence of its traditional medicinal value.

  16. In vitro antimicrobial activity of Persian shallot (Allium hirtifolium).

    PubMed

    Soroush, Setareh; Taherikalani, Morovat; Asadollahi, Parisa; Asadollahi, Khairollah; Taran, Mojtaba; Emaneini, Mohammad; Alizadeh, Sajjad

    2012-01-01

    Allium hirtifolium is a Persian native plant grown in cool mountain slopes of Iran. It has been used as a spice in Iran for many years. According to the literature review, there are no considerable reports on the antimicrobial properties of this plant. In this study, the antimicrobial activity of Persian shallot hydroalcoholic extract and F1 fraction of the plant (containing amino acid derivatives and/or other cationic compounds) was investigated on some Gram positive cocci and bacilli, Gram negative bacilli, two protozoa, a yeast and a fungus. Excellent activity against Candida albicans (MIC = 64 microg/ml, MBC = 128 microg/ml), Leishmania infantum (MIC = 0.2 mg/ml on the first day of study) and Trichomonas vaginalis (MIC = 5 microg/ml in PSDE form) and a moderate activity against Bacillus spp and Pseudomonas aeroginosa (MIC = 128 microg/ml) was observed. The results showed that this plant contains some anti-trichomonas and anti-leishmania components.

  17. Essential oil composition and antimicrobial activity of Diplotaenia damavandica.

    PubMed

    Eftekhar, Fereshteh; Yousefzadi, Morteza; Azizian, Dina; Sonboli, Ali; Salehi, Peyman

    2005-01-01

    Antimicrobial activity of the essential oils obtained from leaves, root and the seeds of Diplotaenia damavandica Mozaffarian, Hedge & Lamond, an endemic plant to Iran, was determined against 10 microorganisms using the disk susceptibility test as well as measuring minimum inhibitory concentrations. The results showed that all three oils had antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. The essential oil from the leaves had the highest antimicrobial activity against all test microorganisms including the fungal strains. The essential oils compositions were analyzed and determined by GC and GC-MS. The oils analyses resulted in the identification of 16, 17 and 20 compounds representing 94.2%, 96.4% and 95.1% of the total oils, respectively. The main components of the leaf essential oils were (Z)-beta-ocimene (21.6%), alpha-phellandrene (21.3%) and terpinolene (20%). Dill apiol (30.1%) and gamma-terpinene (16.2%) were the main components of the root and seed essential oils, respectively.

  18. Antimicrobial activity of some Clerodendrum species from Egypt.

    PubMed

    Abouzid, Sameh F; Wahba, Haytham M; Elshamy, Ali; Cos, Paul; Maes, Louis; Apers, Sandra; Pieters, Luc; Shahat, Abdelaaty A

    2013-01-01

    Chloroformic and methanolic extracts of four Clerodendrum species cultivated in Egypt were screened for antimicrobial activities. Chloroformic extracts of the flowers of Clerodendrum chinense and Clerodendrum splendens were active against Plasmodium falciparum (IC50 < 10 µg mL(-1)). Chloroformic extracts of the stem and flowers of C. chinense were active against Trypanosoma cruzi (IC50 = 1.21 and 1.12 µg mL(-1), respectively) with marginal cytotoxicity. Chloroformic extracts of the leaves of C. chinense and C. splendens showed promising activities against T. cruzi (IC50 = 3.39 and 1.98 µg mL(-1), respectively) without cytotoxic effect on a human cell line. None of the selected plants showed significant activity against Gram-negative or Gram-positive bacteria or Candida albicans. Verbascoside, a phenyl propanoid glycoside isolated from the leaves of C. chinense, showed marginal activity against T. cruzi. Rengyolone, a cyclohexyl ethanoid isolated from the leaves of C. chinense, showed a broad but not specific activity against the tested organisms.

  19. Antimicrobial activity of the solvent fractions from Bulbine natalensis Tuber.

    PubMed

    Yakubu, M T; Mostafa, M; Ashafa, A O T; Afolayan, A J

    2012-01-01

    Bulbine natalensis Baker has been acclaimed to be used as an antimicrobial agent in the folklore medicine of South Africa without scientific evidence to substantiate or refute this claim. In view of this, the in vitro antimicrobial activity of solvent fractions (ethanol, ethyl acetate, n-butanol and water) from Bulbine natalensis Tuber against 4 Gram positive and 12 Gram negative bacteria as well as 3 fungal species were investigated using agar dilution. The ethanolic extract, n-butanol and ethyl acetate fractions inhibited 75, 87.5 and 100% respectively of the bacterial species in this study. The ethanolic, n-butanol and ethyl acetate fractions produced growth inhibition at MIC range of 1-10, 3-10 as well as 1 and 5 mg/ml respectively whereas the water fraction did not inhibit the growth of any of the bacterial species. Again, it was only the ethyl acetate fraction that inhibited the growth of Shigelli flexneri, Staphyloccus aureus and Escherichia coli. The ethanolic, ethyl acetate and n-butanolic fractions dose dependently inhibited the growth of Aspergillus niger and A. flavus whereas the water fraction produced 100% growth inhibition of the Aspergillus species at all the doses investigated. In contrast, no growth inhibition was produced on Candida albicans. The growth inhibition produced by the solvent fractions of B. natalensis Tuber in this study thus justifies the acclaimed use of the plant as an antimicrobial agent. The ethyl acetate fraction was the most potent.

  20. Antimicrobial activity of antihypertensive food-derived peptides and selected alanine analogues.

    PubMed

    McClean, Stephen; Beggs, Louise B; Welch, Robert W

    2014-03-01

    This study evaluated four food-derived peptides with known antihypertensive activities for antimicrobial activity against pathogenic microorganisms, and assessed structure-function relationships using alanine analogues. The peptides (EVSLNSGYY, barley; PGTAVFK, soybean; TTMPLW, α-casein; VHLPP, α-zein) and the six alanine substitution peptides of PGTAVFK were synthesised, characterised and evaluated for antimicrobial activity using the bacteria, Escherichia coli, Staphylococcus aureus, and Micrococcus luteus and the yeast, Candida albicans. The peptides TTMPLW and PGTAVFK inhibited growth of all four microorganisms tested, with activities of a similar order of magnitude to ampicillin and ethanol controls. EVSLNSGYY inhibited the growth of the bacteria, but VHLPP showed no antimicrobial activity. The alanine analogue, PGAAVFK showed the highest overall antimicrobial activity and PGTAVFA showed no activity; overall, the activities of the analogues were consistent with their structures. Some peptides with antihypertensive activity also show antimicrobial activity, suggesting that food-derived peptides may exert beneficial effects via a number of mechanisms.

  1. Phytochemical profiles, antioxidant and antimicrobial activities of three Potentilla species

    PubMed Central

    2013-01-01

    Background Extracts from Potentilla species have been applied in traditional medicine and exhibit antioxidant, hypoglycemic, anti-inflammatory, antitumor and anti-ulcerogenic properties, but little has been known about the diversity of phytochemistry and pharmacology on this genus. This study investigated and compared the phytochemical profiles, antioxidant and antimicrobial activities of leaf extracts from three Potentilla species (Potentilla fruticosa, Potentilla glabra and Potentilla parvifolia) in order to discover new resources for lead structures and pharmaceutical products. Methods Chemical composition and content of six phenolic compounds were evaluated and determined by RP-HPLC; Total phenolic and total flavonoid content were determined using Folin-Ciocalteau colourimetric method and sodium borohydride/chloranil-based method (SBC); Antioxidant activities were determined using DPPH, ABTS and FRAP assays; Antimicrobial properties were investigated by agar dilution and mycelial growth rate method. Results The results showed hyperoside was the predominant phenolic compound in three Potentilla species by RP-HPLC assay, with the content of 8.86 (P. fruticosa), 2.56 (P. glabra) and 2.68 mg/g (P. parvifolia), respectively. The highest content of total identified phenolic compounds (hyperoside, (+)-catechin, caffeic acid, ferulic acid, rutin and ellagic acid) was observed in P. parvifolia (14.17 mg/g), follow by P. fruticosa (10.01 mg/g) and P. glabra (7.01 mg/g). P. fruticosa possessed the highest content of total phenolic (84.93 ± 0.50 mmol gallic acid equivalent/100 g) and total flavonoid (84.14 ± 0.03 mmol quercetin equivalent/100 g), which were in good correlation with its significant DPPHIC50 (16.87 μg/mL), ABTS (2763.48 μmol Trolox equivalent/g) and FRAP (1398.70 μmol Trolox equivalent/g) capacities. Furthermore, the effective methodology to distinguish the different species of Potentilla was also established by chromatographic fingerprint analysis for

  2. Antimicrobial activity of extractable conifer heartwood compounds toward Phytophthora ramorum.

    PubMed

    Manter, Daniel K; Kelsey, Rick G; Karchesy, Joseph J

    2007-11-01

    Ethyl acetate extracts from heartwood of seven western conifer trees and individual volatile compounds in the extracts were tested for antimicrobial activity against Phytophthora ramorum. Extracts from incense and western redcedar exhibited the strongest activity, followed by yellow-cedar, western juniper, and Port-Orford-cedar with moderate activity, and no activity for Douglas-fir and redwood extracts. Chemical composition of the extracts varied both qualitatively and quantitatively among the species with a total of 37 compounds identified by mass spectrometry. Of the 13 individual heartwood compounds bioassayed, three showed strong activity with a Log(10) EC(50) less than or equal to 1.0 ppm (hinokitiol, thymoquinone, and nootkatin), three expressed moderate activity ranging from 1.0-2.0 ppm (nootkatol, carvacrol, and valencene-11,12-diol), four compounds had weak activity at 2.0-3.0 ppm [alpha-terpineol, valencene-13-ol, (+)-beta-cedrene, (-)-thujopsene], and three had no activity [(+)-cedrol, delta-cadinene, and methyl carvacrol]. All of the most active compounds contained a free hydroxyl group, except thymoquinone. The importance of a free hydroxyl was demonstrated by the tremendous difference in activity between carvacrol (Log(10) EC(50) 1.81 +/- 0.08 ppm) and methyl carvacrol (Log(10) EC(50) >3.0 ppm). A field trial in California, showed that heartwood chips from redcedar placed on the forest floor for 4 months under Umbellularia californica (California bay laurel) with symptoms of P. ramorum leaf blight significantly limited the accumulation of P. ramorum DNA in the litter layer, compared with heartwood chips from redwood.

  3. Olive Mill Waste Extracts: Polyphenols Content, Antioxidant, and Antimicrobial Activities

    PubMed Central

    Leouifoudi, Inass; Harnafi, Hicham; Zyad, Abdelmajid

    2015-01-01

    Natural polyphenols extracts have been usually associated with great bioactive properties. In this work, we investigated in vitro antioxidant and antimicrobial potential of the phenolic olive mill wastewater extracts (OWWE) and the olive cake extracts (OCE). Using the Folin Ciocalteux method, OWWE contained higher total phenol content compared to OCE (8.90 ± 0.728 g/L versus 0.95 ± 0.017 mg/g). The phenolic compounds identification was carried out with a performance liquid chromatograph coupled to tandem mass spectrometry equipment (HPLC-ESI-MS). With this method, a list of polyphenols from OWWE and OCE was obtained. The antioxidant activity was measured in aqueous (DPPH) and emulsion (BCBT) systems. Using the DPPH assay, the results show that OWWE was more active than OCE and interestingly the extracts originating from mountainous areas were more active than those produced from plain areas (EC50 = 12.1 ± 5.6 μg/mL; EC50 = 157.7 ± 34.9 μg/mL, resp.). However, when the antioxidant activity was reversed in the BCBT, OCE produced from plain area was more potent than mountainous OCE. Testing by the gel diffusion assay, all the tested extracts have showed significant spectrum antibacterial activity against Staphylococcus aureus, whereas the biophenols extracts showed more limited activity against Escherichia coli and Streptococcus faecalis. PMID:26693221

  4. Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Janaki, A. Chinnammal; Sailatha, E.; Gunasekaran, S.

    2015-06-01

    The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

  5. Synthesis, characteristics and antimicrobial activity of ZnO nanoparticles.

    PubMed

    Janaki, A Chinnammal; Sailatha, E; Gunasekaran, S

    2015-06-05

    The utilization of various plant resources for the bio synthesis of metallic nano particles is called green technology and it does not utilize any harmful protocols. Present study focuses on the green synthesis of ZnO nano particles by Zinc Carbonate and utilizing the bio-components of powder extract of dry ginger rhizome (Zingiber officinale). The ZnO nano crystallites of average size range of 23-26 nm have been synthesized by rapid, simple and eco friendly method. Zinc oxide nano particles were characterized by using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDX). FTIR spectra confirmed the adsorption of surfactant molecules at the surface of ZnO nanoparticles and the presence of ZnO bonding. Antimicrobial activity of ZnO nano particles was done by well diffusion method against pathogenic organisms like Klebsiella pneumonia, Staphylococcus aureus and Candida albicans and Penicillium notatum. It is observed that the ZnO synthesized in the process has the efficient antimicrobial activity.

  6. Novel imidazolium salt--peptide conjugates and their antimicrobial activity.

    PubMed

    Reinhardt, A; Horn, M; Schmauck, J Pieper Gen; Bröhl, A; Giernoth, R; Oelkrug, C; Schubert, A; Neundorf, I

    2014-12-17

    Our study presents innovative research dealing with the synthesis and biological evaluation of conjugates out of antimicrobial peptides (AMPs) and imidazolium cations that are derived from ionic liquids. AMPs are considered as promising alternatives to common antibiotics due to their different activity mechanisms. Antibacterial effects have also been described for ionic liquids bearing imidazolium cations . Besides single coupling of carboxy-functionalized imidazolium cations to the peptide N-terminal we also developed conjugates bearing multiple copies of imidazolium cations. The combination of both compounds resulted in synergistic effects that were most pronounced when more imidazolium cations were attached to the peptides. In addition, antibacterial activity even in drug-resistant bacterial strains could be observed. Moreover, the novel compounds showed good selectivity only against bacterial cells, an observation that was further proven by lipid interaction studies using giant unilamellar vesicles.

  7. Antimicrobial activity of extracts from Tamarindus indica L. leaves

    PubMed Central

    Escalona-Arranz, Julio César; Péres-Roses, Renato; Urdaneta-Laffita, Imilci; Camacho-Pozo, Miladis Isabel; Rodríguez-Amado, Jesús; Licea-Jiménez, Irina

    2010-01-01

    Tamarindus indica L. leaves are reported worldwide as antibacterial and antifungal agents; however, this observation is not completely accurate in the case of Cuba. In this article, decoctions from fresh and sun dried leaves, as well as fluid extracts prepared with 30 and 70% ethanol-water and the pure essential oil from tamarind leaves were microbiologically tested against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomona aeruginosa and Candida albicans. Aqueous and fluid extracts were previously characterized by spectrophotometric determination of their total phenols and flavonoids, while the essential oil was chemically evaluated by gas chromatography/mass spectroscopy (GC/MS). Experimental data suggest phenols as active compounds against B. subtilis cultures, but not against other microorganisms. On the other hand, the essential oil exhibited a good antimicrobial spectrum when pure, but its relative low concentrations in common folk preparations do not allow for any good activity in these extracts. PMID:20931087

  8. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    PubMed Central

    2012-01-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics. PMID:22625664

  9. In vitro antimicrobial activity of peroxide-based bleaching agents.

    PubMed

    Napimoga, Marcelo Henrique; de Oliveira, Rogério; Reis, André Figueiredo; Gonçalves, Reginaldo Bruno; Giannini, Marcelo

    2007-06-01

    Antibacterial activity of 4 commercial bleaching agents (Day White, Colgate Platinum, Whiteness 10% and 16%) on 6 oral pathogens (Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis, Candida albicans, Lactobacillus casei, and Lactobacillus acidophilus) and Staphylococcus aureus were evaluated. A chlorhexidine solution was used as a positive control, while distilled water was the negative control. Bleaching agents and control materials were inserted in sterilized stainless-steel cylinders that were positioned under inoculated agar plate (n = 4). After incubation according to the appropriate period of time for each microorganism, the inhibition zones were measured. Data were analyzed by 2-way analysis of variance and Tukey test (a = 0.05). All bleaching agents and the chlorhexidine solution produced antibacterial inhibition zones. Antimicrobial activity was dependent on peroxide-based bleaching agents. For most microorganisms evaluated, bleaching agents produced inhibition zones similar to or larger than that observed for chlorhexidine. C albicans, L casei, and L acidophilus were the most resistant microorganisms.

  10. Polyhexamethylene biguanide functionalized cationic silver nanoparticles for enhanced antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Ashraf, Sumaira; Akhtar, Nasrin; Ghauri, Muhammad Afzal; Rajoka, Muhammad Ibrahim; Khalid, Zafar M.; Hussain, Irshad

    2012-05-01

    Polyhexamethylene biguanide (PHMB), a broad spectrum disinfectant against many pathogens, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles. The particles formed were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering, electrophoretic mobility, and TEM to measure their morphology and surface chemistry. PHMB-functionalized silver nanoparticles were then evaluated for their antimicrobial activity against a gram-negative bacterial strain, Escherichia coli. These silver nanoparticles were found to have about 100 times higher bacteriostatic and bactericidal activities, compared to the previous reports, due to the combined antibacterial effect of silver nanoparticles and PHMB. In addition to other applications, PHMB-functionalized silver nanoparticles would be extremely useful in textile industry due to the strong interaction of PHMB with cellulose fabrics.

  11. Antimicrobial activity of Ammodaucus leucotrichus fruit oil from Algerian Sahara.

    PubMed

    El-Haci, Imad Abdelhamid; Bekhechi, Chahrazed; Atik-Bekkara, Fewzia; Mazari, Wissame; Gherib, Mohamed; Bighelli, Ange; Casanova, Joseph; Tomi, Félix

    2014-05-01

    Three fruit oil samples of Ammodaucus leucotrichus Cosson & Durieu from Algerian Sahara were obtained by hydrodistillation and analyzed by GC(RI), GC-MS and 13C NMR spectroscopy. The main compounds were perillaldehyde (87.0-87.9%) and limonene (7.4-8.2%). The antimicrobial effect of the essential oil was evaluated against bacteria, yeasts and filamentous fungi. High antibacterial activity was observed against Escherichia coli, Staphylococcus aureus. Enterobacter cloaceae, Bacillus cereus and Salmonella typhimurium, with MIC values between 0.5-1.0 microL/mL. Fungal strains were also sensitive to the essential oil (MIC values: 0.25-0.75 microL/mL).The most potent activity was observed against the filamentous fungi, Fusarium oxysporum and Aspergillusflavus (0.25-0.50 microL/mL).

  12. Preparation and antimicrobial activity of scleraldehyde from Schizophyllum commune.

    PubMed

    Jayakumar, Gladstone Christopher; Kanth, Swarna V; Chandrasekaran, B; Raghava Rao, J; Nair, B U

    2010-10-13

    The present study investigates the antimicrobial activity of oxidized schizophyllan (scleraldehyde) against Gram-positive and Gram-negative bacteria by diffusion and tube dilution analysis. Schizophyllan is a natural polysaccharide produced by fungi of the genus Schizophyllum. Periodate oxidation specifically cleaves the vicinal glycols in scleraldehyde to form their dialdehyde derivatives. The antibacterial activity exhibited by scleraldehyde was defined using various tests such as the disc diffusion assay, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). MIC and MBC values were found to be in the range of 3.0-8.0 mg/mL. Hence, the present studies establish that the scleraldehyde possesses effective antibacterial properties and can be used as a biopreservative for preservation of raw hides and skins.

  13. Antimicrobial activity of tea as affected by the degree of fermentation and manufacturing season.

    PubMed

    Chou, C C; Lin, L L; Chung, K T

    1999-05-01

    Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas fluorescens, Salmonella sp. and Staphylococcus aureus were used to test the antimicrobial activity of tea flush extract and extracts of various tea products. Among the six test organisms, P. fluorescens was the most sensitive to the extracts, while B. subtilis was the least sensitive. In general, antimicrobial activity decreased when the extents of tea fermentation increased. The antimicrobial activities of tea flush extract and extracts of tea products with different extents of fermentation varied with test organisms. Tea flush and Green tea, the unfermented tea, exerted the strongest antimicrobial activity followed by the partially fermented tea products such as Longjing, Tieh-Kuan-Ying, Paochung, and Oolong teas. On the other hand, Black tea, the completely fermented tea, showed the least antimicrobial activity. It was also noted that extracts of Oolong tea prepared in summer exhibited the strongest antimicrobial activity, followed by those prepared in spring, winter and fall.

  14. Analysis of the antimicrobial activities of a chemokine-derived peptide (CDAP-4) on Pseudomonas aeruginosa

    SciTech Connect

    Martinez-Becerra, Francisco; Dominguez-Ramirez, Lenin; Mendoza-Hernandez, Guillermo; Lopez-Vidal, Yolanda; Soldevila, Gloria . E-mail: garciaze@servidor.unam.mx

    2007-04-06

    Chemokines are key molecules involved in the control of leukocyte trafficking. Recently, a novel function as antimicrobial proteins has been described. CCL13 is the only member of the MCP chemokine subfamily displaying antimicrobial activity. To determine Key residues involved in its antimicrobial activity, CCL13 derived peptides were synthesized and tested against several bacterial strains, including Pseudomonas aeruginosa. One of these peptides, corresponding to the C-terminal region of CCL13 (CDAP-4) displayed good antimicrobial activity. Electron microscopy studies revealed remarkable morphological changes after CDAP-4 treatment. By computer modeling, CDAP-4 in {alpha} helical configuration generated a positive electrostatic potential that extended beyond the surface of the molecule. This feature is similar to other antimicrobial peptides. Altogether, these findings indicate that the antimicrobial activity was displayed by CCL13 resides to some extent at the C-terminal region. Furthermore, CDAP-4 could be considered a good antimicrobial candidate with a potential use against pathogens including P. aeruginosa.

  15. Antimicrobial activity of Ulva reticulata and its endophytes

    NASA Astrophysics Data System (ADS)

    Dhanya, K. I.; Swati, V. I.; Vanka, Kanth Swaroop; Osborne, W. J.

    2016-04-01

    Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy (GC-MS) revealed the existence of phenol, 3, 5-bis (1, 1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas stutzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

  16. Foeniculum vulgare essential oils: chemical composition, antioxidant and antimicrobial activities.

    PubMed

    Miguel, Maria Graça; Cruz, Cláudia; Faleiro, Leonor; Simões, Mariana T F; Figueiredo, Ana Cristina; Barroso, José G; Pedro, Luis G

    2010-02-01

    The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, 1 h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), alpha-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity > 50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h.

  17. In vitro antimicrobial activity of four Ficus carica latex fractions against resistant human pathogens (antimicrobial activity of Ficus carica latex).

    PubMed

    Aref, Houda Lazreg; Salah, Karima Bel Hadj; Chaumont, Jean Pierre; Fekih, Abdelwaheb; Aouni, Mahjoub; Said, Khaled

    2010-01-01

    Methanolic, hexanoïc, chloroformic and ethyl acetate extracts of Ficus carica latex were investigated for their in vitro antimicrobial proprieties against five bacteria species and seven strains of fungi. The green fruit latex was collected from Chott Mariam Souse, Middle East coast of Tunisia. The antimicrobial activity of the extracts was evaluated and based respectively on the inhibition zone using the disc-diffusion assay, minimal inhibition concentration (MIC) for bacterial testing and the method by calculating inhibition percentage (I%) for fungi-inhibiting activities. The methanolic extract had no effect against bacteria except for Proteus mirabilis while the ethyl acetate extract had inhibition effect on the multiplication of five bacteria species (Enterococcus fecalis, Citobacter freundei, Pseudomonas aeruginosa, Echerchia coli and Proteus mirabilis). For the opportunist pathogenic yeasts, ethyl acetate and chlorophormic fractions showed a very strong inhibition (100%); methanolic fraction had a total inhibition against Candida albicans (100%) at a concentration of 500 microg/ml and a negative effect against Cryptococcus neoformans. Microsporum canis was strongly inhibited with methanolic extract (75%) and totally with ethyl acetate extract at a concentration of 750 microg/ml. Hexanoïc extract showed medium results.

  18. A screening for antimicrobial activities of Caribbean herbal remedies

    PubMed Central

    2013-01-01

    Background The TRAMIL program aims to understand, validate and expand health practices based on the use of medicinal plants in the Caribbean, which is a “biodiversity hotspot” due to high species endemism, intense development pressure and habitat loss. The antibacterial activity was examined for thirteen plant species from several genera that were identified as a result of TRAMIL ethnopharmacological surveys or were reported in ethnobotanical accounts from Puerto Rico. The aim of this study was to validate the traditional use of these plant species for the treatment of bacterial infections, such as conjunctivitis, fever, otitis media and furuncles. Methods An agar disc diffusion assay was used to examine five bacterial strains that are associated with the reported infections, including Staphylococcus saprophyticus (ATCC 15305), S. aureus (ATCC 6341), Escherichia coli (ATCC 4157), Haemophilus influenzae (ATCC 8142), Pseudomonas aeruginosa (ATCC 7700) and Proteus vulgaris (ATCC 6896), as well as the fungus Candida albicans (ATCC 752). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined for each of the extracts that showed inhibitory activity. Results The decoctions of Pityrogramma calomelanos, Tapeinochilus ananassae, and Syzygium jambos, as well as the juice of Gossypium barbadense, showed > 20% growth inhibition against several bacteria relative to the positive control, which was the antibiotic Streptomycin. Extracts with the best antimicrobial activities were S. jambos that showed MIC = 31 μg/mL and MBC = 1.0 mg/mL against P. vulgaris and T. ananassae that showed MIC = 15 μg/mL against S. aureus. Conclusion This report confirms the traditional use of P. calomelanos for the treatment of kidney infections that are associated with stones, as well as the antimicrobial and bactericidal effects of T. ananassae against P. vulgaris and S. saprophyticus and the effects of S. jambos against S

  19. Antimicrobial, antibiofilm and cytotoxic activities of Hakea sericea Schrader extracts

    PubMed Central

    Luís, Ângelo; Breitenfeld, Luiza; Ferreira, Susana; Duarte, Ana Paula; Domingues, Fernanda

    2014-01-01

    Background: Hakea sericea Schrader is an invasive shrub in Portuguese forests. Objective: The goal of this work was to evaluate the antimicrobial activity of H. sericea extracts against several strains of microorganisms, including the ability to inhibit the formation of biofilms. Additionally the cytotoxic properties of these extracts, against human cells, were assessed. Materials and Methods: The antimicrobial activity of the methanolic extracts of H. sericea was assessed by disk diffusion assay and Minimum Inhibitory Concentration (MIC) value determination. The antibiofilm activity was determined by quantification of total biofilm biomass with crystal violet. Cytotoxicity was evaluated by hemolysis assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Results: For Gram-positive bacteria, MIC values of H. sericea methanolic extracts ranged between 0.040 and 0.625 mg/mL, whereas the fruits extract yielded the lowest MIC for several strains of microorganisms, namely, S. aureus, B. cereus, L. monocytogenes and clinical methicillin-resistant S. aureus (MRSA). Stems and fruits extract at 2.5 mg/mL effectively eradicated the biofilm of S. aureus ATCC 25923, SA 01/10 and MRSA 12/10. Regarding leaves extract, hemolysis was not observed, and in the case of stems and fruits, hemolysis was verified only for higher concentrations, suggesting its low toxicity. Fruits extract presented no toxic effect to normal human dermal fibroblasts (NHDF) cells however for concentrations of 0.017 and 0.008 mg/mL this extract was able to decrease human breast adenocarcinoma cells (MCF-7) viability in about 60%, as MTT test results had confirmed. This is a clearly demonstrator of the cytotoxicity of this extract against MCF-7 cells. PMID:24914310

  20. Synthesis and antimicrobial activity of gold/silver-tellurium nanostructures.

    PubMed

    Chang, Hsiang-Yu; Cang, Jinshun; Roy, Prathik; Chang, Huan-Tsung; Huang, Yi-Cheng; Huang, Chih-Ching

    2014-06-11

    Gold-tellurium nanostructures (Au-Te NSs), silver-tellurium nanostructures (Ag-Te NSs), and gold/silver-tellurium nanostructures (Au/Ag-Te NSs) have been prepared through galvanic reactions of tellurium nanotubes (Te NTs) with Au(3+), Ag(+), and both ions, respectively. Unlike the use of less environmentally friendly hydrazine, fructose as a reducing agent has been used to prepare Te NTs from TeO2 powders under alkaline conditions. The Au/Ag-Te NSs have highly catlaytic activity to convert nonfluorescent Amplex Red to form fluorescent product, revealing their great strength of generating reactive oxygen species (ROS). Au/Ag-Te NSs relative to the other two NSs exhibit greater antimicrobial activity toward the growth of E. coli, S. enteritidis, and S. aureus; the minimal inhibitory concentration (MIC) values of Au/Ag-Te NSs were much lower (>10-fold) than that of Ag-Te NSs and Au-Te NSs. The antibacterial activity of Au/Ag-Te NSs is mainly due to the release of Ag(+) ions and Te-related ions and also may be due to the generated ROS which destroys the bacteria membrane. In vitro cytotoxicity and hemolysis analyses have revealed their low toxicity in selected human cell lines and insignificant hemolysis in red blood cells. In addition, inhibition zone measurements using a Au/Ag-Te NSs-loaded konjac jelly film have suggested that it has great potential in practial application such as wound dressing for reducing bacterial wound infection. Having great antibacterial activitiy and excellent biocompatibility, the low-cost Au/Ag-Te NSs hold great potential as effective antimicrobial drugs.

  1. Antimicrobial and Antioxidant Activities of Plants from Northeast of Mexico

    PubMed Central

    Salazar-Aranda, Ricardo; Pérez-López, Luis Alejandro; López-Arroyo, Joel; Alanís-Garza, Blanca Alicia; Waksman de Torres, Noemí

    2011-01-01

    Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000 μg ml−1. We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125 μg ml−1), C. glabrata (MICs 31.25 μg ml−1) and C. parapsilosis (MICs between 31.25 and 125 μg ml−1); Chrysanctinia mexicana against C. glabrata (MICs 31.25 μg ml−1); Colubrina greggii against E. faecalis (MICs 250 μg ml−1) and Cordia boissieri against C. glabrata (MIC 125 μg ml−1). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri. PMID:19770266

  2. Antimicrobial and antioxidant activities of plants from northeast of Mexico.

    PubMed

    Salazar-Aranda, Ricardo; Pérez-López, Luis Alejandro; López-Arroyo, Joel; Alanís-Garza, Blanca Alicia; Waksman de Torres, Noemí

    2011-01-01

    Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalis and two Staphylococcus aureus strains), and seven clinically isolated yeasts (Candida albicans, C. krusei, C. tropicalis, C. parapsilosis and C. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000 μg ml(-1). We report here for the first time activity of Ceanothus coeruleus against S. aureus (flowers, minimal inhibitory concentration (MIC) 125 μg ml(-1)), C. glabrata (MICs 31.25 μg ml(-1)) and C. parapsilosis (MICs between 31.25 and 125 μg ml(-1)); Chrysanctinia mexicana against C. glabrata (MICs 31.25 μg ml(-1)); Colubrina greggii against E. faecalis (MICs 250 μg ml(-1)) and Cordia boissieri against C. glabrata (MIC 125 μg ml(-1)). Furthermore, this is the first report about antioxidant activity of extracts from Ceanothus coeruleus, Chrysanctinia mexicana, Colubrina greggii and Cyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the species Ceanothus coeruleus, Schinus molle, Colubrina greggii and Cordia boissieri.

  3. In Vitro and In Vivo Activities of Antimicrobial Peptides Developed Using an Amino Acid-Based Activity Prediction Method

    PubMed Central

    Wu, Xiaozhe; Wang, Zhenling; Li, Xiaolu; Fan, Yingzi; He, Gu; Wan, Yang; Yu, Chaoheng; Tang, Jianying; Li, Meng; Zhang, Xian; Zhang, Hailong; Xiang, Rong; Pan, Ying; Liu, Yan; Lu, Lian

    2014-01-01

    To design and discover new antimicrobial peptides (AMPs) with high levels of antimicrobial activity, a number of machine-learning methods and prediction methods have been developed. Here, we present a new prediction method that can identify novel AMPs that are highly similar in sequence to known peptides but offer improved antimicrobial activity along with lower host cytotoxicity. Using previously generated AMP amino acid substitution data, we developed an amino acid activity contribution matrix that contained an activity contribution value for each amino acid in each position of the model peptide. A series of AMPs were designed with this method. After evaluating the antimicrobial activities of these novel AMPs against both Gram-positive and Gram-negative bacterial strains, DP7 was chosen for further analysis. Compared to the parent peptide HH2, this novel AMP showed broad-spectrum, improved antimicrobial activity, and in a cytotoxicity assay it showed lower toxicity against human cells. The in vivo antimicrobial activity of DP7 was tested in a Staphylococcus aureus infection murine model. When inoculated and treated via intraperitoneal injection, DP7 reduced the bacterial load in the peritoneal lavage solution. Electron microscope imaging and the results indicated disruption of the S. aureus outer membrane by DP7. Our new prediction method can therefore be employed to identify AMPs possessing minor amino acid differences with improved antimicrobial activities, potentially increasing the therapeutic agents available to combat multidrug-resistant infections. PMID:24982064

  4. In vitro and in vivo activities of antimicrobial peptides developed using an amino acid-based activity prediction method.

    PubMed

    Wu, Xiaozhe; Wang, Zhenling; Li, Xiaolu; Fan, Yingzi; He, Gu; Wan, Yang; Yu, Chaoheng; Tang, Jianying; Li, Meng; Zhang, Xian; Zhang, Hailong; Xiang, Rong; Pan, Ying; Liu, Yan; Lu, Lian; Yang, Li

    2014-09-01

    To design and discover new antimicrobial peptides (AMPs) with high levels of antimicrobial activity, a number of machine-learning methods and prediction methods have been developed. Here, we present a new prediction method that can identify novel AMPs that are highly similar in sequence to known peptides but offer improved antimicrobial activity along with lower host cytotoxicity. Using previously generated AMP amino acid substitution data, we developed an amino acid activity contribution matrix that contained an activity contribution value for each amino acid in each position of the model peptide. A series of AMPs were designed with this method. After evaluating the antimicrobial activities of these novel AMPs against both Gram-positive and Gram-negative bacterial strains, DP7 was chosen for further analysis. Compared to the parent peptide HH2, this novel AMP showed broad-spectrum, improved antimicrobial activity, and in a cytotoxicity assay it showed lower toxicity against human cells. The in vivo antimicrobial activity of DP7 was tested in a Staphylococcus aureus infection murine model. When inoculated and treated via intraperitoneal injection, DP7 reduced the bacterial load in the peritoneal lavage solution. Electron microscope imaging and the results indicated disruption of the S. aureus outer membrane by DP7. Our new prediction method can therefore be employed to identify AMPs possessing minor amino acid differences with improved antimicrobial activities, potentially increasing the therapeutic agents available to combat multidrug-resistant infections.

  5. Peptides from the scorpion Vaejovis punctatus with broad antimicrobial activity.

    PubMed

    Ramírez-Carreto, Santos; Jiménez-Vargas, Juana María; Rivas-Santiago, Bruno; Corzo, Gerardo; Possani, Lourival D; Becerril, Baltazar; Ortiz, Ernesto

    2015-11-01

    The antimicrobial potential of two new non-disulfide bound peptides, named VpAmp1.0 (LPFFLLSLIPSAISAIKKI, amidated) and VpAmp2.0 (FWGFLGKLAMKAVPSLIGGNKSSSK) is here reported. These are 19- and 25-aminoacid-long peptides with +2 and +4 net charges, respectively. Their sequences correspond to the predicted mature regions from longer precursors, putatively encoded by cDNAs derived from the venom glands of the Mexican scorpion Vaejovis punctatus. Both peptides were chemically synthesized and assayed against a variety of microorganisms, including pathogenic strains from clinical isolates and strains resistant to conventional antibiotics. Two shorter variants, named VpAmp1.1 (FFLLSLIPSAISAIKKI, amidated) and VpAmp2.1 (FWGFLGKLAMKAVPSLIGGNKK), were also synthesized and tested. The antimicrobial assays revealed that the four synthetic peptides effectively inhibit the growth of both Gram-positive (Staphylococcus aureus and Streptococcus agalactiaea) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, with MICs in the range of 2.5-24.0 μM; yeasts (Candida albicans and Candida glabrata) with MICs of 3.1-50.0 μM; and two clinically isolated strains of Mycobacterium tuberculosis-including a multi-drug resistant one- with MICs in the range of 4.8-30.5 μM. A comparison between the activities of the original peptides and their derivatives gives insight into the structural/functional role of their distinctive residues.

  6. Influence of montmorillonite on antimicrobial activity of tetracycline and ciprofloxacin

    NASA Astrophysics Data System (ADS)

    Lv, Guocheng; Pearce, Cody W.; Gleason, Andrea; Liao, Libing; MacWilliams, Maria P.; Li, Zhaohui

    2013-11-01

    Antibiotics are used not only to fight infections and inhibit bacterial growth, but also as growth promotants in farm livestock. Farm runoff and other farm-linked waste have led to increased antibiotic levels present in the environment, the impact of which is not completely understood. Soil, more specifically clays, that the antibiotic contacts may alter its effectiveness against bacteria. In this study a swelling clay mineral montmorillonite was preloaded with antibiotics tetracycline and ciprofloxacin at varying concentrations and bioassays were conducted to examine whether the antibiotics still inhibited bacterial growth in the presence of montmorillonite. Escherichia coli was incubated with montmorillonite or antibiotic-adsorbed montmorillonite, and then the number of viable bacteria per mL was determined. The antimicrobial activity of tetracycline was affected in the presence of montmorillonite, as the growth of non-resistant bacteria was still found even when extremely high TC doses were used. Conversely, in the presence of montmorillonite, ciprofloxacin did inhibit E. coli bacterial growth at high concentrations. These results suggest that the effectiveness of antimicrobial agents in clayey soils depends on the amount of antibiotic substance present, and on the interactions between the antibiotic and the clays in the soil, as well.

  7. Structure and antimicrobial activity of phloroglucinol derivatives from Achyrocline satureioides.

    PubMed

    Casero, Carina; Machín, Félix; Méndez-Álvarez, Sebastián; Demo, Mirta; Ravelo, Ángel G; Pérez-Hernández, Nury; Joseph-Nathan, Pedro; Estévez-Braun, Ana

    2015-01-23

    The new prenylated phloroglucinol α-pyrones 1-3 and the new dibenzofuran 4, together with the known 23-methyl-6-O-demethylauricepyrone (5), achyrofuran (6), and 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A), were isolated from the aerial parts of Achyrocline satureioides. Their structures were determined by 1D and 2D NMR spectroscopic studies, while the absolute configuration of the sole stereogenic center of 1 was established by vibrational circular dichroism measurements in comparison to density functional theory calculated data. The same (S) absolute configuration of the α-methylbutyryl chain attached to the phloroglucinol nucleus was assumed for compounds 2-6 based on biogenetic considerations. Derivatives 7-16 were prepared from 1 and 5, and the antimicrobial activities of the isolated metabolites and some of the semisynthetic derivatives against a selected panel of Gram-positive and Gram-negative bacteria, as well as a set of yeast molds, were determined.

  8. Quaternary ammonium poly(diethylaminoethyl methacrylate) possessing antimicrobial activity.

    PubMed

    Farah, Shady; Aviv, Oren; Laout, Natalia; Ratner, Stanislav; Beyth, Nurit; Domb, Abraham J

    2015-04-01

    Quaternary ammonium (QA) methacrylate monomers and polymers were synthesized from a N-alkylation of N,N-diethylaminoethyl methacrylate (DEAEM) monomer. Linear copolymers, and for the first time reported crosslinked nanoparticles (NPs), based QA-PDEAEM were prepared by radical polymerization of the quaternized QA-DEAEM monomers with either methyl methacrylate (MMA) or a divinyl monomer. QA-PDEAEM NPs of 50-70 nm were embedded in polyethylene vinyl acetate coating. QA-polymers with N-C8 and N-C18 alkyl chains and copolymers with methyl methacrylate were prepared at different molar ratios and examined for their antimicrobial effectiveness. These coatings exhibited strong antibacterial activity against four representative Gram-positive and Gram-negative bacteria.

  9. A new effective assay to detect antimicrobial activity of filamentous fungi.

    PubMed

    Pereira, Eric; Santos, Ana; Reis, Francisca; Tavares, Rui M; Baptista, Paula; Lino-Neto, Teresa; Almeida-Aguiar, Cristina

    2013-01-15

    The search for new antimicrobial compounds and the optimization of production methods turn the use of antimicrobial susceptibility tests a routine. The most frequently used methods are based on agar diffusion assays or on dilution in agar or broth. For filamentous fungi, the most common antimicrobial activity detection methods comprise the co-culture of two filamentous fungal strains or the use of fungal extracts to test against single-cell microorganisms. Here we report a rapid, effective and reproducible assay to detect fungal antimicrobial activity against single-cell microorganisms. This method allows an easy way of performing a fast antimicrobial screening of actively growing fungi directly against yeast. Because it makes use of an actively growing mycelium, this bioassay also provides a way for studying the production dynamics of antimicrobial compounds by filamentous fungi. The proposed assay is less time consuming and introduces the innovation of allowing the direct detection of fungal antimicrobial properties against single cell microorganisms without the prior isolation of the active substance(s). This is particularly useful when performing large screenings for fungal antimicrobial activity. With this bioassay, antimicrobial activity of Hypholoma fasciculare against yeast species was observed for the first time.

  10. An active principle of Nigella sativa L., thymoquinone, showing significant antimicrobial activity against anaerobic bacteria

    PubMed Central

    Randhawa, Mohammad Akram; Alenazy, Awwad Khalaf; Alrowaili, Majed Gorayan; Basha, Jamith

    2017-01-01

    Aim/Background: Thymoquinone (TQ) is the major active principle of Nigella sativa seed (black seed) and is known to control many fungi, bacteria, and some viruses. However, the activity of TQ against anaerobic bacteria is not well demonstrated. Anaerobic bacteria can cause severe infections, including diarrhea, aspiration pneumonia, and brain abscess, particularly in immunodeficient individuals. The present study aimed to investigate the in vitro antimicrobial activity of TQ against some anaerobic pathogens in comparison to metronidazole. Methods: Standard, ATCC, strains of four anaerobic bacteria (Clostridium difficile, Clostridium perfringens, Bacteroides fragilis, and Bacteroides thetaiotaomicron), were initially isolated on special Brucella agar base (with hemin and vitamin K). Then, minimum inhibitory concentrations (MICs) of TQ and metronidazole were determined against these anaerobes when grown in Brucella agar, using serial agar dilution method according to the recommended guidelines for anaerobic organisms instructed by the Clinical and Laboratory Standards Institute. Results: TQ showed a significant antimicrobial activity against anaerobic bacteria although much weaker than metronidazole. MICs of TQ and metronidazole against various anaerobic human pathogens tested were found to be between 10-160 mg/L and 0.19-6.25 mg/L, respectively. Conclusions: TQ controlled the anaerobic human pathogenic bacteria, which supports the use of N. sativa in the treatment of diarrhea in folk medicine. Further investigations are in need for determination of the synergistic effect of TQ in combination with metronidazole and the activity of derivatives of TQ against anaerobic infections. PMID:28163966

  11. Synthesis, antimicrobial activity and advances in structure-activity relationships (SARs) of novel tri-substituted thiazole derivatives.

    PubMed

    Reddy, Guda Mallikarjuna; Garcia, Jarem Raul; Reddy, Vemulapati Hanuman; de Andrade, Ageo Meier; Camilo, Alexandre; Pontes Ribeiro, Renan Augusto; de Lazaro, Sergio Ricardo

    2016-11-10

    Trisubstituted thiazoles were synthesized and studied for their antimicrobial activity and supported by theoretical calculations. In addition, MIC, MBC and MFC were also tested. Moreover, the present study was analyzed to scrutinize comprehensive structure-activity relationships. In fact, LUMO orbital energy and orbital orientation was reliable to explain their antibacterial and antifungal assay. Amongst the tested compounds, tri-methyl-substituted thiazole compound showed higher antimicrobial activity and low MIC value due to highest LUMO energy.

  12. Antimicrobial activity of Antarctic bryozoans: an ecological perspective with potential for clinical applications.

    PubMed

    Figuerola, Blanca; Sala-Comorera, Laura; Angulo-Preckler, Carlos; Vázquez, Jennifer; Jesús Montes, M; García-Aljaro, Cristina; Mercadé, Elena; Blanch, Anicet R; Avila, Conxita

    2014-10-01

    The antimicrobial activity of Antarctic bryozoans and the ecological functions of the chemical compounds involved remain largely unknown. To determine the significant ecological and applied antimicrobial effects, 16 ether and 16 butanol extracts obtained from 13 different bryozoan species were tested against six Antarctic (including Psychrobacter luti, Shewanella livingstonensis and 4 new isolated strains) and two bacterial strains from culture collections (Escherichia coli and Bacillus cereus). Results from the bioassays reveal that all ether extracts exhibited antimicrobial activity against some bacteria. Only one butanol extract produced inhibition, indicating that antimicrobial compounds are mainly lipophilic. Ether extracts of the genus Camptoplites inhibited the majority of bacterial strains, thus indicating a broad-spectrum of antimicrobial activity. Moreover, most ether extracts presented activities against bacterial strains from culture collections, suggesting the potential use of these extracts as antimicrobial drugs against pathogenic bacteria.

  13. Alanine-Scanning Mutational Analysis of Durancin GL Reveals Residues Important for Its Antimicrobial Activity.

    PubMed

    Ju, Xingrong; Chen, Xinquan; Du, Lihui; Wu, Xueyou; Liu, Fang; Yuan, Jian

    2015-07-22

    Durancin GL is a novel class IIa bacteriocin with 43 residues produced by Enterococcus durans 41D. This bacteriocin demonstrates narrow inhibition spectrum and potent antimicrobial activity against several Listeria monocytogenes strains, including nisin-resistant L. monocytogenes NR30. A systematic alanine-scanning mutational analysis with site-directed mutagenesis was performed to analyze durancin GL residues important for antimicrobial activity and specificity. Results showed that three mutations lost their antimicrobial activity, ten mutations demonstrated a decreased effect on the activity, and seven mutations exhibited relatively high activity. With regard to inhibitory spectrum, four mutants demonstrated a narrower antimicrobial spectrum than wild-type durancin GL. Another four mutants displayed a broader target cell spectrum and increased potency relative to wild-type durancin GL. These findings broaden our understanding of durancin GL residues important for its antimicrobial activity and contribute to future rational design of variants with increased potency.

  14. The antiviral and antimicrobial activities of licorice, a widely-used Chinese herb

    PubMed Central

    Wang, Liqiang; Yang, Rui; Yuan, Bochuan; Liu, Ying; Liu, Chunsheng

    2015-01-01

    Licorice is a common herb which has been used in traditional Chinese medicine for centuries. More than 20 triterpenoids and nearly 300 flavonoids have been isolated from licorice. Recent studies have shown that these metabolites possess many pharmacological activities, such as antiviral, antimicrobial, anti-inflammatory, antitumor and other activities. This paper provides a summary of the antiviral and antimicrobial activities of licorice. The active components and the possible mechanisms for these activities are summarized in detail. This review will be helpful for the further studies of licorice for its potential therapeutic effects as an antiviral or an antimicrobial agent. PMID:26579460

  15. Contribution of Amphipathicity and Hydrophobicity to the Antimicrobial Activity and Cytotoxicity of β-Hairpin Peptides

    PubMed Central

    2016-01-01

    Bacteria have acquired extensive resistance mechanisms to protect themselves against antibiotic action. Today the bacterial membrane has become one of the “final frontiers” in the search for new compounds acting on novel targets to address the threat of multi-drug resistant (MDR) and XDR bacterial pathogens. β-Hairpin antimicrobial peptides are amphipathic, membrane-binding antibiotics that exhibit a broad range of activities against Gram-positive, Gram-negative, and fungal pathogens. However, most members of the class also possess adverse cytotoxicity and hemolytic activity that preclude their development as candidate antimicrobials. We examined peptide hydrophobicity, amphipathicity, and structure to better dissect and understand the correlation between antimicrobial activity and toxicity, membrane binding, and membrane permeability. The hydrophobicity, pI, net charge at physiological pH, and amphipathic moment for the β-hairpin antimicrobial peptides tachyplesin-1, polyphemusin-1, protegrin-1, gomesin, arenicin-3, and thanatin were determined and correlated with key antimicrobial activity and toxicity data. These included antimicrobial activity against five key bacterial pathogens and two fungi, cytotoxicity against human cell lines, and hemolytic activity in human erythrocytes. Observed antimicrobial activity trends correlated with compound amphipathicity and, to a lesser extent, with overall hydrophobicity. Antimicrobial activity increased with amphipathicity, but unfortunately so did toxicity. Of note, tachyplesin-1 was found to be 8-fold more amphipathic than gomesin. These analyses identify tachyplesin-1 as a promising scaffold for rational design and synthetic optimization toward an antibiotic candidate. PMID:27331141

  16. Investigating antimicrobial activity in Rheinheimera sp. due to hydrogen peroxide generated by l-lysine oxidase activity.

    PubMed

    Chen, Wen Ming; Lin, Chang Yi; Sheu, Shih Yi

    2010-05-05

    A greenish yellow pigmented bacterial strain, designated GR5, was recently isolated from a freshwater culture pond for a soft-shell turtle. Phylogenetic analyses based on 16S rRNA gene sequences indicate that strain GR5 belongs to the genus Rheinheimera and its only closest neighbor is the type strain of Rheinheimera texasensis (98.2%). Based on the antibiogram assay, strain GR5 possesses a broad spectrum of antimicrobial activity including Gram-positive and Gram-negative bacteria, yeast, algae, and strain GR5 itself. Strain GR5 can synthesize a macromolecule with antimicrobial activity due to the generation of hydrogen peroxide and this antimicrobial effect can be inhibited by catalase. This antimicrobial activity is active only in complex culture media or chemically defined culture media containing l-lysine. This antimicrobial macromolecule in strain GR5 is shown to be a monomeric protein with a molecular mass of 71kDa and isoelectric point of approximately 3.68. Liquid chromatography-tandem mass spectrometry analyses reveal close similarity of a 19-amino acid fragment derived from this protein to the antibacterial protein, AlpP from the marine bacterium Pseudoalteromonas tunicata D2, and to the antibacterial protein, marinocine, from the marine bacterium Marinomonas mediterranea. This study explores the nature of antimicrobial macromolecule such as l-lysine oxidase. This is the first report on a freshwater bacterium producing antimicrobial activity by generating hydrogen peroxide through its enzymatic activity of l-lysine oxidase.

  17. Activity of antimicrobial peptide mimetics in the oral cavity: I. Activity against biofilms of Candida albicans.

    PubMed

    Hua, J; Yamarthy, R; Felsenstein, S; Scott, R W; Markowitz, K; Diamond, G

    2010-12-01

    Naturally occurring antimicrobial peptides hold promise as therapeutic agents against oral pathogens such as Candida albicans but numerous difficulties have slowed their development. Synthetic, non-peptidic analogs that mimic the properties of these peptides have many advantages and exhibit potent, selective antimicrobial activity. Several series of mimetics (with molecular weight < 1000) were developed and screened against oral Candida strains as a proof-of-principle for their antifungal properties. One phenylalkyne and several arylamide compounds with reduced mammalian cytotoxicities were found to be active against C. albicans. These compounds demonstrated rapid fungicidal activity in liquid culture even in the presence of saliva, and demonstrated synergy with standard antifungal agents. When assayed against biofilms grown on denture acrylic, the compounds exhibited potent fungicidal activity as measured by metabolic and fluorescent viability assays. Repeated passages in sub-minimum inhibitory concentration levels did not lead to resistant Candida, in contrast to fluconazole. Our results demonstrate the proof-of principle for the use of these compounds as anti-Candida agents, and their further testing is warranted as novel anti-Candida therapies.

  18. Antimicrobial activity of amine oxides: mode of action and structure-activity correlation.

    PubMed

    Subík, J; Takácsová, G; Psenák, M; Devínsky, F

    1977-08-01

    The effect of N-alkyl derivatives of saturated heterocyclic amine oxides on the growth and metabolism of microorganisms has been studied. 4-Dodecylmorpholine-N-oxide inhibited the differentiation and growth of Bacillus cereus, of different species of filamentous fungi, and of the yeast Saccharomyces cerevisiae. For vegetative cells, the effect of 4-dodecylmorpholine-N-oxide was lethal. Cells of S. cerevisiae, after interaction with 4-dodecylmorpholine-N-oxide, released intracellular K(+) and were unable to oxidize or ferment glucose. The functions of isolated yeast mitochondria were also impaired. 4-Dodecylmorpholine-N-oxide at growth-inhibiting concentrations induced rapid lysis of osmotically stabilized yeast protoplasts, with the rate of lysis a function of temperature and of amine oxide concentration. A study of the relationships between structure, antimicrobial activity, and cytolytic activity was made with a group of structurally different amine oxides involving a series of homologous 4-alkylmorpholine-N-oxides, 1-alkylpiperidine-N-oxides, 1-dodecylpyrrolidine-N-oxide, 1-dodecylperhydroasepine-N-oxide, and N,N-dimethyldodecylamine oxide. Disorganization of the membrane structure after interaction of cells with the tested amine oxides was primarily responsible for the antimicrobial activity of the amine oxides. This activity was found to be dependent on the chain length of the hydrophobic alkyl group and was only moderately influenced by other substituents of the polarized N-oxide group.

  19. Native Thrombocidin-1 and Unfolded Thrombocidin-1 Exert Antimicrobial Activity via Distinct Structural Elements

    PubMed Central

    Kwakman, Paulus H. S.; Krijgsveld, Jeroen; de Boer, Leonie; Nguyen, Leonard T.; Boszhard, Laura; Vreede, Jocelyne; Dekker, Henk L.; Speijer, Dave; Drijfhout, Jan W.; te Velde, Anje A.; Crielaard, Wim; Vogel, Hans J.; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2011-01-01

    Chemokines (chemotactic cytokines) can have direct antimicrobial activity, which is apparently related to the presence of a distinct positively charged patch on the surface. However, chemokines can retain antimicrobial activity upon linearization despite the loss of their positive patch, thus questioning the importance of this patch for activity. Thrombocidin-1 (TC-1) is a microbicidal protein isolated from human blood platelets. TC-1 only differs from the chemokine NAP-2/CXCL7 by a two-amino acid C-terminal deletion, but this truncation is crucial for antimicrobial activity. We assessed the structure-activity relationship for antimicrobial activity of TC-1. Reduction of the charge of the TC-1-positive patch by replacing lysine 17 with alanine reduced the activity against bacteria and almost abolished activity against the yeast Candida albicans. Conversely, augmentation of the positive patch by increasing charge density or size resulted in a 2–3-fold increased activity against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis but did not substantially affect activity against C. albicans. Reduction of TC-1 resulted in loss of the folded conformation, but this disruption of the positive patch did not affect antimicrobial activity. Using overlapping 15-mer synthetic peptides, we demonstrate peptides corresponding to the N-terminal part of TC-1 to have similar antimicrobial activity as intact TC-1. Although we demonstrate that the positive patch is essential for activity of folded TC-1, unfolded TC-1 retained antimicrobial activity despite the absence of a positive patch. This activity is probably exerted by a linear peptide stretch in the N-terminal part of the molecule. We conclude that intact TC-1 and unfolded TC-1 exert antimicrobial activity via distinct structural elements. PMID:22025617

  20. Enhanced anti-cancer and antimicrobial activities of curcumin nanoparticles.

    PubMed

    Adahoun, Mo'ath Ahmad; Al-Akhras, Mohammed-Ali Hassan; Jaafar, Mohamad Suhaimi; Bououdina, Mohamed

    2017-02-01

    curcumin and nanocurcumin. In conclusion, all these findings not only indicate that nanocurcumin safe compound has a potent ability as anti-cancer and antimicrobial activities, but also well justify the avail of using nanocurcumin as prostate cells PC3 anti-cancer, and antimicrobial agent for nanocurcumin are markedly improved by decreasing particle size to the nano-scale regime.

  1. Antimicrobial activity of Alstonia macrophylla: a folklore of bay islands.

    PubMed

    Chattopadhyay, D; Maiti, K; Kundu, A P; Chakraborty, M S; Bhadra, R; Mandal, S C; Mandal, A B

    2001-09-01

    The methanolic crude and methanol-aqueous extract of Alstonia macrophylla leaves and n-butanol part of the crude extract showed antimicrobial activity against various strains of Staphylococcus aureus, Staphylococcus saprophyticus, Streptococcus faecalis, Escherichia coli, Proteus mirabilis, Trichophyton rubrum, Trichophyton mentagrophytes var. mentagrophytes and Microsporum gypseum. The minimum inhibitory concentration (MIC) values ranges from 64 to 1000 microg/ml for bacteria and 32-128 mg/ml for dermatophytes. However, the strains of Pseudomonas aeruginosa, Klebsiella sp. and Vibrio cholerae showed resistance against in vitro treatment of the extracts up to 2000 microg/ml concentration, while the two yeast species were resistant even at 128 mg/ml concentration. The stem bark extract prepared similarly was found to be less active compared to the leaves. Phytochemical study indicates that the crude extract contains tannins, flavonoids, saponins, sterols, triterpene and reducing sugars. Further fractionation and purification of n-butanol part of the extract showed the presence of beta-sitosterol, ursolic acid, beta-sitosterol glucoside and a mixture of minor compounds only detected in TLC.

  2. Antimicrobial activities of isothiocyanates against Campylobacter jejuni isolates.

    PubMed

    Dufour, Virginie; Alazzam, Bachar; Ermel, Gwennola; Thepaut, Marion; Rossero, Albert; Tresse, Odile; Baysse, Christine

    2012-01-01

    Food-borne human infection with Campylobacter jejuni is a medical concern in both industrialized and developing countries. Efficient eradication of C. jejuni reservoirs within live animals and processed foods is limited by the development of antimicrobial resistances and by practical problems related to the use of conventional antibiotics in food processes. We have investigated the bacteriostatic and bactericidal activities of two phytochemicals, allyl-isothiocyanate (AITC), and benzyl isothiocyanate (BITC), against 24 C. jejuni isolates from chicken feces, human infections, and contaminated foods, as well as two reference strains NCTC11168 and 81-176. AITC and BITC displayed a potent antibacterial activity against C. jejuni. BITC showed a higher overall antibacterial effect (MIC of 1.25-5 μg mL(-1)) compared to AITC (MIC of 50-200 μg mL(-1)). Both compounds are bactericidal rather than bacteriostatic. The sensitivity levels of C. jejuni isolates against isothiocyanates were neither correlated with the presence of a GGT (γ-Glutamyl Transpeptidase) encoding gene in the genome, with antibiotic resistance nor with the origin of the biological sample. However the ggt mutant of C. jejuni 81-176 displayed a decreased survival rate compared to wild-type when exposed to ITC. This work determined the MIC of two ITC against a panel of C. jejuni isolates, showed that both compounds are bactericidal rather than bacteriostatic, and highlighted the role of GGT enzyme in the survival rate of C. jejuni exposed to ITC.

  3. Analysis of essential oils from Voacanga africana seeds at different hydrodistillation extraction stages: chemical composition, antioxidant activity and antimicrobial activity.

    PubMed

    Liu, Xiong; Yang, Dongliang; Liu, Jiajia; Ren, Na

    2015-01-01

    In this study, essential oils from Voacanga africana seeds at different extraction stages were investigated. In the chemical composition analysis, 27 compounds representing 86.69-95.03% of the total essential oils were identified and quantified. The main constituents in essential oils were terpenoids, alcohols and fatty acids accounting for 15.03-24.36%, 21.57-34.43% and 33.06-57.37%, respectively. Moreover, the analysis also revealed that essential oils from different extraction stages possessed different chemical compositions. In the antioxidant evaluation, all analysed oils showed similar antioxidant behaviours, and the concentrations of essential oils providing 50% inhibition of DPPH-scavenging activity (IC50) were about 25 mg/mL. In the antimicrobial experiments, essential oils from different extraction stages exhibited different antimicrobial activities. The antimicrobial activity of oils was affected by extraction stages. By controlling extraction stages, it is promising to obtain essential oils with desired antimicrobial activities.

  4. Synthesis, antimicrobial, and antiproliferative activities of substituted phenylfuranylnicotinamidines

    PubMed Central

    Youssef, Magdy M; Arafa, Reem K; Ismail, Mohamed A

    2016-01-01

    This research work deals with the design and synthesis of a series of substituted phenylfuranylnicotinamidines 4a–i. Facile preparation of the target compounds was achieved by Suzuki coupling-based synthesis of the nitrile precursors 3a–i, followed by their conversion to the corresponding nicotinamidines 4a–i utilizing LiN(TMS)2. The antimicrobial activities of the newly synthesized nicotinamidine derivatives were evaluated against the Gram-negative bacterial strains Escherichia coli and Pseudomonas aeruginosa as well as the Gram-positive bacterial strains Staphylococcus aureus and Bacillus megaterium. The minimum inhibitory concentration values of nicotinamidines against all tested microorganisms were in the range of 10–20 μM. In specific, compounds 4a and 4b showed excellent minimum inhibitory concentration values of 10 μM against Staphylococcus aureus bacterial strain and were similar to ampicillin as an antibacterial reference. On the other hand, selected nicotinamidine derivatives were biologically screened for their cytotoxic activities against a panel of 60 cell lines representing nine types of human cancer at a single high dose at National Cancer Institute, Bethesda, MD, USA. Nicotinamidines showing promising activities were further assessed in a five-dose screening assay to determine their compound concentration causing 50% growth inhibition of tested cell (GI50), compound concentration causing 100% growth inhibition of tested cell (TGI), and compound concentration causing 50% lethality of tested cell (LC50) values. Structure-activity relationship studies demonstrated that the activity of members of this series can be modulated from cytostatic to cytotoxic based on the substitution pattern/nature on the terminal phenyl ring. The most active compound was found to be 4e displaying a submicromolar GI50 value of 0.83 μM, with TGI and LC50 values of 2.51 and 100 μM, respectively. Finally, the possible underlying mechanism of action of this series of

  5. Molecular design, structures, and activity of antimicrobial peptide-mimetic polymers.

    PubMed

    Takahashi, Haruko; Palermo, Edmund F; Yasuhara, Kazuma; Caputo, Gregory A; Kuroda, Kenichi

    2013-10-01

    There is an urgent need for new antibiotics which are effective against drug-resistant bacteria without contributing to resistance development. We have designed and developed antimicrobial copolymers with cationic amphiphilic structures based on the mimicry of naturally occurring antimicrobial peptides. These copolymers exhibit potent antimicrobial activity against a broad spectrum of bacteria including methicillin-resistant Staphylococcus aureus with no adverse hemolytic activity. Notably, these polymers also did not result in any measurable resistance development in E. coli. The peptide-mimetic design principle offers significant flexibility and diversity in the creation of new antimicrobial materials and their potential biomedical applications.

  6. Antimicrobial Organometallic Dendrimers with Tunable Activity against Multidrug-Resistant Bacteria.

    PubMed

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola; Overy, David P; Lanteigne, Martin; McQuillan, Katherine; Kerr, Russell G

    2015-11-09

    Multidrug-resistant pathogens are an increasing threat to public health. In an effort to curb the virulence of these pathogens, new antimicrobial agents are sought. Here we report a new class of antimicrobial organometallic dendrimers with tunable activity against multidrug-resistant Gram-positive bacteria that included methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Mechanistically, these redox-active, cationic organometallic dendrimers induced oxidative stress on bacteria and also disrupted the microbial cell membrane. The minimum inhibitory concentrations, which provide a quantitative measure of the antimicrobial activity of these dendrimers, were in the low micromolar range. AlamarBlue cell viability assay also confirms the antimicrobial activity of these dendrimers. Interestingly, these dendrimers were noncytotoxic to epidermal cell lines and to mammalian red blood cells, making them potential antimicrobial platforms for topical applications.

  7. Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus *

    PubMed Central

    Zhang, Hui; Zhang, Lu; Peng, Li-juan; Dong, Xiao-wu; Wu, Di; Wu, Vivian Chi-Hua; Feng, Feng-qin

    2012-01-01

    Fatty acids and derivatives (FADs) are resources for natural antimicrobials. In order to screen for additional potent antimicrobial agents, the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay. Monoglycerides of fatty acids were the most potent class of fatty acids, among which monotridecanoin possessed the most potent antimicrobial activity. The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR: R 2=0.942, Q 2 LOO=0.910; CoMFA: R 2=0.979, Q 2=0.588, respectively). Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structure-activity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents. PMID:22302421

  8. Antimicrobial activity of ProRoot MTA in contact with blood

    PubMed Central

    Farrugia, C.; Baca, P.; Camilleri, J.; Arias Moliz, M. T.

    2017-01-01

    Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations. PMID:28128328

  9. Antimicrobial activity of ProRoot MTA in contact with blood.

    PubMed

    Farrugia, C; Baca, P; Camilleri, J; Arias Moliz, M T

    2017-01-27

    Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations.

  10. Spirostanol glycosides with hemostatic and antimicrobial activities from Trillium kamtschaticum.

    PubMed

    Chen, Yu; Ni, Wei; Yan, Huan; Qin, Xu-Jie; Khan, Afsar; Liu, Hui; Shu, Tong; Jin, Ling-Yu; Liu, Hai-Yang

    2016-11-01

    Ten spirostanol glycosides, trillikamtosides A-J, together with eleven known analogues, were isolated from the hemostatic fraction of the 75% aqueous EtOH extract of the whole herbs of Trillium kamtschaticum. Their structures were established by extensive spectroscopic data analysis and chemical methods. The aglycones of three of these compounds had unique 3β,17α-dihydroxy-spirostanes featuring a double bond between C-4 and C-5, while two others represent a rare class of spirostanol glycosides which possess a 5(6 → 7) abeo-steroidal aglycone. All the compounds were evaluated for their hemostatic and antimicrobial activities. Three of the spirostanol glycosides exhibited induced-platelet aggregation at a concentration of 300 μg/mL with maximal induced-platelet aggregation rates of 72%, 71%, and 62% in rabbits, respectively, and their EC50 values were 492.7, 203.3, and 109.8 μM. Five of the spirostanol glycosides showed an anti-Candida albicans effect with MIC values of 21.1, 10.6, 8.8, 21.6, and 11.0 μM, respectively.

  11. Synthesis and antimicrobial activity of gold nanoparticle conjugates with cefotaxime

    NASA Astrophysics Data System (ADS)

    Titanova, Elena O.; Burygin, Gennady L.

    2016-04-01

    Gold nanoparticles (GNPs) have attracted significant interest as a novel platform for various applications to nanobiotechnology and biomedicine. The conjugates of GNPs with antibiotics and antibodies were also used for selective photothermal killing of protozoa and bacteria. Also the conjugates of some antibiotics with GNPs decreased the number of bacterial growing cells. In this work was made the procedure optimization for conjugation of cefotaxime (a third-generation cephalosporin antibiotic) with GNPs (15 nm) and we examined the antimicrobial properties of this conjugate to bacteria culture of E. coli K-12. Addition of cefotaxime solution to colloidal gold does not change their color and extinction spectrum. For physiologically active concentration of cefotaxime (3 μg/mL), it was shown that the optimum pH for the conjugation was more than 9.5. A partial aggregation of the GNPs in saline medium was observed at pH 6.5-7.5. The optimum concentration of K2CO3 for conjugation cefotaxime with GNPs-15 was 5 mM. The optimum concentration of cefotaxime was at 0.36 μg/mL. We found the inhibition of the growth of E. coli K12 upon application cefotaxime-GNP conjugates.

  12. Two new iridoids from selected Penstemon species--antimicrobial activity.

    PubMed

    Zajdel, Sybilla M; Graikou, Konstantia; Sotiroudis, Georgios; Głowniak, Kazimierz; Chinou, Ioanna

    2013-01-01

    Eighteen secondary metabolites, belonging to three different chemical groups, were isolated from the methanolic extracts of the aerial parts of selected penstemon plants [Penstemon fruticosus (Pursh) Greene var. fruticosus, Penstemon palmeri Gray and Penstemon venustus Doug. ex Lindl.], and their structures were elucidated on the basis of spectral evidence. Six iridoid glucosides (1-6), three phenylpropanoid glucosides (13-15) and two acetophenone derivatives (16,17), obtained from P. fruticosus, five iridoids (2, 7-10), one phenylpropanoid glucoside (15) and two acetophenones (16, 18), isolated from P. palmeri while three iridoids (2, 11, 12) and three phenylpropanoids (13-15) were identified in P. venustus. Two of the iridoid glucosides (4, 5) from P. fruticosus are new natural products named accordingly as cis- and trans- forms of 10-O-p-methoxycinnamoylaucubin. All isolated compounds, as well as crude methanolic extracts, were evaluated for their antimicrobial activities against six Gram-positive and Gram-negative bacteria and three human pathogenic fungi.

  13. Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

    PubMed Central

    Badawy, Hope; Brunellière, Jérôme; Veryaskina, Marina; Brotons, Guillaume; Sablé, Sophie; Lanneluc, Isabelle; Lambert, Kelly; Marmey, Pascal; Milsted, Amy; Cutright, Teresa; Nourry, Arnaud; Mouget, Jean-Luc; Pasetto, Pamela

    2015-01-01

    There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred. PMID:25706513

  14. Extracellular Streptomyces lividans vesicles: composition, biogenesis and antimicrobial activity.

    PubMed

    Schrempf, Hildgund; Merling, Philipp

    2015-07-01

    We selected Streptomyces lividans to elucidate firstly the biogenesis and antimicrobial activities of extracellular vesicles that a filamentous and highly differentiated Gram-positive bacterium produces. Vesicle types range in diameter from 110 to 230 nm and 20 to 60 nm, respectively; they assemble to clusters, and contain lipids and phospholipids allowing their in situ imaging by specific fluorescent dyes. The presence of the identified secondary metabolite undecylprodigiosin provokes red fluorescence of a portion of the heterogeneous vesicle populations facilitating in vivo monitoring. Protuberances containing vesicles generate at tips, and alongside of substrate hyphae, and enumerate during late vegetative growth to droplet-like exudates. Owing to in situ imaging in the presence and absence of a green fluorescent vancomycin derivative, we conclude that protuberances comprising vesicles arise at sites with enhanced levels of peptidoglycan subunits [pentapeptide of lipid II (C55)-linked disaccharides], and reduced levels of polymerized and cross-linked peptidoglycan within hyphae. These sites correlate with enhanced levels of anionic phospholipids and lipids. Vesicles provoke pronounced damages of Aspergillus proliferans, Verticillium dahliae and induced clumping and distortion of Escherichia coli. These harmful effects are likely attributable to the action of the identified vesicular compounds including different enzyme types, components of signal transduction cascades and undecylprodigiosin. Based on our pioneering findings, we highlight novel clues with environmental implications and application potential.

  15. Essential oils of Alpinia rafflesiana and their antimicrobial activities.

    PubMed

    Jusoh, Shariha; Sirat, Hasnah Mohd; Ahmad, Farediah

    2013-09-01

    The essential oils from the leaves, pseudostems, rhizomes and fruits of Alpinia rafflesiana were isolated by hydrodistillation. The oils were analysed by capillary GC and GC-MS. The most abundant components in the leaf oil were trans-caryophyllene (32.61%), caryophyllene oxide (8.67%), (2E,6Z)-farnesol (4.91%) and alpha-terpineol (4.25%), while 1,8-cineole (32.25%), myrcene (13.63%), alpha-terpineol (9.90%) and trans-caryophyllene (9.80%) were the main constituents in the pseudostem oil. The rhizome constituted of tetracosane (42.61%), tau-cadinol (7.46%), alpha-terpineol (6.71%) were the major components, whereas tetracosane (13.39%), (2E,6E)-farnesol (7.31%), alpha-terpineol (8.51%) and caryophyllene oxide (8.05%) were the main components in the fruit oil. Antimicrobial assay revealed that all the essential oils showed moderate to weak inhibition against the tested microorganisms. The leaf oil was the most active and inhibited both S. aureus and E. coli with MIC values of 7.81 microg/mL and 15.6 microg/mL, respectively.

  16. Antimicrobial activity of new porphyrins of synthetic and natural origin

    NASA Astrophysics Data System (ADS)

    Gyulkhandanyan, Grigor V.; Ghazaryan, Robert K.; Paronyan, Marina H.; Ulikhanyan, Ghukas I.; Gyulkhandanyan, Aram G.; Sahakyan, Lida A.

    2012-03-01

    Antimicrobial photodynamic inactivation has been successfully used against Gram (+) microorganisms, but most of the photosensitizers (PSs) on Gram (-) bacteria acts weakly. PSs are the natural or synthetic origin dyes, mainly porphyrins. We have synthesized more than 100 new cationic porphyrins and metalloporphyrins with different functional groups (hydroxyethyl, butyl, allyl, methallyl) and metals (cobalt, iron, copper, zinc, silver and other); from the nettle have also been purified pheophytin (a+b) and pheophytin (a) and have synthesized their Ag-and Zn-metalloporphyrins. It was found that in the dark (cytotoxic) mode, the most highly efficiency against microorganisms showed Agmetalloporphyrins of both types of porphyrins (synthetic and natural). Metalloporphyrin of natural origin Ag-pheophytin (a + b) is a strong antibacterial agent and causes 100% death as the Gram (+) microorganisms (St. aureus and MRSA) and the Gram (-) microorganisms (E.coli and Salmonella). It is established that for the destruction of Gram (+) and Gram (-) microorganisms in photodynamic mode cationic water-soluble synthetic metalloporphyrins, especially Zn-TBut4PyP, many times more effective than pheophytins. In vivo conditions on mice established that the best therapeutic activity against various strains of the microorganism St. aureus has the synthetic metalloporphyrin Ag-TBut4PyP. It is significantly more efficient than known drug "Chlorophyllipt" (2.5-3 times) and leads the survival rate of animals up to 50-60%.

  17. Antimicrobial activity of human α-defensin 5 and its linear analogs: N-terminal fatty acylation results in enhanced antimicrobial activity of the linear analogs.

    PubMed

    Mathew, Basil; Nagaraj, Ramakrishnan

    2015-09-01

    Human α-defensin 5 (HD5) exhibits broad spectrum antimicrobial activity and plays an important role in mucosal immunity of the small intestine. Although there have been several studies, the structural requirements for activity and mechanism of bacterial killing is yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD5 and linear analogs. Cysteine deletions attenuated the antibacterial activity considerably. Candidacidal activity was affected to a lesser extent. Fatty acid conjugated linear analogs showed antimicrobial activity comparable activity to HD5. Effective surface charge neutralization of bacteria was observed for HD5 as compared to the non-fatty acylated linear analogs. Our results show that HD5 and non-fatty acylated linear analogs enter the bacterial cytoplasm without causing damage to the bacterial inner membrane. Although fatty acylated peptides exhibited antimicrobial activity comparable to HD5, their mechanism of action involved permeabilization of the Escherichia coli inner membrane. HD5 and analogs had the ability to bind plasmid DNA. HD5 had greater binding affinity to plasmid DNA as compared to the analogs. The three dimensional structure of HD5 favors greater interaction with the bacterial cell surface and also with DNA. Antibacterial activity of HD5 involves entry into bacterial cytoplasm and binding to DNA which would result in shut down of the bacterial metabolism leading to cell death. We show how a moderately active linear peptide derived from the α-defensin HD5 can be engineered to enhance antimicrobial activity almost comparable to the native peptide.

  18. Antimicrobial activities of Ichnocarpus frutescens (L.) R.Br. and Hemidesmus indicus R.Br. Roots

    PubMed Central

    Malathy, N S; Sini, S

    2009-01-01

    Hexane, chloroform and aqueous extracts from Hemidesmus indicus and Ichnocarpus frutescens roots were evaluated for their antimicrobial activity. The chloroform extract of both plants showed antibacterial and antifungal activities against the tested organisms. Both the plants showed highest antibacterial and antifungal activity against Eschericia coli and Aspergillus flavus respectively. With increase in concentration of the extract a corresponding increase in diameter of inhibition vgme was observed. The roots of the common substitute of H.Indicus namely Ifrutescenspossess similar antimicrobial properties. PMID:22557326

  19. In-vitro activity of sparfloxacin in comparison with currently available antimicrobials against respiratory tract pathogens.

    PubMed

    Baquero, F; Cantón, R

    1996-05-01

    Bacterial resistance to antimicrobial agents is an ever-increasing problem. The in-vitro activity of sparfloxacin compared with that of currently available antimicrobial agents against pathogens implicated in respiratory tract infections is reviewed. Sparfloxacin is a fluoroquinolone active against both penicillin-susceptible and -resistant strains of Streptococcus pneumoniae. It is also active against many other respiratory tract pathogens and may be a suitable alternative for empirical therapy of community-acquired respiratory tract infections.

  20. Simultaneous Antibiofilm and Antiviral Activities of an Engineered Antimicrobial Peptide during Virus-Bacterium Coinfection

    PubMed Central

    Melvin, Jeffrey A.; Lashua, Lauren P.; Kiedrowski, Megan R.; Yang, Guanyi; Deslouches, Berthony; Montelaro, Ronald C.

    2016-01-01

    ABSTRACT Antimicrobial-resistant infections are an urgent public health threat, and development of novel antimicrobial therapies has been painstakingly slow. Polymicrobial infections are increasingly recognized as a significant source of severe disease and also contribute to reduced susceptibility to antimicrobials. Chronic infections also are characterized by their ability to resist clearance, which is commonly linked to the development of biofilms that are notorious for antimicrobial resistance. The use of engineered cationic antimicrobial peptides (eCAPs) is attractive due to the slow development of resistance to these fast-acting antimicrobials and their ability to kill multidrug-resistant clinical isolates, key elements for the success of novel antimicrobial agents. Here, we tested the ability of an eCAP, WLBU2, to disrupt recalcitrant Pseudomonas aeruginosa biofilms. WLBU2 was capable of significantly reducing biomass and viability of P. aeruginosa biofilms formed on airway epithelium and maintained activity during viral coinfection, a condition that confers extraordinary levels of antibiotic resistance. Biofilm disruption was achieved in short treatment times by permeabilization of bacterial membranes. Additionally, we observed simultaneous reduction of infectivity of the viral pathogen respiratory syncytial virus (RSV). WLBU2 is notable for its ability to maintain activity across a broad range of physiological conditions and showed negligible toxicity toward the airway epithelium, expanding its potential applications as an antimicrobial therapeutic. IMPORTANCE Antimicrobial-resistant infections are an urgent public health threat, making development of novel antimicrobials able to effectively treat these infections extremely important. Chronic and polymicrobial infections further complicate antimicrobial therapy, often through the development of microbial biofilms. Here, we describe the ability of an engineered antimicrobial peptide to disrupt biofilms

  1. Studies on antimicrobial activities of solvent extracts of different spices.

    PubMed

    Keskin, Dilek; Toroglu, Sevil

    2011-03-01

    The antimicrobial activities of the ethyl acetate, acetone and methanol extract of 12 plant species were studied. The extract of Capsicum annuum (red pepper) (fruit) Zingiber officinale (ginger) (root), Cuminum cyminum (cumin), Alpinia ficinarum (galingale), Coriandrum sativum (coriander), Cinnamomun zeylanicum Nees (cinnamomun), Origanum onites L. (thyme), Folium sennae (senna), Eugenia caryophyllata (cloves), Flos tiliae (lime), Folium menthae crispae (peppermint) and Piper nigrum (blackpepper) were tested in vitro against 2 fungi and 8 bacterial species by the disc diffusion method. Klebsiella pneumonia 13883, Bacillus megaterium NRS, Pseudomonas aeroginosa ATCC 27859, Staphylococcus aureus 6538 P, Escherichia coil ATCC 8739, Enterobacter cloaca ATCC 13047, Corynebacterium xerosis UC 9165, Streptococcus faecalis DC 74, Kluyveromyces marxianus, Rhodotorula rubra were used in this investigation. The results indicated that extracts of different spices has shown antibacterial activity in the range of 7-24 mm 30 microl(-1) inhibition zone Eugenia caryophyllata (clove), 7-20 mm 30microl(-1) inhibition zone Capsicum annum (red pepper) and Cinnamomun zeylanicum (cinnamon) bark, 7-18 mm 30microl(-1) inhibition zone Folium sennae (senna) leaves, 7-16 mm 30 microl(-1) inhibition zone Zingiber officinale (ginger) root, 7-15 mm 30microl(-1) inhibition zone Cuminum cyminum (cumin) seed, 7-14 mm 30 microl(-1) inhibition zone Folium menthae crispae (peppermint), Origanum onites (thyme) leaves and Alpinia ficinarum (galingale) root, 7-12 mm 30 microl(-1) inhibiton zone Piper nigrum (blackpepper), 7-11 mm 30microl(-1) inhibition zone Flos tiliae (lime) leaves, 7-8 mm 30microl(-1) inhibition zone Coriandrum sativum (coriander) to the microorganisms tested.

  2. Bioprotective properties of Dragon's blood resin: In vitro evaluation of antioxidant activity and antimicrobial activity

    PubMed Central

    2011-01-01

    Background Food preservation is basically done to preserve the natural characteristics and appearance of the food and to increase the shelf life of food. Food preservatives in use are natural, chemical and artificial. Keeping in mind the adverse effects of synthetic food preservatives, there is a need to identify natural food preservatives. The aims of this study were to evaluate in vitro antioxidant and antimicrobial activities of Dragon's blood resin obtained from Dracaena cinnabari Balf f., with a view to develop safer food preservatives. Methods In this study, three solvents of varying polarity were used to extract and separate the medium and high polarity compounds from the non-polar compounds of the Dragon's blood resin. The extracts were evaluated for their antimicrobial activity against the food borne pathogens. The antioxidant activities of the extracts were assessed using DPPH and ABTS radical scavenging, FRAP, metal chelating and reducing power assays. Total phenolics, flavonoids and flavonols of extracts were also estimated using the standard methods. Results Phytochemical analysis of extracts revealed high phenolic content in CH2Cl2 extract of resin. Free radical scavenging of CH2Cl2 extract was found to be highest which is in good correlation with its total phenolic content. All test microorganisms were also inhibited by CH2Cl2 extract. Conclusions Our result provide evidence that CH2Cl2 extract is a potential source of natural antioxidant compounds and exhibited good inhibitory activity against various food borne pathogens. Thus, CH2Cl2 extract of Dragon's blood resin could be considered as possible source of food preservative. PMID:21329518

  3. Quantification, antioxidant and antimicrobial activity of phenolics isolated from different extracts of Capsicum frutescens (Pimenta Malagueta).

    PubMed

    Nascimento, Patrícia L A; Nascimento, Talita C E S; Ramos, Natália S M; Silva, Girliane R; Gomes, José Erick Galindo; Falcão, Rosângela E A; Moreira, Keila A; Porto, Ana L F; Silva, Tania M S

    2014-04-24

    This paper presents the quantification, antioxidant and antimicrobial activity of capsaicin, dihydrocapsaicin and the flavonoid chrysoeriol isolated from different extracts (hexane and acetonitrile extracts from whole fruit, peel and seed) of Capsicum frutescens (pimenta malagueta). The acetonitrile extract of the seeds, peel and whole fruits contained capsaicin as a major component, followed in abundance by dihydrocapsaicin and chrysoeriol. The antimicrobial activity of the isolated compounds against seven microorganisms showed chrysoeriol was the most active compound. In the antioxidant test, the acetonitrile extract from the whole fruit showed the highest activity. The antioxidant activity of pimenta malagueta may be correlated with its phenolic content, principally with the most active compound, capsaicin.

  4. [Antimicrobial activity of the epicarp of the fruits of Paulownia fortunei and Paulownia tomentosa].

    PubMed

    Cercós, A P

    1982-01-01

    One antimicrobial substance was obtained from the epicarp of the fruits of Paulownia fortunei and Paulownia tomentosa. Other parts of the fruits and leaves had no detectable antimicrobial activity. The substance was active in vitro for Staphylococcus aureus and Bacillus subtilis while it had lower activity for Saccharomyces carlsbergensis and the lowest was for Escherichia coli. The active material was extracted with organic solvents (ether, ethanol and acetone). The activity "in vitro" was demonstrated by the method of dilution in nutrient agar media. The active substance looked as a resin and was insoluble in water at neutral or acid pH. It was very soluble in strong alkaline pH solution.

  5. Synthesis and structure-activity relationships of novel cationic lipids with anti-inflammatory and antimicrobial activities.

    PubMed

    Myint, Melissa; Bucki, Robert; Janmey, Paul A; Diamond, Scott L

    2015-07-15

    Certain membrane-active cationic steroids are known to also possess both anti-inflammatory and antimicrobial properties. This combined functionality is particularly relevant for potential therapies of infections associated with elevated tissue damage, for example, cystic fibrosis airway disease, a condition characterized by chronic bacterial infections and ongoing inflammation. In this study, six novel cationic glucocorticoids were synthesized using beclomethasone, budesonide, and flumethasone. Products were either monosubstituted or disubstituted, containing one or two steroidal groups, respectively. In vitro evaluation of biological activities demonstrated dual anti-inflammatory and antimicrobial properties with limited cytotoxicity for all synthesized compounds. Budesonide-derived compounds showed the highest degree of both glucocorticoid and antimicrobial properties within their respective mono- and disubstituted categories. Structure-activity analyses revealed that activity was generally related to the potency of the parent glucocorticoid. Taken together, these data indicate that these types of dual acting cationic lipids can be synthesized with the appropriate starting steroid to tailor activities as desired.

  6. Improving the water solubility and antimicrobial activity of silymarin by nanoencapsulation.

    PubMed

    Lee, Ji-Soo; Hong, Da Young; Kim, Eun Suh; Lee, Hyeon Gyu

    2017-03-08

    The aims of this study were to improve the water solubility and antimicrobial activity of milk thistle silymarin by nanoencapsulation and to assess the functions of silymarin nanoparticle-containing film as an antimicrobial food-packaging agent. Silymarin nanoparticles were prepared using water-soluble chitosan (WCS) and poly-γ-glutamic acid (γ-PGA). As the WCS and silymarin concentrations increased, particle size and polydispersity index (PDI) significantly increased. Nanoencapsulation significantly improved the water solubility of silymarin 7.7-fold. Antimicrobial activity of silymarin was effectively improved when silymarin was entrapped within the nanocapsule compared to when it was not entrapped. Films incorporating silymarin nanoparticles had better antimicrobial activity than films incorporating free silymarin. The results suggest that silymarin nanoparticles have applications in antimicrobial food additives and food packing.

  7. Antimicrobial activity and phytochemical analysis of crude extracts and essential oils from medicinal plants.

    PubMed

    Silva, N C C; Barbosa, L; Seito, L N; Fernandes, A

    2012-01-01

    We aimed to establish a phytochemical analysis of the crude extracts and performed GC-MS of the essential oils (EOs) of Eugenia uniflora L. (Myrtaceae) and Asteraceae species Baccharis dracunculifolia DC, Matricaria chamomilla L. and Vernonia polyanthes Less, as well as determining their antimicrobial activity. Establishment of the minimal inhibitory concentrations of the crude extracts and EOs against 16 Staphylococcus aureus and 16 Escherichia coli strains from human specimens was carried out using the dilution method in Mueller-Hinton agar. Some phenolic compounds with antimicrobial properties were established, and all EOs had a higher antimicrobial activity than the extracts. Matricaria chamomilla extract and E. uniflora EO were efficient against S. aureus strains, while E. uniflora and V. polyanthes extracts and V. polyanthes EO showed the best antimicrobial activity against E. coli strains. Staphylococcus aureus strains were more susceptible to the tested plant products than E. coli, but all natural products promoted antimicrobial growth inhibition.

  8. Antimicrobial activity and main chemical composition of two smoke condensates from Peganum harmala seeds.

    PubMed

    Shahverdi, Ahmad R; Monsef-Esfahani, Hamid R; Nickavar, Bahman; Bitarafan, Lila; Khodaee, Samira; Khoshakhlagh, Narges

    2005-01-01

    The smoke of Peganum harmala seeds is traditionally used in Iran as a disinfectant agent. The aim of this study was to determine the antimicrobial activity of two smoke condensates from Peganum harmala seeds. Furthermore the composition of smoke preparations was studied using gas chromatography and mass spectroscopy analysis. The most prevalent compound detected in a dichloromethane extract was harmine. Standard harmine as well as the dichloromethane extract showed antimicrobial activity against all test strains. Harmine was not detected in an n-hexane extract and we did not observe antimicrobial activity from this smoke preparation at the tested concentrations.

  9. Total Phenolic, Total Flavonoids, Antioxidant and Antimicrobial Activities of Scrophularia Striata Boiss Extracts

    PubMed Central

    Mahboubi, Mohaddese; Kazempour, Nastaran; Boland Nazar, Ali Reza

    2013-01-01

    Background Scrophularia striata (Scrophulariaceae family) is an herbaceous plant that is traditionally used for treatment of microbial infections. Objectives Antimicrobial and antioxidant activity of different extracts (methanolic, ethanolic, aqueous and ethyl acetate) from S. striata aerial parts was evaluated. Materials and Methods The antimicrobial activity of different extracts from S. striata was evaluated against a large number of bacteria and fungi by micro broth dilution. Total phenolic and flavonoid contents were measured and their antioxidant activities evaluated by DPPH assay and beta carotene linoleic acid test. Results Antimicrobial screening exhibited the positive relation between the total phenolic content and its antimicrobial activity but their antioxidant activity had a negative relation. Conclusions Further studies are recommended against clinical isolate of sensitive bacteria and deep investigation on flavonoid and phenolic compounds of S. striata and detecting the antioxidant portion in aqueous extract. PMID:24624181

  10. Antimicrobial activity of tannin components from Vaccinium vitis-idaea L.

    PubMed

    Ho, K Y; Tsai, C C; Huang, J S; Chen, C P; Lin, T C; Lin, C C

    2001-02-01

    Reactive oxygen species have been implicated as important pathological mediators in many clinical disorders, including periodontal disease. As a possible alternative for the treatment of periodontal disease, the antimicrobial activity of six tannins isolated from Vaccinium vitis-idaea L., with confirmed antioxidant activity, were assayed by the agar dilution method against selected periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia. The results showed that epicatechin-(4beta-->8)-epicatechin-(4beta-->8, 2beta-->O-->7)-catechin had strong antimicrobial activity against P. gingivalis and P. intermedia, but not A. actinomycetemcomitans. The other tannins tested did not show antimicrobial activity. We conclude that tannins isolated from V. vitis-idaea L. with antimicrobial activity could potentially be used for the treatment of periodontal disease.

  11. A multicenter evaluation of linezolid antimicrobial activity in North America.

    PubMed

    Ballow, Charles H; Jones, Ronald N; Biedenbach, Douglas J

    2002-05-01

    Overall, 141 centers in North America enrolled in this international surveillance study designed to evaluate the in vitro antimicrobial activity and spectrum of linezolid, a new oxazolidinone. Each participant tested the susceptibility of clinical isolates of staphylococcal species (n = 85) against 12 drugs, and enterococcal species (n = 40) against 6 drugs using reference broth microdilution trays; and of streptococcal species (n = 25) against 6 drugs using Etests (AB BIODISK, Solna, Sweden). Quality control testing was conducted using recommended strains, and verification of resistance to linezolid and select other agents was performed by a regional monitor. Of the 20,161 isolates collected from sites across the United States (US; n = 132) and Canada (n = 9), 18,307 were included in this analysis. Oxacillin resistance occurred in 38.7 and 70.6% of Staphylococcus aureus and coagulase-negative staphylococcal (CoNS) isolates, respectively. Vancomycin resistance was reported in 65.9 and 2.6% of Enterococcus faecium and E. faecalis, respectively. Penicillin resistance occurred in 37.2% of Streptococcus pneumoniae, 17.5% constituting high-level resistance (MIC, > or =2 microg/ml). The MIC(90) for linezolid was 1 microg/ml for streptococci, 2 microg/ml for enterococci and CoNS isolates, and 4 microg/ml for S. aureus. Using the US FDA-recommended susceptible breakpoints for linezolid, there were no confirmed reports of linezolid resistance (i.e., MIC > or =8 microg/ml). The occurrence of linezolid MICs was unimodal and generally varied between, 1-4 microg/ml for staphylococci (94% of recorded results), 1-2 microg/ml for enterococci (93%), and 0.5-1 microg/ml for streptococci (85%). Susceptibility to linezolid was not influenced by susceptibility to other antiicrobials such as vancomycin, beta-lactams or macrolides. Only linezolid was universally active against essentially all tested Gram-positive specimens. The unimodal susceptibility pattern is indicative of excellent

  12. Effects of dimerization on the structure and biological activity of antimicrobial peptide Ctx-Ha.

    PubMed

    Lorenzón, E N; Cespedes, G F; Vicente, E F; Nogueira, L G; Bauab, T M; Castro, M S; Cilli, E M

    2012-06-01

    It is well known that cationic antimicrobial peptides (cAMPs) are potential microbicidal agents for the increasing problem of antimicrobial resistance. However, the physicochemical properties of each peptide need to be optimized for clinical use. To evaluate the effects of dimerization on the structure and biological activity of the antimicrobial peptide Ctx-Ha, we have synthesized the monomeric and three dimeric (Lys-branched) forms of the Ctx-Ha peptide by solid-phase peptide synthesis using a combination of 9-fluorenylmethyloxycarbonyl (Fmoc) and t-butoxycarbonyl (Boc) chemical approaches. The antimicrobial activity assay showed that dimerization decreases the ability of the peptide to inhibit growth of bacteria or fungi; however, the dimeric analogs displayed a higher level of bactericidal activity. In addition, a dramatic increase (50 times) in hemolytic activity was achieved with these analogs. Permeabilization studies showed that the rate of carboxyfluorescein release was higher for the dimeric peptides than for the monomeric peptide, especially in vesicles that contained sphingomyelin. Despite different biological activities, the secondary structure and pore diameter were not significantly altered by dimerization. In contrast to the case for other dimeric cAMPs, we have shown that dimerization selectively decreases the antimicrobial activity of this peptide and increases the hemolytic activity. The results also show that the interaction between dimeric peptides and the cell wall could be responsible for the decrease of the antimicrobial activity of these peptides.

  13. Characteristics and antimicrobial activity of copper-based materials

    NASA Astrophysics Data System (ADS)

    Li, Bowen

    In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger

  14. Antimicrobial activity of de novo designed cationic peptides against multi-resistant clinical isolates.

    PubMed

    Faccone, Diego; Veliz, Omar; Corso, Alejandra; Noguera, Martin; Martínez, Melina; Payes, Cristian; Semorile, Liliana; Maffía, Paulo Cesar

    2014-01-01

    Antibiotic resistance is one of the main problems concerning public health or clinical practice. Antimicrobial peptides appear as good candidates for the development of new therapeutic drugs. In this study we de novo designed a group of cationic antimicrobial peptides, analyzed its physicochemical properties, including its structure by circular dichroism and studied its antimicrobial properties against a panel of clinical isolates expressing different mechanisms of resistance. Three cationic alpha helical peptides exhibited antimicrobial activity comparable to, or even better than the comparator omiganan (MBI-226).

  15. Cerecidins, Novel Lantibiotics from Bacillus cereus with Potent Antimicrobial Activity

    PubMed Central

    Wang, Jian; Zhang, Li; Teng, Kunling; Sun, Shutao; Sun, Zhizeng

    2014-01-01

    Lantibiotics are ribosomally synthesized and posttranslationally modified antimicrobial peptides that are widely produced by Gram-positive bacteria, including many species of the Bacillus group. In the present study, one novel gene cluster coding lantibiotic cerecidins was unveiled in Bacillus cereus strain As 1.1846 through genomic mining and PCR screening. The designated cer locus is different from that of conventional class II lantibiotics in that it included seven tandem precursor cerA genes, one modification gene (cerM), two processing genes (cerT and cerP), one orphan regulator gene (cerR), and two immunity genes (cerF and cerE). In addition, one unprecedented quorum sensing component, comQXPA, was inserted between cerM and cerR. The expression of cerecidins was not detected in this strain of B. cereus, which might be due to repressed transcription of cerM. We constitutively coexpressed cerA genes and cerM in Escherichia coli, and purified precerecidins were proteolytically processed with the endoproteinase GluC and a truncated version of putative serine protease CerP. Thus, two natural variants of cerecidins A1 and A7 were obtained which contained two terminal nonoverlapping thioether rings rarely found in lantibiotics. Both cerecidins A1 and A7 were active against a broad spectrum of Gram-positive bacteria. Cerecidin A7, especially its mutant Dhb13A, showed remarkable efficacy against multidrug-resistant Staphylococcus aureus (MDRSA), vancomycin-resistant Enterococcus faecalis (VRE), and even Streptomyces. PMID:24532070

  16. Synthesis of Cu/CNTs nanocomposites for antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Singhal, Sunil Kumar; Lal, Maneet; Lata; Ranjan Kabi, Soumya; Behari Mathur, Rakesh

    2012-12-01

    We report a facile method for the synthesis of Cu/multi-walled carbon nanotubes (CNTs) composite powder employing a chemical reduction method followed by high-energy ball milling involving the use of sodium borohydride as a reducing agent and copper sulphate as the precursor material. Control of oxidation of Cu nanoparticles (CuNPs) is a key factor in the synthesis of Cu/CNTs nanocomposites via chemical reduction methods and other methods. To overcome this problem we have applied a new facile rapid synthesis method using a combination of molecular-level mixing followed by high-energy ball milling to produce mostly CuNPs. X-ray diffraction results indicated the presence of mostly CuNPs in composite powder. Scanning electron microscopy and high resolution transmission electron microscopy (HRTEM) was used to ascertain the dispersion of CNTs in Cu matrix. Most of the CuNPs synthesized in the present work had a particle size ranging from 20-50 nm as revealed by HRTEM characterization. Moreover, the CNTs were also found to be homogeneously dispersed in Cu matrix. The Cu/CNTs nanocomposite has a wide range of applications from fuel cells to electronic chip components. In the present work we have investigated the antimicrobial activity of Cu powder and varying concentrations of Cu/CNTs nanocomposite against gram negative Providencia sp. bacteria, and gram positive Bacillus sp. bacteria. These findings suggest that Cu/CNTs nanocomposite can be used in antibacterial controlling systems and as an effective growth inhibitor in the case of various microorganisms.

  17. In vitro antimicrobial activity against 10 North American and European Lawsonia intracellularis isolates.

    PubMed

    Wattanaphansak, Suphot; Singer, Randall S; Gebhart, Connie J

    2009-03-02

    The objective of this study was to determine the in vitro minimum inhibitory concentration (MIC) of antimicrobials against 10 isolates of Lawsonia intracellularis, the etiological agent of proliferative enteropathy (PE). Antimicrobials tested included carbadox, chlortetracycline, lincomycin, tiamulin, tylosin and valnemulin. The MIC of each antimicrobial against L. intracellularis was determined using a tissue culture system and was identified as the lowest concentration that inhibited 99% of L. intracellularis growth, as compared to the antimicrobial-free control. Each antimicrobial concentration was evaluated for both intracellular and extracellular activity against L. intracellularis, an obligately intracellular bacterium. When tested for intracellular activity, carbadox, tiamulin, and valnemulin were the most active antimicrobials with MICs of < or =0.5microg/ml. Tylosin (MICs ranging from 0.25 to 32microg/ml) and chlortetracycline (MICs ranging from 0.125 to 64microg/ml) showed intermediate activities and lincomycin (MICs ranging from 8 to >128mIcog/ml) showed the least activity. When tested for extracellular activity, valnemulin (MICs ranging from 0.125 to 4microg/ml) was the most active against most L. intracellularis isolates. Chlortetracycline (MICs ranging from 16 to 64microg/ml), tylosin (MICs ranging from 1 to >128microg/ml), and tiamulin (MICs ranging from 1 to 32microg/ml) showed intermediate activities. Lincomycin (MICs ranging from 32 to >128microg/ml) showed the least activity. Our in vitro results showed that each L. intracellularis isolate had a different antimicrobial sensitivity pattern and these data can be utilized as an in vitro guideline for the further antimicrobial evaluation of field L. intracellularis isolates.

  18. Synergistic antimicrobial activity of Camellia sinensis and Juglans regia against multidrug-resistant bacteria.

    PubMed

    Farooqui, Amber; Khan, Adnan; Borghetto, Ilaria; Kazmi, Shahana U; Rubino, Salvatore; Paglietti, Bianca

    2015-01-01

    Synergistic combinations of antimicrobial agents with different mechanisms of action have been introduced as more successful strategies to combat infections involving multidrug resistant (MDR) bacteria. In this study, we investigated synergistic antimicrobial activity of Camellia sinensis and Juglans regia which are commonly used plants with different antimicrobial agents. Antimicrobial susceptibility of 350 Gram-positive and Gram-negative strains belonging to 10 different bacterial species, was tested against Camellia sinensis and Juglans regia extracts. Minimum inhibitory concentrations (MICs) were determined by agar dilution and microbroth dilution assays. Plant extracts were tested for synergistic antimicrobial activity with different antimicrobial agents by checkerboard titration, Etest/agar incorporation assays, and time kill kinetics. Extract treated and untreated bacteria were subjected to transmission electron microscopy to see the effect on bacterial cell morphology. Camellia sinensis extract showed higher antibacterial activity against MDR S. Typhi, alone and in combination with nalidixic acid, than to susceptible isolates." We further explore anti-staphylococcal activity of Juglans regia that lead to the changes in bacterial cell morphology indicating the cell wall of Gram-positive bacteria as possible target of action. The synergistic combination of Juglans regia and oxacillin reverted oxacillin resistance of methicillin resistant Staphylococcus aureus (MRSA) strains in vitro. This study provides novel information about antimicrobial and synergistic activity of Camellia sinensis and Juglans regia against MDR pathogens.

  19. Evaluation of the flora of northern Mexico for in vitro antimicrobial and antituberculosis activity.

    PubMed

    Molina-Salinas, G M; Pérez-López, A; Becerril-Montes, P; Salazar-Aranda, R; Said-Fernández, S; de Torres, N Waksman

    2007-02-12

    The aim of the present study was to evaluate the potential antimicrobial activity of 14 plants used in northeast México for the treatment of respiratory diseases, against drug-sensitive and drug-resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae type b and Mycobacterium tuberculosis. Forty-eight organic and aqueous extracts were tested against these bacterial strains using a broth microdilution test. No aqueous extracts showed antimicrobial activity, whereas most of the organic extracts presented antimicrobial activity against at least one of the drug-resistant microorganisms tested. Methanol-based extracts from the roots and leaves of Leucophyllum frutescens and ethyl ether extract from the roots of Chrysanctinia mexicana showed the greatest antimicrobial activity against the drug-resistant strain of Mycobacterium tuberculosis; the minimal inhibitory concentration (MIC) were 62.5, 125 and 62.5 microg/mL, respectively; methanol-based extract from the leaves of Cordia boissieri showed the best antimicrobial activity against the drug-resistant strain of Staphylococcus aureus (MIC 250 microg/mL); the hexane-based extract from the fruits of Schinus molle showed considerable antimicrobial activity against the drug-resistant strain of Streptococcus pneumoniae (MIC 62.5 microg/mL). This study supports that selecting plants by ethnobotanical criteria enhances the possibility of finding species with activity against resistant microorganisms.

  20. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity.

    PubMed

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J; Dong, He

    2015-12-07

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.

  1. Oxygen limitation favors the production of protein with antimicrobial activity in Pseudoalteromonas sp

    PubMed Central

    López, Ruth; Monteón, Víctor; Chan, Ernesto; Montejo, Rubí; Chan, Manuel

    2012-01-01

    This study examined the effect of dissolved oxygen concentration on the production of biomass and metabolites with antimicrobial activity of Pseudoalteromonas sp cultured at 0, 150, 250, or 450 revolutions per minute (rev. min-1). Dissolved oxygen (D.O) was monitored during the fermentation process, biomass was quantified by dry weight, and antimicrobial activity was assessed using the disk diffusion method. The bacterium Pseudoalteromonas reached similar concentration of biomass under all experimental agitation conditions, whereas antimicrobial activity was detected at 0 and 150 rev. min-1 registering 0% and 12% of D.O respectively corresponding to microaerophilic conditions. Antibiotic activity was severely diminished when D.O was above 20% of saturation; this corresponded to 250 or 450 rev. min-1. SDS-PAGE electrophoresis revealed a protein with a molecular weight of approximately 80 kilodaltons (kDa) with antimicrobial activity. Pseudoalteromonas is capable of growing under oxic and microaerophilic conditions but the metabolites with antimicrobial activity are induced under microaerophilic conditions. The current opinion is that Pseudoalteromonas are aerobic organisms; we provide additional information on the amount of dissolved oxygen during the fermentation process and its effect on antimicrobial activity. PMID:24031945

  2. Gram-positive bacterial cell envelopes: The impact on the activity of antimicrobial peptides.

    PubMed

    Malanovic, Nermina; Lohner, Karl

    2016-05-01

    A number of cationic antimicrobial peptides, effectors of innate immunity, are supposed to act at the cytoplasmic membrane leading to permeabilization and eventually membrane disruption. Thereby, interaction of antimicrobial peptides with anionic membrane phospholipids is considered to be a key factor in killing of bacteria. Recently, evidence was provided that killing takes place only when bacterial cell membranes are completely saturated with peptides. This adds to an ongoing debate, which role cell wall components such as peptidoglycan, lipoteichoic acid and lipopolysaccharide may play in the killing event, i.e. if they rather entrap or facilitate antimicrobial peptides access to the cytoplasmic membrane. Therefore, in this review we focused on the impact of Gram-positive cell wall components for the mode of action and activity of antimicrobial peptides as well as in innate immunity. This led us to conclude that interaction of antimicrobial peptides with peptidoglycan may not contribute to a reduction of their antimicrobial activity, whereas interaction with anionic lipoteichoic acids may reduce the local concentration of antimicrobial peptides on the cytoplasmic membrane necessary for sufficient destabilization of the membranes and bacterial killing. Further affinity studies of antimicrobial peptides toward the different cell wall as well as membrane components will be needed to address this problem on a quantitative level. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert.

  3. Antimicrobial activities of natural antimicrobial compounds against susceptible and antibiotic-resistant pathogens in the absence and presence of food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to improve microbial food safety, we are studying the antimicrobial activities of different classes of natural compounds including plant essential oils, apple, grape, olive, and tea extracts, bioactive components, and seashell-derived chitosans against multiple foodborne pathogens in cu...

  4. Extraction methods and bioautography for evaluation of medicinal plant antimicrobial activity.

    PubMed

    Nostro, A; Germanò, M P; D'angelo, V; Marino, A; Cannatelli, M A

    2000-05-01

    A comparative study on the antimicrobial properties of extracts from medicinal plants obtained by two different methods was carried out. The screening of the antimicrobial activity of extracts from six plants was conducted by a disc diffusion test against Gram-positive, -negative and fungal organisms. The most active extracts (inhibition diameter >/=12 mm) were assayed for the minimum inhibitory concentration and submitted to phytochemical screening by thin-layer chromatography and bioautography. The results obtained indicate that the diethyl ether extracts were the most efficient antimicrobial compounds. The activity was more pronounced against Gram-positive and fungal organisms than against Gram-negative bacteria. Bioautography showed that the antimicrobial activity was probably due to flavonoids and terpenes.

  5. Evaluation of antimicrobial activity of Malus domestica fruit extract from Kashan area

    PubMed Central

    Jelodarian, Sara; Haghir Ebrahimabadi, Abdolrasoul; Jookar Kashi, Fereshteh

    2013-01-01

    Objective: Many species of plants present noticeable potency against human bacterial and fungal pathogens. Materials and Methods: In the current study, antimicrobial activity of the fresh fruits of 4 cultivars (A to D) of Malus domestica cultivated in the Qamsar area of Kashan, Iran was investigated. The disk diffusion and minimal inhibitory concentration (MIC) evaluation antimicrobial activity tests were performed. Results: The samples showed moderate antimicrobial activities with inhibition zones from 11 to 16 mm in these tests. Cultivar D with inhibition zones of 16, 14, and 12 mm for E. coli, S. epidermidis and K. pneumoniae, respectively exhibited the best results in these tests. Cultivar A also showed a zone of inhibition of 11 mm against P. aerouginosa. Conclusion: Moderate antimicrobial activities were observed for the studied apple cultivars. PMID:25050254

  6. Antioxidant and antimicrobial activities of individual and combined phenolics in Olea europaea leaf extract.

    PubMed

    Lee, Ok-Hwan; Lee, Boo-Yong

    2010-05-01

    Olive leaves, an agricultural waste, have great potential as a natural antioxidant. The current study was made to assess the antioxidant and antimicrobial activities of both the individual and combined phenolics in olive leaf extract. A combined phenolics mixture was prepared by amount ratios of the phenolic compounds in the olive leaf extract. The results showed that both the individual and combined phenolics exhibited good radical scavenging abilities, and also revealed superoxide dismutase (SOD)-like activity. In terms of antimicrobial activity, both oleuropein and caffeic acid showed inhibition effects against microorganisms. Furthermore, the antimicrobial effect of the combined phenolics was significantly higher than those of the individual phenolics. These results show that the combination of olive leaf extract phenolics possessed antioxidant and antimicrobial activities. This study indicates that olive leaf extract might be a valuable bioactive source, and would seem to be applicable in both the health and medical food.

  7. The in vitro Antimicrobial Activity and Chemometric Modelling of 59 Commercial Essential Oils against Pathogens of Dermatological Relevance.

    PubMed

    Orchard, Ané; Sandasi, Maxleene; Kamatou, Guy; Viljoen, Alvaro; van Vuuren, Sandy

    2017-01-01

    This study reports on the inhibitory concentration of 59 commercial essential oils recommended for dermatological conditions, and identifies putative compounds responsible for antimicrobial activity. Essential oils were investigated for antimicrobial activity using minimum inhibitory concentration assays. Ten essential oils were identified as having superior antimicrobial activity. The essential oil compositions were determined using gas chromatography coupled to mass spectrometry and the data analysed with the antimicrobial activity using multivariate tools. Orthogonal projections to latent structures models were created for seven of the pathogens. Eugenol was identified as the main biomarker responsible for antimicrobial activity in the majority of the essential oils. The essential oils mostly displayed noteworthy antimicrobial activity, with five oils displaying broad-spectrum activity against the 13 tested micro-organisms. The antimicrobial efficacies of the essential oils highlight their potential in treating dermatological infections and through chemometric modelling, bioactive volatiles have been identified.

  8. Activity of antimicrobial peptide mimetics in the oral cavity: II. Activity against periopathogenic biofilms and anti-inflammatory activity.

    PubMed

    Hua, J; Scott, R W; Diamond, G

    2010-12-01

    Whereas periodontal disease is ultimately of bacterial etiology, from multispecies biofilms of gram-negative anaerobic microorganisms, much of the deleterious effects are caused by the resultant epithelial inflammatory response. Hence, development of a treatment that combines anti-biofilm antibiotic activity with anti-inflammatory activity would be of great utility. Antimicrobial peptides (AMPs) such as defensins are naturally occurring peptides that exhibit broad-spectrum activity as well as a variety of immunomodulatory activities. Furthermore, bacteria do not readily develop resistance to these agents. However, clinical studies have suggested that they do not represent optimal candidates for exogenous therapeutic agents. Small-molecule mimetics of these AMPs exhibit similar activities to the parent peptides, in addition to having low toxicity, high stability and low cost. To determine whether AMP mimetics have the potential for treatment of periodontal disease, we examined the activity of one mimetic, mPE, against biofilm cultures of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Metabolic assays as well as culture and biomass measurement assays demonstrated that mPE exhibits potent activity against biofilm cultures of both species. Furthermore, as little as 2 μg ml(-1) mPE was sufficient to inhibit interleukin-1β-induced secretion of interleukin-8 in both gingival epithelial cells and THP-1 cells. This anti-inflammatory activity is associated with a reduction in activation of nuclear factor-κB, suggesting that mPE can act both as an anti-biofilm agent in an anaerobic environment and as an anti-inflammatory agent in infected tissues.

  9. [In vitro evaluation of antimicrobial activity of absorbable topical hemostatic agents used in the operating room].

    PubMed

    Piana, Andrea; Mura, Ida; Deidda, Silvia; Lo Curto, Paola; Are, Bianca Maria; Maida, Giorgio; Masia, Maria Dolores

    2013-01-01

    The aim of this study was to evaluate the antimicrobial activity of three absorbable, sterile, regenerated oxidized cellulose gauzes against ATCC and clinical isolates of bacterial and fungal strains, in particular those most frequently involved in surgical site infections. The three cellulose devices showed rapid antimicrobial activity against the microbial species tested. Their use could be a valuable adjunct to antibiotic prophylaxis in the prevention of surgical site infections.

  10. Surface-Bonded Antimicrobial Activity of an Organosilicon Quaternary Ammonium Chloride

    PubMed Central

    Isquith, A. J.; Abbott, E. A.; Walters, P. A.

    1972-01-01

    The hydrolysis product of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride exhibited antimicrobial activity against a broad range of microorganisms while chemically bonded to a variety of surfaces. The chemical was not removed from surfaces by repeated washing with water, and its antimicrobial activity could not be attributed to a slow release of the chemical, but rather to the surface-bonded chemical. Images PMID:4650597

  11. Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity against ESKAPE Pathogens

    DTIC Science & Technology

    2013-01-01

    Antimicrobial peptides containing unnatural amino acid exhibit potent bactericidal activity against ESKAPE pathogens R. P. Hicks a, J. J. Abercrombie...tic classes, membrane-disruptors and non -membrane-disrup- tors.30,31 Five different mechanisms have been proposed at one time or another to explain...DATES COVERED - 4. TITLE AND SUBTITLE Antimicrobial Peptides Containing Unnatural Amino Acid Exhibit Potent Bactericidal Activity Against

  12. Antimicrobial activity of biodegradable polysaccharide and protein-based films containing active agents.

    PubMed

    Kuorwel, Kuorwel K; Cran, Marlene J; Sonneveld, Kees; Miltz, Joseph; Bigger, Stephen W

    2011-04-01

    Significant interest has emerged in the introduction of food packaging materials manufactured from biodegradable polymers that have the potential to reduce the environmental impacts associated with conventional packaging materials. Current technologies in active packaging enable effective antimicrobial (AM) packaging films to be prepared from biodegradable materials that have been modified and/or blended with different compatible materials and/or plasticisers. A wide range of AM films prepared from modified biodegradable materials have the potential to be used for packaging of various food products. This review examines biodegradable polymers derived from polysaccharides and protein-based materials for their potential use in packaging systems designed for the protection of food products from microbial contamination. A comprehensive table that systematically analyses and categorizes much of the current literature in this area is included in the review.

  13. Effect of Fatty Acid Conjugation on Antimicrobial Peptide Activity

    DTIC Science & Technology

    2004-12-01

    killing mechanism of antimicrobial peptides makes them an interesting alternative to traditional antibiotics, as target bacteria may be less able...C14-AKK and C16-AKK to within a 7% error are 220 and 16mM respectively. Since amphipathicity is requisite for antimicrobial action KAK is not...Schnaare, 2000: Antimicrobial evaluation of N-alkyl betaines and N-alkyl-N,N-dimethylamine oxides with variations in chain length. Antimicrobial Agents

  14. Antimicrobial and antileishmanial activities of diterpenoids isolated from the roots of Salvia deserta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four diterpenes with biological activity were isolated from Salvia deserta roots. Taxodione was considered leishmanicidal, with IC50 value of 0.46 µg/mL against Leishimania donovani and also exhibited antifungal and antimicrobial activities. Ferruginol displayed the greatest activity (24-h IC50 1.29...

  15. Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

    PubMed

    Ignatova, Milena; Stoilova, Olya; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2010-08-11

    New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

  16. Antimicrobial screening of some Egyptian plants and active flavones from Lagerstroemia indica leaves.

    PubMed

    Diab, Y; Atalla, K; Elbanna, K

    2012-08-01

    One hundred and twenty four plant extracts were evaluated for their antimicrobial activity against four pathogenic bacteria (Staphylococcus aureus (ATCC 8095), Salmonella enteritides (ATCC 13076), Escherichia coli (ATCC 25922), and Listeria monocytogenes (ATCC 15313)) and Candida albicans yeast (ATCC 10231) using the disk diffusion and broth microdilution methods. Of the plant extracts, fourteen exhibited antimicrobial activity against two or more of the five microorganisms tested. Only the methanol extract of Lagerstroemia indica leaves exhibited antimicrobial activity against all pathogenic bacteria and C. albicans yeast that were tested. Purification of the methanol extract of L. indica leaves using antimicrobial assay-guided isolation yielded one pure active compound. The chemical structure of the isolated active compound was found to be '4-methoxy apigenin-8-C-β-D-glucopyranoside; cytisoside according to detailed spectroscopic analysis of its nuclear magnetic resonance and mass spectrometry data. The compound exhibited antimicrobial activity against C. albicans (minimum lethal concentration (MLC): 32 μg/mL), S. aureus (MLC: 16 μg/mL), S. enteritides (MLC: 16 μg/mL), E. coli (MLC: 16 μg/mL), and L. monocytogenes (MLC: 16 μg/mL). The present study found that the methanol extract of L. indica leaves holds great promise as a potential source of beneficial antimicrobial components for different applications.

  17. Screening of antimicrobial activity of macroalgae extracts from the Moroccan Atlantic coast.

    PubMed

    El Wahidi, M; El Amraoui, B; El Amraoui, M; Bamhaoud, T

    2015-05-01

    The aim of this work is the screening of the antimicrobial activity of seaweed extracts against pathogenic bacteria and yeasts. The antimicrobial activity of the dichloromethane and ethanol extracts of ten marine macroalgae collected from the Moroccan's Atlantic coast (El-Jadida) was tested against two Gram+ (Bacillus subtilis and Staphylococcus aureus) and two Gram- (Escherichia coli and Pseudomonas aeruginosa) human pathogenic bacteria, and against two pathogenic yeasts (Candida albicans and Cryptococcus neoformans) using the agar disk-diffusion method. Seven algae (70%) of ten seaweeds are active against at least one pathogenic microorganisms studied. Five (50%) are active against the two studied yeast with an inhibition diameter greater than 15 mm for Cystoseira brachycarpa. Six (60%) seaweeds are active against at least one studied bacteria with five (50%) algae exhibiting antibacterial inhibition diameter greater than 15 mm. Cystoseira brachycarpa, Cystoseira compressa, Fucus vesiculosus, and Gelidium sesquipedale have a better antimicrobial activity with a broad spectrum antimicrobial and are a potential source of antimicrobial compounds and can be subject of isolation of the natural antimicrobials.

  18. Effect of Encapsulation on Antimicrobial Activity of
Herbal Extracts with Lysozyme

    PubMed Central

    Matouskova, Petra; Bokrova, Jitka; Benesova, Pavla

    2016-01-01

    Summary Resistance of microorganisms to antibiotics has increased. The use of natural components with antimicrobial properties can be of great significance to reduce this problem. The presented work is focused on the study of the effect of encapsulation of selected plant and animal antimicrobial substances (herbs, spices, lysozyme and nisin) on their activity and stability. Antimicrobial components were packaged into liposomes and polysaccharide particles (alginate, chitosan and starch). Antimicrobial activity was tested against two Gram-positive (Bacillus subtilis and Micrococcus luteus) and two Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Encapsulation was successful in all types of polysaccharide particles and liposomes. The prepared particles exhibited very good long-term stability, especially in aqueous conditions. Antimicrobial activity was retained in all types of particles. Liposomes with encapsulated herb and spice extracts exhibited very good inhibitory effect against all tested bacterial strains. Most of herbal extracts had very good antimicrobial effect against the tested Gram-negative bacterial strains, while Gram-positive bacteria were more sensitive to lysozyme particles. Thus, particles with co-encapsulated herbs and lysozyme are more active against different types of bacteria, and more stable and more effective during long-term storage. Particles with encapsulated mixture of selected plant extracts and lysozyme could be used as complex antimicrobial preparation with controlled release in the production of food and food supplements, pharmaceutical and cosmetic industries. PMID:27956862

  19. Antimicrobial and antioxidative activities in the bark extracts of Sonneratia caseolaris, a mangrove plant

    PubMed Central

    Simlai, Aritra; Rai, Archana; Mishra, Saumya; Mukherjee, Kalishankar; Roy, Amit

    2014-01-01

    The present study deals with the phytochemical contents, antimicrobial and antioxidative activities of bark tissue of Sonneratia caseolaris, a mangrove plant from Sundarban estuary, India. Phytochemical analyses revealed the presence of high amounts of phenolics, flavonoids, tannins, alkaloids and saponins. Antimicrobial efficacies of various extracts of S. caseolaris were assessed by disc diffusion method against two Gram-positive (Bacillus subtilis and Bacillus coagulans), two Gram-negative (Escherichia coli and Proteus vulgaris) bacteria and one fungus (Saccharomyces cerevisiae). The methanolic extract among others showed significant minimum inhibitory concentration (MIC) values. The antioxidant activity as indicated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the bark tissue extract from the species was found to be quite appreciable. The extracts were found to retain their antimicrobial activities despite pH and thermal treatments, thus indicating the stability of their activity even at extreme conditions. The antioxidant activity was also found to be considerably stable after thermal treatments. The components of the tissue extracts were subjected to separation using thin layer chromatography (TLC). The constituents with antimicrobial and antioxidative properties were identified using TLC-bioautography by agar-overlay and DPPH spraying methods respectively. A number of bioactive constituents with antimicrobial and radical scavenging properties were observed on the developed bioautography plate. The fractions with antimicrobial properties were isolated from the reference TLC plates and subjected to gas chromatography-mass spectrometry (GC-MS) analysis for partial characterization and identification of the metabolites that might be responsible for the activities. The study suggests Sonneratia caseolaris bark as a potential source of bioactive compounds with stable antimicrobial and antioxidative properties and can be used as natural

  20. Antimicrobial and antioxidative activities in the bark extracts of Sonneratia caseolaris, a mangrove plant.

    PubMed

    Simlai, Aritra; Rai, Archana; Mishra, Saumya; Mukherjee, Kalishankar; Roy, Amit

    2014-01-01

    The present study deals with the phytochemical contents, antimicrobial and antioxidative activities of bark tissue of Sonneratia caseolaris, a mangrove plant from Sundarban estuary, India. Phytochemical analyses revealed the presence of high amounts of phenolics, flavonoids, tannins, alkaloids and saponins. Antimicrobial efficacies of various extracts of S. caseolaris were assessed by disc diffusion method against two Gram-positive (Bacillus subtilis and Bacillus coagulans), two Gram-negative (Escherichia coli and Proteus vulgaris) bacteria and one fungus (Saccharomyces cerevisiae). The methanolic extract among others showed significant minimum inhibitory concentration (MIC) values. The antioxidant activity as indicated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the bark tissue extract from the species was found to be quite appreciable. The extracts were found to retain their antimicrobial activities despite pH and thermal treatments, thus indicating the stability of their activity even at extreme conditions. The antioxidant activity was also found to be considerably stable after thermal treatments. The components of the tissue extracts were subjected to separation using thin layer chromatography (TLC). The constituents with antimicrobial and antioxidative properties were identified using TLC-bioautography by agar-overlay and DPPH spraying methods respectively. A number of bioactive constituents with antimicrobial and radical scavenging properties were observed on the developed bioautography plate. The fractions with antimicrobial properties were isolated from the reference TLC plates and subjected to gas chromatography-mass spectrometry (GC-MS) analysis for partial characterization and identification of the metabolites that might be responsible for the activities. The study suggests Sonneratia caseolaris bark as a potential source of bioactive compounds with stable antimicrobial and antioxidative properties and can be used as natural

  1. Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera

    PubMed Central

    Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto CP

    2015-01-01

    We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms. PMID:26445537

  2. Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera.

    PubMed

    Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto C P

    2015-01-01

    We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms.

  3. Poly(anhydride-esters) Comprised Exclusively of Naturally Occurring Antimicrobials and EDTA: Antioxidant and Antibacterial Activities

    PubMed Central

    2015-01-01

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways. PMID:24702678

  4. Poly(anhydride-esters) comprised exclusively of naturally occurring antimicrobials and EDTA: antioxidant and antibacterial activities.

    PubMed

    Carbone-Howell, Ashley L; Stebbins, Nicholas D; Uhrich, Kathryn E

    2014-05-12

    Carvacrol, thymol, and eugenol are naturally occurring phenolic compounds known to possess antimicrobial activity against a range of bacteria, as well as antioxidant activity. Biodegradable poly(anhydride-esters) composed of an ethylenediaminetetraacetic acid (EDTA) backbone and antimicrobial pendant groups (i.e., carvacrol, thymol, or eugenol) were synthesized via solution polymerization. The resulting polymers were characterized to confirm their chemical composition and understand their thermal properties and molecular weight. In vitro release studies demonstrated that polymer hydrolytic degradation was complete after 16 days, resulting in the release of free antimicrobials and EDTA. Antioxidant and antibacterial assays determined that polymer release media exhibited bioactivity similar to that of free compound, demonstrating that polymer incorporation and subsequent release had no effect on activity. These polymers completely degrade into components that are biologically relevant and have the capability to promote preservation of consumer products in the food and personal care industries via antimicrobial and antioxidant pathways.

  5. Antimicrobial activity of copper and silver nanofilms on nosocomial bacterial species.

    PubMed

    Codiţă, Irina; Caplan, Dana Magdalena; Drăgulescu, Elena-Carmina; Lixandru, Brînduşa-Elena; Coldea, Ileana Luminiţa; Dragomirescu, Cristiana Cerasella; Surdu-Bob, Cristina; Bădulescu, Marius

    2010-01-01

    Contaminated surfaces are possible vehicles in infection transmission. It is known that both Copper (Cu) and Silver (Ag) efficiently inactivate microbes by direct contact. Aiming at using these metals for benefitting from their antimicrobial effect, but to avoid subsequent toxic effects, we evaluated the antimicrobial activity of nanometric thin Silver and Copper films covering less expensive materials. Using a modified version of the Japan Industrial Standard JIS Z 2801:2000, we demonstrated the antimicrobial activity of the surfaces covered with metal ions nanofilms on microorganisms possibly involved in nosocomial infections and on Bacillus anthracis, bacteria with possible implication in bioterrorist attacks. Copper covered surfaces proved to have better antimicrobial activity than Silver surfaces. Silver covered surfaces showed better activity on Gram negative bacteria than on Gram positive cocci. Going deeper with studies on antimicrobial effects using new methods with better direct and/or functional discriminatory capacity is needed in order to provide additional information on the mechanisms of Silver and Copper nanofilms antimicrobial activity.

  6. Application of Artificial Intelligence to the Prediction of the Antimicrobial Activity of Essential Oils.

    PubMed

    Daynac, Mathieu; Cortes-Cabrera, Alvaro; Prieto, Jose M

    2015-01-01

    Essential oils (EOs) are vastly used as natural antibiotics in Complementary and Alternative Medicine (CAM). Their intrinsic chemical variability and synergisms/antagonisms between its components make difficult to ensure consistent effects through different batches. Our aim is to evaluate the use of artificial neural networks (ANNs) for the prediction of their antimicrobial activity. Methods. The chemical composition and antimicrobial activity of 49 EOs, extracts, and/or fractions was extracted from NCCLS compliant works. The fast artificial neural networks (FANN) software was used and the output data reflected the antimicrobial activity of these EOs against four common pathogens: Staphylococcus aureus, Escherichia coli, Candida albicans, and Clostridium perfringens as measured by standardised disk diffusion assays. Results. ANNs were able to predict >70% of the antimicrobial activities within a 10 mm maximum error range. Similarly, ANNs were able to predict 2 or 3 different bioactivities at the same time. The accuracy of the prediction was only limited by the inherent errors of the popular antimicrobial disk susceptibility test and the nature of the pathogens. Conclusions. ANNs can be reliable, fast, and cheap tools for the prediction of the antimicrobial activity of EOs thus improving their use in CAM.

  7. Application of Artificial Intelligence to the Prediction of the Antimicrobial Activity of Essential Oils

    PubMed Central

    Daynac, Mathieu; Cortes-Cabrera, Alvaro; Prieto, Jose M.

    2015-01-01

    Essential oils (EOs) are vastly used as natural antibiotics in Complementary and Alternative Medicine (CAM). Their intrinsic chemical variability and synergisms/antagonisms between its components make difficult to ensure consistent effects through different batches. Our aim is to evaluate the use of artificial neural networks (ANNs) for the prediction of their antimicrobial activity. Methods. The chemical composition and antimicrobial activity of 49 EOs, extracts, and/or fractions was extracted from NCCLS compliant works. The fast artificial neural networks (FANN) software was used and the output data reflected the antimicrobial activity of these EOs against four common pathogens: Staphylococcus aureus, Escherichia coli, Candida albicans, and Clostridium perfringens as measured by standardised disk diffusion assays. Results. ANNs were able to predict >70% of the antimicrobial activities within a 10 mm maximum error range. Similarly, ANNs were able to predict 2 or 3 different bioactivities at the same time. The accuracy of the prediction was only limited by the inherent errors of the popular antimicrobial disk susceptibility test and the nature of the pathogens. Conclusions. ANNs can be reliable, fast, and cheap tools for the prediction of the antimicrobial activity of EOs thus improving their use in CAM. PMID:26457111

  8. Antimicrobial activity of bacterial isolates from different floral sources of honey.

    PubMed

    Lee, Hyungjae; Churey, John J; Worobo, Randy W

    2008-08-15

    More than two thousand bacterial strains isolated from six US domestic honeys and two manuka honeys from New Zealand were screened for production of antimicrobial compounds. A high incidence of antimicrobial inhibition determined by deferred inhibition assays was observed with the bacterial isolates from all eight honey samples. In total, 2217 isolates out of 2398 strains (92.5% of total isolates) exhibited antimicrobial activity against at least one of the tested microorganisms. Antifungal activity by bacterial isolates originating from the eight honeys ranged from 44.4% to 98.0%. Bacterial isolates from manuka honey (MH1) exhibited antimicrobial activity against Bacillus subtilis ATCC 6633 and Bacillus cereus F4552, at 51.5% and 53.3% of the isolates, respectively. However, less than 30% of the bacterial isolates from the other manuka honey (MH2) and six domestic honey sources exhibited anti-Bacillus activity. Listeria monocytogenes F2-586 1053 showed higher overall rates of sensitivity to between 11 and 66% of the bacterial isolates. The high rate of antimicrobial activity exhibited by the bacterial strains isolated from different honey sources could provide potential sources of novel antimicrobial compounds.

  9. A novel direct contact method for the assessment of the antimicrobial activity of dental cements.

    PubMed

    Costa, E M; Silva, S; Madureira, A R; Cardelle-Cobas, A; Tavaria, F K; Pintado, M M

    2013-06-01

    Dental cements are a crucial part of the odontological treatment, however, due to the hazardous nature and reduced biological efficiency of some of the used materials, newer and safer alternatives are needed, particularly so those possessing higher antimicrobial activity than their traditional counterparts. The evaluation of the antimicrobial properties of solid and semi-solid antimicrobials, such as dental cements and gels, is challenging, particularly due to the low sensitivity of the current methods. Thus, the main aim of this study was the evaluation of the antimicrobial activity of a novel chitosan containing dental cement while simultaneous assessing/validating a new, more efficient, method for the evaluation of the antimicrobial activity of solid and gel like materials. The results obtained showed that the proposed method exhibited a higher sensitivity than the standard 96 well microtiter assay and allowed the determination of bactericidal activity. Additionally, it is interesting to note that the chitosan containing cement, which presented higher antimicrobial activity than the traditional zinc oxide/eugenol mix, was capable of inducing a viable count reduction above 5 log of CFU for all of the studied microorganisms.

  10. Immunomodulatory and Antimicrobial Activity of Babassu Mesocarp Improves the Survival in Lethal Sepsis

    PubMed Central

    Prado, Dayanna S.; Barcellos, Priscila S.; Gonçalves, Azizedite G.

    2016-01-01

    Attalea speciosa syn Orbignya phalerata Mart. (babassu) has been used in the treatment of inflammatory and infectious diseases. Aim of the study. To investigate the antimicrobial and immunological activity of babassu mesocarp extract (EE). Material and Methods. The in vitro antimicrobial activity was evaluated by disk diffusion assay and by determination of the minimum inhibitory concentration (MIC) to Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The flavonoids and phenolic acids content were determined by chromatography. The in vivo assays were performed in Swiss mice submitted to sepsis by cecal ligation and puncture (CLP). The mice received EE subcutaneously (125 or 250 mg/Kg), 6 hours after the CLP. The number of lymphoid cells was quantified and the cytokines production was determined by ELISA after 12 h. Results. EE was effective as antimicrobial to E. faecalis, S. aureus, and MRSA. EE is rich in phenolic acids, a class of compounds with antimicrobial and immunological activity. An increased survival can be observed in those groups, possibly due to a significant inhibition of TNF-α and IL-6. Conclusions. The EE showed specific antimicrobial activity in vitro and an important antiseptic effect in vivo possibly due to the antimicrobial and immunomodulatory activity. PMID:27630733

  11. Immunomodulatory and Antimicrobial Activity of Babassu Mesocarp Improves the Survival in Lethal Sepsis.

    PubMed

    Barroqueiro, Elizabeth S B; Prado, Dayanna S; Barcellos, Priscila S; Silva, Tonicley A; Pereira, Wanderson S; Silva, Lucilene A; Maciel, Márcia C G; Barroqueiro, Rodrigo B; Nascimento, Flávia R F; Gonçalves, Azizedite G; Guerra, Rosane N M

    2016-01-01

    Attalea speciosa syn Orbignya phalerata Mart. (babassu) has been used in the treatment of inflammatory and infectious diseases. Aim of the study. To investigate the antimicrobial and immunological activity of babassu mesocarp extract (EE). Material and Methods. The in vitro antimicrobial activity was evaluated by disk diffusion assay and by determination of the minimum inhibitory concentration (MIC) to Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). The flavonoids and phenolic acids content were determined by chromatography. The in vivo assays were performed in Swiss mice submitted to sepsis by cecal ligation and puncture (CLP). The mice received EE subcutaneously (125 or 250 mg/Kg), 6 hours after the CLP. The number of lymphoid cells was quantified and the cytokines production was determined by ELISA after 12 h. Results. EE was effective as antimicrobial to E. faecalis, S. aureus, and MRSA. EE is rich in phenolic acids, a class of compounds with antimicrobial and immunological activity. An increased survival can be observed in those groups, possibly due to a significant inhibition of TNF-α and IL-6. Conclusions. The EE showed specific antimicrobial activity in vitro and an important antiseptic effect in vivo possibly due to the antimicrobial and immunomodulatory activity.

  12. Optimized dispersion of ZnO nanoparticles and antimicrobial activity against foodborne pathogens and spoilage microorganisms

    NASA Astrophysics Data System (ADS)

    Espitia, Paula Judith Perez; Soares, Nilda de Fátima Ferreira; Teófilo, Reinaldo F.; Vitor, Débora M.; Coimbra, Jane Sélia dos Reis; de Andrade, Nélio José; de Sousa, Frederico B.; Sinisterra, Rubén D.; Medeiros, Eber Antonio Alves

    2013-01-01

    Single primary nanoparticles of zinc oxide (nanoZnO) tend to form particle collectives, resulting in loss of antimicrobial activity. This work studied the effects of probe sonication conditions: power, time, and the presence of a dispersing agent (Na4P2O7), on the size of nanoZnO particles. NanoZnO dispersion was optimized by response surface methodology (RSM) and characterized by the zeta potential (ZP) technique. NanoZnO antimicrobial activity was investigated at different concentrations (1, 5, and 10 % w/w) against four foodborne pathogens and four spoilage microorganisms. The presence of the dispersing agent had a significant effect on the size of dispersed nanoZnO. Minimum size after sonication was 238 nm. An optimal dispersion condition was achieved at 200 W for 45 min of sonication in the presence of the dispersing agent. ZP analysis indicated that the ZnO nanoparticle surface charge was altered by the addition of the dispersing agent and changes in pH. At tested concentrations and optimal dispersion, nanoZnO had no antimicrobial activity against Pseudomonas aeruginosa, Lactobacillus plantarum, and Listeria monocytogenes. However, it did have antimicrobial activity against Escherichia coli, Salmonella choleraesuis, Staphylococcus aureus, Saccharomyces cerevisiae, and Aspergillus niger. Based on the exhibited antimicrobial activity of optimized nanoZnO against some foodborne pathogens and spoilage microorganisms, nanoZnO is a promising antimicrobial for food preservation with potential application for incorporation in polymers intended as food-contact surfaces.

  13. Antimicrobial and cytotoxicity activities of the medicinal plant Primula macrophylla.

    PubMed

    Najmus-Saqib, Qazi; Alam, Fiaz; Ahmad, Mansoor

    2009-06-01

    Primula macrophylla (Primulaceae) is reported as to be useful in asthma, restlessness, insomnia and fish poisoning. Antifungal and toxic activities of crude extract, fractions and a pure isolated compound exhibited statistically significant activities. Excellent antifungal activity was found in the crude extract, benzene and ethyl acetate fractions against T. longifusis and against M. canis with different MIC values. Antileishmanial activity (IC(50) = 50ug/mL) was observed as compared to standard drug Amphotericin B, and cytotoxic activity (LD(50) = 47.919microg/mL) was also found in the chloroform fraction. While pure compound 2-phenylchromone (Flavone) isolated from the chloroform fraction showed good activity (IC(50) = 25microg/mL) against Leishmania and cytotoxicity (LD(50) = 2.0116 microg/mL) in Brine Shrimp experiments. From antileishmanial and cytotoxic activity it can be concluded that 2-phenylchromone is the major compound responsible for these activities.

  14. Antileishmanial, antimicrobial and antifungal activities of some new aryl azomethines.

    PubMed

    Al-Kahraman, Yasser M S A; Madkour, Hassan M F; Ali, Dildar; Yasinzai, Masoom

    2010-01-28

    A series of eighteen azomethines has been synthesized by the reaction of appropriate primary aromatic amines with aryl and/or heteroaryl carboxaldehydes. The synthesized azomethines have been evaluated for their in vitro antileishmanial, antibacterial and antifungal activities. The results revealed some antifungal activity of most of the synthesized compounds, whereas the antileishmaniasis activity results highlighted that all synthesized azomethines inhibited parasite growth and most of them showed highly potent action towards Leishmania major promastigotes. No remarkable bactericidal activities were observed.

  15. Identification and Antimicrobial Activity Detection of Lactic Acid Bacteria Isolated from Corn Stover Silage

    PubMed Central

    Li, Dongxia; Ni, Kuikui; Pang, Huili; Wang, Yanping; Cai, Yimin; Jin, Qingsheng

    2015-01-01

    A total of 59 lactic acid bacteria (LAB) strains were isolated from corn stover silage. According to phenotypic and chemotaxonomic characteristics, 16S ribosomal DNA (rDNA) sequences and recA gene polymerase chain reaction amplification, these LAB isolates were identified as five species: Lactobacillus (L.) plantarum subsp. plantarum, Pediococcus pentosaceus, Enterococcus mundtii, Weissella cibaria and Leuconostoc pseudomesenteroides, respectively. Those strains were also screened for antimicrobial activity using a dual-culture agar plate assay. Based on excluding the effects of organic acids and hydrogen peroxide, two L. plantarum subsp. plantarum strains ZZU 203 and 204, which strongly inhibited Salmonella enterica ATCC 43971T, Micrococcus luteus ATCC 4698T and Escherichia coli ATCC 11775T were selected for further research on sensitivity of the antimicrobial substance to heat, pH and protease. Cell-free culture supernatants of the two strains exhibited strong heat stability (60 min at 100°C), but the antimicrobial activity was eliminated after treatment at 121°C for 15 min. The antimicrobial substance remained active under acidic condition (pH 2.0 to 6.0), but became inactive under neutral and alkaline condition (pH 7.0 to 9.0). In addition, the antimicrobial activities of these two strains decreased remarkably after digestion by protease K. These results preliminarily suggest that the desirable antimicrobial activity of strains ZZU 203 and 204 is the result of the production of a bacteriocin-like substance, and these two strains with antimicrobial activity could be used as silage additives to inhibit proliferation of unwanted microorganism during ensiling and preserve nutrients of silage. The nature of the antimicrobial substances is being investigated in our laboratory. PMID:25924957

  16. Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nanoparticles: an overview and comments.

    PubMed

    Durán, Nelson; Nakazato, Gerson; Seabra, Amedea B

    2016-08-01

    The antimicrobial impact of biogenic-synthesized silver-based nanoparticles has been the focus of increasing interest. As the antimicrobial activity of nanoparticles is highly dependent on their size and surface, the complete and adequate characterization of the nanoparticle is important. This review discusses the characterization and antimicrobial activity of biogenic synthesized silver nanoparticles and silver chloride nanoparticles. By revising the literature, there is confusion in the characterization of these two silver-based nanoparticles, which consequently affects the conclusion regarding to their antimicrobial activities. This review critically analyzes recent publications on the synthesis of biogenic silver nanoparticles and silver chloride nanoparticles by attempting to correlate the characterization of the nanoparticles with their antimicrobial activity. It was difficult to correlate the size of biogenic nanoparticles with their antimicrobial activity, since different techniques are employed for the characterization. Biogenic synthesized silver-based nanoparticles are not completely characterized, particularly the nature of capped proteins covering the nanomaterials. Moreover, the antimicrobial activity of theses nanoparticles is assayed by using different protocols and strains, which difficult the comparison among the published papers. It is important to select some bacteria as standards, by following international foundations (Pharmaceutical Microbiology Manual) and use the minimal inhibitory concentration by broth microdilution assays from Clinical and Laboratory Standards Institute, which is the most common assay used in antibiotic ones. Therefore, we conclude that to have relevant results on antimicrobial effects of biogenic silver-based nanoparticles, it is necessary to have a complete and adequate characterization of these nanostructures, followed by standard methodology in microbiology protocols.

  17. Antimicrobial activity of Datura innoxia and Datura stramonium.

    PubMed

    Eftekhar, Fereshteh; Yousefzadi, Morteza; Tafakori, V

    2005-01-01

    The antibacterial activity of the methanol extracts of the aerial parts of the Datura innoxia and Datura stramonium was investigated. The extracts showed activity against Gram (+) bacteria in a dose dependent manner. Little or no antibacterial activity was found against Escherichia coli and Pseudomonas aeruginosa.

  18. Antimicrobial and antioxidant activities of two endemic plants from Aksaray in Turkey.

    PubMed

    Ozusaglam, Meltem Asan; Darilmaz, Derya Onal; Erzengin, Mahmut; Teksen, Mehtap; Erkul, Seher Karaman

    2013-01-01

    This study was designed to examine the in vitro antimicrobial and antioxidant activities of the methanol, ethanol, water, n-hexane and dicholoromethane extracts of two Allium species (Allium scabriflorum and Allium tchihatschewii) which are endemic for the flora of Turkey. The antimicrobial efficiency of the plant was evaluated according to disc diffusion and microdilution broth methods. The antimicrobial test results showed that the extracts of A. scabriflorum and A. tchihatschewii showed varying degrees of antimicrobial activity on the tested microorganisms. The extracts were screened for their possible antioxidant activities by three complementary tests; DPPH free radical-scavenging, scavenging of hydrogen peroxide and metal chelating activity assays. All the extracts of A. scabriflorum and A. tchihatschewii exhibited lower DPPH free radical scavenging activity but higher metal chelating activity when compared to standards. The values of scavenging of hydrogen peroxide of the extracts were higher than the standards that of α-tocopherol, BHA, BHT and trolox, but close to that of ascorbic acid. In addition to the antioxidant activity of these plants, the total phenolic compounds and flavonoids were also measured in the extracts. The results presented here may suggest that the extracts of A. scabriflorum and A. tchihatschewii possess antimicrobial and antioxidant properties, and therefore, they can be used as a natural preservative ingredient in food and/or pharmaceutical industry.

  19. Synthesis, antimicrobial evaluation, and structure-activity relationship of α-pinene derivatives.

    PubMed

    Dhar, Preeti; Chan, PuiYee; Cohen, Daniel T; Khawam, Fadi; Gibbons, Sarah; Snyder-Leiby, Teresa; Dickstein, Ellen; Rai, Prashant Kumar; Watal, Geeta

    2014-04-23

    Several (+)- and (-)-α-pinene derivatives were synthesized and evaluated for their antimicrobial activity toward Gram-positive bacteria Micrococcus luteus and Staphylococcus aureus, Gram-negative bacterium Escherichia coli, and the unicellular fungus Candida albicans using bioautographic assays. (+)-α-Pinene 1a showed modest activity against the test organisms, whereas (-)-α-pinene 1b showed no activity at the tested concentration. Of all the α-pinene derivatives evaluated, the β-lactam derivatives (10a and 10b) were the most antimicrobial. The increase in the antimicrobial activity of 10a compared to 1a ranged from nearly 3.5-fold (C. albicans) to 43-fold (S. aureus). The mean ± standard deviation for the zone of inhibition (mm) for 10a (C. albicans) was 31.9 ± 4.3 and that for S. aureus was 51.1 ± 2.9. Although (-)-α-pinene 1b was not active toward the test microorganisms, the corresponding β-lactam 10b, amino ester 13b, and amino alcohol 14b showed antimicrobial activity toward the test microorganisms. The increase in the antimicrobial activity of 10b compared to 1b ranged from 32-fold (S. aureus) to 73-fold (M. luteus). The mean ± standard deviation for the zone of inhibition (mm) for 10b (S. aureus) was 32.0 ± 0.60 and that for M. luteus was 73.2 ± 0.30.

  20. Antimicrobial activity of some ethnomedicinal plants used by Paliyar tribe from Tamil Nadu, India

    PubMed Central

    Duraipandiyan, Veeramuthu; Ayyanar, Muniappan; Ignacimuthu, Savarimuthu

    2006-01-01

    Background Antimicrobial activity of 18 ethnomedicinal plant extracts were evaluated against nine bacterial strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Ervinia sp, Proteus vulgaris) and one fungal strain (Candida albicans). The collected ethnomedicinal plants were used in folk medicine in the treatment of skin diseases, venereal diseases, respiratory problems and nervous disorders. Methods Plants were collected from Palni hills of Southern Western Ghats and the ethnobotanical data were gathered from traditional healers who inhabit the study area. The hexane and methanol extracts were obtained by cold percolation method and the antimicrobial activity was found using paper disc diffusion method. All microorganisms were obtained from Christian Medical College, Vellore, Tamil Nadu, India. Results The results indicated that out of 18 plants, 10 plants exhibited antimicrobial activity against one or more of the tested microorganisms at three different concentrations of 1.25, 2.5 and 5 mg/disc. Among the plants tested, Acalypha fruticosa, Peltophorum pterocarpum, Toddalia asiatica,Cassia auriculata, Punica granatum and Syzygium lineare were most active. The highest antifungal activity was exhibited by methanol extract of Peltophorum pterocarpum and Punica granatum against Candida albicans. Conclusion This study evaluated the antimicrobial activity of the some ethnomedicinal plants used in folkloric medicine. Compared to hexane extract, methanol extract showed significant activity against tested organisms. This study also showed that Toddalia asiatica, Syzygium lineare, Acalypha fruticosa and Peltophorum pterocarpum could be potential sources of new antimicrobial agents. PMID:17042964

  1. Bacillus subtilis as a tool for screening soil metagenomic libraries for antimicrobial activities.

    PubMed

    Biver, Sophie; Steels, Sébastien; Portetelle, Daniel; Vandenbol, Micheline

    2013-06-28

    Finding new antimicrobial activities by functional metagenomics has been shown to depend on the heterologous host used to express the foreign DNA. Therefore, efforts are devoted to developing new tools for constructing metagenomic libraries in shuttle vectors replicatable in phylogenetically distinct hosts. Here we evaluated the use of the Escherichia coli-Bacillus subtilis shuttle vector pHT01 to construct a forest-soil metagenomic library. This library was screened in both hosts for antimicrobial activities against four opportunistic bacteria: Proteus vulgaris, Bacillus cereus, Staphylococcus epidermidis, and Micrococcus luteus. A new antibacterial activity against B. cereus was found upon screening in B. subtilis. The new antimicrobial agent, sensitive to proteinase K, was not active when the corresponding DNA fragment was expressed in E. coli. Our results validate the use of pHT01 as a shuttle vector and B. subtilis as a host to isolate new activities by functional metagenomics.

  2. Lateral Antimicrobial Resistance Genetic Transfer is active in the open environment.

    PubMed

    Chamosa, Luciana S; Álvarez, Verónica E; Nardelli, Maximiliano; Quiroga, María Paula; Cassini, Marcelo H; Centrón, Daniela

    2017-03-31

    Historically, the environment has been viewed as a passive deposit of antimicrobial resistance mechanisms, where bacteria show biological cost for maintenance of these genes. Thus, in the absence of antimicrobial pressure, it is expected that they disappear from environmental bacterial communities. To test this scenario, we studied native IntI1 functionality of 11 class 1 integron-positive environmental strains of distant genera collected in cold and subtropical forests of Argentina. We found natural competence and successful site-specific insertion with no significant fitness cost of both aadB and bla VIM-2 antimicrobial resistance gene cassettes, in a model system without antibiotic pressure. A bidirectional flow of antimicrobial resistance gene cassettes between natural and nosocomial habitats is proposed, which implies an active role of the open environment as a reservoir, recipient and source of antimicrobial resistance mechanisms, outlining an environmental threat where novel concepts of rational use of antibiotics are extremely urgent and mandatory.

  3. Antimicrobial activity of Calotropis procera Ait. (Asclepiadaceae) and isolation of four flavonoid glycosides as the active constituents.

    PubMed

    Nenaah, Gomah

    2013-07-01

    Antimicrobial activity of solvent extracts and flavonoids of Calotropis procera growing wild in Saudi Arabia was evaluated using the agar well-diffusion method. A bioassay-guided fractionation of the crude flavonoid fraction (Cf3) of MeOH extract which showed the highest antimicrobial activity led to the isolation of four flavonoid glycosides as the bioactive constituents. Structure of compounds have been elucidated using physical and spectroscopic methods including (UV, IR, (1)H, (13)C-NMR, DEPT, 2D (1)H-(1)H COSY, HSQC, HMBC and NOESY). Compounds were found to be the 3-O-rutinosides of quercetin, kaempferol and isorhamnetin, besides the flavonoid 5-hydroxy-3,7-dimethoxyflavone-4'-O-β-glucopyranoside. Most of the isolated extracts showed antimicrobial activity against the test microorganisms, where the crude flavonoid fraction was the most active, diameter of inhibition zones ranged between 15.5 and 28.5 mm against the tested bacterial strains, while reached 30 mm against the fungal Candida albicans. The minimal inhibitory concentrations varied from 0.04 to 0.32 mg/ml against all of the tested microorganisms in case of the crude flavonoid fraction. Quercetin-3-O-rutinoside showed superior activity over the remainder flavonoids. The Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) were more susceptible than the Gram-negative (Pseudomonas aeruginosa and Salmonella enteritidis) and the yeast species were more susceptible than the filamentous fungi. The study recommend the use of such natural products as antimicrobial biorationals.

  4. Antimicrobial activity of ibuprofen: new perspectives on an "Old" non-antibiotic drug.

    PubMed

    Obad, Jelena; Šušković, Jagoda; Kos, Blaženka

    2015-04-25

    Pharmaceutical industry has been encountering antimicrobial activity of non-antibiotics during suitability tests carried out prior to routine pharmacopoeial microbiological purity analysis of finished dosage forms. These properties are usually ignored or perceived as a nuisance during pharmaceutical analysis. The aim of this study was: (i) to compare the available data to our method suitability test results carried out on products containing ibuprofen, i.e. to demonstrate that method suitability can be a valuable tool in identifying new antimicrobials, (ii) to demonstrate the antimicrobial activity of ibuprofen and ibuprofen lysine. Microbiological purity method suitability testing was carried out according to European Pharmacopoeia (EP), chapters 2.6.12. and 2.6.13. Antimicrobial activity of ibuprofen and ibuprofen lysine was demonstrated by a disk diffusion method, a modification of the European Committee for Antimicrobial Susceptibility Testing method (EUCAST), against test microorganisms recommended in the EP. It was confirmed that ibuprofen may be responsible for the broad spectrum of antimicrobial activity of the tested products, and that method suitability tests according to the EP can indeed be exploited by the scientific community in setting guidelines towards future research of new antimicrobials. In the disk diffusion assay, inhibition zones were obtained with more than 62.5 μg and 250 μg for Staphylococcus aureus, 125 μg and 250 μg for Bacillus subtilis, 31.3 μg and 125 μg for Candidaalbicans, 31.3 μg and 62.5 μg for Aspergillusbrasiliensis, of ibuprofen/disk, and ibuprofen lysine/disk, respectively. For Escherichiacoli, Pseudomonasaeruginosa and Salmonellatyphimurium inhibition zones were not obtained. Antimicrobial activity of ibuprofen is considered merely as a side effect, and it is not mentioned in the patient information leaflets of ibuprofen drugs. As such, for the patient, it could represent an advantage, but, it could also introduce

  5. Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi.

    PubMed

    Amin, M; Kapadnis, B P

    2005-08-01

    To study antimicrobial activity of shallot in comparison with that of garlic and onion against 23 strains of fungi and bacteria, water extracts of garlic, shallot and onion bulbs were prepared. Each extract was studied in different forms for their antimicrobial activity viz., fresh extract, dry extract and autoclaved extract. Minimal inhibitory concentration and minimal lethal concentrations of these extracts were determined against all organisms by broth dilution susceptibility test. Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion and shallot. However, dried and autoclaved extracts of shallot showed more activity than similar extracts of onion and garlic. Fungi were more sensitive to shallot extract than bacteria. Amongst bacteria, B. cereus was most sensitive (MIC=5 mg ml(-1)). The lowest minimum bactericidal concentration of shallot extract amongst bacteria tested was 5 mg ml(-1) for B. cereus. Amongst fungi, Aureobasidium pullulans and Microsporum gypseum were most sensitive (MIC= 0.15 mg ml(-1)). The lowest minimum lethal concentration was 2.5 mg ml(-1) for Microsporum gypseum and Trichophyton mentagrophytes. It was therefore, expected that the antimicrobial principle of shallot was different than the antimicrobial compounds of onion and garlic. In addition, the antimicrobial component of the shallot extract was stable at 121 degrees C.

  6. The diversity and antimicrobial activity of Preussia sp. endophytes isolated from Australian dry rainforests.

    PubMed

    Mapperson, Rachel R; Kotiw, Michael; Davis, Rohan A; Dearnaley, John D W

    2014-01-01

    Limited knowledge currently exists regarding species diversity and antimicrobial activity of endophytic isolates of Preussia within Australia. This report describes endophytic Preussia species that were identified through molecular analysis of the internal transcribed spacer region. Screening for antimicrobial secondary metabolites was determined by testing crude ethyl acetate (EtOAc) extracts derived from fungal mycelia against a panel of ATCC type strains which included Bacillus cereus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Serratia marcescens, methicillin-resistant Staphylococcus aureus (MRSA) and the opportunist yeast pathogen Candida albicans. Subsequently, high-performance liquid chromatography generated fractions of bioactive EtOAc extracts which were subject to confirmatory testing using the Clinical and Laboratory Standards Institute reference microdilution antimicrobial activity assay. A total of 18 Preussia were isolated from nine host plants with 6/18 having a <97 % sequence similarity to other known species in Genbank, suggesting that they are new species. In preliminary screening, 13/18 Preussia isolates revealed antimicrobial activity against at least one of the microbes tested, whilst 6/18 isolates, including 4/6 putative new species showed specific antimicrobial activity against MRSA and C. albicans. These results highlight the antimicrobial potential of Australian Preussia spp. and also the importance of Australian dry rainforests as an untapped repository of potentially significant bioactive compounds.

  7. Structure-Activity Relationship of a U-Type Antimicrobial Microemulsion System

    PubMed Central

    Zhang, Hui; Taxipalati, Maierhaba; Yu, Liyi; Que, Fei; Feng, Fengqin

    2013-01-01

    The structure-activity relationship of a U-type antimicrobial microemulsion system containing glycerol monolaurate and ethanol at a 1∶1 mass ratio as oil phase and Tween 20 as surfactant were investigated along a water dilution line at a ratio of 80∶20 mass% surfactant/oil phase, based on a pseudo-ternary phase diagram. The differential scanning calorimetry results showed that in the region of up to 33% water, all water molecules are confined to the hydrophilic core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, and transforms into bicontinuous in the region of 33–39% water, and finally the microemulsion become o/w in the region of above 39% water. The microstructure characterization was confirmed by the dynamic light scattering measurements and freeze-fracture transmission electron microscope observation. The antimicrobial activity assay using kinetics of killing analysis demonstrated that the microemulsions in w/o regions exhibited relatively high antimicrobial activity against Escherichia coli and Staphylococcus aureus due to the antimicrobial oil phase as the continuous phase, while the antimicrobial activity started to decrease when the microemulsions entered the bicontinuous region, and decreased rapidly as the water content increased in the o/w region, as a result of the dilution of antimicrobial oil droplets in the aqueous continuous phase. PMID:24204605

  8. Structure-activity relationship of a u-type antimicrobial microemulsion system.

    PubMed

    Zhang, Hui; Taxipalati, Maierhaba; Yu, Liyi; Que, Fei; Feng, Fengqin

    2013-01-01

    The structure-activity relationship of a U-type antimicrobial microemulsion system containing glycerol monolaurate and ethanol at a 1∶1 mass ratio as oil phase and Tween 20 as surfactant were investigated along a water dilution line at a ratio of 80∶20 mass% surfactant/oil phase, based on a pseudo-ternary phase diagram. The differential scanning calorimetry results showed that in the region of up to 33% water, all water molecules are confined to the hydrophilic core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, and transforms into bicontinuous in the region of 33-39% water, and finally the microemulsion become o/w in the region of above 39% water. The microstructure characterization was confirmed by the dynamic light scattering measurements and freeze-fracture transmission electron microscope observation. The antimicrobial activity assay using kinetics of killing analysis demonstrated that the microemulsions in w/o regions exhibited relatively high antimicrobial activity against Escherichia coli and Staphylococcus aureus due to the antimicrobial oil phase as the continuous phase, while the antimicrobial activity started to decrease when the microemulsions entered the bicontinuous region, and decreased rapidly as the water content increased in the o/w region, as a result of the dilution of antimicrobial oil droplets in the aqueous continuous phase.

  9. Antimicrobial Activity of Marine Bacterial Symbionts Retrieved from Shallow Water Hydrothermal Vents.

    PubMed

    Eythorsdottir, Arnheidur; Omarsdottir, Sesselja; Einarsson, Hjorleifur

    2016-06-01

    Marine sponges and other sessile macro-organisms were collected at a shallow water hydrothermal site in Eyjafjörður, Iceland. Bacteria were isolated from the organisms using selective media for actinomycetes, and the isolates were screened for antimicrobial activity. A total of 111 isolates revealed antimicrobial activity displaying different antimicrobial patterns which indicates production of various compounds. Known test strains were grown in the presence of ethyl acetate extracts from one selected isolate, and a clear growth inhibition of Staphylococcus aureus was observed down to 0.1 % extract concentration in the medium. Identification of isolates shows different species of Actinobacteria with Streptomyces sp. playing the largest role, but also members of Bacilli, Alphaproteobacteria and Gammaproteobacteria. Sponges have an excellent record regarding production of bioactive compounds, often involving microbial symbionts. At the hydrothermal vents, however, the majority of active isolates originated from other invertebrates such as sea anemones or algae. The results indicate that antimicrobial assays involving isolates in full growth can detect activity not visible by other methods. The macro-organisms inhabiting the Eyjafjörður hydrothermal vent area host diverse microbial species in the phylum Actinobacteria with antimicrobial activity, and the compounds responsible for the activity will be subject to further research.

  10. A novel approach to the antimicrobial activity of maggot debridement therapy

    PubMed Central

    Andersen, Anders S.; Sandvang, Dorthe; Schnorr, Kirk M.; Kruse, Thomas; Neve, Søren; Joergensen, Bo; Karlsmark, Tonny; Krogfelt, Karen A.

    2010-01-01

    Objectives Commercially produced sterile green bottle fly Lucilia sericata maggots are successfully employed by practitioners worldwide to clean a multitude of chronic necrotic wounds and reduce wound bacterial burdens during maggot debridement therapy (MDT). Secretions from the maggots exhibit antimicrobial activity along with other activities beneficial for wound healing. With the rise of multidrug-resistant bacteria, new approaches to identifying the active compounds responsible for the antimicrobial activity within this treatment are imperative. Therefore, the aim of this study was to use a novel approach to investigate the output of secreted proteins from the maggots under conditions mimicking clinical treatments. Methods cDNA libraries constructed from microdissected salivary glands and whole maggots, respectively, were treated with transposon-assisted signal trapping (TAST), a technique selecting for the identification of secreted proteins. Several putative secreted components of insect immunity were identified, including a defensin named lucifensin, which was produced recombinantly as a Trx-fusion protein in Escherichia coli, purified using immobilized metal affinity chromatography and reverse-phase HPLC, and tested in vitro against Gram-positive and Gram-negative bacterial strains. Results Lucifensin was active against Staphylococcus carnosus, Streptococcus pyogenes and Streptococcus pneumoniae (MIC 2 mg/L), as well as Staphylococcus aureus (MIC 16 mg/L). The peptide did not show antimicrobial activity towards Gram-negative bacteria. The MIC of lucifensin for the methicillin-resistant S. aureus and glycopeptide-intermediate S. aureus isolates tested ranged from 8 to >128 mg/L. Conclusions The TAST results did not reveal any highly secreted compounds with putative antimicrobial activity, implying an alternative antimicrobial activity of MDT. Lucifensin showed antimicrobial activities comparable to other defensins and could have potential as a future drug

  11. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides.

    PubMed

    Mitchell, Daniel E; Gibson, Matthew I

    2015-10-12

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs.

  12. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides

    PubMed Central

    2015-01-01

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs. PMID:26407233

  13. Antimicrobial and Antimycobacterial Activity of Cyclostellettamine Alkaloids from Sponge Pachychalina sp.

    PubMed Central

    de Oliveira, Jaine H. H. L.; Seleghim, Mirna H. R.; Timm, Christoph; Grube, Achim; Köck, Matthias; Nascimento, Gislene G.F.; Martins, Ana Claudia T.; Silva, Elissa G. O.; de Souza, Ana Olívia; Minarini, Paulo R. R.; Galetti, Fabio C. S.; Silva, Célio L.; Hajdu, Eduardo; Berlinck, Roberto G. S.

    2006-01-01

    Cyclostellettamines A – F (1 – 6) isolated from the sponge Pachychalina sp. and cyclostellettamines G - I, K and L (7 – 11) obtained by synthesis were evaluated in bioassays of antimicrobial activity against susceptible and antibiotic-resistant Staphylococcus aureus, Pseudomonas aeruginosa and antibiotic-susceptible Escherichia coli and Candida albicans, as well as in antimycobacterial activity against Mycobacterium tuberculosis H37Rv bioassays. The results obtained indicated that cyclostellettamines display different antimicrobial activity depending on the alkyl-chain size, suggesting that, if a mechanism-of action is implied, it is dependent on the distance between the two pyridinium moieties of cyclostellettamines.

  14. Chemical composition, antimicrobial and antioxidant activities of essential oils from organically cultivated fennel cultivars.

    PubMed

    Shahat, Abdelaaty A; Ibrahim, Abeer Y; Hendawy, Saber F; Omer, Elsayed A; Hammouda, Faiza M; Abdel-Rahman, Fawzia H; Saleh, Mahmoud A

    2011-02-01

    Essential oils of the fruits of three organically grown cultivars of Egyptian fennel (Foeniculum vulgare var. azoricum, Foeniculum vulgare var. dulce and Foeniculum vulgare var. vulgare) were examined for their chemical constituents, antimicrobial and antioxidant activities. Gas chromatography/mass spectrometry analysis of the essential oils revealed the presence of 18 major monoterpenoids in all three cultivars but their percentage in each oil were greatly different. trans-Anethole, estragole, fenchone and limonene were highly abundant in all of the examined oils. Antioxidant activities of the essential oils were evaluated using the DPPH radical scavenging, lipid peroxidation and metal chelating assays. Essential oils from the azoricum and dulce cultivars were more effective antioxidants than that from the vulgare cultivar. Antimicrobial activities of each oil were measured against two species of fungi, two species of Gram negative and two species of Gram positive bacteria. All three cultivars showed similar antimicrobial activity.

  15. Antimicrobial activity and chemical composition of the essential oil of Nepeta crispa Willd. from Iran.

    PubMed

    Sonboli, Ali; Salehi, Peyman; Yousefzadi, Morteza

    2004-01-01

    The composition and antimicrobial activity of the essential oil of Nepeta crispa Willd., an endemic species from Iran, was studied. The oil was obtained from the aerial parts of the plant and analyzed by GC and GC/MS. Twenty-three compounds, accounting for 99.8% of the total oil, were identified. The main constituents were 1,8-cineol (47.9%) and 4aalpha,7alpha,7abetanepetalactone (20.3%). The antimicrobial activity of essential oil of N. crispa was tested against seven gram-negative or gram-positive bacteria and four fungi. The results of the bioassays showed the interesting antimicrobial activity, in which the gram-positive bacteria, Bacillus subtilis and Staphylococcus aureus, were the most sensitive to the oil. Also, the oil exhibited a remarkable antifungal activity against all the tested fungi.

  16. Antimicrobial Activity of Seven Essential Oils From Iranian Aromatic Plants Against Common Causes of Oral Infections

    PubMed Central

    Zomorodian, Kamiar; Ghadiri, Pooria; Saharkhiz, Mohammad Jamal; Moein, Mohammad Reza; Mehriar, Peiman; Bahrani, Farideh; Golzar, Tahereh; Pakshir, Keyvan; Fani, Mohammad Mehdi

    2015-01-01

    Background: Over the past two decades, there has been a growing trend in using oral hygienic products originating from natural resources such as essential oils (EOs) and plant extracts. Seven aromatic plants used in this study are among popular traditional Iranian medicinal plants with potential application in modern medicine as anti-oral infectious diseases. Objectives: This study was conducted to determine the chemical composition and antimicrobial activities of essential oils from seven medicinal plants against pathogens causing oral infections. Materials and Methods: The chemical compositions of EOs distilled from seven plants were analyzed by gas chromatography/mass spectrometry (GC/MS). These plants included Satureja khuzestanica, S. bachtiarica, Ocimum sanctum, Artemisia sieberi, Zataria multiflora, Carum copticum and Oliveria decumbens. The antimicrobial activity of the essential oils was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) methods. Results: The tested EOs inhibited the growth of examined oral pathogens at concentrations of 0.015-16 µL/mL. Among the examined oral pathogens, Enterococcus faecalis had the highest Minimum Inhibitory Concentrations (MICs) and Minimum Microbicidal Concentrations (MMCs). Of the examined EOs, S. khuzestanica, Z. multiflora and S. bachtiarica, showed the highest antimicrobial activities, respectively, while Artemisia sieberi exhibited the lowest antimicrobial activity. Conclusions: The excellent antimicrobial activities of the tested EOs might be due to their major phenolic or alcoholic monoterpenes with known antimicrobial activities. Hence, these EOs can be possibly used as an antimicrobial agent in treatment and control of oral pathogens. PMID:25793100

  17. Antimicrobial activity in the cuticle of the American lobster, Homarus americanus.

    PubMed

    Mars Brisbin, Margaret; McElroy, Anne E; Pales Espinosa, Emmanuelle; Allam, Bassem

    2015-06-01

    American lobster, Homarus americanus, continues to be an ecologically and socioeconomically important species despite a severe decline in catches from Southern New England and Long Island Sound (USA) and a high prevalence of epizootic shell disease in these populations. A better understanding of lobster immune defenses remains necessary. Cuticle material collected from Long Island Sound lobsters was found to be active against a broad spectrum of bacteria, including Gram-negative and -positive species. The antimicrobial activity was characterized by boiling, muffling, and size fractioning. Boiling did not significantly reduce activity, while muffling did have a significant effect, suggesting that the active component is organic and heat stable. Size fractioning with 3 and 10 kDa filters did not significantly affect activity. Fast protein liquid chromatography fractions were also tested for antimicrobial activity, and fractions exhibiting protein peaks remained active. MALDI mass spectrometry revealed peptide peaks at 1.6, 2.8, 4.6, and 5.6 kDa. The data presented suggest that one or several antimicrobial peptides contribute to antimicrobial activity present in the American lobster cuticle.

  18. Antimicrobial activity of coupled hydroxyanthracenones isolated from plants of the genus Karwinskia.

    PubMed

    Salazar, Ricardo; Rivas, Verónica; González, Gloria; Waksman, Noemí

    2006-07-01

    The in vitro activity of some isolated hydroxyanthracenones belonging to the genus Karwinskia against four bacteria, six filamentous fungi and four yeast are reported. These hydroxyanthracenones were found to possess antimicrobial activity, particularly against Streptococcus pyogenes, Candida albicans, C. boidinii, C. glabrata and Cryptococcus neoformans; minimal inhibitory concentrations range between 16 and 2 microg/ml.

  19. Antimicrobial and antioxidative activity of extracts and essential oils of Myrtus communis L.

    PubMed

    Aleksic, Verica; Knezevic, Petar

    2014-04-01

    Since synthetic antimicrobial agents and food additives can cause a number of adverse effects, there is a growing interest from consumers in ingredients from natural sources. Medicinal plants, such as Myrtus communis L. are a source of new compounds which can be used in both the food industry and for medical purposes, primarily as antimicrobial agents. In this review, the characteristics of myrtle essential oils and extracts are summarized, with particular attention to their chemical composition, biological activities and potential applications.

  20. Isolation and Antimicrobial Activity of Flavonoid Compounds from Mahagony Seeds (Swietenia macrophylla, King)

    NASA Astrophysics Data System (ADS)

    Mursiti, S.; Supartono

    2017-02-01

    Flavonoid is one of the secondary metabolites compounds in mahogany seeds. Mahogany seeds can be used as an antimicrobial. This study aims to determine the antimicrobial activity of flavonoid compounds from mahogany seeds against Escherichia coli (E.coli) and Bacillus cereus (B.cereus). Isolation of flavonoid compounds done step by step. First, the maceration using n-hexane, then with methanol. The methanol extract was dissolved in ethyl acetate and aquadest, then separated. Ethyl acetate extract evaporated Flavonoid compounds were. The testing of antimicrobial activity of flavonoid compounds using the absorption method. The results showed that the antimicrobial activity of flavonoid compounds from mahogany seeds shows the inhibitory activity and provide clear zone against bacteria E.coli with value Inhibitory Regional Diameter 18.50 mm respectively, and 14.50 mm to the bacteria. Based on the results of the study, it can be concluded that flavonoid compounds from mahogany seeds have antimicrobial activity against E.coli and B.cereus.

  1. Pyrazole derived ultra-short antimicrobial peptidomimetics with potent anti-biofilm activity.

    PubMed

    Ahn, Mija; Gunasekaran, Pethaiah; Rajasekaran, Ganesan; Kim, Eun Young; Lee, Soo-Jae; Bang, Geul; Cho, Kun; Hyun, Jae-Kyung; Lee, Hyun-Ju; Jeon, Young Ho; Kim, Nam-Hyung; Ryu, Eun Kyoung; Shin, Song Yub; Bang, Jeong Kyu

    2017-01-05

    In this study, we report on the first chemical synthesis of ultra-short pyrazole-arginine based antimicrobial peptidomimetics derived from the newly synthesized N-alkyl/aryl pyrazole amino acids. Through the systematic tuning of hydrophobicity, charge, and peptide length, we identified the shortest peptide Py11 with the most potent antimicrobial activity. Py11 displayed greater antimicrobial activity against antibiotic-resistant bacteria, including MRSA, MDRPA, and VREF, which was approximately 2-4 times higher than that of melittin. Besides its higher selectivity (therapeutic index) toward bacterial cells than LL-37, Py11 showed highly increased proteolytic stability against trypsin digestion and maintained its antimicrobial activity in the presence of physiological salts. Interestingly, Py11 exhibited higher anti-biofilm activity against MDRPA compared to LL-37. The results from fluorescence spectroscopy and transmission electron microscopy (TEM) suggested that Py11 kills bacterial cells possibly by integrity disruption damaging the cell membrane, leading to the cytosol leakage and eventual cell lysis. Furthermore, Py11 displayed significant anti-inflammatory (endotoxin-neutralizing) activity by inhibiting LPS-induced production of nitric oxide (NO) and TNF-α. Collectively, our results suggest that Py11 may serve as a model compound for the design of antimicrobial and antisepsis agents.

  2. Antimicrobial activity of commercial Olea europaea (olive) leaf extract.

    PubMed

    Sudjana, Aurelia N; D'Orazio, Carla; Ryan, Vanessa; Rasool, Nooshin; Ng, Justin; Islam, Nabilah; Riley, Thomas V; Hammer, Katherine A

    2009-05-01

    The aim of this research was to investigate the activity of a commercial extract derived from the leaves of Olea europaea (olive) against a wide range of microorganisms (n=122). Using agar dilution and broth microdilution techniques, olive leaf extract was found to be most active against Campylobacter jejuni, Helicobacter pylori and Staphylococcus aureus [including meticillin-resistant S. aureus (MRSA)], with minimum inhibitory concentrations (MICs) as low as 0.31-0.78% (v/v). In contrast, the extract showed little activity against all other test organisms (n=79), with MICs for most ranging from 6.25% to 50% (v/v). In conclusion, olive leaf extract was not broad-spectrum in action, showing appreciable activity only against H. pylori, C. jejuni, S. aureus and MRSA. Given this specific activity, olive leaf extract may have a role in regulating the composition of the gastric flora by selectively reducing levels of H. pylori and C. jejuni.

  3. Diverse antimicrobial activity from Enterococcus faecium NRRL B-30746 bacteriocin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotic therapy to resolve bacterial disease has been compromised by the increased prevalence and magnitude of bacterial antibiotic resistance. In our efforts to identify new effective antimicrobials, bacteria isolated from poultry intestinal contents were screened for bacteriocin synthesis again...

  4. Human β-defensin 4 with non-native disulfide bridges exhibit antimicrobial activity.

    PubMed

    Sharma, Himanshu; Nagaraj, Ramakrishnan

    2015-01-01

    Human defensins play multiple roles in innate immunity including direct antimicrobial killing and immunomodulatory activity. They have three disulfide bridges which contribute to the stability of three anti-parallel β-strands. The exact role of disulfide bridges and canonical β-structure in the antimicrobial action is not yet fully understood. In this study, we have explored the antimicrobial activity of human β-defensin 4 (HBD4) analogs that differ in the number and connectivity of disulfide bridges. The cysteine framework was similar to the disulfide bridges present in μ-conotoxins, an unrelated class of peptide toxins. All the analogs possessed enhanced antimicrobial potency as compared to native HBD4. Among the analogs, the single disulfide bridged peptide showed maximum potency. However, there were no marked differences in the secondary structure of the analogs. Subtle variations were observed in the localization and membrane interaction of the analogs with bacteria and Candida albicans, suggesting a role for disulfide bridges in modulating their antimicrobial action. All analogs accumulated in the cytosol where they can bind to anionic molecules such as nucleic acids which would affect several cellular processes leading to cell death. Our study strongly suggests that native disulfide bridges or the canonical β-strands in defensins have not evolved for maximal activity but they play important roles in determining their antimicrobial potency.

  5. Antimicrobial activity of transition metal acid MoO(3) prevents microbial growth on material surfaces.

    PubMed

    Zollfrank, Cordt; Gutbrod, Kai; Wechsler, Peter; Guggenbichler, Josef Peter

    2012-01-01

    Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H(2)MoO(4)), which is based on molybdenum trioxide (MoO(3)). The modification of various materials (e.g. polymers, metals) with MoO(3) particles or sol-gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments.

  6. Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles.

    PubMed

    Sim, Kyoung Mi; Kim, Kyung Hwan; Hwang, Gi Byoung; Seo, SungChul; Bae, Gwi-Nam; Jung, Jae Hee

    2014-09-15

    Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles.

  7. Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.

    PubMed

    Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel

    2013-07-01

    Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork.

  8. Silver Nanoparticle Impregnated Bio-Based Activated Carbon with Enhanced Antimicrobial Activity

    NASA Astrophysics Data System (ADS)

    Selvakumar, R.; Suriyaraj, S. P.; Jayavignesh, V.; Swaminathan, K.

    2013-08-01

    The present study involves the production of silver nanoparticles using a novel yeast strain Saccharomyces cerevisiae BU-MBT CY-1 isolated from coconut cell sap. The biological reduction of silver nitrate by the isolate was deducted at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400°C for 1 h and its properties were analyzed using Fourier transform infra-red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscopy. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. The carbonized silver nanoparticles containing yeast cells (CSY) were made into bioactive emulsion and tested for its efficacy against various pathogenic Gram positive and Gram negative bacteria. The antimicrobial activity studies indicated that CSY bioactive nanoemulsion was effective against Gram negative organisms than Gram positive organism.

  9. Self-assembly of cationic multidomain peptide hydrogels: supramolecular nanostructure and rheological properties dictate antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Jiang, Linhai; Xu, Dawei; Sellati, Timothy J.; Dong, He

    2015-11-01

    Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would also protect the hydrogel itself from being adversely affected by microbial attachment to its surface. We have previously demonstrated the broad-spectrum antimicrobial activity of supramolecular assemblies of cationic multi-domain peptides (MDPs) in solution. Here, we extend the 1-D soluble supramolecular assembly to 3-D hydrogels to investigate the effect of the supramolecular nanostructure and its rheological properties on the antimicrobial activity of self-assembled hydrogels. Among designed MDPs, the bactericidal activity of peptide hydrogels was found to follow an opposite trend to that in solution. Improved antimicrobial activity of self-assembled peptide hydrogels is dictated by the combined effect of supramolecular surface chemistry and storage modulus of the bulk materials, rather than the ability of individual peptides/peptide assemblies to penetrate bacterial cell membrane as observed in solution. The structure-property-activity relationship developed through this study will provide important guidelines for designing biocompatible peptide hydrogels with built-in antimicrobial activity for various biomedical applications.Hydrogels are an important class of biomaterials that have been widely utilized for a variety of biomedical/medical applications. The biological performance of hydrogels, particularly those used as wound dressing could be greatly advanced if imbued with inherent antimicrobial activity capable of staving off colonization of the wound site by opportunistic bacterial pathogens. Possessing such antimicrobial properties would

  10. Antimicrobial activity and phytochemical analyses of Polygonum aviculare L. (Polygonaceae), naturally growing in Egypt

    PubMed Central

    Salama, Hediat M.H.; Marraiki, Najat

    2009-01-01

    Polygonum aviculare (Polygonaceae) is an herb commonly distributed in Mediterranean coastal regions in Egypt and used in folkloric medicine. Organic and aqueous solvent extracts and fractions of P. aviculare were investigated for antimicrobial activities on several microorganisms including bacteria and fungi. Phytochemical constituents of air-dried powered plant parts were extracted using aqueous and organic solvents (acetone, ethanol, chloroform and water). Antimicrobial activity of the concentrated extracts was evaluated by determination of the diameter of inhibition zone against both Gram-negative and Gram-positive bacteria and fungi using paper disc diffusion method. Results of the phytochemical studies revealed the presence of tannins, saponins, flavonoids, alkaloids and sesquiterpenes and the extracts were active against both Gram-negative and Gram-positive bacteria. Chloroform extract gave very good and excellent antimicrobial activity against all tested bacteria and good activity against all tested fungi except Candida albicans. Structural spectroscopic analysis that was carried out on the active substances in the chloroform extract led to the identification of panicudine (6-hydroxy-11-deoxy-13 dehydrohetisane). Evaluation of the antimicrobial activity of panicudine indicated significant activity against all tested Gram-negative and Gram-positive organisms. Panicudine displayed considerable activity against the tested fungi with the exception of C. albicans. Antimicrobial activity of the extracts was unaffected after exposure to different heat treatments, but was reduced at alkaline pH. Studies of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panicudine on the tested organisms showed that the lowest MIC and the MBC were demonstrated against Salmonella paratyphi, Bacillus subtilis and Salmonella typhi and the highest MIC and MBC were against Staphylococcus aureus. PMID:23961059

  11. Model Membrane and Cell Studies of Antimicrobial Activity of Melittin Analogues.

    PubMed

    Jamasbi, Elaheh; Mularski, Anna; Separovic, Frances

    2016-01-01

    Melittin is a 26 residue peptide and the major component of bee (Apis mellifera) venom. Although melittin has both anticancer and antimicrobial properties, utilization has been limited due to its high lytic activity against eukaryotic cells. The mechanism of this lytic activity remains unclear but several mechanisms have been proposed, including pore formation or a detergent like mechanism, which result in lysis of cell membranes. Several analogues of melittin have been synthesized to further understand the role of specific residues in its antimicrobial and lytic activity. Melittin analogues that have a proline residue substituted for an alanine, lysine or cysteine have been studied with both model membrane systems and living cells. These studies have revealed that the proline residue plays a critical role in antimicrobial activity and cytotoxicity. Analogues lacking the proline residue and dimers of these analogues displayed decreased cytotoxicity and minimum inhibition concentrations. Several mutant studies have shown that, when key substitutions are made, the resultant peptides have more activity in terms of pore formation than the native melittin. Designing analogues that retain antimicrobial and anticancer activity while minimizing haemolytic activity will be a promising way to utilize melittin as a potential therapeutic agent.

  12. Anticancer and enhanced antimicrobial activity of biosynthesizd silver nanoparticles against clinical pathogens

    NASA Astrophysics Data System (ADS)

    Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Vanaja, Mahendran; Annadurai, Gurusamy

    2016-07-01

    The present investigation shows the biosynthesis of eco-friendly silver nanoparticles using culture supernatant of Enterococcus sp. and study the effect of enhanced antimicrobial activity, anticancer activity against pathogenic bacteria, fungi and cancer cell lines. Silver nanoparticles was synthesized by adding 1 mM silver nitrate into the 100 ml of 24 h freshly prepared culture supernatant of Enterococcus sp. and were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Selected Area Diffraction X-Ray (SAED), Energy Dispersive X Ray (EDX) and Fourier Transform Infra red Spectroscopy (FT-IR). The synthesized silver nanoparticles were impregnated with commercial antibiotics for evaluation of enhanced antimicrobial activity. Further these synthesized silver nanoparticles were assessed for its anticancer activity against cancer cell lines. In this study crystalline structured nanoparticles with spherical in the size ranges from 10 to 80 nm and it shows excellent enhanced antimicrobial activity than the commercial antibiotics. The in vitro assay of silver nanoparticles on anticancer have great potential to inhibit the cell viability. Amide linkages and carboxylate groups of proteins from Enterococcus sp. may bind with silver ions and convert into nanoparticles. The activities of commercial antibiotics were enhanced by coating silver nanoparticles shows significant improved antimicrobial activity. Silver nanoparticles have the great potential to inhibit the cell viability of liver cancer cells lines (HepG2) and lung cancer cell lines (A549).

  13. Antimicrobial Activity and Phytochemical Analysis of Organic Extracts from Cleome spinosa Jaqc.

    PubMed Central

    da Silva, Ana P. Sant'Anna; Nascimento da Silva, Luís C.; Martins da Fonseca, Caíque S.; de Araújo, Janete M.; Correia, Maria T. dos Santos; Cavalcanti, Marilene da Silva; Lima, Vera L. de Menezes

    2016-01-01

    Due to the use of Cleome spinosa Jacq. (Cleomaceae) in traditional medicine against inflammatory and infectious processes, this study evaluated the in vitro antimicrobial potential and phytochemical composition of extracts from its roots and leaves. From leaves (L) and roots (R) of C. spinosa different extracts were obtained (cyclohexane: ChL and ChR; chloroform: CL and CR; ethyl acetate: EAL and EAR, methanol: ML and MR). The antimicrobial activity was evaluated by the broth microdilution method to obtain the minimum inhibitory (MIC) and microbicidal (MMC) concentrations against 17 species, including bacteria and yeasts. Additionally, antimicrobial and combinatory effects with oxacillin were assessed against eight clinical isolates of Staphylococcus aureus. All C. spinosa extracts showed a broad spectrum of antimicrobial activity, as they have inhibited all tested bacteria and yeasts. This activity seems to be related to the phytochemicals (flavonoid, terpenoids and saponins) detected into the extracts of C. spinosa. ChL and CL extracts were the most actives, with MIC less than 1 mg/mL against S. aureus, Bacillus subtilis, and Micrococcus luteus. It is important to note that these concentrations are much lower than their 50% hemolysis concentration (HC50) values. Strong correlations were found between the average MIC against S. aureus and their phenolic (r = −0.89) and flavonoid content (r = −0.87), reinforcing the possible role of these metabolite classes on the antimicrobial activity of C. spinosa derived extracts. Moreover, CL and CR showed the best inhibitory activity against S. aureus clinical isolates, they also showed synergistic action with oxacillin against all these strains (at least at one combined proportion). These results encourage the identification of active substances which could be used as lead(s) molecules in the development of new antimicrobial drugs. PMID:27446005

  14. Antimicrobial activity of essential oil from Schinus molle Linn.

    PubMed

    Gundidza, M

    1993-11-01

    The essential oil from the fresh leaves of Schinus molle isolated by hydrodistillation was tested for antibacterial activity using the hole plate diffusion method and for antifungal activity using the mycelium or single cell growth inhibition method. Results obtained showed that the volatile oil exhibited significant activity against the following bacterial species: Klebsiella pneumoniae, Alcaligenes faecalis, Pseudomonas aeruginosa, Leuconostoc cremoris, Enterobacter aerogenes, Proteus vulgaris, Clostridium sporogenes, Acinetobacter calcoacetica, Escherichia coli, Beneckea natriegens, Citrobacter freundii, Serratia marcescens, Bacillus subtilis and Brochothrix thermosphacata. The fungal species Aspergillus ochraceus, Aspergillus parasiticus, Fusarium culmorum and Alternaria alternata exhibited significant sensitivity to the volatile oil.

  15. Antimicrobial Activity of Serbian Propolis Evaluated by Means of MIC, HPTLC, Bioautography and Chemometrics

    PubMed Central

    Trifković, Jelena; Berić, Tanja; Vovk, Irena; Milojković-Opsenica, Dušanka; Stanković, Slaviša

    2016-01-01

    New information has come to light about the biological activity of propolis and the quality of natural products which requires a rapid and reliable assessment method such as High Performance Thin-Layer Chromatography (HPTLC) fingerprinting. This study investigates chromatographic and chemometric approaches for determining the antimicrobial activity of propolis of Serbian origin against various bacterial species. A linear multivariate calibration technique, using Partial Least Squares, was used to extract the relevant information from the chromatographic fingerprints, i.e. to indicate peaks which represent phenolic compounds that are potentially responsible for the antimicrobial capacity of the samples. In addition, direct bioautography was performed to localize the antibacterial activity on chromatograms. The biological activity of the propolis samples against various bacterial species was determined by a minimum inhibitory concentration assay, confirming their affiliation with the European poplar type of propolis and revealing the existence of two types (blue and orange) according to botanical origin. The strongest antibacterial activity was exhibited by sample 26 against Staphylococcus aureus, with a MIC value of 0.5 mg/mL, and Listeria monocytogenes, with a MIC as low as 0.1 mg/mL, which was also the lowest effective concentration observed in our study. Generally, the orange type of propolis shows higher antimicrobial activity compared to the blue type. PLS modelling was performed on the HPTLC data set and the resulting models might qualitatively indicate compounds that play an important role in the activity exhibited by the propolis samples. The most relevant peaks influencing the antimicrobial activity of propolis against all bacterial strains were phenolic compounds at RF values of 0.37, 0.40, 0.45, 0.51, 0.60 and 0.70. The knowledge gained through this study could be important for attributing the antimicrobial activity of propolis to specific chemical

  16. An integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin.

    PubMed

    Galdiero, Emilia; Siciliano, Antonietta; Maselli, Valeria; Gesuele, Renato; Guida, Marco; Fulgione, Domenico; Galdiero, Stefania; Lombardi, Lucia; Falanga, Annarita

    This study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (QDs) alone and coated with indolicidin. To meet this objective, we tested the level of antimicrobial activity on Gram-positive and Gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. The antibacterial activity was analyzed against Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 1025), Escherichia coli (ATCC 11229), and Klebsiella pneumoniae (ATCC 10031), and the results showed an improved germicidal action of QDs-Ind. Toxicity studies on Daphnia magna indicated a decrease in toxicity for QDs-Ind compared to QDs alone, lack of bioluminescence inhibition on Vibrio fisheri, and no mutations in Salmonella typhimurium TA 100. The comet assay and oxidative stress experiments performed on D. magna showed a genotoxic and an oxidative damage with a dose-response trend. Indolicidin retained its activity when bound to QDs. We observed an enhanced activity for QDs-Ind. The presence of indolicidin on the surface of QDs was able to decrease its QDs toxicity.

  17. An integrated study on antimicrobial activity and ecotoxicity of quantum dots and quantum dots coated with the antimicrobial peptide indolicidin

    PubMed Central

    Galdiero, Emilia; Siciliano, Antonietta; Maselli, Valeria; Gesuele, Renato; Guida, Marco; Fulgione, Domenico; Galdiero, Stefania; Lombardi, Lucia; Falanga, Annarita

    2016-01-01

    This study attempts to evaluate the antimicrobial activity and the ecotoxicity of quantum dots (QDs) alone and coated with indolicidin. To meet this objective, we tested the level of antimicrobial activity on Gram-positive and Gram-negative bacteria, and we designed an ecotoxicological battery of test systems and indicators able to detect different effects using a variety of end points. The antibacterial activity was analyzed against Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 1025), Escherichia coli (ATCC 11229), and Klebsiella pneumoniae (ATCC 10031), and the results showed an improved germicidal action of QDs-Ind. Toxicity studies on Daphnia magna indicated a decrease in toxicity for QDs-Ind compared to QDs alone, lack of bioluminescence inhibition on Vibrio fisheri, and no mutations in Salmonella typhimurium TA 100. The comet assay and oxidative stress experiments performed on D. magna showed a genotoxic and an oxidative damage with a dose–response trend. Indolicidin retained its activity when bound to QDs. We observed an enhanced activity for QDs-Ind. The presence of indolicidin on the surface of QDs was able to decrease its QDs toxicity. PMID:27616887

  18. [Antimicrobial Activity of Fungi Strains of Trichoderma from Middle Siberia].

    PubMed

    Sadykova, V S; Kurakov, A V; Kuvarina, A E; Rogozhin, E A

    2015-01-01

    The antibiotic activity in 42 strains of 8 species of the Trichoderma genus (T. asperellum, T. viride, T. hamatum, T. koningii, T. atroviride, T. harzianum, T. Citrinoviride, and T. longibrachiatum) isolated from different Siberian ecotops was studied. It was shown that these species differ in the degree of their antibacterial and antifungal activity. The chosen strain, T. citrinoviride TV4-1, exhibited high activity and a wide range of actions against the opportunistic and pathogenic fungi of the Aspergillus and Candida albicans genus; bacteria, including methicillin-resistant Staphylococcus aureus; and cancer cells. According to mass and I R spectrometry data and the spectrum of biological action, peptaibols are probably the most active compounds in the strain culture extracts.

  19. Identification and characterization of antimicrobial activity in two yeast genera.

    PubMed Central

    Bilinski, C A; Innamorato, G; Stewart, G G

    1985-01-01

    A general screening test for the expression of antibacterial activity was performed on over 400 cultures belonging to 31 yeast genera. Of these cultures, only two, Kluyveromyces thermotolerans and Kloeckera apiculata, were found to produce zones of inhibition of bacterial growth on Diagnostic Sensitivity Test Agar medium supplemented with 0.002% methylene blue. Of nine bacteria used as test organisms, only Lactobacillus plantarum and Bacillus megaterium were inhibited. No antibacterial activity was evident against four gram-negative bacteria used in this study. Optimal activities were found to be expressed after yeasts were grown at pH 6. A requirement for cultivation in the presence of methylene blue added to culture media for the expression of apparent antibacterial activity was demonstrated. Images PMID:3937494

  20. Correlation between the sorption of dissolved oxygen onto chitosan and its antimicrobial activity against Esherichia coli.

    PubMed

    Gylienė, Ona; Servienė, Elena; Vepštaitė, Iglė; Binkienė, Rima; Baranauskas, Mykolas; Lukša, Juliana

    2015-10-20

    The ability of chitosan to adsorb dissolved oxygen from solution depends on its physical shape and is related to the surface area. Depending on conditions chitosan is capable of adsorbing or releasing oxygen. Chitosan, modificated by the substances possessing antimicrobial activity, such as succinic acid, Pd(II) ions, metallic Pd or Ag, distinctly increases the ability to adsorb the dissolved oxygen. The additional treatment of chitosan with air oxygen or electrochemically produced oxygen also increases the uptake of dissolved oxygen by chitosan. A strong correlation between the amount of oxygen adsorbed onto chitosan and its antimicrobial activity against Esherichia coli has been observed. This finding suggests that one of the sources of antimicrobial activity of chitosan is the ability to sorb dissolved oxygen, along with other well-known factors such as physical state and chemical composition.

  1. Screening of antimicrobial activity of Cistus ladanifer and Arbutus unedo extracts.

    PubMed

    Ferreira, S; Santos, J; Duarte, A; Duarte, A P; Queiroz, J A; Domingues, F C

    2012-01-01

    In this work, the in vitro antimicrobial activity of different crude extracts obtained from Cistus ladanifer L. and Arbutus unedo L. was investigated. The ethanol, methanol and acetone/water extracts of Cistus ladanifer and Arbutus unedo were prepared using different extraction methods and their antimicrobial activities against reference strains, including three Gram-positive, five Gram-negative and three yeasts, and against clinical isolates of Helicobacter pylori and methicillin-resistant Staphylococcus aureus, were investigated. All the extracts inhibited more than one microorganism; moreover all of them presented antimicrobial activity against the Gram-positive bacteria, Klebsiella pneumonia, Candida tropicalis and Helicobacter pylori. It is noteworthy that the most considerable in vitro effect was observed against Helicobacter pylori. These inhibitory effects can be considered relevant to the development of new agents for inclusion in the treatment or prevention of infections by the tested strains.

  2. Essential oil composition and antimicrobial activity of Angelica archangelica L. (Apiaceae) roots.

    PubMed

    Fraternale, Daniele; Flamini, Guido; Ricci, Donata

    2014-09-01

    In this paper, the chemical composition and the antimicrobial activity of the essential oil of Angelica archangelica L. (Apiaceae) roots from central Italy were analyzed. The major constituents of the oil were α-pinene (21.3%), δ-3-carene (16.5%), limonene (16.4%) and α-phellandrene (8.7%). The oil shows a good antimicrobial activity against Clostridium difficile, Clostridium perfringens, Enterococcus faecalis, Eubacterium limosum, Peptostreptococcus anaerobius, and Candida albicans with minimum inhibitory concentration (MIC) values of 0.25, 0.25, 0.13, 0.25, 2.25, and 0.50% v/v, respectively. A weaker antimicrobial activity against bifidobacteria and lactobacilli-very useful in the intestinal microflora-has also been shown with MIC values >4.0% v/v.

  3. Chemical composition and antimicrobial activity of the essential oils of Onychopetalum amazonicum R.E.Fr.

    PubMed

    de Lima, Bruna R; da Silva, Felipe M A; Soares, Elzalina R; de Almeida, Richardson A; da Silva Filho, Francinaldo A; Pereira Junior, Raimundo C; Hernandez Tasco, Álvaro J; Salvador, Marcos J; Koolen, Hector H F; de Souza, Afonso D L; Pinheiro, Maria L B

    2016-10-01

    The essential oils from leaves, twigs and trunk bark of Onychopetalum amazonicum R.E. Fr. (Annonaceae), obtained by hydrodistillation, were analysed by GC and GC-MS, and also were evaluated for in vitro antimicrobial activity. Forty-one compounds, which correspond to 75.0-92.2% of the oil components, were identified. Major compounds were sesquiterpenes, including (E)-caryophyllene, caryophyllene oxide, spathulenol, α-gurjunene, allo-aromadendrene and α-epi-cadinol. The oils were evaluated for antimicrobial activities against four bacteria strains and five pathogenic fungi. The oil of the trunk bark exhibited good activity against Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 10538 and Kocuria rhizophila ATCC 9341, with a minimal inhibitory concentration of 62.5 μg/mL. The essential oil composition and the antimicrobial evaluation are reported for the first time for the genus Onychopetalum.

  4. Identification of volatile components in Phyllanthus emblica L. and their antimicrobial activity.

    PubMed

    Liu, Xiaoli; Zhao, Mouming; Luo, Wei; Yang, Bao; Jiang, Yueming

    2009-04-01

    The volatile components and in vitro antimicrobial activities of Emblica (Phyllanthus emblica L.) essential oils (EOs) obtained by hydrodistillation (HD-EO) and supercritical fluid extraction (SFE-EO) were investigated. The compositions of volatile compounds in these oils were tentatively determined by gas chromatography-mass spectrometry. The antimicrobial activites of these two extracts were investigated with microbiological tests against Gram-positive and Gram-negative bacteria and three pathogenic fungi. The main components of both oils were beta-caryophyllene, beta-bourbonene, 1-octen-3-ol, thymol, and methyleugenol. Both essential oils showed a broad spectrum of antimicrobial activity against all the tested microorganisms. Gram-positive bacteria were more sensitive to the investigated oils than Gram-negative bacteria. SFE-EO exhibited a higher antifungal activity compared to HD-EO.

  5. Probiotic Potential of Lactobacillus Strains with Antimicrobial Activity against Some Human Pathogenic Strains

    PubMed Central

    Shokryazdan, Parisa; Sieo, Chin Chin; Kalavathy, Ramasamy; Liang, Juan Boo; Alitheen, Noorjahan Banu; Faseleh Jahromi, Mohammad; Ho, Yin Wan

    2014-01-01

    The objective of this study was to isolate, identify, and characterize some lactic acid bacterial strains from human milk, infant feces, and fermented grapes and dates, as potential probiotics with antimicrobial activity against some human pathogenic strains. One hundred and forty bacterial strains were isolated and, after initial identification and a preliminary screening for acid and bile tolerance, nine of the best isolates were selected and further identified using 16 S rRNA gene sequences. The nine selected isolates were then characterized in vitro for their probiotic characteristics and their antimicrobial activities against some human pathogens. Results showed that all nine isolates belonged to the genus Lactobacillus. They were able to tolerate pH 3 for 3 h, 0.3% bile salts for 4 h, and 1.9 mg/mL pancreatic enzymes for 3 h. They exhibited good ability to attach to intestinal epithelial cells and were not resistant to the tested antibiotics. They also showed good antimicrobial activities against the tested pathogenic strains of humans, and most of them exhibited stronger antimicrobial activity than the reference strain L. casei Shirota. Thus, the nine Lactobacillus strains could be considered as potential antimicrobial probiotic strains against human pathogens and should be further studied for their human health benefits. PMID:25105147

  6. Phytochemical screening and in vitro antimicrobial activity of Thymus lanceolatus Desf. from Algeria

    PubMed Central

    Benbelaïd, Fethi; Khadir, Abdelmounaïm; Abdoune, Mohamed Amine; Bendahou, Mourad

    2013-01-01

    Objective To investigate the antimicrobial activity of an endemic Thyme, Thymus lanceolatus (T. lanceolatus), against a large number of pathogens. Methods Four solvent extracts were evaluated for antimicrobial activity using disc diffusion method and MIC determination on twenty-one strains. Results T. lanceolatus extracts showed a broad-spectrum antimicrobial activity, especially ethanol extract with inhibition zone diameters ranging from 14 to 32 mm, and MIC values from 0.052 to 0.500 mg/mL. Chloroform extract was more active against Gram-positive bacteria, since it has an inhibitory potency on Staphylococcus aureus and Enterococcus faecalis at only 31 µg/mL. While, hexane and water extracts were less effective since they were inactive against several strains. Conclusions The findings of this study indicate that T. lanceolatus has a strong antimicrobial potential, which justifies its use in folk medicine for treatment of infectious diseases. Since this species is poorly investigated, further refined studies on it pure secondary metabolites are needed and very important, in the perspective to identify new antimicrobial molecules from this endemic plant.

  7. Chemical constituents from the rhizomes of Smilax glabra and their antimicrobial activity.

    PubMed

    Xu, Shuo; Shang, Ming-Ying; Liu, Guang-Xue; Xu, Feng; Wang, Xuan; Shou, Cheng-Chao; Cai, Shao-Qing

    2013-05-08

    Six new phenolic compounds, named smiglabrone A (1), smiglabrone B (2), smilachromanone (3), smiglastilbene (4), smiglactone (5), smiglabrol (6), together with fifty-seven known ones 7-63 were isolated from the rhizomes of Smilax glabra. Their structures were elucidated on the basis of extensive spectroscopic analyses, as well as by comparison with literature data. Twenty-seven of these compounds were obtained from and identified in the genus Smilax for the first time. The absolute configuration of (2S)-1,2-O-di-trans-p-coumaroylglycerol (43) was determined for the first time using the exciton-coupled circular dichroism (ECCD) method. Thirty isolated compounds were evaluated for their antimicrobial activity against three Gram-negative bacteria, three Gram-positive bacteria and one fungus, and the corresponding structure-activity relationships were also discussed. Eighteen compounds were found to be antimicrobial against the microorganisms tested and the minimum inhibitory concentrations (MIC) were in the range of 0.0794-3.09 mM. Among them, compound 1 showed antimicrobial activity against Canidia albicans with MIC value of 0.146 mM, which was stronger than cinchonain Ia with an MIC of 0.332 mM. Compounds 3 and 4 exhibited inhibitory activity against Staphylococcus aureus with MIC values of 0.303 and 0.205 mM, respectively. The results indicated that these antimicrobial constituents of this crude drug might be responsible for its clinical antimicrobial effect.

  8. Antimicrobial activities of ozenoxacin against isolates of propionibacteria and staphylococci from Japanese patients with acne vulgaris.

    PubMed

    Nakajima, Akiko; Ikeda, Fumiaki; Kanayama, Shoji; Okamoto, Kazuaki; Matsumoto, Tatsumi; Ishii, Ritsuko; Fujikawa, Akira; Takei, Katsuaki; Kawashima, Makoto

    2016-08-01

    Ozenoxacin, a novel non-fluorinated topical quinolone, was assessed for in vitro antimicrobial activity against clinical isolates of propionibacteria and staphylococci according to the broth microdilution method recommended by the Clinical and Laboratory Standards Institute. The isolates used in this study were collected from Japanese patients with acne vulgaris during a period from 2012 to 2013. The MIC90s of ozenoxacin against Propionibacterium acnes (n=266), Propionibacterium granulosum (n=10), Staphylococcus aureus (n=23), Staphylococcus epidermidis (n=229) and other coagulase-negative staphylococci (n=82) were ≤0.06, ≤0.06, ≤0.06, 0.125 and ≤0.06 µg ml-1, respectively. The antimicrobial activity of ozenoxacin against the clinical isolates of propionibacteria and staphylococci was greater than that of five reference antimicrobial agents which have been used for the treatment of acne vulgaris. The MICs of ozenoxacin were correlated with those of nadifloxacin in P. acnes and S. epidermidis isolates. However, the MICs of ozenoxacin were 0.25-0.5 µg ml-1 and 0.5-8 µg ml-1 against nadifloxacin-resistant P. acnes (MIC: ≥8 µg ml-1; n=8) and S. epidermidis (MIC: ≥64 µg ml-1; n=10), respectively. These results indicated the potent antimicrobial activity against P. acnes and S. epidermidis isolates resistant to nadifloxacin. Topical ozenoxacin could represent an alternative therapeutic drug for acne vulgaris based on its potent antimicrobial activity against the isolates of propionibacteria and staphylococci from acne patients.

  9. In vitro antimicrobial activity of five essential oils on multidrug resistant Gram-negative clinical isolates

    PubMed Central

    Sakkas, Hercules; Gousia, Panagiota; Economou, Vangelis; Sakkas, Vassilios; Petsios, Stefanos; Papadopoulou, Chrissanthy

    2016-01-01

    Aim/Background: The emergence of drug-resistant pathogens has drawn attention on medicinal plants for potential antimicrobial properties. The objective of the present study was the investigation of the antimicrobial activity of five plant essential oils on multidrug resistant Gram-negative bacteria. Materials and Methods: Basil, chamomile blue, origanum, thyme, and tea tree oil were tested against clinical isolates of Acinetobacter baumannii (n = 6), Escherichia coli (n = 4), Klebsiella pneumoniae (n = 7), and Pseudomonas aeruginosa (n = 5) using the broth macrodilution method. Results: The tested essential oils produced variable antibacterial effect, while Chamomile blue oil demonstrated no antibacterial activity. Origanum, Thyme, and Basil oils were ineffective on P. aeruginosa isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values ranged from 0.12% to 1.50% (v/v) for tea tree oil, 0.25-4% (v/v) for origanum and thyme oil, 0.50% to >4% for basil oil and >4% for chamomile blue oil. Compared to literature data on reference strains, the reported MIC values were different by 2SD, denoting less successful antimicrobial activity against multidrug resistant isolates. Conclusions: The antimicrobial activities of the essential oils are influenced by the strain origin (wild, reference, drug sensitive, or resistant) and it should be taken into consideration whenever investigating the plants’ potential for developing new antimicrobials. PMID:27366345

  10. Antimicrobial activity of Northwestern Mexican plants against Helicobacter pylori.

    PubMed

    Robles-Zepeda, Ramón E; Velázquez-Contreras, Carlos A; Garibay-Escobar, Adriana; Gálvez-Ruiz, Juan C; Ruiz-Bustos, Eduardo

    2011-10-01

    Helicobacter pylori is the major etiologic agent of such gastric disorders as chronic active gastritis and gastric carcinoma. Over the past few years, the appearance of antibiotic-resistant bacteria has led to the development of better treatments, such as the use of natural products. This study evaluated the anti-H. pylori activity of 17 Mexican plants used mainly in the northwestern part of Mexico (Sonora) for the empirical treatment of gastrointestinal disorders. The anti-H. pylori activity of methanolic extracts of the plants was determined by using the broth microdilution method. The 50% minimum inhibitory concentrations ranged from less than 200 to 400 μg/mL for Castella tortuosa, Amphipterygium adstringens, Ibervillea sonorae, Pscalium decompositum, Krameria erecta, Selaginella lepidophylla, Pimpinella anisum, Marrubium vulgare, Ambrosia confertiflora, and Couterea latiflora and were greater than 800 μg/mL for Byophyllum pinnatum, Tecoma stans linnaeus, Kohleria deppena, Jatropha cuneata, Chenopodium ambrosoides, and Taxodium macronatum. Only Equisetum gigantum showed no activity against H. pylori. This study suggests the important role that these plants may have in the treatment of gastrointestinal disorders caused by H. pylori. The findings set the groundwork for further characterization and elucidation of the active compounds responsible for such activity.

  11. Synthesis and antimicrobial activity of new 4-heteroarylamino coumarin derivatives containing nitrogen and sulfur as heteroatoms.

    PubMed

    Dekić, Biljana R; Radulović, Niko S; Dekić, Vidoslav S; Vukićević, Rastko D; Palić, Radosav M

    2010-03-30

    Synthesis, spectral analysis and bioactivity of new coumarin derivatives are described in this paper. Eight new coumarin derivatives were synthesized in moderate to good yields by condensation of 4-chloro-3-nitrocoumarin and the corresponding heteroarylamine. The synthesized compounds were tested for their in vitro antimicrobial activity, in a standard disk diffusion assay, against thirteen strains of bacteria and three fungal strains. They have shown a wide range of activity - from one completely inactive compound to medium active ones.

  12. Diverse deep-sea fungi from the South China Sea and their antimicrobial activity.

    PubMed

    Zhang, Xiao-Yong; Zhang, Yun; Xu, Xin-Ya; Qi, Shu-Hua

    2013-11-01

    We investigated the diversity of fungal communities in nine different deep-sea sediment samples of the South China Sea by culture-dependent methods followed by analysis of fungal internal transcribed spacer (ITS) sequences. Although 14 out of 27 identified species were reported in a previous study, 13 species were isolated from sediments of deep-sea environments for the first report. Moreover, these ITS sequences of six isolates shared 84-92 % similarity with their closest matches in GenBank, which suggested that they might be novel phylotypes of genera Ajellomyces, Podosordaria, Torula, and Xylaria. The antimicrobial activities of these fungal isolates were explored using a double-layer technique. A relatively high proportion (56 %) of fungal isolates exhibited antimicrobial activity against at least one pathogenic bacterium or fungus among four marine pathogenic microbes (Micrococcus luteus, Pseudoaltermonas piscida, Aspergerillus versicolor, and A. sydowii). Out of these antimicrobial fungi, the genera Arthrinium, Aspergillus, and Penicillium exhibited antibacterial and antifungal activities, while genus Aureobasidium displayed only antibacterial activity, and genera Acremonium, Cladosporium, Geomyces, and Phaeosphaeriopsis displayed only antifungal activity. To our knowledge, this is the first report to investigate the diversity and antimicrobial activity of culturable deep-sea-derived fungi in the South China Sea. These results suggest that diverse deep-sea fungi from the South China Sea are a potential source for antibiotics' discovery and further increase the pool of fungi available for natural bioactive product screening.

  13. Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell (Scrophulariaceae)

    PubMed Central

    2014-01-01

    Background Endophytes, which reside in plant tissues, have the potential to produce novel metabolites with immense benefits for health industry. Cytotoxic and antimicrobial activities of endophytic fungi isolated from Bacopa monnieri (L.) Pennell were investigated. Methods Endophytic fungi were isolated from the Bacopa monnieri. Extracts from liquid cultures were tested for cytotoxicity against a number of cancer cell lines using the MTT assay. Antimicrobial activity was determined using the micro dilution method. Results 22% of the examined extracts showed potent (IC50 of <20 μg/ml) cytotoxic activity against HCT-116 cell line. 5.5%, 11%, 11% of the extracts were found to be cytotoxic for MCF-7, PC-3, and A-549 cell lines respectively. 33% extracts displayed antimicrobial activity against at least one test organism with MIC value 10–100 μg/ml. The isolate B9_Pink showed the most potent cytotoxic activity for all the cell lines examined and maximum antimicrobial activity against the four pathogens examined which was followed by B19. Conclusions Results indicated the potential for production of bioactive agents from endophytes of Bacopa monnieri. PMID:24512530

  14. Synthesis and Antimicrobial Activity of 9-O-Substituted Palmatine Derivatives

    PubMed Central

    Li, Z. C.; Kong, X. B.; Mai, W. P.; Sun, G. C.; Zhao, S. Z.

    2015-01-01

    A series of new palmatine derivatives with alkyl or alkyl with N-heterocyclic structures were designed and synthesized at C-9-O according to the principle of association. These compounds were characterised by 1H NMR, 13C NMR, ESI-MS and elemental analysis, and tested for their antimicrobial activity in vitro to evaluate structure-activity relationships. The results indicated that 9-O-substituted palmatine derivatives exhibit varying degrees of antimicrobial activity. Antibacterial activities of compounds (3a-f) against Gram +ve bacteria increased 2- to 64-fold than that of palmatine. The compounds (3a-f) possessed relatively weaker inhibitory effects against Gram −ve bacteria and fungi than that against Gram +ve bacteria. Antimicrobial activities of compounds (5a-e) are lower than that of compounds (3a-f). Compound 3d showed the highest antimicrobial activity of all the compounds. The LD50 values of compounds (3a-f) decreased as the alkyl side chain was elongated. Compound 3f showed least toxicity. PMID:26009653

  15. Activity of a novel-designed antimicrobial peptide and its interaction with lipids.

    PubMed

    Yu, Lanlan; Fan, Qiannan; Yue, Xiu; Mao, Yexuan; Qu, Lingbo

    2015-04-01

    A new antimicrobial peptide l-RW containing double amphipathic binding sequences was designed, and its biological activities were investigated in the present study. L-RW showed antibacterial activity against several bacterial strains but low cytotoxicity to mammalian cells and low hemolytic activity to red blood cells, which makes it a potential and promising peptide for further development. Microscale thermophoresis (MST), a new technique, was applied to study the antimicrobial peptide-lipid interaction for the first time, which examined the binding affinities of this new antimicrobial peptide to various lipids, including different phospholipids, mixture lipids and bacterial lipid extracts. The results demonstrated that l-RW bound preferentially to negatively charged lipids over neutral lipids, which was consistent with the biological activities, revealing the important role of electrostatic interaction in the binding process. L-RW also showed higher binding affinity for lipid extract from Staphyloccocus aureus compared with Pseudomonas aeruginosa and Escherichia coli, which were in good agreement with the higher antibacterial activity against S. aureus than P. aeruginosa and E. coli, suggesting that the binding affinity is capable to predict the antibacterial activity to some extent. Additionally, the binding of l-RW to phospholipids was also performed in fetal bovine serum solution by MST, which revealed that the components in biological solution may have interference with the binding event. The results proved that MST is a useful and potent tool in antimicrobial peptide-lipid interaction investigation.

  16. Fungi Treated with Small Chemicals Exhibit Increased Antimicrobial Activity against Facultative Bacterial and Yeast Pathogens

    PubMed Central

    Zutz, Christoph; Bandian, Dragana; Neumayer, Bernhard; Speringer, Franz; Wagner, Martin; Strauss, Joseph

    2014-01-01

    For decades, fungi have been the main source for the discovery of novel antimicrobial drugs. Recent sequencing efforts revealed a still high number of so far unknown “cryptic” secondary metabolites. The production of these metabolites is presumably epigenetically silenced under standard laboratory conditions. In this study, we investigated the effect of six small mass chemicals, of which some are known to act as epigenetic modulators, on the production of antimicrobial compounds in 54 spore forming fungi. The antimicrobial effect of fungal samples was tested against clinically facultative pathogens and multiresistant clinical isolates. In total, 30 samples of treated fungi belonging to six different genera reduced significantly growth of different test organisms compared to the untreated fungal sample (growth log reduction 0.3–4.3). For instance, the pellet of Penicillium restrictum grown in the presence of butyrate revealed significant higher antimicrobial activity against Staphylococcus (S.) aureus and multiresistant S. aureus strains and displayed no cytotoxicity against human cells, thus making it an ideal candidate for antimicrobial compound discovery. Our study shows that every presumable fungus, even well described fungi, has the potential to produce novel antimicrobial compounds and that our approach is capable of rapidly filling the pipeline for yet undiscovered antimicrobial substances. PMID:25121102

  17. Black cobra (Naja naja karachiensis) lysates exhibit broad-spectrum antimicrobial activities.

    PubMed

    Sagheer, Mehwish; Siddiqui, Ruqaiyyah; Iqbal, Junaid; Khan, Naveed Ahmed

    2014-04-01

    It is hypothesized that animals living in polluted environments possess antimicrobials to counter pathogenic microbes. The fact that snakes feed on germ-infested rodents suggests that they encounter pathogenic microbes and likely possess antimicrobials. The venom is used only to paralyze the rodent, but the ability of snakes to counter potential infections in the gut due to disease-ridden rodents requires robust action of the immune system against a broad range of pathogens. To test this hypothesis, crude lysates of different organs of Naja naja karachiensis (black cobra) were tested for antimicrobial properties. The antimicrobial activities of extracts were tested against selected bacterial pathogens (neuropathogenic Escherichia coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Streptococcus pneumonia), protist (Acanthamoeba castellanii), and filamentous fungus (Fusarium solani). The findings revealed that plasma and various organ extracts of N. n. karachiensis exhibited antimicrobial activity against E. coli K1, MRSA, P. aeruginosa, S. pneumoniae, A. castellanii, and F. solani in a concentration-dependent manner. The results of this study are promising for the development of new antimicrobials.

  18. Synthesis, antimicrobial and cytotoxic activities of pyrimidinyl benzoxazole, benzothiazole and benzimidazole.

    PubMed

    Seenaiah, D; Reddy, P Ramachandra; Reddy, G Mallikarjuna; Padmaja, A; Padmavathi, V; Krishna, N Siva

    2014-04-22

    A variety of pyrimidinyl benzoxazoles, benzothiazoles and benzimidazoles linked by thio, methylthio and amino moieties were prepared and studied their antimicrobial and cytotoxic activities. The compound pyrimidinyl bis methylthio benzimidazole 22 was a potent antimicrobial agent particularly against Staphylococcus aureus (29 mm, MIC 12.5 μg/mL) and Penicillium chrysogenum (38 mm, MIC 12.5 μg/mL). The amino linked pyrimidinyl bis benzothiazole 24 exhibited cytotoxic activity on A549 cells with IC50 value of 10.5 μM.

  19. Phytochemical analysis of Gymnema sylvestre and evaluation of its antimicrobial activity.

    PubMed

    Chodisetti, Bhuvaneswari; Rao, Kiranmayee; Giri, Archana

    2013-01-01

    Gymnema sylvestre (CS 149), known to be a rich source of saponins and other valuable phytochemicals, has been analysed for antimicrobial activity. The chloroform extracts of aerial and root parts of G. sylvestre exhibited higher antimicrobial activity as compared to diethyl ether and acetone. The root extracts of chloroform have shown competitive minimum inhibitory concentration and minimum bactericidal concentration values in the range of 0.04-1.28 mg mL(-1) and 0.08-2.56 mg/mL, respectively, towards the pathogens. The GC-MS analysis of chloroform extracts has shown the presence of compounds like eicosane, oleic acid, stigmasterol and vitamin E.

  20. Structure-activity relationships and action mechanisms of collagen-like antimicrobial peptides.

    PubMed

    Masuda, Ryo; Dazai, Yui; Mima, Takehiko; Koide, Takaki

    2017-01-01

    An antimicrobial triple-helical peptide, R3, was previously obtained from a collagen-like combinatorial peptide library. In this research, based on structure-activity relationship studies of R3, a more potent peptide, RR4, with increased positive net charge and charge density relative to R3, was developed. RR4 exhibited antimicrobial activity against both Gram-negative and Gram-positive bacterial strains, including multidrug-resistant strains. Its action could be attributed to entry into cells and interactions with intercellular molecules such as DNA/RNA that inhibited cell division rather than increasing bacterial membrane permeability. Furthermore, RR4 exhibited remarkable stability in serum and low cytotoxicity.

  1. Unsaturated fatty acids lactose esters: cytotoxicity, permeability enhancement and antimicrobial activity.

    PubMed

    Lucarini, Simone; Fagioli, Laura; Campana, Raffaella; Cole, Hannah; Duranti, Andrea; Baffone, Wally; Vllasaliu, Driton; Casettari, Luca

    2016-10-01

    Sugar based surfactants conjugated with fatty acid chains are an emerging broad group of highly biocompatible and biodegradable compounds with established and potential future applications in the pharmaceutical, cosmetic and food industries. In this work, we investigated absorption enhancing and antimicrobial properties of disaccharide lactose, monoesterified with unsaturated fatty acids through an enzymatic synthetic approach. After chemical and cytotoxicity characterizations, their permeability enhancing activity was demonstrated using intestinal Caco-2 monolayers through transepithelial electrical resistance (TEER) and permeability studies. The synthesized compounds, namely lactose palmitoleate (URB1076) and lactose nervonate (URB1077), were shown to exhibit antimicrobial activity versus eight pathogenic species belonging to Gram-positive, Gram-negative microorganisms and fungi.

  2. Antimicrobial activity of the synthesized non-allergenic urushiol derivatives.

    PubMed

    Cho, Jeong-Yong; Park, Keun Young; Kim, Seon-Jae; Oh, Sejong; Moon, Jae-Hak

    2015-01-01

    Synthesized urushiol derivatives possessing different carbon atomic length in the alkyl side chain inhibited the growth of food spoilage and pathogenic microorganisms. Particularly, non-allergenic 3-pentylcatechol showed a broad antimicrobial spectrum on an agar plate. Most food spoilage and pathogenic microorganisms were sensitive to urushiol derivatives in the liquid culture. The morphologies of the microorganisms were changed after treatment of 3-pentylcatechol.

  3. Antimicrobial Activity of Oleanolic and Ursolic Acids: An Update

    PubMed Central

    Jesus, Jéssica A.; Lago, João Henrique G.; Laurenti, Márcia D.; Yamamoto, Eduardo S.; Passero, Luiz Felipe D.

    2015-01-01

    Triterpenoids are the most representative group of phytochemicals, as they comprise more than 20,000 recognized molecules. These compounds are biosynthesized in plants via squalene cyclization, a C30 hydrocarbon that is considered to be the precursor of all steroids. Due to their low hydrophilicity, triterpenes were considered to be inactive for a long period of time; however, evidence regarding their wide range of pharmacological activities is emerging, and elegant studies have highlighted these activities. Several triterpenic skeletons have been described, including some that have presented with pentacyclic features, such as oleanolic and ursolic acids. These compounds have displayed incontestable biological activity, such as antibacterial, antiviral, and antiprotozoal effects, which were not included in a single review until now. Thus, the present review investigates the potential use of these triterpenes against human pathogens, including their mechanisms of action, via in vivo studies, and the future perspectives about the use of compounds for human or even animal health are also discussed. PMID:25793002

  4. Preliminary report on antimicrobial activity of Helichrysum litoreum Guss.

    PubMed

    Guida, M; Casoria, P; Guarino, C; Melluso, G

    1999-01-01

    The authors present the preliminary results regarding the antibacterial action of extracts of Helichrysum litoreum Guss. The leaves and the young stems of this species, gathered on the slopes of Mt Vesuvius, in the Campania region, were ground and four extracts were made as follows: with dichloromethane, ethanol and water (70:30 v/v), water and methanol. The antibacterial activity of each of the samples was tested in order to determine which of the extracts was more antibacterial. The results of the test showed that the extract with the ethanol/water (70/30 v/v) was the most active one. This will allow us to advance in the research, purifying the extract and hopefully identifying the active principles.

  5. Antimicrobial Dendrimeric Peptides: Structure, Activity and New Therapeutic Applications.

    PubMed

    Scorciapino, Mariano A; Serra, Ilaria; Manzo, Giorgia; Rinaldi, Andrea C

    2017-03-03

    Microbial resistance to conventional antibiotics is one of the most outstanding medical and scientific challenges of our times. Despite the recognised need for new anti-infective agents, however, very few new drugs have been brought to the market and to the clinic in the last three decades. This review highlights the properties of a new class of antibiotics, namely dendrimeric peptides. These intriguing novel compounds, generally made of multiple peptidic sequences linked to an inner branched core, display an array of antibacterial, antiviral and antifungal activities, usually coupled to low haemolytic activity. In addition, several peptides synthesized in oligobranched form proved to be promising tools for the selective treatment of cancer cells.

  6. Chemical composition, cytotoxicity, antimicrobial and antifungal activity of several essential oils.

    PubMed

    Cannas, Sara; Usai, Donatella; Tardugno, Roberta; Benvenuti, Stefania; Pellati, Federica; Zanetti, Stefania; Molicotti, Paola

    2016-01-01

    Essential oils (EOs) are known and used for their biological, antibacterial, antifungal and antioxidant properties. Numerous studies have shown that EOs exhibit a large spectrum of biological activities in vitro. The incidence of drug-resistant pathogens and the toxicity of antibiotics have drawn attention to the antimicrobial activity of natural products, encouraging the development of alternative treatments. The aim of this study was to analyse the phytochemical and the cytotoxic characteristic of 36 EOs; we then evaluated the antimicrobial activity of the less-toxic EOs on Gram-positive, Gram-negative and fungi strains. The results showed low cytotoxicity in seven EOs and good activity against Gram-negative and Candida spp. strains. Based on our results, EOs could be proposed as a novel group of therapeutic agents. Further experiments are necessary to confirm their pharmacological effectiveness, and to determine potential toxic effects and the mechanism of their activity in in vivo models.

  7. Expeditious Synthesis, Antimicrobial and Antimalarial Activities of Novel Heterocycles Bearing Imidazole-oxadiazole Based Hybrid Pharmacophores.

    PubMed

    Balaji, K; Bhatt, P; Jha, A

    2016-11-01

    A facile synthesis of 2-substituted-5-amino-oxadiazole derivatives has been achieved by refluxing/sonicating a mixture of semicarbazide with various aromatic acids in conc. sulphuric acid alone. The isolated products were further condensed with p-dimethylaminobenzaldehyde/p-hydroxybenzaldehyde to obtain respective imino derivatives. Finally, some potentially biologically active imidazole analogues were obtained by reacting ammonium acetate and 5-bromoisatin with the synthesized imino products. All the newly synthesized compounds were thoroughly characterized by standard analytical techniques. These imidazole-oxadiazole hybrid compounds were also evaluated for their antimicrobial and antimalarial activities. The compounds all exhibited moderate to significant antimicrobial activity (6-10 mm, zone of inhibition) and promising antimalarial activity (IC50 0.037-0.100 µM). This report entails a detailed synthetic procedure, spectroscopic elucidation and activities of the synthesized compounds.

  8. Antimicrobial activity of butyrate glycerides toward Salmonella Typhimurium and Clostridium perfringens.

    PubMed

    Namkung, H; Yu, H; Gong, J; Leeson, S

    2011-10-01

    The antimicrobial activities of n-butyric acid and its derivatives against Salmonella Typhimurium and Clostridium perfringens were studied. n-Butyric acid and its derivatives (monobutyrin and a mixture of mono-, di-, and tri-glycerides of butyric acid) were added at different concentrations (ranging from 250 to 7,000 mg/kg to a media inoculated with either Salmonella Typhimurium or C. perfringens. The antimicrobial activity of butyric acid against C. perfringens was measured at 2 bacterium concentrations and 2 inoculations involving ambient aerobic or anaerobic conditions. The most effective antimicrobial activity for Salmonella Typhimurium was observed with n-butyric acid, with 90% inhibition rate at a concentration of 1,500 mg/kg. Although minimal inhibition for Salmonella Typhimurium was observed with butyric acid glycerides, lipase addition to a mixture of mono-, di-, and triglycerides of butyric acid increased (P < 0.01) antimicrobial activity of these derivatives. Antimicrobial activity of butyric acid and its derivative against C. perfringens was higher when using a moderate initial inoculation concentration (10(5)) compared with a higher initial concentration (10(7)) of this bacterium. At a lower inoculation of C. perfringens (10(5)), >90% inhibition rate by all butyric acid glycerides was observed with prior aerobic inoculation at 2,000 mg/kg, whereas using anaerobic inoculation, only 50% monobutyrin maintained >90% inhibitory effect at 3,000 mg/kg. The antimicrobial effect of monobutyrin against C. perfringens was generally higher (P < 0.01) for 50% monobutyrin than for 100% monobutyrin. Either a mixture of butyric acid derivatives or 50% monobutyrin decreased (P < 0.01) C. perfringens in a media containing intestinal contents whereas only 50% monobutyrin decreased (P < 0.01) Salmonella Typhimurium within a media containing cecal contents from mature Leghorns. These results show that n-butyric acid and 50% monobutyrin could be used to control Salmonella

  9. Investigation of cream and ointment on antimicrobial activity of Mangifera indica extract.

    PubMed

    Awad El-Gied, Amgad A; Abdelkareem, Abdelkareem M; Hamedelniel, Elnazeer I

    2015-01-01

    Medicinal plants have curative properties due to the presence of various complex chemical substance of different composition, which are found as secondary plant metabolites in one or more parts of these plants. Mangifera indica Linn (MI L.) is a species of mango in the Anacardiaceae family. Phytoconstituents in the seed extracts may be responsible for the antimicrobial activity of the plant. The purpose of the study was to formulate and evaluate the antimicrobial herbal ointment and cream from extracts of the seeds of mango (MI L.) The formulated ointments containing oleaginous-based showed the best formulation compared to the emulsion water in oil type, the ointment and cream bases in different concentration 1%, 5% and 10%. The formulated ointment and cream of MI L. were subjected to evaluation of Uniformity of Weight, measurement of pH, viscosity, Spreadability, Acute skin irritation study, stability study and antimicrobial activity. Our study shows that MI has high potential as an antimicrobial agent when formulated as ointment and creams for topical use. Thus, the present study concludes that the formulated formulations of the MI are safe and efficient carriers, with potent antimicrobial activity.

  10. Diversity, Antimicrobial Action and Structure-Activity Relationship of Buffalo Cathelicidins.

    PubMed

    Brahma, Biswajit; Patra, Mahesh Chandra; Karri, Satyanagalakshmi; Chopra, Meenu; Mishra, Purusottam; De, Bidhan Chandra; Kumar, Sushil; Mahanty, Sourav; Thakur, Kiran; Poluri, Krishna Mohan; Datta, Tirtha Kumar; De, Sachinandan

    2015-01-01

    Cathelicidins are an ancient class of antimicrobial peptides (AMPs) with broad spectrum bactericidal activities. In this study, we investigated the diversity and biological activity of cathelicidins of buffalo, a species known for its disease resistance. A series of new homologs of cathelicidin4 (CATHL4), which were structurally diverse in their antimicrobial domain, was identified in buffalo. AMPs of newly identified buffalo CATHL4s (buCATHL4s) displayed potent antimicrobial activity against selected Gram positive (G+) and Gram negative (G-) bacteria. These peptides were prompt to disrupt the membrane integrity of bacteria and induced specific changes such as blebing, budding, and pore like structure formation on bacterial membrane. The peptides assumed different secondary structure conformations in aqueous and membrane-mimicking environments. Simulation studies suggested that the amphipathic design of buCATHL4 was crucial for water permeation following membrane disruption. A great diversity, broad-spectrum antimicrobial action, and ability to induce an inflammatory response indicated the pleiotropic role of cathelicidins in innate immunity of buffalo. This study suggests short buffalo cathelicidin peptides with potent bactericidal properties and low cytotoxicity have potential translational applications for the development of novel antibiotics and antimicrobial peptidomimetics.

  11. Functional analysis of Pacific oyster (Crassostrea gigas) β-thymosin: Focus on antimicrobial activity.

    PubMed

    Nam, Bo-Hye; Seo, Jung-Kil; Lee, Min Jeong; Kim, Young-Ok; Kim, Dong-Gyun; An, Cheul Min; Park, Nam Gyu

    2015-07-01

    An antimicrobial peptide, ∼5 kDa in size, was isolated and purified in its active form from the mantle of the Pacific oyster Crassostrea gigas by C18 reversed-phase high-performance liquid chromatography. Matrix-assisted laser desorption ionisation time-of-flight analysis revealed 4656.4 Da of the purified and unreduced peptide. A comparison of the N-terminal amino acid sequence of oyster antimicrobial peptide with deduced amino acid sequences in our local expressed sequence tag (EST) database of C. gigas (unpublished data) revealed that the oyster antimicrobial peptide sequence entirely matched the deduced amino acid sequence of an EST clone (HM-8_A04), which was highly homologous with the β-thymosin of other species. The cDNA possessed a 126-bp open reading frame that encoded a protein of 41 amino acids. To confirm the antimicrobial activity of C. gigas β-thymosin, we overexpressed a recombinant β-thymosin (rcgTβ) using a pET22 expression plasmid in an Escherichia coli system. The antimicrobial activity of rcgTβ was evaluated and demonstrated using a bacterial growth inhibition test in both liquid and solid cultures.

  12. Diversity, Antimicrobial Action and Structure-Activity Relationship of Buffalo Cathelicidins

    PubMed Central

    Brahma, Biswajit; Patra, Mahesh Chandra; Karri, Satyanagalakshmi; Chopra, Meenu; Mishra, Purusottam; De, Bidhan Chandra; Kumar, Sushil; Mahanty, Sourav; Thakur, Kiran; Poluri, Krishna Mohan; Datta, Tirtha Kumar; De, Sachinandan

    2015-01-01

    Cathelicidins are an ancient class of antimicrobial peptides (AMPs) with broad spectrum bactericidal activities. In this study, we investigated the diversity and biological activity of cathelicidins of buffalo, a species known for its disease resistance. A series of new homologs of cathelicidin4 (CATHL4), which were structurally diverse in their antimicrobial domain, was identified in buffalo. AMPs of newly identified buffalo CATHL4s (buCATHL4s) displayed potent antimicrobial activity against selected Gram positive (G+) and Gram negative (G-) bacteria. These peptides were prompt to disrupt the membrane integrity of bacteria and induced specific changes such as blebing, budding, and pore like structure formation on bacterial membrane. The peptides assumed different secondary structure conformations in aqueous and membrane-mimicking environments. Simulation studies suggested that the amphipathic design of buCATHL4 was crucial for water permeation following membrane disruption. A great diversity, broad-spectrum antimicrobial action, and ability to induce an inflammatory response indicated the pleiotropic role of cathelicidins in innate immunity of buffalo. This study suggests short buffalo cathelicidin peptides with potent bactericidal properties and low cytotoxicity have potential translational applications for the development of novel antibiotics and antimicrobial peptidomimetics. PMID:26675301

  13. Investigation of cream and ointment on antimicrobial activity of Mangifera indica extract

    PubMed Central

    Awad El-Gied, Amgad A.; Abdelkareem, Abdelkareem M.; Hamedelniel, Elnazeer I.

    2015-01-01

    Medicinal plants have curative properties due to the presence of various complex chemical substance of different composition, which are found as secondary plant metabolites in one or more parts of these plants. Mangifera indica Linn (MI L.) is a species of mango in the Anacardiaceae family. Phytoconstituents in the seed extracts may be responsible for the antimicrobial activity of the plant. The purpose of the study was to formulate and evaluate the antimicrobial herbal ointment and cream from extracts of the seeds of mango (MI L.) The formulated ointments containing oleaginous-based showed the best formulation compared to the emulsion water in oil type, the ointment and cream bases in different concentration 1%, 5% and 10%. The formulated ointment and cream of MI L. were subjected to evaluation of Uniformity of Weight, measurement of pH, viscosity, Spreadability, Acute skin irritation study, stability study and antimicrobial activity. Our study shows that MI has high potential as an antimicrobial agent when formulated as ointment and creams for topical use. Thus, the present study concludes that the formulated formulations of the MI are safe and efficient carriers, with potent antimicrobial activity. PMID:25878974

  14. Antimicrobial activity of Paenibacillus kribbensis POC 115 against the dermatophyte Trichophyton rubrum.

    PubMed

    Cotta, Simone Raposo; da Mota, Fabio Faria; Tupinambá, Gleiser; Ishida, Kelly; Rozental, Sonia; E Silva, Davi Oliveira; da Silva, Antônio Jorge Ribeiro; Bizzo, Humberto Ribeiro; Alviano, Daniela Sales; Alviano, Celuta Sales; Seldin, Lucy

    2012-03-01

    In a search for an antifungal substance with activity against the dermatophyte fungus Trichophyton rubrum, strain POC 115 was chosen among different Paenibacillus strains for its phenotypic and genetic characterization and for preliminary characterization of its antimicrobial substance. Strain POC 115 was identified as belonging to Paenibacillus kribbensis. Physico-chemical characterization of the antimicrobial substance showed that it was not stable during heat and organic solvents treatments, but its activity was preserved at a wide range of pH and after treatment with pronase E, trypsin and DNase I. The crude concentrated supernatant of POC 115 culture was partially purified and the fraction presenting antimicrobial activity was further analyzed by UPLC/Mass Spectrometry. Two peaks were observed at 2.02 (mass 1,207 D) and 2.71 (mass 1,014 D) min in the mass chromatogram. The antimicrobial substance produced by POC 115 was correlated to iturin family compounds based on a set of primers designed for the amplification of PKS operon in the POC 115 genome. As happens with the mode of action of the antibiotics of the iturin group, the AMS produced by POC 115 caused the disruption of cytoplasmic membrane of T. rubrum and the subsequent withdraw of the intracellular material. This is the first report on the production of antimicrobial substances in P. kribbensis, and it may be of great relevance as an alternative or supplementary substance to antifungal drugs currently used against dermatophytes.

  15. Characterization of Yuhushiella sp. TD-032 from the Thar Desert and its antimicrobial activity

    PubMed Central

    Ibeyaima, A.; Rana, Jyoti; Dwivedi, Anuj; Gupta, Sanjay; Sharma, Sanjeev K.; Saini, Narendra; Sarethy, Indira P.

    2016-01-01

    During a screening program for antimicrobial compounds from underexplored habitats, a Gram-positive bacterium TD-032, was isolated from arid soil, Thar Desert (India), and analyzed for its morphological, physicochemical, and antimicrobial properties. The 16S ribosomal DNA (rDNA) sequence of the isolate was further studied for the novelty of γ-hyper variable region. TD-032 was grown in large-scale culture, and aqueous and organic solvent extracts analyzed for antimicrobial activity. Culture characteristics showed a lack of diffusible and melanoid pigments. The morphological features were pale yellow aerial mycelium colony color with brownish yellow substrate mycelium and leathery texture. The isolate could grow at 1% concentration of sodium chloride, temperature of 40°C, and a wide range of pH (7.0–12.0). An evaluation for extracellular enzymatic activities showed secretion of gelatinase(s), cellulase(s), and lipase(s). The γ-hyper variable region of 16S rDNA sequence of TD-032 showed 98.33% relatedness to Yuhushiella deserti, indicating a potential new species. Aqueous and ethyl acetate extracts showed antimicrobial activity against Gram-positive and Gram-negative bacteria inclusive clinical isolates. Inhibition of both test bacteria suggests that TD-032 produces a broad spectrum of antimicrobial substances. PMID:27144149

  16. Synthesis, DNA cleavage and antimicrobial activity of 4-thiazolidinones-benzothiazole conjugates.

    PubMed

    Singh, Meenakshi; Gangwar, Mayank; Nath, Gopal; Singh, Sushil K

    2014-11-01

    Antimicrobial screening of several novel 4-thiazolidinones with benzothiazole moiety has been performed. These compounds were evaluated for antimicrobial activity against a panel of bacterial and fungal strains. The strains were treated with these benzothiazole derivatives at varying concentrations, and MIC's were calculated. Structures of these compounds have been determined by spectroscopic studies viz., FT-IR, 1H NMR, 13C NMR and elemental analysis. Significant antimicrobial activity was observed for some members of the series, and compounds viz. 3-(4-(benzo[d]thiazol-2-yl) phenyl-2-(4-methoxyphenyl)thiazolidin-4-one and 3-(4-(benzo[d]thiazol-2-yl)phenyl)-2-(4-hydroxy phenyl)thiazolidin-4-one were found to be the most active against E.coli and C. albicans with MIC values in the range of 15.6-125 microg/ml. Preliminary study of the structure-activity relationship revealed that electron donating groups associated with thiazolidine bearing benzothiazole rings had a great effect on the antimicrobial activity of these compounds and contributes positively for the action. DNA cleavage experiments gave valuable hints with supporting evidence for describing the mechanism of action and hence showed a good correlation between their calculated MIC's and its lethality.

  17. Isolation and Antimicrobial and Antioxidant Evaluation of Bio-Active Compounds from Eriobotrya Japonica Stems

    PubMed Central

    Rashed, Khaled Nabih; Butnariu, Monica

    2014-01-01

    Purpose: The present study was carried out to evaluate antimicrobial and antioxidant activities from Eriobotrya japonica stems as well investigation of its chemical composition. Methods: Methanol 80% extract of Eriobotrya japonica stems was tested for antimicrobial activity against bacterial and fungal strains and for antioxidant activity using oxygen radical absorbance capacity (ORAC) and the trolox equivalent antioxidant capacity (TEAC) assays and also total content of polyphenols with phytochemical analysis of the extract were determined. Results: The results showed that the extract has a significant antimicrobial activity, it inhibited significantly the growth of Candida albicans suggesting that it can be used in the treatment of fungal infections, and it showed no effect on the other bacterial and fungal strains, the extract has a good antioxidant activity, it has shown high values of oxygen radical absorbance capacity and trolox equivalent antioxidant capacity, while it showed a low value of polyphenol content. Phytochemical analysis of the extract showed the presence of carbohydrates, terpenes, tannins and flavonoids, further phytochemical analysis resulted in the isolation and identification of three triterpenic acids, oleanolic, ursolic and corosolic acids and four flavonoids, naringenin, quercetin, kaempferol 3-O-β-glucoside and quercetin 3-O-α-rhamnoside. Conclusion: These results may help to discover new chemical classes of natural antimicrobial antioxidant substances. PMID:24409413

  18. Chemical composition and antimicrobial activity of essential oils from Chromolaena laevigata during flowering and fruiting stages.

    PubMed

    Murakami, Cynthia; Lago, João H G; Perazzo, Fábio F; Ferreira, Karen S; Lima, Marcos E L; Moreno, Paulo R H; Young, Maria C M

    2013-04-01

    The chemical compositions and antimicrobial activities of essential oils from the leaves, stems, capitula, and cypselas of Chromolaena laevigata were evaluated at two different phenological stages, flowering and fruiting. Thirty-eight compounds were identified in the crude oils by GC/MS. The sesquiterpene laevigatin was the major constituent of the leaf, capitulum, and cypsela oils, while the sesquiterpene spathulenol was the main component in the stem oils. The antimicrobial activities of the oils were evaluated against Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Stem oil obtained from Chromolaena laevigata during the fruiting stage generally showed the highest activity with minimum inhibitory concentration (MIC) values of 62.5 μg/ml against Candida albicans and S. aureus, and 500 μg/ml against P. aeruginosa and E. coli. Pure laevigatin exhibited MIC values of 500 and 125 μg/ml against C. albicans and S. aureus, respectively, indicating that this constituent could be responsible, at least in part, for the antimicrobial activities detected in the crude oils. More studies concerning the biological activities of isolated derivatives are required to improve our knowledge of the antimicrobial potential of volatile compounds present in native plants.

  19. Screening of antimicrobial activity and cytotoxic effects of two Cladonia species.

    PubMed

    Açikgöz, Birkan; Karalti, Iskender; Ersöz, Melike; Coşkun, Zeynep M; Cobanoğlu, Gülşah; Sesal, Cenk

    2013-01-01

    The present study explores the antimicrobial activity and cytotoxic effects in culture assays of two fruticose soil lichens, Cladonia rangiformis Hoffm. and Cladonia convoluta (Lamkey) Cout., to contribute to possible pharmacological uses of lichens. In vitro antimicrobial activities of methanol and chloroform extracts against two Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), and the yeast Candida albicans were examined using the paper disc method and through determination of minimal inhibitory concentrations (MICs). The data showed the presence of antibiotic substances in the chloroform and the methanol extracts of the lichen species. The chloroform extracts exhibited more significant antimicrobial activity than the methanol extracts. However, a higher antifungal activity was noted in the methanol extract of C. rangiformis. The maximum antimicrobial activity was recorded for the chloroform extract of C. convoluta against E. coli. The cytotoxic effects of the lichen extracts on human breast cancer MCF-7 cells were evaluated by the trypan blue assay yielding IC50 values of ca. 173 and 167 microg/ml for the extracts from C. rangiformis and C. convoluta, respectively.

  20. Impact of pectin esterification on the antimicrobial activity of nisin-loaded pectin particles.

    PubMed

    Krivorotova, Tatjana; Staneviciene, Ramune; Luksa, Juliana; Serviene, Elena; Sereikaite, Jolanta

    2017-01-01

    The relationship between pectin structure and the antimicrobial activity of nisin-loaded pectin particles was examined. The antimicrobial activity of five different nisin-loaded pectin particles, i.e., nisin-loaded high methoxyl pectin, low methoxyl pectin, pectic acid, dodecyl pectin with 5.4 and 25% degree of substitution were tested in the pH range of 4.0-7.0 by agar-diffusion assay and agar plate count methods. It was found that the degree of esterification of carboxyl group of galacturonic acid in pectin molecule is important for the antimicrobial activity of nisin-loaded pectin particles. Nisin-loaded particles prepared using pectic acid or the pectin with low degree of esterification exhibit higher antimicrobial activity than nisin-loaded high methoxyl pectin particles. Pectins with free carboxyl groups or of low degree of esterification are the most suitable for particles preparation. Moreover, nisin-loaded pectin particles were active at close to neutral or neutral pH values. Therefore, they could be effectively applied for food preservation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:245-251, 2017.

  1. Chemical composition, antioxidant and antimicrobial activities of essential oil from Wedelia prostrata

    PubMed Central

    Dai, Jiali; Zhu, Liang; Yang, Li; Qiu, Jun

    2013-01-01

    The following study deals with the chemical composition, antioxidant and antimicrobial activity of essential oils of Wedelia prostrata and their main constituents in vitro. A total of 70 components representing 99.26 % of the total oil were identified. The main compounds in the oil were limonene (11.38 %) and α-pinene (10.74 %). Antioxidant assays (1,1-diphenyl-2-picrylhydrazyl, superoxide anion radical, and reducing power test) demonstrate moderate activities for the essential oil and its main components (limonene and α-pinene). The essential oil (1000 μg/disc) exhibited promising antimicrobial activity against 10 strains of test microorganisms as a diameter of zones of inhibition (20.8 to 22.2 mm) and MIC values (125 to 250 µg/ml). The activities of limonene and α-pinene were also determined as main components of the oil. α-Pinene showed higher antimicrobial activity than the essential oil with a diameter of zones of inhibition (20.7 to 22.3 mm) and MIC values (62.5 to 125 µg/ml). The antioxidant and antimicrobial properties of the essential oil may be attributed to the synergistic effects of its diverse major and minor components. PMID:26648809

  2. Lactobacillus plantarum as a Probiotic Potential from Kouzeh Cheese (Traditional Iranian Cheese) and Its Antimicrobial Activity.

    PubMed

    Jabbari, Vahid; Khiabani, Mahmoud Sowti; Mokarram, Reza Rezaei; Hassanzadeh, Azad Mohammad; Ahmadi, Elham; Gharenaghadeh, Sasan; Karimi, Nayyer; Kafil, Hossein Samadi

    2017-02-02

    The aim of this study is to isolate and identify Lactobacillus plantarum isolates from traditional cheese, Kouzeh, and evaluate their antimicrobial activity against some food pathogens. In total, 56 lactic acid bacteria were isolated by morphological and biochemical methods, 12 of which were identified as Lactobacillus plantarum by biochemical method and 11 were confirmed by molecular method. For analyzing the antimicrobial activity of these isolates properly, diffusion method was performed. The isolates were identified by 318 bp band dedicated for L. plantarum. The isolated L. plantarum represented an inhibitory activity against four of the pathogenic bacteria and showed different inhibition halos against each other. The larger halos were observed against Staphylococcus aureus and Staphylococcus epidermidis (15 ± 0.3 and 14.8 ± 0.7 mm, respectively). The inhibition halo of Escherichia coli was smaller than that of other pathogen and some L. plantarum did not show any inhibitory activity against E. coli, which were resistant to antimicrobial compounds produced by L. plantarum. The isolated L. plantarum isolates with the antimicrobial activity in this study had strong probiotic properties. These results indicated the nutritional value of Kouzeh cheese and usage of the isolated isolates as probiotic strains.

  3. Polyethylene/organically-modified layered-silicate nanocomposites with antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Songtipya, P.; Jimenez-Gasco, M. M.; Manias, E.

    2009-03-01

    Despite the very intensive research on polymer nanocomposites, the opportunities for new functionalities possible by nanofillers still remain largely untapped. Here, we present polyethylene/inorganic nanocomposites that exhibit strongly enhanced mechanical performance and, at the same time, also an antimicrobial activity originating from the organo-filler nature. Specifically, PE/organically-modified layered-silicate nanocomposites were prepared via melt-processing, and antimicrobial activity was designed by proper choice of their organic modification. Their antimicrobial activity was measured against three micotoxinogen fungal strains (Penicillium roqueforti and claviforme, and Fusarium graminearum) as model soil-borne plant and food contaminants. Montmorillonite-based organofillers, which only differ in their organic modification, were used to exemplify how these surfactants can be designed to render antifungal activity to the nanocomposites. The comparative discussion of the growth of fungi on unfilled PE and nanocomposite PE films is used to demonstrate how the antimicrobial efficacy is dictated by the surfactant chemistry and, further, how the nanocomposites' inhibitory activity compares to that of the organo-fillers and the surfactants.

  4. Proteolytic and antimicrobial activity of lactic acid bacteria grown in goat milk.

    PubMed

    Atanasova, Jivka; Moncheva, Penka; Ivanova, Iskra

    2014-11-02

    We examined 62 strains and 21 trade starter cultures from the collection of LB Bulgaricum PLC for proteolytic and antimicrobial activity of lactic acid bacteria (LAB) grown in goat milk. The aim of this study was to investigate the fermentation of caseins, α-lactalbumin and β-lactoglobulin by LAB, using the o-phthaldialdehyde (OPA) spectrophotometric assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The proteolysis targeted mainly caseins, especially β-casein. Whey proteins were proteolyzed, essentially β-lactoglobulin. The proteolytic activity of Lactococcus lactis l598, Streptococcus thermophilus t3D1, Dt1, Lactobacillus lactis 1043 and L. delbrueckii subsp. bulgaricus b38, b122 and b24 was notably high. The proteolysis process gave rise to medium-sized peptide populations. Most of the examined strains showed antimicrobial activity against some food pathogens, such as Escherichia coli, Staphylococcus aureus, Salmonella cholere enteridis, Listeria monocytogenes, Listeria innocua and Enterobacter aerogenes. The most active producers of antimicrobial-active peptides were strains of L. delbrueckii subsp. bulgaricus and S. thermophilus, which are of practical importance. The starter cultures containing the examined species showed high proteolytic and antimicrobial activity in skimmed goat milk. The greatest antimicrobial activity of the cultures was detected against E. aerogenes. The obtained results demonstrated the significant proteolytic potential of the examined strains in goat milk and their potential for application in the production of dairy products from goat's milk. The present results could be considered as the first data on the proteolytic capacity of strains and starter cultures in goat milk for the purposes of trade interest of LB Bulgaricum PLC.

  5. Antimicrobial activity of selected essential oils against cariogenic bacteria.

    PubMed

    Aguiar, G P; Carvalho, C E; Dias, H J; Reis, E B; Martins, M H G; Wakabayashi, K A L; Groppo, M; Martins, C H G; Cunha, W R; Crotti, A E M

    2013-01-01

    The antibacterial activity of nine selected essential oils (EOs) against a panel of oral pathogens was investigated in terms of their minimum inhibitory concentrations (MICs) by using the broth microdilution method. Most of the EOs displayed weak activity or were inactive against the selected oral pathogens, with MIC values ranging from 500 to 4000 μg/mL. However, the EO obtained from the leaves of Bidens sulphurea (Asteraceae) was found to display moderate activity against Streptococcus mutans (MIC = 250 μg/mL) and significant activity against Streptococcus mitis (MIC = 31.25 μg/mL). Germacrene D (38.3%), trans-caryophyllene (18.0%), β-elemene (13.9%) and bicyclogermacrene (13.1%) were identified as the main chemical components of this oil. 2,6-Di-tert-butyl-4-methylphenol, previously described as the major constituent in the EO from the flowers of B. sulphurea, was not detected in this study.

  6. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens

    PubMed Central

    Tiwari, Vishvanath; Roy, Ranita; Tiwari, Monalisa

    2015-01-01

    Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem. PMID:26150810

  7. Synthesis and antimicrobial activity of some novel dicationic sulphonophanes.

    PubMed

    Rajakumar, Perumal; Satheeshkumar, Chinnadurai; Mohanraj, Gunasekaran; Mathivanan, Narayanasamy

    2011-07-01

    The synthesis of some novel imidazole-based dicationic sulfonophanes incorporating various spacer units is described. All the sulphonophanes exhibit good antibacterial and antifungal activity against five bacterial strains Bacillus subtilis, Staphylococcus aureus, Vibrio cholera, Escherichia coli, Proteus vulgaris and human pathogenic fungus Candida albicans.

  8. Comparative antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solutions evaluated using a novel standardized assay.

    PubMed

    Thorn, R M S; Robinson, G M; Reynolds, D M

    2013-05-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces.

  9. Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay

    PubMed Central

    Thorn, R. M. S.; Robinson, G. M.

    2013-01-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces. PMID:23459480

  10. Evaluation of three medicinal plants for anti-microbial activity.

    PubMed

    Pratap, Gowd M J S; Manoj, Kumar M G; Sai, Shankar A J; Sujatha, B; Sreedevi, E

    2012-07-01

    Herbal remedies have a long history of use for gum and tooth problems such as dental caries. The present microbiological study was carried out to evaluate the antimicrobial efficacy of three medicinal plants (Terminalia chebula Retz., Clitoria ternatea Linn., and Wedelia chinensis (Osbeck.) Merr.) on three pathogenic microorganisms in the oral cavity (Streptococcus mutans, Lactobacillus casei, and Staphylococcus aureus). Aqueous extract concentrations (5%, 10%, 25%, and 50%) were prepared from the fruits of Terminalia chebula, flowers of Clitoria ternatea, and leaves of Wedelia chinensis. The antimicrobial efficacy of the aqueous extract concentrations of each plant was tested using agar well diffusion method and the size of the inhibition zone was measured in millimeters. The results obtained showed that the diameter of zone of inhibition increased with increase in concentration of extract and the antimicrobial efficacy of the aqueous extracts of the three plants was observed in the increasing order - Wedelia chinensis < Clitoria ternatea < Terminalia chebula. It can be concluded that the tested extracts of all the three plants were effective against dental caries causing bacteria.

  11. Structure and antimicrobial activity of platypus 'intermediate' defensin-like peptide.

    PubMed

    Torres, Allan M; Bansal, Paramjit; Koh, Jennifer M S; Pagès, Guilhem; Wu, Ming J; Kuchel, Philip W

    2014-05-02

    The three-dimensional structure of a chemically synthesized peptide that we have called 'intermediate' defensin-like peptide (Int-DLP), from the platypus genome, was determined by nuclear magnetic resonance (NMR) spectroscopy; and its antimicrobial activity was investigated. The overall structural fold of Int-DLP was similar to that of the DLPs and β-defensins, however the presence of a third antiparallel β-strand makes its structure more similar to the β-defensins than the DLPs. Int-DLP displayed potent antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The four arginine residues at the N-terminus of Int-DLP did not affect the overall fold, but were important for its antimicrobial potency.

  12. Effect of pH on the formation of lysosome-alginate beads for antimicrobial activity.

    PubMed

    Park, Hyun Jung; Min, Jiho; Ahn, Joo-Myung; Cho, Sung-Jin; Ahn, Ji-Young; Kim, Yang-Hoon

    2015-02-01

    In this study, we developed lysosome-alginate beads for application as an oral drug delivery system (ODDS). The beads harboring lysosomes, which have antimicrobial activity, and various concentrations of alginate were characterized and optimized. For application as an ODDS, pH-dependent lysosome-alginate beads were generated, and the level of lysosome release was investigated by using antimicrobial tests. At low pH, lysosomes were not released from the lysosome-alginate beads; however, at neutral pH, similar to the pH in the intestine, lysosome release was confirmed, as determined by a high antimicrobial activity. This study shows the potential of such an ODDS for the in vivo treatment of infection with pathogens.

  13. LEAP-1, a novel highly disulfide-bonded human peptide, exhibits antimicrobial activity.

    PubMed

    Krause, A; Neitz, S; Mägert, H J; Schulz, A; Forssmann, W G; Schulz-Knappe, P; Adermann, K

    2000-09-01

    We report the isolation and characterization of a novel human peptide with antimicrobial activity, termed LEAP-1 (liver-expressed antimicrobial peptide). Using a mass spectrometric assay detecting cysteine-rich peptides, a 25-residue peptide containing four disulfide bonds was identified in human blood ultrafiltrate. LEAP-1 expression was predominantly detected in the liver, and, to a much lower extent, in the heart. In radial diffusion assays, Gram-positive Bacillus megaterium, Bacillus subtilis, Micrococcus luteus, Staphylococcus carnosus, and Gram-negative Neisseria cinerea as well as the yeast Saccharomyces cerevisiae dose-dependently exhibited sensitivity upon treatment with synthetic LEAP-1. The discovery of LEAP-1 extends the known families of mammalian peptides with antimicrobial activity by its novel disulfide motif and distinct expression pattern.

  14. Enzyme-assisted processing increases antimicrobial and antioxidant activity of bilberry.

    PubMed

    Puupponen-Pimiä, Riitta; Nohynek, Liisa; Ammann, Sabine; Oksman-Caldentey, Kirsi-Marja; Buchert, Johanna

    2008-02-13

    The effects of nine cell wall-degrading enzymes on the antimicrobial and antioxidant activities of bilberry were studied. Antimicrobial activity was measured using the human pathogens Salmonella enterica sv. Typhimurium and Staphylococcus aureus as test strains. Enzyme treatments liberated phenolics from the cell wall matrix, which clearly increased the antimicrobial activity of berry juices, press cakes, and berry mashes on the basis of plate counts. Antibacterial effects were stronger against Salmonella than against Staphylococcus bacteria. In general, the increase in activity measured as colony-forming units per milliliter was 3-5 logarithmic units against Salmonella and 1-2 units against Staphylococcus bacteria. Increase in antimicrobial activity was observed only in acidic conditions, which is also the natural environment in various berry products, such as juices. The activity profile of the pectinase preparation affected the chemistry of the phenolics due to the presence of deglycosylating activities in some preparations. The difference in phenolic profiles was reflected in the antimicrobial effects. Bilberry mashes treated with Pectinex Ultra SP-L, Pectinex 3 XL, and Pectinex BE XXL were most efficient against Salmonella bacteria, whereas mashes treated with Pectinex Smash, Pectinex BE 3-L, and Biopectinase CCM showed the strongest antimicrobial activity against Staphylococcus bacteria. Due to the liberation of phenolics from the cell wall matrix the antioxidant activity measured as radical scavenging activity was also increased on average about 30% by the enzymatic treatments. The highest increase in phenolic compounds was about 40%. Highest increases in anthocyanins and in antioxidant activity were observed in berry mash treated with Pectinex Smash XXL enzyme, and the lowest increase was observed after treatment with Pectinex BE 3-L. Enzyme-assisted processing is traditionally used to improve berry and fruit juice yields. However, enzymatic treatments also

  15. Antimicrobial Activity of 8-Quinolinols, Salicylic Acids, Hydroxynaphthoic Acids, and Salts of Selected Quinolinols with Selected Hydroxy-Acids

    PubMed Central

    Gershon, Herman; Parmegiani, Raulo

    1962-01-01

    Seventy-seven compounds were screened by the disc-plate method against strains of five bacteria and five fungi. A new constant was proposed to describe the antimicrobial activity of a compound in a defined system of organisms. This constant includes not only the inhibitory level of activity of the material but also the number of organisms inhibited. This constant, the antimicrobial spectrum index, was compared with the antimicrobial index of Albert. PMID:13898066

  16. Antimicrobial Activity of Croton macrostachyus Stem Bark Extracts against Several Human Pathogenic Bacteria

    PubMed Central

    Obey, Jackie K.; von Wright, Atte; Orjala, Jimmy; Kauhanen, Jussi; Tikkanen-Kaukanen, Carina

    2016-01-01

    In Kenya, leaves and roots from Croton macrostachyus are used as a traditional medicine for infectious diseases such as typhoid and measles, but reports on possible antimicrobial activity of stem bark do not exist. In this study, the antibacterial and antifungal effects of methanol, ethyl acetate and butanol extracts, and purified lupeol of C. macrostachyus stem bark were determined against important human gram-negative pathogens Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, and Enterobacter aerogenes, gram-positive Listeria monocytogenes, and a fungus Candida albicans. The most promising broad scale antimicrobial activity against all the studied pathogens was shown by the ethyl acetate extract. The ethyl acetate extract induced the zone of inhibition between 10.1 ± 0.6 mm and 16.0 ± 1.2 mm against S. typhi, E. coli, K. pneumoniae, E. aerogenes, and L. monocytogenes with weaker antimicrobial activity against C. albicans (zone of inhibition: 5.6 ± 1.0 mm). The antibiotic controls (amoxicillin, ciprofloxacin, ampicillin, benzylpenicillin, clotrimazole, and cefotaxime) showed antimicrobial activity with zones of inhibition within 13.4 ± 0.7–22.1 ± 0.9 mm. The ethyl acetate extract had MIC in the range of 125–250 mg/mL against all the studied bacteria and against C. albicans MIC was 500 mg/mL. The present results give scientific evidence and support the traditional use of C. macrostachyus stem bark as a source for antimicrobials. We show that C. macrostachyus stem bark lupeol is a promising antimicrobial agent against several important human pathogens. PMID:27293897

  17. Antimicrobial activity of various 4- and 5-substituted 1-phenylnaphthalenes

    PubMed Central

    Kelley, Cody; Lu, Songfeng; Parhi, Ajit; Kaul, Malvika; Pilch, Daniel S.; LaVoie, Edmond J.

    2014-01-01

    Bacterial cell division occurs in conjunction with the formation of a cytokinetic Z-ring structure comprised of FtsZ subunits. Agents that can disrupt Z-ring formation have the potential, through this unique mechanism, to be effective against several of the newly emerging multi-drug resistant strains of infectious bacteria. 1- and 12-Aryl substituted benzo[c]phenanthridines have been identified as antibacterial agents that could exert their activity by disruption of Z-ring formation. Substituted 4- and 5-amino-1-phenylnaphthalenes represent substructures within the pharmacophore of these benzo[c]phenanthridines. Several 4- and 5-substituted 1-phenylnaphthalenes were synthesized and evaluated for antibacterial activity against Staphylococcus aureus and Enterococcus faecalis. The impact of select compounds on the polymerization dynamics of S. aureus FtsZ was also assessed. PMID:23314053

  18. Antimicrobial Dendrimeric Peptides: Structure, Activity and New Therapeutic Applications

    PubMed Central

    Scorciapino, Mariano A.; Serra, Ilaria; Manzo, Giorgia; Rinaldi, Andrea C.

    2017-01-01

    Microbial resistance to conventional antibiotics is one of the most outstanding medical and scientific challenges of our times. Despite the recognised need for new anti-infective agents, however, very few new drugs have been brought to the market and to the clinic in the last three decades. This review highlights the properties of a new class of antibiotics, namely dendrimeric peptides. These intriguing novel compounds, generally made of multiple peptidic sequences linked to an inner branched core, display an array of antibacterial, antiviral and antifungal activities, usually coupled to low haemolytic activity. In addition, several peptides synthesized in oligobranched form proved to be promising tools for the selective treatment of cancer cells. PMID:28273806

  19. Antimicrobial activity of plant extracts against sexually transmitted pathogens.

    PubMed

    Jadhav, Nutan; Kulkarni, Sangeeta; Mane, Arati; Kulkarni, Roshan; Palshetker, Aparna; Singh, Kamalinder; Joshi, Swati; Risbud, Arun; Kulkarni, Smita

    2015-01-01

    Comprehensive management of sexually transmitted infections (STIs) using vaginal or rectal microbicide-based intervention is one of the strategies for prevention of HIV infection. Herbal products have been used for treating STIs traditionally. Herein, we present in vitro activity of 10 plant extracts and their 34 fractions against three sexually transmitted/reproductive tract pathogens - Neisseria gonorrhoeae, Haemophilus ducreyi and Candida albicans. The plant parts were selected; the extracts/fractions were prepared and screened by disc diffusion method. The minimum inhibitory and minimum cidal concentrations were determined. The qualitative phytochemical analysis of selected extracts/fractions showing activity was performed. Of the extracts/fractions tested, three inhibited C. albicans, ten inhibited N. gonorrhoeae and five inhibited H. ducreyi growth. Our study demonstrated that Terminalia paniculata Roth. extracts/fractions inhibited growth of all three organisms. The ethyl acetate fraction of Syzygium cumini Linn. and Bridelia retusa (L.) Spreng. extracts was found to inhibit N. gonorrhoeae at lowest concentrations.

  20. Antimicrobial and antioxidant activities of essential oils of Satureja thymbra growing wild in Libya.

    PubMed

    Giweli, Abdulhmid; Džamić, Ana M; Soković, Marina; Ristić, Mihailo S; Marin, Petar D

    2012-04-26

    The composition of essential oil isolated from Satureja thymbra, growing wild in Libya, was analyzed by GC and GC-MS. The essential oil was characterized by γ-terpinene (39.23%), thymol (25.16%), p-cymene (7.17%) and carvacrol (4.18%) as the major constituents. Antioxidant activity was analyzed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. It possessed strong antioxidant activity (IC50 = 0.0967 mg/mL). The essential oil was also screened for its antimicrobial activity against eight bacterial and eight fungal species, showing excellent antimicrobial activity against the microorganisms used, in particular against the fungi. The oil of S. thymbra showed bacteriostatic activity at 0.001-0.1 mg/mL and was bactericidal at 0.002-0.2 mg/mL; fungistatic effects at 0.001-0.025 mg/mL and fungicidal effects at 0.001-0.1 mg/mL. The main constituents thymol, carvacrol and γ-terpinene also showed strong antimicrobial activity. The commercial fungicide bifonazole showed much lower antifungal activity than the tested oil.

  1. Synthesis and characterization of some abundant nanoparticles, their antimicrobial and enzyme inhibition activity.

    PubMed

    Khan, Shams T; Malik, Ajmaluddin; Wahab, Rizwan; Abd-Elkader, Omar H; Ahamed, Maqusood; Ahmad, Javed; Musarrat, Javed; Siddiqui, Maqsood A; Al-Khedhairy, Abdulaziz A

    2017-02-20

    Although the antimicrobial activity of the engineered nanoparticles (NPs) is well known, the biochemical mechanisms underlying this activity are not clearly understood. Therefore, four NPs with the highest global production, namely SiO2, TiO2, ZnO, and Ag, were synthesized and characterized. The synthesized SiO2, TiO2, ZnO, and Ag NPs exhibit an average size of 11.12, 13.4, 35, and 50 nm, respectively. The antimicrobial activity of the synthesized NPs against bacteria and fungi were also determined. NPs-mediated inhibition of two very important enzymes, namely urease and DNA polymerase, is also reported. The synthesized NPs especially Ag and ZnO show significant antimicrobial activity against bacteria and fungi including methicillin-resistant Staphylococcus aureus even at low concentration. The DNA polymerase activity was inhibited at a very low concentration range of 2-4 µg/ml, whereas the urease activity was inhibited at a high concentration range of 50-100 µg/ml. Based on their ability to inhibit the urease and DNA polymerase, NPs can be arranged in the following order: Ag > ZnO > SiO2 > TiO2 and Ag > SiO2 > ZnO > TiO2, respectively. As the synthesized NPs inhibit bacterial growth and suppress the activity of urease and DNA polymerase, the use of these NPs to control pathogens is proposed.

  2. Chemical Compositions, Antioxidant and Antimicrobial Activities of Essential Oils of Piper caninum Blume

    PubMed Central

    Salleh, Wan Mohd Nuzul Hakimi Wan; Ahmad, Farediah; Yen, Khong Heng; Sirat, Hasnah Mohd

    2011-01-01

    Chemical composition, antioxidant and antimicrobial activities of the fresh leaves and stems oils of Piper caninum were investigated. A total of forty eight constituents were identified in the leaves (77.9%) and stems (87.0%) oil which were characterized by high proportions of phenylpropanoid, safrole with 17.1% for leaves and 25.5% for stems oil. Antioxidant activities were evaluated by using β-carotene/linoleic acid bleaching, DPPH radical scavenging and total phenolic content. Stems oil showed the highest inhibitory activity towards lipid peroxidation (114.9 ± 0.9%), compared to BHT (95.5 ± 0.5%), while leaves oil showed significant total phenolic content (27.4 ± 0.5 mg GA/g) equivalent to gallic acid. However, the essential oils showed weak activity towards DPPH free-radical scavenging. Evaluation of antimicrobial activity revealed that both oils exhibited strong activity against all bacteria strains with MIC values in the range 62.5 to 250 μg/mL, but weak activity against fungal strains. These findings suggest that the essential oils can be used as antioxidant and antimicrobial agents for therapeutic, nutraceutical industries and food manufactures. PMID:22174627

  3. Total antioxidant activity and antimicrobial potency of the essential oil and oleoresin of Zingiber officinale Roscoe

    PubMed Central

    Bellik, Yuva

    2014-01-01

    Objective To compare in vitro antioxidant and antimicrobial activities of the essential oil and oleoresin of Zingiber officinale Roscoe. Methods The antioxidant activity was evaluated based on the ability of the ginger extracts to scavenge ABTS°+ free radical. The antimicrobial activity was studied by the disc diffusion method and minimal inhibitory concentration was determined by using the agar incorporation method. Results Ginger extracts exerted significant antioxidant activity and dose-depend effect. In general, oleoresin showed higher antioxidant activity [IC50=(1.820±0.034) mg/mL] when compared to the essential oil [IC50=(110.14±8.44) mg/mL]. In terms of antimicrobial activity, ginger compounds were more effective against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, and less effective against Bacillus cereus. Aspergillus niger was least, whereas, Penicillium spp. was higher sensitive to the ginger extracts; minimal inhibitory concentrations of the oleoresin and essential oil were 2 mg/mL and 869.2 mg/mL, respectively. Moreover, the studied extracts showed an important antifungal activity against Candida albicans. Conclusions The study confirms the wide application of ginger oleoresin and essential oil in the treatment of many bacterial and fungal diseases.

  4. Antimicrobial activity of an endophytic Xylaria sp.YX-28 and identification of its antimicrobial compound 7-amino-4-methylcoumarin.

    PubMed

    Liu, Xiaoli; Dong, Mingsheng; Chen, Xiaohong; Jiang, Mei; Lv, Xin; Zhou, Jianzhong

    2008-02-01

    An endophytic Xylaria sp., having broad antimicrobial activity, was isolated and characterized from Ginkgo biloba L. From the culture extracts of this fungus, a bioactive compound P3 was isolated by bioactivity-guided fractionation and identified as 7-amino-4-methylcoumarin by nuclear magnetic resonance, infrared, and mass spectrometry spectral data. The compound showed strong antibacterial and antifungal activities in vitro against Staphylococcus aureus [minimal inhibitory concentrations (MIC) 16 microg.ml(-1)], Escherichia coli (MIC, 10 microg.ml(-1)), Salmonella typhia (MIC, 20 microg.ml(-1)), Salmonella typhimurium (MIC, 15 microg.ml(-1)), Salmonella enteritidis (MIC, 8.5 microg.ml(-1)), Aeromonas hydrophila (MIC, 4 microg.ml(-1)), Yersinia sp. (MIC, 12.5 microg.ml(-1)), Vibrio anguillarum (MIC, 25 microg.ml(-1)), Shigella sp. (MIC, 6.3 microg.ml(-1)), Vibrio parahaemolyticus (MIC, 12.5 microg.ml(-1)), Candida albicans (MIC, 15 microg.ml(-1)), Penicillium expansum (MIC, 40 microg.ml(-1)), and Aspergillus niger (MIC, 25 microg.ml(-1)). This is the first report of 7-amino-4-methylcoumarin in fungus and of the antimicrobial activity of this metabolite. The obtained results provide promising baseline information for the potential use of this unusual endophytic fungus and its components in the control of food spoilage and food-borne diseases.

  5. Antimicrobial activities of N-chloramines and diazolidinyl urea.

    PubMed Central

    Llabres, C M; Ahearn, D G

    1985-01-01

    A combination of MICs of an N-chloramine, a simple chlorinated amino acid, and diazolidinyl urea gave synergistic activity against bacteria, but not fungi. The two compounds at a higher concentration, 0.1 and 0.3%, respectively, gave synergistic inhibition of fungi; kill times were 1 h for Trichophyton tonsurans, 3 h for Aspergillus niger and Fusarium moniliforme, and 6 h for Aspergillus fumigatus. PMID:3920962

  6. Optimized antimicrobial and antiproliferative activities of titanate nanofibers containing silver

    PubMed Central

    Su, Yong Hua; Yin, Zi Fei; Xin, Hai Liang; Zhang, Hui Qing; Sheng, Jia Yu; Yang, Yan Long; Du, Juan; Ling, Chang Quan

    2011-01-01

    Titanate nanofibers containing silver have been demonstrated through the experiments reported herein to have effective antifungal and antiproliferative activities in the presence of UV light. The titanate nanofibers containing silver can be fabricated by means of ion exchange followed by a topochemical process in an environment suitable for reductive reactions. Excellent antibacterial, antifungal, and antiproliferative activities could be demonstrated by both Ag2Ti5O11 · xH2O and Ag/titanate (UV light irradiation) due to their unique structures and compositions, which have photocatalytic activities to generate reactive oxygen species and capabilities to continuously release the silver ions. Therefore these materials have the potential to produce a membrane for the treatment of superficial malignant tumor, esophageal cancer, or cervical carcinoma. They may also hold utility if incorporated into a coating on stents in moderate and advanced stage esophageal carcinoma or for endoscopic retrograde biliary drainage. These approaches may significantly reduce infections, inhibit tumor growth, and importantly, improve quality of life and prolong survival time for patients with tumors. PMID:21845048

  7. Draft Genome Sequence of Lactobacillus crispatus EM-LC1, an Isolate with Antimicrobial Activity Cultured from an Elderly Subject.

    PubMed

    Power, Susan E; Harris, Hugh M B; Bottacini, Francesca; Ross, R Paul; O'Toole, Paul W; Fitzgerald, Gerald F

    2013-12-19

    Here we report the 1.86-Mb draft genome sequence of Lactobacillus crispatus EM-LC1, a fecal isolate with antimicrobial activity. This genome sequence is expected to provide insights into the antimicrobial activity of L. crispatus and improve our knowledge of its potential probiotic traits.

  8. Antimicrobial activity of different filling pastes for deciduous tooth treatment.

    PubMed

    Antoniazzi, Bruna Feltrin; Pires, Carine Weber; Bresolin, Carmela Rampazzo; Weiss, Rita Niederauer; Praetzel, Juliana Rodrigues

    2015-01-01

    Guedes-Pinto paste is the filling material most employed in Brazil for endodontic treatment of deciduous teeth; however, the Rifocort® ointment has been removed. Thus, the aim of this study was to investigate the antimicrobial potential of filling pastes, by proposing three new pharmacological associations to replace Rifocort® ointment with drugs of already established antimicrobial power: Nebacetin® ointment, 2% Chlorhexidine Gluconate gel, and Maxitrol® ointment. A paste composed of Iodoform, Rifocort® ointment and Camphorated Paramonochlorophenol (CPC) was employed as the gold standard (G1). The other associations were: Iodoform, Nebacetin® ointment and CPC (G2); Iodoform, 2% Chlorhexidine Digluconate gel and CPC (G3); Iodoform, Maxitrol® ointment and CPC (G4). The associations were tested for Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus oralis (S. oralis), Enterococcus faecalis (E. faecalis), Escherichia coli (E. coli), and Bacillus subtilis (B. subtilis), using the methods of dilution on solid medium - orifice agar - and broth dilution. The results were tested using statistical analysis ANOVA and Kruskal-Wallis. They showed that all the pastes had a bacteriostatic effect on all the microorganisms, without any statistically significant difference, compared with G1. S. aureus was statistically significant (multiple comparison test of Tukey), insofar as G2 and G3 presented the worst and the best performance, respectively. All associations were bactericidal for E. coli, S. aureus, S. mutans and S. oralis. Only G3 and G4 were bactericidal for E. faecalis, whereas no product was bactericidal for B. subtilis. Thus, the tested pastes have antimicrobial potential and have proved acceptable for endodontic treatment of primary teeth.

  9. Assessment of factors influencing antimicrobial activity of carvacrol and cymene against Vibrio cholerae in food.

    PubMed

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2010-11-01

    Carvacrol and cymene, phenolic compounds naturally present in the essential oil of oregano and thyme, were examined for their antimicrobial activity against Vibrio cholerae (ATCC 14033, VC1, and VC7) inoculated in carrot juice. Carvacrol exhibited a dose dependent inhibitory effect on the bacteria. Although cymene did not have antimicrobial activity against the bacteria, it enhanced the inhibitory ability of carvacrol. At 25 °C, the lowest concentrations of carvacrol and cymene required for zero detectable viable count varied depending on bacterial strains; 5 and 5 ppm, respectively, for VC7; 5 and 7.5 ppm, respectively, for VC1; and 7.5 and 7.5 ppm, respectively, for ATCC 14033. This study also examined several factors influencing the antimicrobial activity of carvacrol and cymene against V. cholerae ATCC 14033, including temperature, bacterial cell number, and food substrate. Carvacrol and cymene inhibited the bacterium in carrot juice at 25 °C more efficiently than at 15 and 4 °C. The doses of both compounds required for zero detectable viable count increased as the number of the bacterial cells in the carrot juice increased. The fat content and the complexity of foods were shown to decrease the antimicrobial activity of the compounds.

  10. Antimicrobial activity of essential oils against E. coli O157:H7 in organic soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil can be a significant source of preharvest contamination of produce by pathogens. Demand for natural pesticides such as essential oils for organic farming continues to increase. Antimicrobial activity of essential oils in vitro has been well documented, but there is no information about their ef...

  11. Improvement of in vivo antimicrobial activity of HBcARD peptides by D-arginine replacement.

    PubMed

    Chen, Heng-Li; Su, Pei-Yi; Shih, Chiaho

    2016-11-01

    We previously identified a novel antimicrobial peptide with a broad spectrum bactericidal activity from human hepatitis B virus (HBV) core protein (HBc) arginine-rich domain (ARD). We compared the antimicrobial activities of HBcARD peptides from different hepadnaviruses which share similar amino acid sequences. In general, mammalian HBcARD peptides exhibited stronger antimicrobial activity than avian peptides. Using the strategy of D-amino acid substitutions, we improved the antimicrobial efficacy of human HBcARD peptide. This D-HBcARD peptide was much more resistant than L-HBcARD peptide to proteolytic degradation in vitro. Moreover, this D-HBcARD peptide maintained similar minimal bactericidal concentrations (MBC) against tested bacteria, and showed very low hemolytic activity. In the Staphylococcus aureus-infected mouse model, this D-HBcARD peptide was more protective than the L-HBcARD peptide. Repeated treatments with either L- or D-HBcARD peptides induced no significant immunogenicity. New derivatives of HBcARD peptides could serve as alternatives to the conventional antibiotics in clinical medicine in the future.

  12. Antimicrobial profile of some novel keto esters: Synthesis, crystal structures and structure-activity relationship studies.

    PubMed

    Khan, Imtiaz; Saeed, Aamer; Arshad, Mohammad Ifzan; White, Jonathan Michael

    2016-01-01

    Rapid increase in bacterial resistance has become a major public concern by escalating alongside a lack of development of new anti-infective drugs. Novel remedies in the battle against multidrug-resistant bacterial strains are urgently needed. So, in this context, the present work is towards the investigation of antimicrobial efficacy of some novel keto ester derivatives, which are prepared by the condensation of substituted benzoic acids with various substituted phenacyl bromides in dimethylformamide at room temperature using triethylamine as a catalyst. The structural build-up of the target compounds was accomplished by spectroscopic techniques including FTIR, (1)H and (13)C NMR spectroscopy and mass spectrometry. The purity of the synthesized compounds was ascertained by elemental analysis. The molecular structures of compounds (4b) and (4l) were established by X-ray crystallographic analysis. The prepared analogues were evaluated for their antimicrobial activity against Gram-positive (Staphylococcus aureus, Micrococcus leuteus) and Gram-negative (Pseudomonas picketti, Salmonella setuball) bacteria and two fungal pathogenic strains (Aspergillus niger, Aspergillus flavus), respectively. Among the screened derivatives, several compounds were found to possess significant activity but (4b) and (4l) turned out to be lead molecules with remarkable antimicrobial efficacy. The structure-activity relationship analysis of this study also revealed that structural modifications on the basic skeleton affected the antimicrobial activity of the synthesized compounds.

  13. Chemical compositions and antimicrobial activities of four different Anatolian propolis samples.

    PubMed

    Uzel, Ataç; Sorkun, Kadriye; Onçağ, Ozant; Cogŭlu, Dilşah; Gençay, Omür; Salih, Bekir

    2005-01-01

    Propolis means a gum that is gathered by bees from various plants. It is known for its biological properties, having antibacterial, antifungal and healing properties. The aims of this study were to evaluate the antimicrobial activity of four different Anatolian propolis samples on different groups of microorganisms including some oral pathogens and comparison between their chemical compositions. Ethanol extracts of propolis (EEP) were prepared from four different Anatolian propolis samples and examined whether EEP inhibit the growth of the test microorganisms or not. For the antimicrobial activity assays, minimum inhibitory concentrations (MIC) were determined by using macrodilution method. The MIC values of the most effective propolis (TB) were 2 microg/ml for Streptococcus sobrinus and Enterococcus faecalis, 4 microg/ml for Micrococcus luteus, Candida albicans and C. krusei, 8 microg/ml for Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis and Enterobacter aerogenes, 16 microg/ml for Escherichia coli and C. tropicalis and 32 microg/ml for Salmonella typhimurium and Pseudomonas aeruginosa. The chemical compositions of EEP's were determined by high-temperature high-resolution gas chromatography coupled to mass spectrometry. The main compounds of four Anatolian propolis samples were flavonoids such as pinocembrin, pinostropin, isalpinin, pinobanksin, quercetin, naringenin, galangine and chrysin. Although propolis samples were collected from different regions of Anatolia all showed significant antimicrobial activity against the Gram positive bacteria and yeasts. Propolis can prevent dental caries since it demonstrated significant antimicrobial activity against the microorganisms such as Streptococcus mutans, Streptococcus sobrinus and C. albicans, which involves in oral diseases.

  14. Complete genome of Bacillus sp. Pc3 isolated from the Antarctic seawater with antimicrobial activity.

    PubMed

    Guo, Wenbin; Cui, Pengfei; Chen, Xinhua

    2015-04-01

    Bacillus sp. Pc3 was isolated from the Antarctic seawater with strong antifungal activity against several plant pathogenic fungi. Here, we report the complete sequence of the 3.9-Mbp genome of this strain. The genome sequence may provide fundamental molecular information on elucidating the metabolic pathway of antimicrobial compounds in this strain.

  15. Antimicrobial activity of essential oil and various extracts of fruits of greater cardamom.

    PubMed

    Agnihotri, Supriya; Wakode, S

    2010-09-01

    Greater cardamom (Amomum subulatum Roxb. Zingiberaceae) commonly known as "Bari ilaichi" is a well known plant used in Ayurvedic and Unani medicine. It has been used for the treatment of various diseases and disorders like gastric ulcer. Therefore antimicrobial activity of petroleum ether, methanol and aqueous extracts from leaves and roots, essential oil and isolated vasicine from A. vasica were tested against various microorganisms. Antimicrobial activity was done by disc diffusion method. The zone of inhibition observed was compared with that of standard drugs, ciprofloxacin and fluconazole. Minimum inhibitory concentration was determined against microorganisms used in the study. The results of this study reveal that methanol extract of fruits of A. subulatum shows remarkable antimicrobial activity against Escherichia coli whereas in case of other microorganisms used it was found inferior to the standard drug used. Methanol extract of rind showed good antimicrobial activity against Staphylococcus aureus. It was found that the essential oil isolated was effective against majority of microorganisms used viz. Bacillus pumilus, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Saccharomyces cerevisiae.

  16. Activity of an antimicrobial peptide mimetic against planktonic and biofilm cultures of oral pathogens.

    PubMed

    Beckloff, Nicholas; Laube, Danielle; Castro, Tammy; Furgang, David; Park, Steven; Perlin, David; Clements, Dylan; Tang, Haizhong; Scott, Richard W; Tew, Gregory N; Diamond, Gill

    2007-11-01

    Antimicrobial peptides (AMPs) are naturally occurring, broad-spectrum antimicrobial agents that have recently been examined for their utility as therapeutic antibiotics. Unfortunately, they are expensive to produce and are often sensitive to protease digestion. To address this problem, we have examined the activity of a peptide mimetic whose design was based on the structure of magainin, exhibiting its amphiphilic structure. We demonstrate that this compound, meta-phenylene ethynylene (mPE), exhibits antimicrobial activity at nanomolar concentrations against a variety of bacterial and Candida species found in oral infections. Since Streptococcus mutans, an etiological agent of dental caries, colonizes the tooth surface and forms a biofilm, we quantified the activity of this compound against S. mutans growing under conditions that favor biofilm formation. Our results indicate that mPE can prevent the formation of a biofilm at nanomolar concentrations. Incubation with 5 nM mPE prevents further growth of the biofilm, and 100 nM mPE reduces viable bacteria in the biofilm by 3 logs. Structure-function analyses suggest that mPE inhibits the bioactivity of lipopolysaccharide and binds DNA at equimolar ratios, suggesting that it may act both as a membrane-active molecule, similar to magainin, and as an intracellular antibiotic, similar to other AMPs. We conclude that mPE and similar molecules display great potential for development as therapeutic antimicrobials.

  17. Imidazolium tagged acridines: Synthesis, characterization and applications in DNA binding and anti-microbial activities

    NASA Astrophysics Data System (ADS)

    Raju, Gembali; Vishwanath, S.; Prasad, Archana; Patel, Basant K.; Prabusankar, Ganesan

    2016-03-01

    New water soluble 4,5-bis imidazolium tagged acridines have been synthesized and structurally characterized by multinuclear NMR and single crystal X-ray diffraction techniques. The DNA binding and anti-microbial activities of these acridine derivatives were investigated by fluorescence and far-UV circular dichroism studies.

  18. Complete Genome Sequence of a Staphylococcus epidermidis Strain with Exceptional Antimicrobial Activity

    PubMed Central

    Lassen, Simon B.; Lomholt, Hans B.

    2017-01-01

    ABSTRACT Staphylococcus epidermidis is a Gram-positive bacterium that is prevalent on human skin. The species is associated with skin health, as well as with opportunistic infections. Here, we report the complete genome sequence of S. epidermidis 14.1.R1, isolated from human skin. In bacterial interference assays, the strain showed exceptional antimicrobial activity. PMID:28280007

  19. Antimicrobial activity of snakin-defensin hybrid protein in tobacco and potato plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To augment plant protection against phytopathogens, we constructed a fusion gene for the simultaneous expression of snakin-1 (SN1) and defensin-1 (PTH1) antimicrobial proteins as a hybrid protein (SAP) in plant cells. Prior to in vivo evaluation of SAP phytoprotective activity, the hybrid protein ex...

  20. ANTIMICROBIAL ACTIVITY OF COPPER AND ZINC ACCUMULATED BY EASTERN OYSTER AMEBOCYTES

    EPA Science Inventory

    Fisher, William S. Submitted. Antimicrobial Activity of Copper and Zinc Accumulated by Eastern Oyster Amebocytes. J. Shellfish Res. 54 p. (ERL,GB 1196).

    The distribution of eastern oysters Crassostrea virginica near terrestrial watersheds has led to a general impression t...

  1. Structure-activity relationships for the beta-hairpin cationic antimicrobial peptide polyphemusin I.

    PubMed

    Powers, Jon-Paul S; Rozek, Annett; Hancock, Robert E W

    2004-05-06

    The solution structure of polyphemusin I was determined using (1)H-NMR spectroscopy. Polyphemusin I was found to be an amphipathic, beta-hairpin connected by a type I' beta-turn. The 17 low-energy structures aligned very well over the beta-sheet region while both termini were poorly defined due in part to a hinge-like region centred in the molecule about arginine residues 6 and 16. Conversely, a linear analogue, PM1-S, with all cysteines simultaneously replaced with serine was found to be dynamic in nature, and a lack of medium and long-range NOEs indicated that this molecule displayed no favoured conformation. Circular dichroism (CD) spectroscopy confirmed that in solution, 50% trifluoroethanol (TFE) and in the presence of liposomes, PM1-S remained unstructured. The antimicrobial activity of PM1-S was found to be 4- to 16-fold less than that of polyphemusin I and corresponded with a 4-fold reduction in bacterial membrane depolarization. Both peptides were able to associate with lipid bilayers in a similar fashion; however, PM1-S was completely unable to translocate model membranes while polyphemusin I retained this activity. It was concluded that the disulfide-constrained, beta-sheet structure of polyphemusin I is required for maximum antimicrobial activity. Disruption of this structure results in reduced antimicrobial activity and completely abolishes membrane translocation indicating that the linear PM1-S acts through a different antimicrobial mechanism.

  2. Molecular mechanisms behind the antimicrobial activity of hop iso-α-acids in Lactobacillus brevis.

    PubMed

    Schurr, Benjamin C; Hahne, Hannes; Kuster, Bernhard; Behr, Jürgen; Vogel, Rudi F

    2015-04-01

    The main bittering component in beer, hop iso-α-acids, have been characterised as weak acids, which act as ionophores impairing microbial cells' function under acidic conditions as present in beer. Besides medium pH, divalent cations play a central role regarding the efficacy of the antimicrobial effect. The iso-α-acids' non-bitter derivatives humulinic acids can be found in isomerised hop extracts and can be generated during hop storage. Therefore, they have been under investigation concerning their influence on beer sensory properties. This study sketches the molecular mechanism behind iso-α-acids' antimicrobial activity in Lactobacillus (L.) brevis regarding their ionophore activity versus the dependence of the inhibitory potential on manganese binding, and suggests humulinic acids as novel tasteless food preservatives. We designed and synthesised chemically modified iso-α-acids to enhance the basic understanding of the molecular mechanism of antimicrobial iso-α-acids. It could be observed that a manganese-binding dependent transmembrane redox reaction (oxidative stress) plays a crucial role in inhibition. Privation of an acidic hydroxyl group neither erased ionophore activity, nor did it entirely abolish antimicrobial activity. Humulinic acids proved to be highly inhibitory, even outperforming iso-α-acids.

  3. Membrane-active Antimicrobial Peptides as Template Structures for Novel Antibiotic Agents.

    PubMed

    Lohner, Karl

    2017-01-01

    The increase of pathogens being resistant to antibiotics represents a global health problem and therefore it is a pressing need to develop antibiotics with novel mechanisms of action. Host defense peptides, which have direct antimicrobial activity (also termed antimicrobial peptides) or immune modulating activity, are valuable template structures for the development of such compounds. Antimicrobial peptides exhibit remarkably different structures as well as biological activity profiles with multiple targets. A large fraction of these peptides interfere physically with the cell membrane of bacteria (focus of this review), but can also translocate into the cytosol, where they interact with nucleic acids, ribosomes and proteins. Several potential interaction sites have to be considered on the route of the peptides from the environment to the cytoplasmic membrane. Translocation of peptides through the cell wall may not be impaired by the thick but relatively porous peptidoglycan layer. However, interaction with lipopolysaccharides of the outer membrane of Gram-negative bacteria and (lipo)teichoic acids of Gram-positive bacteria may reduce the effective concentration at the cytoplasmic membrane, where supposedly the killing event takes place. On a molecular level several mechanisms are discussed, which are important for the rational design of improved antimicrobial compounds: toroidal pore formation, carpet model (coverage of membrane surface by peptides), interfacial activity, void formation, clustering of lipids and effects of membrane curvature. In summary, many of these models just represent special cases that can be interrelated to each other and depend on both the nature of lipids and peptides.

  4. Antimicrobial and antioxidant activities of lignin from residue of corn stover to ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve the economic viability of the biofuel production from biomass resource, a value-added lignin byproduct from this process is increasingly interested. Antioxidant and antimicrobial activities of lignin extracted from residue of corn stover to ethanol production were investigated. The lignin...

  5. The Influence of Interfering Substances on the Antimicrobial Activity of Selected Quaternary Ammonium Compounds.

    PubMed

    Araújo, Paula A; Lemos, Madalena; Mergulhão, Filipe; Melo, Luís; Simões, Manuel

    2013-01-01

    Standard cleaning processes may not remove all the soiling typically found in food industry, such as carbohydrates, fats, or proteins. Contaminants have a high impact in disinfection as their presence may reduce the activity of disinfectants. The influence of alginic acid, bovine serum albumin, yeast extract, and humic acids was assessed on the antimicrobial activities of benzalkonium chloride and cetyltrimethyl ammonium bromide against Bacillus cereus vegetative cells and Pseudomonas fluorescens. The bacteria (single and consortium) were exposed to surfactants (single and combined) in the absence and presence of potential disinfection interfering substances. The antimicrobial effects of the surfactants were assessed based on the bacterial respiratory activity measured by oxygen uptake rate due to glucose oxidation. The tested surfactants were efficient against both bacteria (single and consortium) with minimum bactericidal concentrations ranging from 3 to 35 mg·L(-1). The strongest effect was caused by humic acids that severely quenched antimicrobial action, increasing the minimum bactericidal concentration of the surfactants on P. fluorescens and the consortium. The inclusion of the other interfering substances resulted in mild interferences in the antibacterial activity. This study clearly demonstrates that humic acids should be considered as an antimicrobial interfering substance in the development of disinfection strategies.

  6. Chemical Diversity and Antimicrobial Activity of Salvia multicaulis Vahl Essential Oils.

    PubMed

    Fahed, Layal; Stien, Didier; Ouaini, Naïm; Eparvier, Véronique; El Beyrouthy, Marc

    2016-05-01

    The chemical compositions and antimicrobial activities of the essential oils (EOs) of aerial parts of Salvia multicaulis Vahl, collected during the same week from two different Lebanese regions, were investigated. The EOs were obtained by hydrodistillation using a Clevenger-type apparatus and characterized by GC and GC/MS analyses. The minimum inhibitory concentrations of these EOs were determined against one Gram-negative and two Gram-positive bacteria, one yeast, and five dermatophytes using the broth microdilution technique. One EO was notably active against Staphylococcus aureus, methicillin-resistant S. aureus, and all of the Trichophyton species tested. Nerolidol was found to be the major compound in the active oil; nerolidol was also absent from the inactive oil. This study demonstrated that nerolidol shows antimicrobial activity and therefore significantly contributes to the antimicrobial potential of the oil. The chemical diversity of worldwide S. multicaulis EOs was analyzed, revealing that the EOs of this study belong to two different chemotypes found in the literature. The nerolidol chemotype appears to be restricted to Lebanon, and it can be used as antimicrobial agent against external bacterial and fungal infections.

  7. Phytochemical screening, antioxidant, and antimicrobial activities of the crude leaves’ extract from Ipomoea batatas (L.) Lam

    PubMed Central

    Pochapski, Márcia Thaís; Fosquiera, Eliana Cristina; Esmerino, Luís Antônio; dos Santos, Elizabete Brasil; Farago, Paulo Vitor; Santos, Fábio André; Groppo, Francisco Carlos

    2011-01-01

    Background: Ipomoea batatas (L.) Lam., popularly known as sweet potato (SP), has played an important role as an energy and a phytochemical source in human nutrition and animal feeding. Ethnopharmacological data show that SP leaves have been effectively used in herbal medicine to treat inflammatory and/or infectious oral diseases in Brazil. The aim of this research was to evaluate the phytochemical, antioxidant, and antimicrobial activities of the crude leaves’ extract of SP leaves. Materials and Methods: The screening was performed for triterpenes/steroids, alkaloids, anthraquinones, coumarins, flavonoids, saponins, tannins, and phenolic acids. The color intensity or the precipitate formation was used as analytical responses to these tests. The total antioxidant capacity was evaluated by the phosphomolybdenum complex method. Antimicrobial activity was made by agar disk and agar well diffusion tests. Results: The phytochemical screening showed positive results for triterpenes/steroids, alkaloids, anthraquinones, coumarins, flavonoids, saponins, tannins, and phenolic acids. Total contents of 345.65, 328.44, and 662.02 mg were respectively obtained for alkaloids, anthraquinones, and phenolic compounds in 100 g of the dry sample. The total antioxidant capacity was 42.94% as compared to ascorbic acid. For antimicrobial studies, no concentration of the SP freeze dried extract was able to inhibit the growth of Streptococcus mutans, S. mitis, Staphylococcus aureus, and Candida albicans in both agar disk and agar well diffusion tests. Conclusions: SP leaves demonstrated the presence of secondary metabolites with potential biological activities. No antimicrobial activity was observed. PMID:21716926

  8. Heat treatment effects on the antimicrobial activity of macrolide and lincosamide antibiotics in milk.

    PubMed

    Zorraquino, M A; Althaus, R L; Roca, M; Molina, M P

    2011-02-01

    Antibiotic residues in milk can cause serious problems for consumers and the dairy industry. Heat treatment of milk may diminish the antimicrobial activity of these antibiotic residues. This study analyzed the effect of milk processing (60 °C for 30 min, 120 °C for 20 min, and 140 °C for 10 s) on the antimicrobial activity of milk samples fortified with three concentrations of three macrolides (erythromycin: 20, 40 and 80 μg/liter; spiramycin: 100, 200, and 400 μg/liter; and tylosin: 500, 1,000, and 2,000 μg/liter) and one lincosamide (lincomycin: 1,000, 2,000, and 4,000 μg/liter). To measure the loss of antimicrobial activity, a bioassay based on the growth inhibition of Micrococcus luteus was done. The data were analyzed using a multiple linear regression model. The results indicate that treatment at 120 °C for 20 min produces inactivation percentages of 93% (erythromycin), 64% (spiramycin), 51% (tylosin), and 5% (lincomycin), while treatment at 140 °C for 10 s results in generally lower percentages (30% erythromycin, 35% spiramycin, 12% tylosin, and 5% lincomycin). The lowest loss or lowest reduction of antimicrobial activity (21% erythromycin and 13% spiramycin) was obtained by treatment at 60 °C for 30 min.

  9. Antimicrobial activity of oregano oil on iceberg lettuce with different attachment conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, the antimicrobial activity of oregano oil was investigated under different attachment conditions of Salmonella spp. to iceberg lettuce. Inoculated lettuce was either not dried or dried for 30 min, 60 min or 120 min, under either static air or moving air. Washing iceberg lettuce with 5...

  10. A broad-spectrum antimicrobial activity of Bacillus subtilis RLID 12.1.

    PubMed

    Ramachandran, Ramya; Chalasani, Ajay Ghosh; Lal, Ram; Roy, Utpal

    2014-01-01

    In the present study, an attempt was made to biochemically characterize the antimicrobial substance from the soil isolate designated as RLID 12.1 and explore its potential applications in biocontrol of drug-resistant pathogens. The antimicrobial potential of the wild-type isolate belonging to the genus Bacillus was determined by the cut-well agar assay. The production of antimicrobial compound was recorded maximum at late exponential growth phase. The ultrafiltered concentrate was insensitive to organic solvents, metal salts, surfactants, and proteolytic and nonproteolytic enzymes. The concentrate was highly heat stable and active over a wide range of pH values. Partial purification, zymogram analysis, and TLC were performed to determine the preliminary biochemical nature. The molecular weight of the antimicrobial peptide was determined to be less than 2.5 kDa in 15% SDS-PAGE and in zymogram analysis against Streptococcus pyogenes. The N-terminal amino acid sequence by Edman degradation was partially determined to be T-P-P-Q-S-X-L-X-X-G, which shows very insignificant identity to other antimicrobial peptides from bacteria. The minimum inhibitory concentrations of dialysed and partially purified ion exchange fractions were determined against some selected gram-positive and gram-negative bacteria and some pathogenic yeasts. The presence of three important antimicrobial peptide biosynthesis genes ituc, fend, and bmyb was determined by PCR.

  11. Actinomycetes with antimicrobial activity isolated from paper wasp (Hymenoptera: Vespidae: Polistinae) nests.

    PubMed

    Madden, Anne A; Grassetti, Andrew; Soriano, Jonathan-Andrew N; Starks, Philip T

    2013-08-01

    Actinomycetes-a group of antimicrobial producing bacteria-have been successfully cultured and characterized from the nest material of diverse arthropods. Some are symbionts that produce antimicrobial chemicals found to protect nest brood and resources from pathogenic microbes. Others have no known fitness relationship with their associated insects, but have been found to produce antimicrobials in vitro. Consequently, insect nest material is being investigated as a new source of novel antimicrobial producing actinomycetes, which could be harnessed for therapeutic potential. To extend studies of actinomycete-insect associations beyond soil-substrate dwelling insects and wood boring excavators, we conducted a preliminary assessment of the actinomycetes within the nests of the paper wasp, Polistes dominulus (Christ). We found that actinomycetes were readily cultured from nest material across multiple invasive P. dominulus populations-including members of the genera Streptomyces, Micromonospora, and Actinoplanes. Thirty of these isolates were assayed for antimicrobial activity against the challenge bacteria Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Serratia marcescens, and Bacillus subtilis. Sixty percent of isolates inhibited the growth of at least one challenge strain. This study provides the first assessment of bacteria associated with nests of P. dominulus, and the first record of antimicrobial producing actinomycetes isolated from social wasps. We provide a new system to explore nest associated actinomycetes from a ubiquitous and cosmopolitan group of insects.

  12. Isolation, identification and antimicrobial activities of two secondary metabolites of Talaromyces verruculosus.

    PubMed

    Miao, Fang; Yang, Rui; Chen, Dong-Dong; Wang, Ying; Qin, Bao-Fu; Yang, Xin-Juan; Zhou, Le

    2012-11-28

    From the ethyl acetate extract of the culture broth of Talaromyces verruculosus, a rhizosphere fungus of Stellera chamaejasme L., (-)-8-hydroxy-3-(4-hydroxypentyl)-3,4-dihydroisocoumarin (1) and (E)-3-(2,5-dioxo-3-(propan-2-ylidene)pyrrolidin-1-yl)acrylic acid (2) were isolated and evaluated for their antimicrobial activities. Their structures were elucidated by UV, IR, MS, 1H-NMR, 13C-NMR and 2D NMR spectra. Compound 1 exhibited the significant activities in vitro against two strains of bacteria and four strains of fungi. Compound 2 gave slight activities on the fungi at 100 µg mL(-1), but no activities on the bacteria. Compound 1 should be considered as a new lead or model compound to develop new isocoumarin antimicrobial agents.

  13. Antimalarial, antimicrobial, cytotoxic, DNA interaction and SOD like activities of tetrahedral copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Mehta, Jugal V.; Gajera, Sanjay B.; Patel, Mohan N.

    2015-02-01

    The mononuclear copper(II) complexes with P, O-donor ligand and different fluoroquinolones have been synthesized and characterized by elemental analysis, electronic spectra, TGA, EPR, FT-IR and LC-MS spectroscopy. An antimicrobial efficiency of the complexes has been tested against five different microorganisms in terms of minimum inhibitory concentration (MIC) and displays very good antimicrobial activity. The binding strength and binding mode of the complexes with Herring Sperm DNA (HS DNA) have been investigated by absorption titration and viscosity measurement studies. The studies suggest the classical intercalative mode of DNA binding. Gel electrophoresis assay determines the ability of the complexes to cleave the supercoiled form of pUC19 DNA. Synthesized complexes have been tested for their SOD mimic activity using nonenzymatic NBT/NADH/PMS system and found to have good antioxidant activity. All the complexes show good cytotoxic and in vitro antimalarial activities.

  14. Antimicrobial, antiviral and antioxidant activities of "água-mel" from Portugal.

    PubMed

    Miguel, Maria G; Faleiro, Leonor; Antunes, Maria D; Aazza, Smail; Duarte, Joana; Silvério, Ana R

    2013-06-01

    "Água-mel" is a honey-based product produced in Portugal for ancient times. Several attributes have been reported to "água-mel" particularly in the alleviation of simple symptoms of upper respiratory tract. Samples of "água-mel" from diverse beekeepers from different regions of Portugal were studied in what concerns antimicrobial, antioxidant and antiviral properties. The amounts of phenol and brown pigment were also evaluated and correlated with the antioxidant activities. A great variability on the levels of these compounds was found among samples which were responsible for the variability detected also on the antioxidant activities, independent on the method used. Generally, antioxidant activity correlated better with brown pigments' amount than with phenols' content. The antimicrobial activity found for "água-mel" samples confirm the virtues reported by popular findings. In addition, this work also reveals the antiviral properties of "água-mel" evidenced by a decrease on the infectivity of the Qβ bacteriophage.

  15. Antimicrobial and antioxidant activities of mycelia of 10 wild mushroom species.

    PubMed

    Kalyoncu, Fatih; Oskay, Mustafa; Sağlam, Hüsniye; Erdoğan, Tuğçe Fafal; Tamer, A Usame

    2010-04-01

    Antimicrobial and antioxidant activities of mycelia obtained from 10 wild edible mushrooms-Armillaria mellea, Meripilus giganteus, Morchella costata, Morchella elata, Morchella esculenta var. vulgaris, Morchella hortensis, Morchella rotunda, Paxillus involutus, Pleurotus eryngii, and Pleurotus ostreatus-were investigated. For determination of antimicrobial activities of these mushrooms, ethanol extracts were examined with 11 test microorganisms by the agar well diffusion method. P. ostreatus and M. giganteus were the most active species against both bacteria and yeast. Antioxidant properties of ethanol extracts were studied by the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging method. Among the mushroom extracts, M. elata showed the most potent radical scavenging activity. This research has shown that these 10 wild macrofungi have potential as natural antioxidants and antibiotics.

  16. Activity.

    ERIC Educational Resources Information Center

    Clearing: Nature and Learning in the Pacific Northwest, 1984

    1984-01-01

    Presents three activities: (1) investigating succession in a schoolground; (2) investigating oak galls; and (3) making sun prints (photographs made without camera or darkroom). Each activity includes a list of materials needed and procedures used. (JN)

  17. Draft genome of Bacillus sp. A053 isolated from the Arctic seawater with antimicrobial activity.

    PubMed

    Guo, Wenbin; Chen, Zhiteng; Cui, Pengfei; Chen, Xinhua

    2015-08-01

    Bacillus sp. A053, isolated from the Arctic seawater, shows strong antifungal activity against plant pathogenic fungi. Here, we report the draft sequence of the approximately 4.1-Mbp genome of this strain. To the best of our knowledge, this is the first genome sequence of Bacillus strain isolated from the Arctic seawater with antifungal activity. The genome sequence may provide fundamental molecular information on elucidating the metabolic pathway of antimicrobial compound in this strain.

  18. Antimicrobial, antioxidant, and antimutagenic activities of selected marine natural products and tobacco cembranoids.

    PubMed

    Aqil, Farrukh; Zahin, Maryam; El Sayed, Khalid A; Ahmad, Iqbal; Orabi, Khaled Y; Arif, Jamal M

    2011-04-01

    Multidrug resistance (MDR) in microorganisms is a cause of major concern for clinicians and pharmaceutical industries. Continuous development of new antimicrobial drugs with multiple targets and potentials is expected to efficiently combat MDR in these microorganisms. In a continued exploration of new antimicrobial drug leads, 11 marine natural products, semisynthetic, or related synthetic analogs (1-11) and two tobacco cembranoids (12 and 13) were screened for their antimicrobial, antioxidant, and antimutagenic activities. Eight compounds showed varying levels of both antibacterial and antifungal activities. Compounds such as 17-O-methyllatrunculin-A, verongiaquinol, (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol), and manzamine-A showed a broad spectrum of activity, inhibiting six of seven tested bacteria with zone of inhibition diameter from 9 to 30 mm. Four of these active compounds also showed antifungal activity. The findings of the in vitro time-kill assay of the most active compound, verongiaquinol, against Staphylococcus aureus indicated its subinhibitory effect at the level lower than the minimal inhibitory concentration (MIC) values (i.e., 2 and 4 µg/mL). At the MIC (8 µg/mL), bacterial cells were completely killed within 18 hours of incubation. DPPH free radical scavenging activity was demonstrated by five compounds in the range of 89.65-36.19% decolorization. Further, four compounds evaluated for their antimutagenic activity against the directly acting mutagens, methyl methanesulfonate and sodium azide, in Salmonella typhimurium strains, interestingly, showed no sign of mutagenicity. Verongiaquinol and manzamine A, in fact, reduced the mutagenicity by 50-75% at a dose of 5 µg/plate in different test strains. Our study seems to provide some novel antimicrobial leads with strong antioxidant potential and the associated ability of antimutagenicity.

  19. Development of active biofilms of quinoa (Chenopodium quinoa W.) starch containing gold nanoparticles and evaluation of antimicrobial activity.

    PubMed

    Pagno, Carlos H; Costa, Tania M H; de Menezes, Eliana W; Benvenutti, Edilson V; Hertz, Plinho F; Matte, Carla R; Tosati, Juliano V; Monteiro, Alcilene R; Rios, Alessandro O; Flôres, Simone H

    2015-04-15

    Active biofilms of quinoa (Chenopodium quinoa, W.) starch were prepared by incorporating gold nanoparticles stabilised by an ionic silsesquioxane that contains the 1,4-diazoniabicyclo[2.2.2]octane chloride group. The biofilms were characterised and their antimicrobial activity was evaluated against Escherichiacoli and Staphylococcusaureus. The presence of gold nanoparticles produces an improvement in the mechanical, optical and morphological properties, maintaining the thermal and barrier properties unchanged when compared to the standard biofilm. The active biofilms exhibited strong antibacterial activity against food-borne pathogens with inhibition percentages of 99% against E. coli and 98% against S. aureus. These quinoa starch biofilms containing gold nanoparticles are very promising to be used as active food packaging for the maintenance of food safety and extension of the shelf life of packaged foods.

  20. Antimicrobial activity of three baccharis species used in the traditional medicine of Northern Chile.

    PubMed

    Morales, Glauco; Paredes, Adrián; Sierra, Patricia; Loyola, Luis A

    2008-04-06

    The antimicrobial activities of aqueous ethanol and chloroform extracts of three Baccharis species currently used in Northern Chile folk medicine for the treatment of several infectious and inflammatory disorders were tested against Gram-positive and negative bacteria and fungal spp. using the agar-disc diffusion assay. The results indicated that the activity was more pronounced against Gram-positive than against Gram-negative bacteria and yeast. No significant differences on the antibacterial activity were observed in the aqueous ethanol versus chloroform extracts. None of the plant extracts evaluated exhibited any activity against ten fungi tested.

  1. Enhancement of the Antifungal Activity of Antimicrobial Drugs by Eugenia uniflora L.

    PubMed Central

    Santos, Karla K.A.; Matias, Edinardo F.F.; Tintino, Saulo R.; Souza, Celestina E.S.; Braga, Maria F.B.M.; Guedes, Gláucia M.M.; Costa, José G.M.; Menezes, Irwin R.A.

    2013-01-01

    Abstract Candidiasis is the most frequent infection by opportunistic fungi such as Candida albicans, Candida tropicalis, and Candida krusei. Ethanol extract from Eugenia uniflora was assayed, for its antifungal activity, either alone or combined with four selected chemotherapeutic antimicrobial agents, including anphotericin B, mebendazole, nistatin, and metronidazole against these strains. The obtained results indicated that the association of the extract of E. uniflora to metronidazole showed a potential antifungal activity against C. tropicalis. However, no synergistic activity against the other strains was observed, as observed when the extract was associated with the other, not enhancing their antifungal activity. PMID:23819641

  2. Antimicrobial agents from plants: antibacterial activity of plant volatile oils.

    PubMed

    Dorman, H J; Deans, S G

    2000-02-01

    The volatile oils of black pepper [Piper nigrum L. (Piperaceae)], clove [Syzygium aromaticum (L.) Merr. & Perry (Myrtaceae)], geranium [Pelargonium graveolens L'Herit (Geraniaceae)], nutmeg [Myristica fragrans Houtt. (Myristicaceae), oregano [Origanum vulgare ssp. hirtum (Link) Letsw. (Lamiaceae)] and thyme [Thymus vulgaris L. (Lamiaceae)] were assessed for antibacterial activity against 25 different genera of bacteria. These included animal and plant pathogens, food poisoning and spoilage bacteria. The volatile oils exhibited considerable inhibitory effects against all the organisms under test while their major components demonstrated various degrees of growth inhibition.

  3. Diterpenoids from Croton laui and their cytotoxic and antimicrobial activities.

    PubMed

    Liu, Cui-Ping; Xu, Jin-Biao; Zhao, Jin-Xin; Xu, Cheng-Hui; Dong, Lei; Ding, Jian; Yue, Jian-Min

    2014-04-25

    Fourteen new diterpenoids including clerodane (1-12), labdane (13), and norlabdane (14) types, as well as nine known analogues were isolated from the aerial parts of Croton laui. Their structures were established on the basis of spectroscopic analysis, and that of crotonolide H (11) was confirmed by single-crystal X-ray crystallography. Crotonolide A (1) exhibited moderate cytotoxicity against two tumor cell lines, HL-60 (human premyelocytic leukemia, IC50 9.42 μM) and P-388 (murine leukemia, IC50 7.45 μM), and crotonolide G (10) displayed significant antibacterial activity against a panel of Gram-positive bacteria.

  4. Antimicrobial Activity of Scabiosa arenaria Forssk. Extracts and Pure Compounds Using Bioguided Fractionation.

    PubMed

    Besbes Hlila, Malek; Mosbah, Habib; Majouli, Kaouther; Ben Nejma, Aymen; Ben Jannet, Hichem; Mastouri, Maha; Aouni, Mahjoub; Selmi, Boulbaba

    2016-10-01

    The emergence of multidrug resistant pathogens threatened the clinical efficacy of many existing antibiotics. This situation has been recognized globally as a serious concern and justifies further research to discover antimicrobial agents from natural origins including plant extracts. The aim of our work was to evaluate the antimicrobial activities of Scabiosa arenaria Forssk. extracts and pure compounds using a bioguided fractionation, and try to explain some traditional use of this genus. The best antimicrobial activity-guided fractionation was obtained by BuOH fractions of flowers, fruits and (stems and leaves) against Escherichia coli, Pseudomonas aeruginosa and Candida albicans with minimum inhibitory concentration (MIC) values from 0.0195 to 5 mg/ml. Escherichia coli was the most affected bug, thus the MIC of fruits BuOH extract showed the best anti-Escherichia coli activity (MIC = 0.0195 mg/ml), followed by the (stems and leaves) and flowers BuOH extracts; MIC = 0.078 and 0.15 mg/ml, respectively. Furthermore, the subfractions obtained from these three mixed fractions showed also an important antimicrobial activity against the three microorganisms, with MIC values between 0.0195 and 0.312 mg/ml. The fractionation of the aerial part BuOH fraction led to the isolation of oleanolic acid (1) and luteolin 7-O-glucopyranoside (2) which are reported here for the first time from S. arenaria. Both compounds showed good antimicrobial activities with MIC values ranging from 170 to 683 μm and 86 to 347 μm, respectively. These results support the use of the Scabiosa genus to inhibit the growth of tested pathogenic bacteria and yeasts which may reduce illnesses associated with their exposure.

  5. Antimicrobial properties of membrane-active dodecapeptides derived from MSI-78.

    PubMed

    Monteiro, Claudia; Fernandes, Mariana; Pinheiro, Marina; Maia, Sílvia; Seabra, Catarina L; Ferreira-da-Silva, Frederico; Costa, Fabíola; Reis, Salette; Gomes, Paula; Martins, M Cristina L

    2015-05-01

    Antimicrobial peptides (AMPs) are a class of broad-spectrum antibiotics known by their ability to disrupt bacterial membranes and their low tendency to induce bacterial resistance, arising as excellent candidates to fight bacterial infections. In this study we aimed at designing short 12-mer AMPs, derived from a highly effective and broad spectrum synthetic AMP, MSI-78 (22 residues), by truncating this peptide at the N- and/or C-termini while spanning its entire sequence with 1 amino acid (aa) shifts. These designed peptides were evaluated regarding antimicrobial activity against selected gram-positive Staphylococcus strains and the gram-negative Pseudomonas aeruginosa (P. aeruginosa). The short 12-mer peptide CEM1 (GIGKFLKKAKKF) was identified as an excellent candidate to fight P. aeruginosa infections as it displays antimicrobial activity against this strain and selectivity, with negligible toxicity to mammalian cells even at high concentrations. However, in general most of the short 12-mer peptides tested showed a reduction in antimicrobial activity, an effect that was more pronounced for gram-positive Staphylococcus strains. Interestingly, CEM1 and a highly similar peptide differing by only one aa-shift (CEM2: IGKFLKKAKKFG), showed a remarkably contrasting AMP activity. These two peptides were chosen for a more detailed study regarding their mechanism of action, using several biophysical assays and simple membrane models that mimic the mammalian and bacterial lipid composition. We confirmed the correlation between peptide helicity and antimicrobial activity and propose a mechanism of action based on the disruption of the bacterial membrane permeability barrier.

  6. Antimicrobial Activity of Essential Oils against Streptococcus mutans and their Antiproliferative Effects

    PubMed Central

    Galvão, Lívia Câmara de Carvalho; Furletti, Vivian Fernandes; Bersan, Salete Meyre Fernandes; da Cunha, Marcos Guilherme; Ruiz, Ana Lúcia Tasca Góis; de Carvalho, João Ernesto; Sartoratto, Adilson; Rehder, Vera Lúcia Garcia; Figueira, Glyn Mara; Teixeira Duarte, Marta Cristina; Ikegaki, Masarahu; de Alencar, Severino Matias; Rosalen, Pedro Luiz

    2012-01-01

    This study aimed to evaluate the activity of essential oils (EOs) against Streptococcus mutans biofilm by chemically characterizing their fractions responsible for biological and antiproliferative activity. Twenty EO were obtained by hydrodistillation and submitted to the antimicrobial assay (minimum inhibitory (MIC) and bactericidal (MBC) concentrations) against S. mutans UA159. Thin-layer chromatography and gas chromatography/mass spectrometry were used for phytochemical analyses. EOs were selected according to predetermined criteria and fractionated using dry column; the resulting fractions were assessed by MIC and MBC, selected as active fractions, and evaluated against S. mutans biofilm. Biofilms formed were examined using scanning electron microscopy. Selected EOs and their selected active fractions were evaluated for their antiproliferative activity against keratinocytes and seven human tumor cell lines. MIC and MBC values obtained for EO and their active fractions showed strong antimicrobial activity. Chemical analyses mainly showed the presence of terpenes. The selected active fractions inhibited S. mutans biofilm formation (P < 0.05) did not affect glycolytic pH drop and were inactive against keratinocytes, normal cell line. In conclusion, EO showed activity at low concentrations, and their selected active fractions were also effective against biofilm formed by S. mutans and human tumor cell lines. PMID:22685486

  7. Mode of Action of Lactoperoxidase as Related to Its Antimicrobial Activity: A Review

    PubMed Central

    Bafort, F.; Parisi, O.; Perraudin, J.-P.; Jijakli, M. H.

    2014-01-01

    Lactoperoxidase is a member of the family of the mammalian heme peroxidases which have a broad spectrum of activity. Their best known effect is their antimicrobial activity that arouses much interest in in vivo and in vitro applications. In this context, the proper use of lactoperoxidase needs a good understanding of its mode of action, of the factors that favor or limit its activity, and of the features and properties of the active molecules. The first part of this review describes briefly the classification of mammalian peroxidases and their role in the human immune system and in host cell damage. The second part summarizes present knowledge on the mode of action of lactoperoxidase, with special focus on the characteristics to be taken into account for in vitro or in vivo antimicrobial use. The last part looks upon the characteristics of the active molecule produced by lactoperoxidase in the presence of thiocyanate and/or iodide with implication(s) on its antimicrobial activity. PMID:25309750

  8. Trichoplaxin - a new membrane-active antimicrobial peptide from placozoan cDNA.

    PubMed

    Simunić, Juraj; Petrov, Dražen; Bouceba, Tahar; Kamech, Nédia; Benincasa, Monica; Juretić, Davor

    2014-05-01

    A method based on the use of signal peptide sequences from antimicrobial peptide (AMP) precursors was used to mine a placozoa expressed sequence tag database and identified a potential antimicrobial peptide from Trichoplax adhaerens. This peptide, with predicted sequence FFGRLKSVWSAVKHGWKAAKSR is the first AMP from a placozoan species, and was named trichoplaxin. It was chemically synthesized and its structural properties, biological activities and membrane selectivity were investigated. It adopts an α-helical structure in contact with membrane-like environments and is active against both Gram-negative and Gram-positive bacterial species (including MRSA), as well as yeasts from the Candida genus. The cytotoxic activity, as assessed by the haemolytic activity against rat erythrocytes, U937 cell permeabilization to propidium iodide and MCF7 cell mitochondrial activity, is significantly lower than the antimicrobial activity. In tests with membrane models, trichoplaxin shows high affinity for anionic prokaryote-like membranes with good fit in kinetic studies. Conversely, there is a low affinity for neutral eukaryote-like membranes and absence of a dose dependent response. With high selectivity for bacterial cells and no homologous sequence in the UniProt, trichoplaxin is a new potential lead compound for development of broad-spectrum antibacterial drugs.

  9. Development of a method to quantify in vitro the synergistic activity of "natural" antimicrobials.

    PubMed

    Dufour, M; Simmonds, R S; Bremer, P J

    2003-08-25

    Despite numerous papers being published on the use of hurdle technology to control food-borne pathogens or spoilage organisms, there is no commonly accepted methodology to quantify the level of synergistic activity. This paper describes a method to quantify in vitro the synergistic activity of antibacterial agents against bacteria. Initially, a microtiter plate growth assay was used to determine the inhibitory concentrations of four "natural" antimicrobials (nisin, lauricidin, totarol, and the lactoperoxidase system (LPS)) against a panel of eight bacteria. Using the same microtiter system, the impact of various combinations of antimicrobials was assessed. The degree of synergy was based on the analysis of three criteria: (1) increase in lag phase, (2) reduction in culture density after 24 h, (3) and residual viability at 24 h. Only the lactoperoxidase system was active against all the Gram-positive and Gram-negative bacteria tested. Nisin, lauricidin, and totarol were only effective against the Gram-positive bacteria. The method successfully identified three combinations (nisin-lauricidin, LPS-nisin, and LPS-lauricidin) previously reported to have synergistic activity and highlighted the synergistic activity of two novel combinations (nisin-totarol and LPS-totarol). The development of a quick and reliable method to identify and quantify synergistic activity is a useful screening tool to establish preservative techniques that could have potential antimicrobial synergy in food-based systems.

  10. In vitro antimicrobial activity on clinical microbial strains and antioxidant properties of Artemisia parviflora

    PubMed Central

    2012-01-01

    Background Artemisia parviflora leaf extracts were evaluated for potential antimicrobial and antioxidant properties. Antimicrobial susceptibility assay was performed against ten standard reference bacterial strains. Antioxidant activity was analyzed using the ferric thiocyanate and 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) assays. Radical scavenging activity and total phenolic content were compared. Phytochemical analyses were performed to identify the major bioactive constitution of the plant extract. Results Hexane, methanol and ethyl acetate extracts of A. parviflora leaves exhibited good activity against the microorganisms tested. The n-hexane extract of A. parviflora showed high inhibition of the growth of Pseudomonas aeruginosa, Escherichia coli and Shigella flexneri. Methanol extract showed strong radical scavenging and antioxidant activity, other extracts showed moderate antioxidant activity. The major derivatives present in the extracts are of terpenes, steroids, phenols, flavonoids, tannins and volatile oil. Conclusions The results obtained with n-hexane extract were particularly significant as it strongly inhibited the growth of P. aeruginosa, E. coli and S. flexneri. The major constituent of the n-hexane extract was identified as terpenes. Strong antioxidant activity could be observed with all the individual extracts. The antimicrobial and antioxidant property of the extracts were attributed to the secondary metabolites, terpenes and phenolic compounds present in A. parviflora and could be of considerable interest in the development of new drugs. PMID:23171441

  11. Characterization of antimicrobial activity and mechanisms of low amphipathic peptides with different α-helical propensity.

    PubMed

    Zhu, Xin; Zhang, Licong; Wang, Jue; Ma, Zhi; Xu, Wei; Li, Jianping; Shan, Anshan

    2015-05-01

    Antimicrobial peptides (AMPs) serve as a defense mechanism within multicellular organisms and are attracting increasing attention because of their potential application in the treatment of multidrug-resistant infections. Amphipathicity has long been believed to be the most important consideration for the structural modification and design of both naturally occurring and synthetic AMPs. Previous studies indicated that disruptive amphipathicity formed by replacing the paired charged amino acid residues on the polar face of an amphipathic helix with tryptophan residues linked with hydrogen bonds on the basis of α-helical protein folding principles endowed the AMPs with increased cell selectivity. In an attempt to augment and hone this strategy further, we designed a series of imperfect amphipathic peptides by placing different types of amino acid residues at the hydrogen bond linked positions of α-helix structures to characterize their antimicrobial properties and mechanism of action. The d-Trp-substituted sequence (PRW4-d) showed greater antimicrobial potency than Cys-(C4), Asp-(D4), Ile-(I4), and Pro-(P4) substituted sequences, comparable to the l-Trp-substituted parent sequence (PRW4). Furthermore, the total replacement of Lys residues with Arg residues along the peptide sequence (PRW4-R) exhibited enhanced antimicrobial activity and cell selectivity. In addition, no cytotoxicity was observed among these synthetic peptides. PRW4-d and PRW4-R maintained their activities in the presence of physiological salts and human serum. The fluorescence spectroscopy, flow cytometry, and electron microscopy observations indicated that the optimized sequences exhibited excellent antimicrobial potency by inducing cytoplasmic membrane potential loss, membrane permeabilization and disruption. Collectively, the results could be useful for designing short AMPs with great antimicrobial activity and cell selectivity.

  12. Antioxidant activity via DPPH, gram-positive and gram-negative antimicrobial potential in edible mushrooms.

    PubMed

    Ahmad, Nisar; Mahmood, Fazal; Khalil, Shahid Akbar; Zamir, Roshan; Fazal, Hina; Abbasi, Bilal Haider

    2014-10-01

    Edible mushrooms (EMs) are nutritionally rich source of proteins and essential amino acids. In the present study, the antioxidant activity via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and antimicrobial potential in EMs (Pleurotus ostreatus, Morchella esculenta, P. ostreatus (Black), P. ostreatus (Yellow) and Pleurotus sajor-caju) were investigated. The DPPH radical scavenging activity revealed that the significantly higher activity (66.47%) was observed in Morchella esculenta at a maximum concentration. Similarly, the dose-dependent concentrations (200, 400, 600, 800 and 1000 µg) were also used for other four EMs. Pleurotus ostreatus exhibited 36.13% activity, P. ostreatus (Black (B)) exhibited 30.64%, P. ostreatus (Yellow (Y)) exhibited 40.75% and Pleurotus sajor-caju exhibited 47.39% activity at higher concentrations. Furthermore, the antimicrobial potential were investigated for its toxicity against gram-negative bacterial strains (Escherichia coli, Pseudomonas aeroginosa, Salmonella typhi, Klebsiella pneumonia, Erwinia carotovora and Agrobacterium tumifaciens), gram-positive bacterial strains (Bacillus subtilis, Bacillus atrophaeus and Staphylococcus aureus) and a fungal strain (Candida albicans) in comparison with standard antibiotics. Antimicrobial screening revealed that the ethanol extract of P. ostreatus was active against all microorganism tested except E. coli. Maximum zone of inhibition (13 mm) was observed against fungus and A. tumifaciens. P. sajor-caju showed best activities (12.5 mm) against B. subtilis, B. atrophaeus and K. pneumonia. P. ostreatus (Y) showed best activities against P. aeroginosa (21.83 mm), B. atrophaeus (20 mm) and C. albicans (21 mm). P. ostreatus (B) exhibited best activities against C. albicans (16 mm) and slightly lower activities against all other microbes except S. typhi. M. esculenta possess maximum activities in terms of inhibition zone against all microorganisms tested except S. typhi.

  13. Antimicrobial Activity of Filling Materials Used in Primary Teeth Pulpotomy

    PubMed Central

    Pimenta, Hévelin Couto; Borges, Álvaro Henrique; Bandeca, Matheus Coelho; Neves, Ana Thereza Sabóia; Fontes, Rodrigo Gusmão; da Silva, Priscila Vieira; Aranha, Andreza Maria Fábio

    2015-01-01

    The aim of this study was to investigate the antibacterial activity of pulp capping materials used in primary teeth (formocresol [FC], zinc oxide and eugenol cement [ZOE], ZOE mixed with FC [ZOEFC], mineral trioxide aggregate [MTA] and calcium hydroxide [CH]) against cariogenic bacteria. The agar plate diffusion test was used for the cultures, including saline solution as a negative control. A base layer of 15 mL of brain heart infusion agar was inoculated with 300 mL of each inoculum. Twelve wells were made and completely filled with one of the testing materials for each bacteria strain. The plates were incubated at 37°C for 48 h. Zones of microbial inhibition and material diffusion were measured and photographed. The results obtained were analyzed by Kruskal–Wallis and Mann–Whitney non-parametric tests. Respectively, the medium zones of bacteria inhibition of FC, ZOE, ZOEFC, MTA and CH against Streptococcus mutans growth were 28.5, 15.2, 20.8, 9.3 and 11.6; against Lactobacillus acidophilus growth were 28.7, 14.8, 15.3, 15.2 and 20.0, and against Actinomyces viscosus growth were 13.6, 13.5, 14.7, 10.0 and 13.6. We might confirmed the high antibacterial activity of FC solution, especially against S. mutans and L. acidophilus, as wells as, the low inhibitory effect of MTA cement on the cariogenic bacteria studied. PMID:25954072

  14. Antimicrobial activity of filling materials used in primary teeth pulpotomy.

    PubMed

    Pimenta, Hévelin Couto; Borges, Álvaro Henrique; Bandeca, Matheus Coelho; Neves, Ana Thereza Sabóia; Fontes, Rodrigo Gusmão; da Silva, Priscila Vieira; Aranha, Andreza Maria Fábio

    2015-04-01

    The aim of this study was to investigate the antibacterial activity of pulp capping materials used in primary teeth (formocresol [FC], zinc oxide and eugenol cement [ZOE], ZOE mixed with FC [ZOEFC], mineral trioxide aggregate [MTA] and calcium hydroxide [CH]) against cariogenic bacteria. The agar plate diffusion test was used for the cultures, including saline solution as a negative control. A base layer of 15 mL of brain heart infusion agar was inoculated with 300 mL of each inoculum. Twelve wells were made and completely filled with one of the testing materials for each bacteria strain. The plates were incubated at 37°C for 48 h. Zones of microbial inhibition and material diffusion were measured and photographed. The results obtained were analyzed by Kruskal-Wallis and Mann-Whitney non-parametric tests. Respectively, the medium zones of bacteria inhibition of FC, ZOE, ZOEFC, MTA and CH against Streptococcus mutans growth were 28.5, 15.2, 20.8, 9.3 and 11.6; against Lactobacillus acidophilus growth were 28.7, 14.8, 15.3, 15.2 and 20.0, and against Actinomyces viscosus growth were 13.6, 13.5, 14.7, 10.0 and 13.6. We might confirmed the high antibacterial activity of FC solution, especially against S. mutans and L. acidophilus, as wells as, the low inhibitory effect of MTA cement on the cariogenic bacteria studied.

  15. Isolation, antimicrobial activities, and primary structures of hamster neutrophil defensins.

    PubMed Central

    Mak, P; Wójcik, K; Thogersen, I B; Dubin, A

    1996-01-01

    Hamster (Mesocricetus auratus) neutrophil granules contain at least four microbicidal peptides belonging to the defensin family. These compounds were purified from granule acid extracts by reverse-phase chromatography and termed HaNP-1 to -4 (hamster neutrophil peptide). HaNP-1 and HaNP-3 revealed the most bactericidal activity, with a 50% inhibitory concentration of 0.3 to 0.8 microg/ml for Staphylococcus aureus and Streptococcus pyogenes strains. The HaNP-4 was always isolated in concentrations exceeding about 10 times the concentrations of other hamster peptides, but its antibacterial activity as well as that of HaNP-2 was relatively lower, probably as a result of conserved Arg residue substitutions. Other microorganisms were also tested, and generally, hamster defensins exhibited less potency against gram-negative bacteria. The amino acid sequence of hamster defensins showed a high percentage of identity to the sequence of mouse enteric defensins, reaching about 60% identical residues in the case of HaNP-3 and cryptdin 3. PMID:8890190

  16. Antimicrobial and mosquitocidal activity of microbial synthesized silver nanoparticles.

    PubMed

    Soni, Namita; Prakash, Soam

    2015-03-01

    Microbial synthesis of nanoparticles is a green approach that interconnects nanotechnology and microbial biotechnology. Here, we synthesized the silver nanoparticles (AgNPs) using bacterial strains of Listeria monocytogenes, Bacillus subtilius and Streptomyces anulatus. We tested the efficacy of AgNPs against the larvae, pupae and adults of Anopheles stephensi and Culex quinquefasciatus. We have also investigated the antifungal activity of AgNPs against the soil keratinophilic fungus of Chrysosporium keratinophilum. The efficacy tests were then performed at different concentrations and varying numbers of hours by probit analysis. The results were obtained using a UV-visible spectrophotometer, and the images were recorded with a transmission electron microscope (TEM). The synthesized AgNPs were in varied shape and sizes. The larvae and pupae of Cx. quinquefasciatus were found highly susceptible to AgNPs synthesized using the L. monocytogenes, B. subtilius and S. anulatus than the An. stephensi, while the adults of An. stephensi were found more susceptible to the AgNPs synthesized using the L. monocytogenes, B. subtilius and S. anulatus the Cx. quinquefasciatus. Further, these nanoparticles have also been tested as antifungal activity against the entomopathogenic fungus C. keratinophilum. The higher zone of inhibition occurred at the concentration level of 50 μl. This study gives an innovative approach to develop eco-friendly AgNPs which act as an effective antifungal agent/fungicide and insecticide.

  17. Enhanced Antimicrobial Activity Of Antibiotics Mixed With Metal Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Kumar, Neeraj; Bhanjana, Gaurav; Thakur, Rajesh; Dilbaghi, Neeraj

    2011-12-01

    Current producers of antimicrobial technology have a long lasting, environmentally safe, non-leaching, water soluble solution that will eventually replace all poisons and heavy metals. The transition metal ions inevitably exist as metal complexes in biological systems by interaction with the numerous molecules possessing groupings capable of complexation or chelation. Nanoparticles of metal oxides offer a wide variety of potential applications in medicine due to the unprecedented advances in nanobiotechnology research. the bacterial action of antibiotics like penicillin, erythryomycin, ampicillin, streptomycin, kanamycin etc. and that of a mixture of antibiotics and metal and metal oxide nanoparticles like zinc oxide, zirconium, silver and gold on microbes was examined by the agar-well-diffusion method, enumeration of colony-forming units (CFU) and turbidimetry.

  18. Structure-activity relation of human beta-defensin 3: influence of disulfide bonds and cysteine substitution on antimicrobial activity and cytotoxicity.

    PubMed

    Klüver, Enno; Schulz-Maronde, Sandra; Scheid, Svenja; Meyer, Bernd; Forssmann, Wolf-Georg; Adermann, Knut

    2005-07-19

    Human beta-defensins form a group of cysteine-rich antimicrobial peptides which have been found in epithelial tissue and, more recently, in the male genital tract. They play a role in the defense against microbial pathogens in innate immunity and display additional chemotactic functions in the adaptive immune system. An important characteristic of antimicrobial peptides is that they also exhibit toxic potential on eukaryotic cells. Very little is known about the structure dependence of antimicrobial and cytotoxic effects. We investigated human beta-defensin 3 (hBD-3), a potent broad-spectrum antimicrobial effector peptide, regarding the influence of structural parameters on the antimicrobial and cytotoxic activity. We have established a structure-activity relation of the hBD-3 using synthetic derivatives differing in length, charge, disulfide connectivity, and overall hydrophobicity. The antimicrobial activity of the peptides was compared to the cyctotoxic effects on monocytic THP-1 cells and the hemolytic activity on human erythrocytes. We found that it is not important for antimicrobial and cytotoxic activity whether and how cysteine residues are arranged to form disulfide bonds. Substitution of half-cystinyl residues by tryptophan resulted in increased activities, while other substitutions did not change activity. Correlation of activities with the structural changes demonstrates that the activity on eukaryotic cells appears to depend strongly on the overall hydrophobicity. In contrast, the antimicrobial potency of hBD-3 peptides is determined by the distribution of positively charged amino acid residues and hydrophobic side chains. The results facilitate the understanding of beta-defensin interaction with different cell types and guide the design of antimicrobially active peptides.

  19. Evaluation of the antimicrobial activity and dimensional alterations of alginate impression disinfectants.

    PubMed

    Semensato, Ana Paula Nocentini; Crosariol, Sonia Khouri; Marchini, Leonardo

    2009-09-01

    This paper offers a quantitative evaluation of the antimicrobial efficacy of eight different disinfection procedures for irreversible hydrocolloid impressions and the dimensional changes induced by them. Samples were collected immediately after impressions, after the disinfection procedures and over casts and analyzed for bacterial growth. Control, enzyme solutions, acetic acid and ultraviolet irradiation samples showed bacterial growth. Chlorhexidine and 1% sodium hypochlorite presented adequate antimicrobial activity, while 2% sodium hypochlorite solution showed the best results. Dimensional changes were similar to those of the controls in all the tested agents. The results indicated 2% hypochlorite was the most appropriate disinfectant tested.

  20. Bioprospecting of antimicrobial activity of extracts of endophytic fungi from Bauhinia guianensis.

    PubMed

    Pinheiro, Eduardo A A; Pina, Jeferson R S; Feitosa, André O; Carvalho, Josiwander M; Borges, Fábio C; Marinho, Patrícia S B; Marinho, Andrey M R

    Antibiotic resistance results in higher medical costs, prolonged hospital stays and increased mortality and is rising to dangerously high levels in all parts of the world. Therefore, this study aims to search for new antimicrobial agents through bioprospecting of extracts of endophytic fungi from Bauhinia guianensis, a typical Amazonian plant used in combating infections. Seventeen (17) fungi were isolated and as result the methanolic extract of the fungus Exserohilum rostratum showed good activity against the bacteria tested. The polyketide monocerin was isolated by the chromatographic technique, identified by NMR and MS, showing broad antimicrobial spectrum.

  1. Divalent metal ion triggered activity of a synthetic antimicrobial in cardiolipin membranes.

    PubMed

    Som, Abhigyan; Yang, Lihua; Wong, Gerard C L; Tew, Gregory N

    2009-10-28

    One member of a prototypical class of antimicrobial oligomers was used to study pore formation in cardiolipin-rich membranes. Both vesicle dye-leakage assays and small-angle X-ray scattering were used to study bilayer remodeling. The results indicate that the presence of negative intrinsic curvature lipids is essential for pore formation by this class of molecules: In Gram-positive bacteria, cardiolipin and divalent metal cations like Ca(2+) and Mg(2+) are needed. This is consistent with the role of phosphatidylethanolamine (PE) lipid in Gram-negative bacteria, where antimicrobial activity is dependent on the negative intrinsic curvature of PE rather than a specific interaction with PE.

  2. Preliminary investigation on the phytochemistry and antimicrobial activity of Senna alata L. flower.

    PubMed

    Idu, M; Omonigho, S E; Igeleke, C L

    2007-03-01

    Preliminary studies on the phytochemistry and extracts of water, methanol, chloroform and petroleum ether, of Senna alata flowers were examined for antimicrobial properties. Extracts tested at a final concentration of 500 microg mL(-1) produced in vitro antimicrobial activities in assays against clinical isolates of Staphylococus aureus, Candida albicans, Escherichia coli, Proteus vulgaris, Pseudomonans aureginosa and Bacillus subtilis. The zones of inhibitions produced by the extracts in agar diffusion assay against the test micro organisms ranged from 4 to 10 mm while the gentamycin antibiotic control, produced zones that measured 5 mm. Preliminary phytochemical analysis of the plant extracts showed the presence of phenols, tannins, anthraquinoes, saponins, flavonoids.

  3. Antimicrobial and antioxidant activities of alcoholic extracts of Rumex dentatus L.

    PubMed

    Humeera, Nisa; Kamili, Azra N; Bandh, Suhaib A; Amin, Shajr-ul-; Lone, Bashir A; Gousia, Nisa

    2013-04-01

    In-vitro antimicrobial and antioxidant activities of various concentrations ranging from 150 to 500 μg/ml of alcoholic (methanol and ethanol) extracts of Rumex dentatus were analyzed on different clinical bacterial strains (Shigella flexneri, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus) and fungal strains (Aspergillus versicolor, Aspergillus flavus, Acremonium spp., Penicillium dimorphosporum, Candida albicans, Candida kruesie, Candida parapsilosis) using agar disk diffusion method and broth dilution method (MIC and MBC determination) for antimicrobial activity and DPPH (1,1-diphenyl-2-picrylhydrazyl) assay, Riboflavin photo-oxidation assay, deoxyribose assay, lipid peroxidation assay for antioxidant activity. The extracts showed maximum inhibitory effect against K. pneumonia and P. aeruginosa with no activity against S. typhimurium from among the bacterial strains while as in case of the fungal strains the maximum effect was observed against C. albicans by both the extracts. MIC and MBC values determined for active fractions of the extracts against some bacterial strains (S. flexneri, K. pneumonia and E. coli) revealed that the test organisms were inhibited by all the extracts with methanol showing lower values of both MIC and MBC indicating it as a better antimicrobial agent. The antioxidant activity showed that the extracts exhibited scavenging effect in concentration-dependent manner on superoxide anion radicals and hydroxyl radicals leading to the conclusion that the plant has got a broad spectrum antimicrobial and antioxidant activity and could be a potential alternative for treating various diseases.

  4. Antimicrobial activities of two edible bivalves M. meretrix and M. casta.

    PubMed

    Sugesh, S; Mayavu, P

    2013-01-01

    The marine invertebrates become one of hot spot for the lead of antimicrobial compounds. Two species of commercially available and edible bivalves (M. meretrix and M. casta) were assayed for antimicrobial activity against 10 bacterial pathogens and 6 fungal pathogens and its biochemical composition. The bivalves were extracted with three different solvent systems respectively methanol, ethanol and acetic acid. All the three extracts of both the species M. meretrix and M. casta showed highest antibacterial activities against S. aureus, E. coli, B. substillus, K. pneumonia, P. fleuroscence and V. cholera. In present investigation the methanolic extract of the two bivalve species of M. meretrix and M. casta was showed inhibition activities against all pathogenic fungal forms. The two bivalve extracts showed high amounts of protein content, which made the variation up to 160-180 microg mg(-1) (wet weight). Both samples had low amount of carbohydrates 4.77-5.77 microg mg(-1) and lipids 0.11-0.17 microg mg(-1), respectively. The results of thin layer chromatography were revealed that presence of pink color spots it clearly indicates the presence of amino acid or peptides in bivalve's samples. Presuming that the antimicrobial compounds were proteins or peptides. In SDS-PAGE on 12% gel, the crude proteins M. meretrix and M. casta showed 5-6 bands ranging from 45-223 kDa. They represent potential pharmacological leads perhaps possessing novel and uncharacterized mechanisms of action that might ultimately benefit the ongoing global search for clinically useful antimicrobial agents.

  5. Antimicrobial Activity of Kefir against Various Food Pathogens and Spoilage Bacteria

    PubMed Central

    Kim, Hyunsook

    2016-01-01

    Kefir is a unique fermented dairy product produced by a mixture of lactic acid bacteria, acetic acid bacteria, and yeast. Here, we compared the antimicrobial spectra of four types of kefirs (A, L, M, and S) fermented for 24, 36, 48, or 72 h against eight food-borne pathogens. Bacillus cereus, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis, Escherichia coli, Salmonella Enteritidis, Pseudomonas aeruginosa, and Cronobacter sakazakii were used as test strains, and antibacterial activity was investigated by the spot on lawn method. The spectra, potencies, and onsets of activity varied according to the type of kefir and the fermentation time. The broadest and strongest antimicrobial spectrum was obtained after at least 36-48 h of fermentation for all kefirs, although the traditional fermentation method of kefir is for 18-24 h at 25℃. For kefir A, B. cereus, E. coli, S. Enteritidis, P. aeruginosa, and C. sakazakii were inhibited, while B. cereus, S. aureus, E. coli, S. Enteritidis, P. aeruginosa, and C. sakazakii were inhibited to different extents by kefirs L, M, and S. Remarkably, S. aureus, S. Enteritidis, and C. sakazakii were only inhibited by kefirs L, M, and S, and L. monocytogenes by kefir M after fermentation for specific times, suggesting that the antimicrobial activity is attributable not only to a low pH but also to antimicrobial substances secreted during the fermentation. PMID:28115890

  6. Antimicrobial activity of Amazon Astrocaryum aculeatum extracts and its association to oxidative metabolism.

    PubMed

    Jobim, Micheli Lamberti; Santos, Roberto Christ Vianna; dos Santos Alves, Camilla Filippi; Oliveira, Raul Moreira; Mostardeiro, Clarice Pinheiro; Sagrillo, Michele Rorato; de Souza Filho, Olmiro Cezimbra; Garcia, Luiz Filipe Machado; Manica-Cattani, Maria Fernanda; Ribeiro, Euler Esteves; da Cruz, Ivana Beatrice Mânica

    2014-04-01

    Several compounds present in fruits as polyphenols are able to kill or inhibit the growth of microorganisms. These proprieties are relevant mainly in tropical areas, as Amazonian region where infectious are highly prevalent. Therefore, this study investigated the antimicrobial activity of tucumã Amazonian fruit against 37 microorganisms. The potential role of oxidative metabolism imbalance was also studied as causal mechanism of antimicrobial activity. The results showed antibacterial effect of pulp and peel tucumã hydro-alcoholic extracts on three Gram-positive bacteria (Enterococcus faecalis, Bacillus cereus, Listeria monocytogenes) and antifungal effect against Candida albicans. The antimicrobial contribution of main chemical compounds (quercetin, rutin, β-carotene and gallic, caffeic and chlorogenic acids) found in tucumã extracts was also investigated showing an inhibitory effect depending of the organism mainly by quercetin in bacteria and rutin in C. albicans. Analysis of kinetic of DNA releasing in extracellular medium by fluorescence using DNA Pico Green assay(®) and reactive oxygen species production (ROS) showed potential oxidative imbalance contribution on tucumã inhibitory effect. In B. cereus and C. albicans this effect was clear since after 24h the ROS levels were higher when compared to negative control group. In conclusion, tucumã extracts present antimicrobial activity to four microorganisms that have large problems of drug resistance, and the possible mechanism of action of this Amazon fruit is related to REDOX imbalance.

  7. Antimicrobial activity and mechanism of PDC213, an endogenous peptide from human milk.

    PubMed

    Sun, Yazhou; Zhou, Yahui; Liu, Xiao; Zhang, Fan; Yan, Linping; Chen, Ling; Wang, Xing; Ruan, Hongjie; Ji, Chenbo; Cui, Xianwei; Wang, Jiaqin

    2017-02-26

    Human milk has always been considered an ideal source of elemental nutrients to both preterm and full term infants in order to optimally develop the infant's tissues and organs. Recently, hundreds of endogenous milk peptides were identified in human milk. These peptides exhibited angiotensin-converting enzyme inhibition, immunomodulation, or antimicrobial activity. Here, we report the antimicrobial activity and mechanism of a novel type of human antimicrobial peptide (AMP), termed PDC213 (peptide derived from β-Casein 213-226 aa). PDC213 is an endogenous peptide and is present at higher levels in preterm milk than in full term milk. The inhibitory concentration curve and disk diffusion tests showed that PDC213 had obvious antimicrobial against S. aureus and Y. enterocolitica, the common nosocomial pathogens in neonatal intensive care units (NICUs). Fluorescent dye methods, electron microscopy experiments and DNA-binding activity assays further indicated that PDC213 can permeabilize bacterial membranes and cell walls rather than bind intracellular DNA to kill bacteria. Together, our results suggest that PDC213 is a novel type of AMP that warrants further investigation.

  8. Antimicrobial Activity of Chitosan Derivatives Containing N-Quaternized Moieties in Its Backbone: A Review

    PubMed Central

    Martins, Alessandro F.; Facchi, Suelen P.; Follmann, Heveline D. M.; Pereira, Antonio G. B.; Rubira, Adley F.; Muniz, Edvani C.

    2014-01-01

    Chitosan, which is derived from a deacetylation reaction of chitin, has attractive antimicrobial activity. However, chitosan applications as a biocide are only effective in acidic medium due to its low solubility in neutral and basic conditions. Also, the positive charges carried by the protonated amine groups of chitosan (in acidic conditions) that are the driving force for its solubilization are also associated with its antimicrobial activity. Therefore, chemical modifications of chitosan are required to enhance its solubility and broaden the spectrum of its applications, including as biocide. Quaternization on the nitrogen atom of chitosan is the most used route to render water-soluble chitosan-derivatives, especially at physiological pH conditions. Recent reports in the literature demonstrate that such chitosan-derivatives present excellent antimicrobial activity due to permanent positive charge on nitrogen atoms side-bonded to the polymer backbone. This review presents some relevant work regarding the use of quaternized chitosan-derivatives obtained by different synthetic paths in applications as antimicrobial agents. PMID:25402643

  9. Anti-microbial activity and composition of manuka and portobello honey.

    PubMed

    Schneider, Monika; Coyle, Shirley; Warnock, Mary; Gow, Iain; Fyfe, Lorna

    2013-08-01

    Recently renewed interest in the therapeutic properties of honey has led to the search for new antimicrobial honeys. This study was undertaken to assess the antimicrobial activity and composition of a locally produced Portobello honey (PBH) on three bacteria known to infect wounds. Manuka honey (MH) was used for comparative purposes. Broth culture and agar disc diffusion assays were used to investigate the antimicrobial properties of honey. The honeys were tested at four concentrations: 75%, 50%, 10% and 1% (v/v) and compared with an untreated control. The composition of honey was determined by measuring: polyphenol content by Folin Ciocalteau method, antioxidant capacity by ferric ion reducing power assay, hydrogen peroxide (H2 O2 ) by catalase test, pH and sugar content by pH strips and refractometer, respectively. Both honeys at 75% and 50% inhibited the majority of the three bacteria tested. 10% PBH exhibited antimicrobial activity to the lesser extent than 10% MH. The difference was very significant (p ≤ 0.001). Both honeys were acidic with pH 4, and both produced H2 O2 . The sugar content of PBH was higher than MH, but the difference was not significant. The MH had significantly higher levels of the polyphenols and antioxidant activity than PBH.

  10. Amyloidogenic amyloid-β-peptide variants induce microbial agglutination and exert antimicrobial activity

    PubMed Central

    Spitzer, Philipp; Condic, Mateja; Herrmann, Martin; Oberstein, Timo Jan; Scharin-Mehlmann, Marina; Gilbert, Daniel F.; Friedrich, Oliver; Grömer, Teja; Kornhuber, Johannes; Lang, Roland; Maler, Juan Manuel

    2016-01-01

    Amyloid-β (Aβ) peptides are the main components of the plaques found in the brains of patients with Alzheimer’s disease. However, Aβ peptides are also detectable in secretory compartments and peripheral blood contains a complex mixture of more than 40 different modified and/or N- and C-terminally truncated Aβ peptides. Recently, anti-infective properties of Aβ peptides have been reported. Here, we investigated the interaction of Aβ peptides of different lengths with various bacterial strains and the yeast Candida albicans. The amyloidogenic peptides Aβ1-42, Aβ2-42, and Aβ3p-42 but not the non-amyloidogenic peptides Aβ1-40 and Aβ2-40 bound to microbial surfaces. As observed by immunocytochemistry, scanning electron microscopy and Gram staining, treatment of several bacterial strains and Candida albicans with Aβ peptide variants ending at position 42 (Aβx-42) caused the formation of large agglutinates. These aggregates were not detected after incubation with Aβx-40. Furthermore, Aβx-42 exerted an antimicrobial activity on all tested pathogens, killing up to 80% of microorganisms within 6 h. Aβ1-40 only had a moderate antimicrobial activity against C. albicans. Agglutination of Aβ1-42 was accelerated in the presence of microorganisms. These data demonstrate that the amyloidogenic Aβx-42 variants have antimicrobial activity and may therefore act as antimicrobial peptides in the immune system. PMID:27624303

  11. Comparative study of volatile oil content and antimicrobial activity of pecan cultivars growing in Egypt.

    PubMed

    El Hawary, Seham S; Zaghloul, Soumaya S; El Halawany, Ali M; El Bishbishy, Mahitab H

    2013-11-01

    The volatile oils obtained from the leaves of four pecan cultivars growing in Egypt were evaluated for their chemical composition and antimicrobial activity. The selected cultivars (cv.) were Carya illinoinensis (Wangneh.) K. Koch. cv. Wichita, C. illinoinensis cv. Western Schley, C. illinoinensis cv. Cherokee, and C. illinoinensis cv. Sioux. The gas chromatography-mass spectrometry analyses revealed that the volatile oils from samples of the different cultivars differ in composition and percentage of their components. β-Curcumene was found as the major constituent of the cv. Wichita oil, whereas germacrene D was the major component of cv. Sioux, cv. Cherokee, and cv. Western Schley. The antimicrobial activity was assayed using the Kirby-Bauer Method by measuring the zone of inhibition of growth. All volatile oils displayed an antimicrobial activity against the tested bacterial strains. On the other hand, only the volatile oil of cv. Wichita showed an antifungal effect on Aspergillus flavus. This work has identified candidates of volatile oils for future in vivo studies to develop antibiotic substitutes for the diminution of human and animal pathogenic bacteria. Nevertheless, the variations of the volatile oil components and antimicrobial potencies of the different studied cultivars, necessitate identifying the cultivars used in future studies.

  12. Chemical composition and antimicrobial activity of hexane leaf extract of Anisopus mannii (Asclepiadaceae)

    PubMed Central

    Musa, Aliyu Muhammad; Ibrahim, Mohammed Auwal; Aliyu, Abubakar Babando; Abdullahi, Mikhail Sabo; Tajuddeen, Nasir; Ibrahim, Halliru; Oyewale, Adebayo Ojo

    2015-01-01

    Objective: The aim was to determine the chemical constituents and antimicrobial activity of the hexane leaf extract of Anisopus mannii against a wide range of human pathogenic microorganisms. Methods: The chemical constituents of the hexane leaf extract was determined using gas chromatography-mass spectrometry (GC-MS) analysis; and the antimicrobial activity was evaluated on “standard strains”, clinical susceptible and resistant bacterial and fungal isolates using the disc diffusion and broth microdilution methods. Results: GC-MS analysis of the hexane leaf extract revealed 32 compounds, representing 73.8% of the identified components. The major compounds were hexadecanoic acid, ethyl ester (34%), oxirane, hexadecyl- (11%) and 9, 12, 15-octadecatrienoic acid, ethyl ester, (Z, Z, Z) (9.6%). Results from the antimicrobial activity demonstrated higher inhibition zones against Bacillus cereus (29 mm), followed by Streptococcus pyogenes (28 mm). Other notable inhibitions were observed with Enterococcus faecalis (27 mm), Proteus vulgaris (26 mm) and MRSA (25 mm). The MIC values ranged from 0.625 mg/mL to 1.25 mg/mL while the MBC/MFC values ranged from 2.5 mg/mL to 5.0 mg/mL. Conclusion: These results support the traditional use of the plant and demonstrate the huge potential of A. mannii as a source of antimicrobial compounds. PMID:26401399

  13. Antimicrobial and antitumor activities of chitosan from shiitake stipes, compared to commercial chitosan from crab shells.

    PubMed

    Chien, Rao-Chi; Yen, Ming-Tsung; Mau, Jeng-Leun

    2016-03-15

    Chitosan was prepared by alkaline N-deacetylation of chitin obtained from shiitake stipes and crab shells and its antimicrobial and antitumor activities were studied. Chitosan from shiitake stipes and crab shells exhibited excellent antimicrobial activities against eight species of Gram positive and negative pathogenic bacteria with inhibition zones of 11.4-26.8mm at 0.5mg/ml. Among chitosan samples, shiitake chitosan C120 was the most effective with inhibition zones of 16.4-26.8mm at 0.5mg/ml. In addition, shiitake and crab chitosan showed a moderate anti-proliferative effect on IMR 32 and Hep G2 cells. At 5mg/ml, the viability of IMR 32 cells incubated with chitosan was 68.8-85.0% whereas that of Hep G2 cells with chitosan was 60.4-82.9%. Overall, shiitake chitosan showed slightly better antimicrobial and antitumor activities than crab chitosan. Based on the results obtained, shiitake and crab chitosan were strong antimicrobial agents and moderate antitumor agents.

  14. Antimicrobial activity of Antrodia camphorata extracts against oral bacteria.

    PubMed

    Lien, Hsiu-Man; Tseng, Chin-Jui; Huang, Chao-Lu; Lin, Yu-Ting; Chen, Chia-Chang; Lai, Ya-Yun

    2014-01-01

    Antrodia camphorata (A. camphorata) is a unique, endemic and extremely rare mushroom species native to Taiwan, and both crude extracts of and purified chemical compounds from A. camphorata have been reported to have a variety of significant beneficial effects, such as anti-tumor and anti-inflammatory activity. However, reports on the effects of A. camphorata against dental pathogens have been limited. Oral health is now recognized as important for overall general health, including conditions such as dental caries, periodontal disease and rheumatoid arthritis. Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis) are the most common bacteria associated with dental plaque and periodontopathic diseases, respectively. Thus, our study examined the ability of five various crude extracts of A. camphorata to inhibit the growth of dental bacteria and anti-adherence in vitro. Among the extracts, the ethanol, ethyl acetate and chloroform extracts exhibited the lowest MICs against P. gingivalis and S. mutans (MIC = 4∼16 µg/mL). The MIC of the aqueous extract was greater than 2048 µg/mL against both P. gingivalis and S. mutans. In vitro adherence of S. mutans was significantly inhibited by the addition of either the ethyl acetate extract or chloroform extract (MIC = 16∼24 µg/mL), while the ethanol extract (MIC = 32∼64 µg/mL) exhibited moderate inhibitory activity. Based on the result of this study, the ethyl acetate and chloroform extracts of A. camphorata may be good candidates for oral hygiene agents to control dental caries and periodontopathic conditions.

  15. Antimicrobial Activity of Antrodia camphorata Extracts against Oral Bacteria

    PubMed Central

    Lien, Hsiu-Man; Tseng, Chin-Jui; Huang, Chao-Lu; Lin, Yu-Ting; Chen, Chia-Chang; Lai, Ya-Yun

    2014-01-01

    Antrodia camphorata (A. camphorata) is a unique, endemic and extremely rare mushroom species native to Taiwan, and both crude extracts of and purified chemical compounds from A. camphorata have been reported to have a variety of significant beneficial effects, such as anti-tumor and anti-inflammatory activity. However, reports on the effects of A. camphorata against dental pathogens have been limited. Oral health is now recognized as important for overall general health, including conditions such as dental caries, periodontal disease and rheumatoid arthritis. Streptococcus mutans (S. mutans) and Porphyromonas gingivalis (P. gingivalis) are the most common bacteria associated with dental plaque and periodontopathic diseases, respectively. Thus, our study examined the ability of five various crude extracts of A. camphorata to inhibit the growth of dental bacteria and anti-adherence in vitro. Among the extracts, the ethanol, ethyl acetate and chloroform extracts exhibited the lowest MICs against P. gingivalis and S. mutans (MIC = 4∼16 µg/mL). The MIC of the aqueous extract was greater than 2048 µg/mL against both P. gingivalis and S. mutans. In vitro adherence of S. mutans was significantly inhibited by the addition of either the ethyl acetate extract or chloroform extract (MIC = 16∼24 µg/mL), while the ethanol extract (MIC = 32∼64 µg/mL) exhibited moderate inhibitory activity. Based on the result of this study, the ethyl acetate and chloroform extracts of A. camphorata may be good candidates for oral hygiene agents to control dental caries and periodontopathic conditions. PMID:25144619

  16. Antimicrobial, Antioxidant and Cytotoxic Activities and Phytochemical Screening of Some Yemeni Medicinal Plants

    PubMed Central

    Abdo, Salah A. A.; Hasson, Sidgi; Althawab, Faisal M. N.; Alaghbari, Sama A. Z.; Lindequist, Ulrike

    2010-01-01

    The traditional medicine still plays an important role in the primary health care in Yemen. The current study represents the investigation of 16 selected plants, which were collected from different localities of Yemen. The plants were dried and extracted with two different solvents (methanol and hot water) to yield 34 crude extracts. The obtained extracts were tested for their antimicrobial activity against three Gram-positive bacteria, two Gram-negative bacteria, one yeast species and three multiresistant Staphylococcus strains using agar diffusion method, for their antioxidant activity using scavenging activity of DPPH radical method and for their cytotoxic activity using the neutral red uptake assay. In addition, a phytochemical screening of the methanolic extracts was done. Antibacterial activity was shown only against Gram-positive bacteria, among them multiresistant bacteria. The highest antimicrobial activity was exhibited by the methanolic extracts of Acalypha fruticosa, Centaurea pseudosinaica, Dodonaea viscosa, Jatropha variegata, Lippia citriodora, Plectranthus hadiensis, Tragia pungens and Verbascum bottae. Six methanolic extracts especially those of A. fruticosa, Actiniopteris semiflabellata, D. viscosa, P. hadiensis, T. pungens and V. bottae showed high free radical scavenging activity. Moreover, remarkable cytotoxic activity against FL-cells was found for the methanolic extracts of A. fruticosa, Iris albicans, L. citriodora and T. pungens. The phytochemical screening demonstrated the presence of different types of compounds like flavonoids, terpenoids and others, which could be responsible for the obtained activities. PMID:18955315

  17. Correlation between Antimicrobial, Antioxidant Activity, and Polyphenols of Alkalized/Nonalkalized Cocoa Powders.

    PubMed

    Todorovic, Vanja; Milenkovic, Marina; Vidovic, Bojana; Todorovic, Zoran; Sobajic, Sladjana

    2017-04-01

    Many factors can influence antioxidative and antimicrobial characteristics of plant materials. The quality of cocoa as functional food ingredient is influenced through its processing. The main aim of this study was to test if there is difference in polyphenol content, antioxidant capacity, and antimicrobial activity between nonalkalized and alkalized cocoa powders. To estimate polyphenol and flavonoid content in cocoa samples the spectrophotometric microassays were used. Flavan-3ols were determined with reversed-phase high-performance liquid chromatography (RP-HPLC). Antimicrobial activity against 3 Gram positive bacteria, 4 Gram negative bacteria and 1 strain of yeast was determined using broth microdilution method. Total polyphenol content was 1.8 times lower in alkalized cocoa samples than in natural ones. Epicatechin/catechin ratio was changed due to the process of alkalization in favor of catechin (2.21 in natural and 1.45 in alkalized cocoa powders). Combined results of 3 antioxidative tests (DPPH, FRAP, ABTS) were used for calculation of RACI (Relative Antioxidant Capacity Index) and GAS (Global Antioxidant Score) values that were consistently higher in natural than in alkalized cocoa extracts. Obtained results have shown significant correlations between these values and phenolic content (0.929 ≤ r ≤ 0.957, P < 0.01). Antimicrobial activity varied from 5.0 to 25.0 mg/ml (MICs), while Candida albicans was the most sensitive tested microorganism. Cocoa powders subjected to alkalization had significantly reduced content of total and specific phenolic compounds and reduced antioxidant capacity (P < 0.05), but their antimicrobial activity was equal for Gram-positive bacteria or even significantly enhanced for Gram-negative bacteria.

  18. Fluorescein dye derivatives and their nanohybrids: Synthesis, characterization and antimicrobial activity.

    PubMed

    Negm, Nabel A; Abou Kana, Maram T H; Abd-Elaal, Ali A; Elwahy, Ahmed H M

    2016-09-01

    Fluorescein (resorcinolphthalein) is a synthetic organic photoactive dye compound soluble in water, alcohol and polar solvents. It is widely used as a fluorescent tracer in medicinal and biological applications and tumor infected tissues tracer. In this study, fluorescein (F) was condensed by five coupling agents namely: p,p-phenylene diamine, p-hydroxy aniline, o-hydroxy aniline, p-methoxy aniline and p-methyl aniline in a molar ratio of 2(F):1 (coupling agent). The chemical structures of the synthesized fluorescein derivatives were confirmed using: microelemental analysis, FTIR spectroscopy, 1H-NMR spectroscopy, and mass spectroscopy. The synthesized compounds were loaded on chemically prepared silver nanoparticles via reduction reaction of silver nitrate. The structures and properties of the formed fluorescein derivatives silver nanohybrids were determined using: UV/Vis spectroscopy, TEM images and dynamic light scattering (DLS). The synthesized compounds and their nanohybrids were evaluated for their antimicrobial activities against different bacterial strains and fungi. The results showed that the formed fluorescein derivatives silver nanohybrids are in moderate diameter range, and the loading of the synthesized compounds protect the silver nanoparticles against coagulation. The antimicrobial activity against the studied microorganisms was comparable to the standard used. Moreover, the antimicrobial activity was increased considerably in case of using fluorescein derivatives silver nanohybrids. The antimicrobial activities were correlated to the chemical structures of the compounds, diameter of the formed nanohybrids and to the nature of the tested bacterial strains. The mechanism of the antimicrobial action of the synthesized compounds and their nanohybrids was proposed.

  19. Antimicrobial Activity of Medicated Soaps Commonly Used By Dar es Salaam Residents in Tanzania.

    PubMed

    Mwambete, K D; Lyombe, F

    2011-01-01

    An in vitro evaluation of the anti-microbial activity of medicated soaps was conducted using ditch-plate and hand washing techniques. Strains of reference microbes namely Candida albicans (ATCC90028), Staphylococcus aureus (ATCC25923), Pseudomonas aureginosa (ATCC27853) and Escherichia coli (ATCC25922) were tested at three different soaps' concentrations (1.0, 4.0 and 8.0 mg/ml). A total of 16 medicated soaps were assayed for their antimicrobial efficacy. Of these, 13 were medicated and 3 non-medicated soaps, which served as control. Ciprofloxacin and ketaconazole were employed as positive controls. Label disclosure for the soaps' ingredients and other relevant information were absorbed. The most common antimicrobial active ingredients were triclosan, trichloroxylenol and trichlorocarbanilide. ANOVA for means of zones of inhibition revealed variability of antimicrobial activity among the medicated soaps. Positive correlation (r=0.318; P<0.01) between zones of inhibition and soaps' concentrations was evidenced. Hand washing frequencies positively correlated with microbial counts. Roberts(®) soap exhibited the largest zone of inhibition (34 mm) on S. aureus. Candida albicans was the least susceptible microbe. Regency(®) and Dalan(®) exhibited the least zone of inhibition on the tested bacteria. Protex(®), Roberts(®), Family(®) and Protector(®) were equally effective (P<0.01) against S. aureus. In conclusion, majority of the assayed medicated soaps have satisfactory antibacterial activity; though lack antifungal effect with exception of Linda(®) liquid soap. The hand washing technique has proved to be inappropriate for evaluation of soaps' antimicrobial efficacy due to presence of the skin microflora.

  20. Antimicrobial Activity of Medicated Soaps Commonly Used By Dar es Salaam Residents in Tanzania

    PubMed Central

    Mwambete, K. D.; Lyombe, F.

    2011-01-01

    An in vitro evaluation of the anti-microbial activity of medicated soaps was conducted using ditch-plate and hand washing techniques. Strains of reference microbes namely Candida albicans (ATCC90028), Staphylococcus aureus (ATCC25923), Pseudomonas aureginosa (ATCC27853) and Escherichia coli (ATCC25922) were tested at three different soaps’ concentrations (1.0, 4.0 and 8.0 mg/ml). A total of 16 medicated soaps were assayed for their antimicrobial efficacy. Of these, 13 were medicated and 3 non-medicated soaps, which served as control. Ciprofloxacin and ketaconazole were employed as positive controls. Label disclosure for the soaps’ ingredients and other relevant information were absorbed. The most common antimicrobial active ingredients were triclosan, trichloroxylenol and trichlorocarbanilide. ANOVA for means of zones of inhibition revealed variability of antimicrobial activity among the medicated soaps. Positive correlation (r=0.318; P<0.01) between zones of inhibition and soaps’ concentrations was evidenced. Hand washing frequencies positively correlated with microbial counts. Roberts® soap exhibited the largest zone of inhibition (34 mm) on S. aureus. Candida albicans was the least susceptible microbe. Regency® and Dalan® exhibited the least zone of inhibition on the tested bacteria. Protex®, Roberts®, Family® and Protector® were equally effective (P<0.01) against S. aureus. In conclusion, majority of the assayed medicated soaps have satisfactory antibacterial activity; though lack antifungal effect with exception of Linda® liquid soap. The hand washing technique has proved to be inappropriate for evaluation of soaps’ antimicrobial efficacy due to presence of the skin microflora. PMID:22131630

  1. Novel designed VmCT1 analogs with increased antimicrobial activity.

    PubMed

    Pedron, Cibele Nicolaski; Torres, Marcelo Der Torossian; Lima, Julia Aparecida da Silva; Silva, Pedro Ismael; Silva, Fernanda Dias; Oliveira, Vani Xavier

    2017-01-27

    Antimicrobial peptides are biologically active molecules produced by a wide range of organisms as an essential component of the innate immune response. They have recently attracted great interest, since they have antimicrobial activity against a broad spectrum of microorganisms. VmCT1 is a cationic peptide from the venom of Vaejovis mexicanus smithi scorpions, which presents antibacterial activity and tends to helical structures. Its analogs were synthesized, characterized and the conformational studies were performed by circular dichroism. The peptides were designed to verify if the single and double substitutions proposed at the hydrophilic and hydrophobic portions of the amphipathic structure would alter antimicrobial activity against Gram-negative and Gram-positive bacteria, yeast and filamentous fungus, besides the hemolytic activity in human erythrocytes. Total charge of the peptides were modified from +2 to +3 by the introduction of a Lysine residue in the hydrophilic face of the amphiphilic helical structure leading to enhanced antimicrobial activity. [K](11)-VmCT1-NH2 presented the lower MIC value against the microorganisms (from 0.39 to 6.25 μmol L(-1)), however it showed higher hemolytic activity. The other Lysine-substituted analogs presented also lower MIC values ranging from 0.39 to 25 μmol L(-1) for the microorganisms assessed. The circular dichroism spectra analyses suggest that the Lysine-substituted analogs tend to adopt helical structures in trifluoroethanol solution and vesicles (fH: 0.43-1), however they were coiled in water. Alanine substitution by a Glutamic acid residue in the hydrophilic face promotes the increase of polar angle in [E](4)-VmCT1-NH2 analog, which was important to led lower hemolytic activity (MHC value = 25 μmol L(-1)). [W](9)-VmCT1-NH2 and [E](4)[W](9)-VmCT1-NH2 were designed to favors hydrophobic interactions by the introduction of Tryptophan residue. [W](9)-VmCT1-NH2 presented MIC values lower or similar than

  2. [Antimicrobial activity and constituents in rumput roman extract as a natural food preservative].

    PubMed

    Sugimoto, Naoki; Tada, Atsuko; Yamazaki, Takashi; Tanamoto, Kenichi

    2007-08-01

    Rumput roman extract is used as a natural food preservative. Its antimicrobial activity and constituents were investigated as part of an ongoing study to evaluate its quality and safety as a food additive. The constituents were analyzed by GC/MS, and 5 major constituents were isolated and identified as capillin, capillene, caryophyllene oxide, alpha-curcumene and methyleugenol using NMR analysis. The antimicrobial activities against E. coli, S. cerevisiae and A. niger were measured by means of the halo test. Based on the results, we confirmed that capillin was the major active constituent. The concentrations of capillin and capillene were determined to 17.9 mg/mL and 36.1 mg/mL, respectively, from standard curves of authentic compounds on HPLC.

  3. Synthesis of novel coumarin appended bis(formylpyrazole) derivatives: Studies on their antimicrobial and antioxidant activities.

    PubMed

    Nagamallu, Renuka; Srinivasan, Bharath; Ningappa, Mylarappa B; Kariyappa, Ajay Kumar

    2016-01-15

    A series of novel coumarin pyrazole hybrids of biological interest were synthesized from the hydrazones, carbazones and thiocarbazones via Vilsmeier Haack formylation reaction. These intermediates and formyl pyrazoles were evaluated for antimicrobial and antioxidant activities. Among the series, compounds 6g and 6h showed excellent antimicrobial activity against different bacterial and fungal strains and compounds 7g, 7h were found to be potent antioxidant agents in both DPPH and hydroxyl radical scavenging assays. Further, detailed quantitative structure-activity relationship (QSAR) analysis indicated the molecular parameters that contribute to increased potency of inhibition. The above findings would further encourage our understanding in employing coumarin pyrazole hybrids as potential antibiotic agents for treating infections caused by pathogenic microbes and fungi. Further, it also paves the way for exploration of these compounds as potential therapeutic agents to treat conditions arising because of excessive oxidative damage.

  4. Synthesis, antimicrobial activity of Schiff base compounds of cinnamaldehyde and amino acids.

    PubMed

    Wang, Hui; Yuan, Haijian; Li, Shujun; Li, Zhuo; Jiang, Mingyue

    2016-02-01

    The purpose of this study was to synthesize hydrophilic cinnamaldehyde Schiff base compounds and investigate those bioactivity. A total of 24 Schiff base compounds were synthesized using a simple approach with 3 cinnamaldehyde derivates and 8 amino acids as raw materials. The structures of synthesized compounds were confirmed using FTIR, (1)HNMR, HRMS purity and melting point. The antimicrobial activities of new compounds were evaluated with fluconazole and ciprofloxacin as the control against Aspergillus niger, Penicillium citrinum, Escherichia coli and Staphylococcus aureus. Findings show that major compounds exhibited significant bioactivity. Results from the structure-activity relationship suggest that both -p-Cl on benzene ring of cinnamaldehyde and the number of -COOK of amino acid salts significantly contributed to antimicrobial activity.

  5. Antimicrobial and antifungal activities of the extracts and essential oils of Bidens tripartita.

    PubMed

    Tomczykowa, Monika; Tomczyk, Michał; Jakoniuk, Piotr; Tryniszewska, Elzbieta

    2008-01-01

    The aim of this study was to determine the antibacterial and antifungal properties of the extracts, subextracts and essential oils of Bidens tripartita flowers and herbs. In the study, twelve extracts and two essential oils were investigated for activity against different Gram-positive Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Gram-negative bacteria Escherichia coli, E. coli (beta-laktamase+), Klebsiella pneumoniae (ESBL+), Pseudomonas aeruginosa and some fungal organisms Candida albicans, C. parapsilosis, Aspergillus fumigatus, A. terreus using a broth microdilution and disc diffusion methods. The results obtained indicate antimicrobial activity of the tested extracts (except butanolic extracts), which however did not inhibit the growth of fungi used in this study. Bacteriostatic effect of both essential oils is insignificant, but they have strong antifungal activity. These results support the use of B. tripartita to treat a microbial infections and it is indicated as an antimicrobial and antifungal agent, which may act as pharmaceuticals and preservatives.

  6. Chemical composition, antimicrobial and insecticidal activities of the essential oils of Conyza linifolia and Chenopodium ambrosioides.

    PubMed

    Harraz, Fathalla M; Hammoda, Hala M; El Ghazouly, Maged G; Farag, Mohamed A; El-Aswad, Ahmed F; Bassam, Samar M

    2015-01-01

    Two essential oil-containing plants growing wildly in Egypt: Conyza linifolia (Willd.) Täckh. (Asteraceae) and Chenopodium ambrosioides L. (Chenopodiaceae) were subjected to essential oil analysis and biological investigation. The essential oils from both plants were prepared by hydrodistillation, and GC/MS was employed for volatiles profiling. This study is the first to perform GC/MS analysis of C. linifolia essential oil growing in Egypt. C. linifolia essential oil contained mainly sesquiterpenes, while that of C. ambrosioides was rich in monoterpenes. Ascaridole, previously identified as the major component of the latter, was found at much lower levels. In addition, the oils were investigated for their antimicrobial activity against two Gram positive and two Gram negative bacteria, and one fungus. The insecticidal activities of both oils, including mosquitocidal and pesticidal potentials, were also evaluated. The results of biological activities encourage further investigation of the two oils as antimicrobial and insecticidal agents of natural origin.

  7. Acrolein contributes strongly to antimicrobial and heterocyclic amine transformation activities of reuterin.

    PubMed

    Engels, Christina; Schwab, Clarissa; Zhang, Jianbo; Stevens, Marc J A; Bieri, Corinne; Ebert, Marc-Olivier; McNeill, Kristopher; Sturla, Shana J; Lacroix, Christophe

    2016-11-07

    Glycerol/diol dehydratases catalyze the conversion of glycerol to 3-hydroxypropionaldehyde (3-HPA), the basis of a multi-component system called reuterin. Reuterin has antimicrobial properties and undergoes chemical conjugation with dietary heterocyclic amines (HCAs). In aqueous solution reuterin is in dynamic equilibrium with the toxicant acrolein. It was the aim of this study to investigate the extent of acrolein formation at various physiological conditions and to determine its role in biological and chemical activities. The application of a combined novel analytical approach including IC-PAD, LC-MS and NMR together with specific acrolein scavengers suggested for the first time that acrolein, and not 3-HPA, is the active compound responsible for HCA conjugation and antimicrobial activity attributed to reuterin. As formation of the HCA conjugate was observed in vivo, our results imply that acrolein is formed in the human gut with implications on detoxification of HCAs. We propose to re-define the term reuterin to include acrolein.

  8. Azurocidin, a natural antibiotic from human neutrophils: expression, antimicrobial activity, and secretion.

    PubMed

    Almeida, R P; Vanet, A; Witko-Sarsat, V; Melchior, M; McCabe, D; Gabay, J E

    1996-06-01

    The azurophil granules of human PMN contain four antibiotic proteins, the serprocidins, which have extensive homology to one another and to serine proteases. Azurocidin, a member of this family, is a 29-kDa glycoprotein with broad spectrum antimicrobial activity and chemotactic activity toward monocytes. Insect cells transfected with a baculovirus vector carrying azurocidin cDNA produced a recombinant azurocidin protein. We purified the recombinant azurocidin protein from the culture medium of the infected cells and showed that it retained the antimicrobial activity of the native neutrophil-derived molecule. In addition, we present evidence that a 49-amino-acid region of the recombinant azurocidin protein is required for its secretion from insect cells.

  9. In vitro activities of antimicrobial agents, alone and in combination, against Acinetobacter baumannii isolated from blood.

    PubMed

    Chang, S C; Chen, Y C; Luh, K T; Hsieh, W C

    1995-11-01

    In vitro activities of 15 antimicrobial agents against 90 strains of Acinetobacter baumannii isolated from blood cultures from hospitalized patients were determined using the agar dilution method. Imipenem, ofloxacin, and ciprofloxacin had the best antimicrobial activity with minimum inhibitory concentrations (MIC50s) of 0.25 mu g/ml and MIC90s of 0.5-1 mu g/ml. beta-lactam antibiotics other than imipenem had poor activity, with MIC50s ranging from 8 to 64 mu g/ml and MIC90s from 32 to > or = 256 mu g/ml. The checkerboard titration method was used to study the effects of combination of two antimicrobial agents. Combinations of ceftazidime, aztreonam, imipenem, or ciprofloxacin with amikacin showed either synergistic effects or partial synergistic effects for 40.9%-86.4% of 22 tested strains. The best in vitro activity was observed with the combination of imipenem and amikacin. No antagonistic effects were observed with the combination of imipenem and amikacin. Synergistic effects were confirmed by time-kill curve studies. In conclusion, imipenem, ofloxacin, and ciprofloxacin were the three most active agents against human blood isolates of A. baumannii. The combination of a beta-lactam or ciprofloxacin with amikacin was synergistic for some of the isolates.

  10. Chemical compositions and antimicrobial activity of the essential oils of Hornstedtia havilandii (Zingiberaceae).

    PubMed

    Hashim, Siti Ernieyanti; Sirat, Hasnah Mohd; Yen, Khong Heng

    2014-01-01

    The chemical compositions and antimicrobial activity of the fresh rhizome and flower oils of Hornstedtia havilandii were studied. The components present were analyzed using GC and GC-MS. A total of forty-eight constituents were successfully identified from the flower and rhizome oils, representing 93.4% and 89.6%, respectively. The most abundant components of the flower oil were beta-pinene, (19.5%), beta-elemene, (10.0%), beta-cubebene, (6.2%), alpha-pinene, (5.6%), gamma-cadinene, (4.3%) and germacrene D, (3.3%), while alpha-copaene, (10.2%), beta-selinene, (8.4%), beta-elemene, (7.0%), gamma-cadinene, (6.9%), beta-cubebene, (5.3%) and germacrene D, (5.3%) were found as the main components of the rhizome oil. The essential oils were tested for antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and yeasts. Both oils showed activity against the Gram-positive bacterium, Staphylococcus aureus, with moderate MIC values of 112.5 micro/mL, however, for Gram-negative bacteria, the flower oil showed weak antimicrobial activity with a MIC value of 225 microg/mL. Only very weak activity was shown against the yeasts Candida albicans and C. glabrata, with MIC values of 900-1800 microg/mL.

  11. Structural Insights into and Activity Analysis of the Antimicrobial Peptide Myxinidin

    PubMed Central

    Cantisani, Marco; Finamore, Emiliana; Mignogna, Eleonora; Falanga, Annarita; Nicoletti, Giovanni Francesco; Pedone, Carlo; Morelli, Giancarlo; Leone, Marilisa

    2014-01-01

    The marine environment has been poorly explored in terms of potential new molecules possessing antibacterial activity. Antimicrobial peptides (AMPs) offer a new potential class of pharmaceuticals; however, further optimization is needed if AMPs are to find broad use as antibiotics. We focused our studies on a peptide derived from the epidermal mucus of hagfish (Myxine glutinosa L.), which was previously characterized and showed high antimicrobial activity against human and fish pathogens. In the present work, the activities of myxinidin peptide analogues were analyzed with the aim of widening the original spectrum of action of myxinidin by suitable changes in the peptide primary structure. The analysis of key residues by alanine scanning allowed for the design of novel peptides with increased activity. We identified the amino acids that are of the utmost importance for the observed antimicrobial activities against a set of pathogens comprising both Gram-negative and Gram-positive bacteria. Overall, optimized bactericidal potency was achieved by adding a tryptophan residue at the N terminus and by the simultaneous substitution of residues present in positions 3, 4, and 11 with arginine. These results indicate that the myxinidin analogues emerge as an attractive alternative for treating drug-resistant infectious diseases and provide key insights into a rational design for novel agents against these pathogens. PMID:24957834

  12. Molecular Characterization and Analysis of Antimicrobial Activity of Endophytic Fungi From Medicinal Plants in Saudi Arabia

    PubMed Central

    Gashgari, Rukaia; Gherbawy, Youssuf; Ameen, Fuad; Alsharari, Salam

    2016-01-01

    Background: Endophytic fungi, which have been reported in numerous plant species, are important components of the forest community and contribute significantly to the diversity of natural ecosystems. Objectives: The current study aimed to evaluate and characterize, at the molecular level, the diversity and antimicrobial activities of endophytic fungi from medicinal plants in Saudi Arabia. Materials and Methods: Fungi growing on plant segments were isolated and identified based on morphological and molecular characteristics. The isolates were grouped into 35 distinct operational taxonomic units, based on the sequence of the internal transcribed spacer regions in the rRNA gene. The colonization frequency and the dominant fungi percentage of these endophytic fungi were calculated. A dual culture technique was adopted to investigate the antifungal activity of these endophytes. Results: Tamarix nilotica showed the highest endophytic diversity with a relative frequency of 27.27%, followed by Cressa cretica with a relative frequency of 19.27%. The most frequently isolated species was Penicillium chrysogenum with an overall colonization rate of 98.57%. Seven out of 35 endophytic fungi exhibited strong antifungal activity to all plant fungal pathogens tested. P. chrysogenum, Fusarium oxysporum, and F. nygamai exhibited the highest inhibition against the human pathogenic bacteria Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Aspergillus sydowii, P. chrysogenum, and Eupenicillium crustaceum showed strong antimicrobial activity against Enterococcus faecalis. Conclusions: The antimicrobial activity of these endophytic microorganisms could be exploited in biotechnology, medicine, and agriculture. PMID:27099679

  13. Antimicrobial activity of phenolics and glucosinolate hydrolysis products and their synergy with streptomycin against pathogenic bacteria.

    PubMed

    Saavedra, Maria J; Borges, Anabela; Dias, Carla; Aires, Alfredo; Bennett, Richard N; Rosa, Eduardo S; Simões, Manuel

    2010-05-01

    The purpose of the present study was to evaluate the in vitro antibacterial effects of different classes of important and common dietary phytochemicals (5 simple phenolics - tyrosol, gallic acid, caffeic acid, ferulic acid, and chlorogenic acid; chalcone - phloridzin; flavan-3-ol - (-) epicatechin; seco-iridoid - oleuropein glucoside; 3 glucosinolate hydrolysis products - allylisothiocyanate, benzylisothiocyanate and 2-phenylethylisothiocyanate) against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus. Another objective of this study was to evaluate the effects of dual combinations of streptomycin with the different phytochemicals on antibacterial activity. A disc diffusion assay was used to evaluate the antibacterial activity of the phytochemicals and 3 standard antibiotics (ciprofloxacin, gentamicin and streptomycin) against the four bacteria. The antimicrobial activity of single compounds and dual combinations (streptomycin-phytochemicals) were quantitatively assessed by measuring the inhibitory halos. The results showed that all of the isothiocyanates had significant antimicrobial activities, while the phenolics were much less efficient. No antimicrobial activity was observed with phloridzin. In general P. aeruginosa was the most sensitive microorganism and L. monocytogenes the most resistant. The application of dual combinations demonstrated synergy between streptomycin and gallic acid, ferulic acid, chlorogenic acid, allylisothiocyanate and 2-phenylethylisothiocyanate against the Gram-negative bacteria. In conclusion, phytochemical products and more specifically the isothiocyanates were effective inhibitors of the in vitro growth of the Gram-negative and Gram-positive pathogenic bacteria. Moreover, they can act synergistically with less efficient antibiotics to control bacterial growth.

  14. The in-vitro antimicrobial activities of some medicinal plants from Cameroon.

    PubMed

    Gangoué-Piéboji, J; Pegnyemb, D E; Niyitegeka, D; Nsangou, A; Eze, N; Minyem, C; Mbing, J Ngo; Ngassam, P; Tih, R Ghogomu; Sodengam, B L; Bodo, B

    2006-04-01

    The antimicrobial activities of 10 plant species (Voacanga africana, Crepis cameroonica, Plagiostyles africana, Crotalaria retusa, Mammea africana, Lophira lanceolata, Ochna afzelii, Ouratea elongata, Ou. flava and Ou. sulcata), each of which is currently used in the traditional medicine of Cameroon, were investigated in vitro. The activities of a methanol extract of each plant were tested, in disc-diffusion assays, against 37 reference or laboratory strains of seven species of microorganism (Staphylococcus aureus, S. epidermidis, Enterococcus hirae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans). The minimal inhibitory concentrations of each extract were then estimated, against each of the more susceptible microorganisms (i.e. those giving an inhibition zone measuring at least 9 mm in diameter in the disc-diffusion assays), by agar dilution. Although, in the disc-diffusion assays, each of the 10 methanol extracts investigated displayed some degree of antimicrobial activity against at least one species of microorganism, no activity against the Gram-negative bacteria (Es. coli, K. pneumoniae and Ps. aeruginosa) was observed. The extract with the greatest antimicrobial activity was that of Pl. africana (Euphorbiaceae).

  15. The syntheses, characterization, antimicrobial, DNA cleavage and cytotoxic activities of novel terephthalato complexes

    NASA Astrophysics Data System (ADS)

    Yıldız, Özge; Çolak, Alper Tolga; Yılmaz, Murat; İça, Tuba; Oztopcu-Vatan, Pinar; Topaloǧlu, Emel; Çolak, Ferdaǧ

    2017-01-01

    [Cu(tp)(dmpd)2] (1), [Cu(tp)(pen)2] (2), [Cu(tp)(dmen)2] (3), [Cu(tp)(deen)2]·4H2O (4), [Cu(tp)(mpen)2]·2H2O (5) and [Cu(tp)(amp)2]·3H2O (6) (H2tp = Benzene-1,4-dicarboxylic acid or terephthalic acid, dmpd = 2,2-dimethyl-1,3-propanediamine, pen = 1,3-propanediamine, dmen = N,N-dimethylethylenediamine, deen = N,N-diethylethylenediamine, mpen = N-methyl-1,3-propanediamine and amp = 2-aminomethylpyridine) were synthesised and characterised by elemental analysis, spectroscopic measurements (UV-vis. and FT-IR spectra) and thermal analysis technique. These complexes have been screened for antimicrobial activities and DNA cleavage. Antimicrobial activity of compounds 1-6 were evaluated by the agar diffusion method. The DNA cleavage activities of the complexes were evaluated by agarose gel electrophoresis. In addition, cytotoxic activities of all complexes were performed prostate carcinoma cells LNCaP and DU145 by MTT assay for 24 and 48 h. Especially after 24 h treatment, 6 complex increased the apoptotic and necrotic cell death in both cell lines in a concentration dependent manner. Particularly, 6 complex good show antimicrobial, nuclease and cytotoxic activity.

  16. Bacteriostatic and bactericidal activities of 24 antimicrobial agents against Campylobacter fetus subsp. jejuni.

    PubMed

    Vanhoof, R; Gordts, B; Dierickx, R; Coignau, H; Butzler, J P

    1980-07-01

    The bacteriostatic and bactericidal activities of 24 antimicrobial agents were tested with the Dynatech MIC 2000 system against 86 strains of Campylobacter fetus subsp. jejuni from human sources. The penicillins (penicillin G, ampicillin, amoxycillin, carbenicillin) had poor activity. Ampicillin and amoxycillin were equally active. Cefotaxime revealed a rather good activity. Erythromycin, gentamicin, tobramycin, amikacin, and furazolidone were the most active compounds. Two strains (2.3%) were resistant to erythromycin. One strain (1.2%) was completely resistant to tobramycin. The tetracyclines (tetracyline, doxycycline, minocycline) were generally effective, but 8% of the strains were totally resistant to them. Minocycline was the most active. Chloramphenicol, thiamphenicol, and clindamycin had good activity. The bacteriostatic and bactericidal distributions for colistin, nalidixic acid, and metronidazole were broad.

  17. Strain specificity in antimicrobial activity of silver and copper nanoparticles.

    PubMed

    Ruparelia, Jayesh P; Chatterjee, Arup Kumar; Duttagupta, Siddhartha P; Mukherji, Suparna

    2008-05-01

    The antimicrobial properties of silver and copper nanoparticles were investigated using Escherichia coli (four strains), Bacillus subtilis and Staphylococcus aureus (three strains). The average sizes of the silver and copper nanoparticles were 3 nm and 9 nm, respectively, as determined through transmission electron microscopy. Energy-dispersive X-ray spectra of silver and copper nanoparticles revealed that while silver was in its pure form, an oxide layer existed on the copper nanoparticles. The bactericidal effect of silver and copper nanoparticles were compared based on diameter of inhibition zone in disk diffusion tests and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of nanoparticles dispersed in batch cultures. Bacterial sensitivity to nanoparticles was found to vary depending on the microbial species. Disk diffusion studies with E. coli and S. aureus revealed greater effectiveness of the silver nanoparticles compared to the copper nanoparticles. B. subtilis depicted the highest sensitivity to nanoparticles compared to the other strains and was more adversely affected by the copper nanoparticles. Good correlation was observed between MIC and MBC (r2=0.98) measured in liquid cultures. For copper nanoparticles a good negative correlation was observed between the inhibition zone observed in disk diffusion test and MIC/MBC determined based on liquid cultures with the various strains (r2=-0.75). Although strain-specific variation in MIC/MBC was negligible for S. aureus, some strain-specific variation was observed for E. coli.

  18. Physicochemical properties, cytotoxicity, and antimicrobial activity of sulphated zirconia nanoparticles

    PubMed Central

    Mftah, Ae; Alhassan, Fatah H; Al-Qubaisi, Mothanna Sadiq; El Zowalaty, Mohamed Ezzat; Webster, Thomas J; Sh-eldin, Mohammed; Rasedee, Abdullah; Taufiq-Yap, Yun Hin; Rashid, Shah Samiur

    2015-01-01

    Nanoparticle sulphated zirconia with Brønsted acidic sites were prepared here by an impregnation reaction followed by calcination at 600°C for 3 hours. The characterization was completed using X-ray diffraction, thermal gravimetric analysis, Fourier transform infrared spectroscopy, Brunner-Emmett-Teller surface area measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and transmission electron microscopy. Moreover, the anticancer and antimicrobial effects were investigated for the first time. This study showed for the first time that the exposure of cancer cells to sulphated zirconia nanoparticles (3.9–1,000 μg/mL for 24 hours) resulted in a dose-dependent inhibition of cell growth, as determined by (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Similar promising results were observed for reducing bacteria functions. In this manner, this study demonstrated that sulphated zirconia nanoparticles with Brønsted acidic sites should be further studied for a wide range of anticancer and antibacterial applications. PMID:25632233

  19. Membrane Active Antimicrobial Peptides: Translating Mechanistic Insights to Design

    PubMed Central

    Li, Jianguo; Koh, Jun-Jie; Liu, Shouping; Lakshminarayanan, Rajamani; Verma, Chandra S.; Beuerman, Roger W.

    2017-01-01

    Antimicrobial peptides (AMPs) are promising next generation antibiotics that hold great potential for combating bacterial resistance. AMPs can be both bacteriostatic and bactericidal, induce rapid killing and display a lower propensity to develop resistance than do conventional antibiotics. Despite significant progress in the past 30 years, no peptide antibiotic has reached the clinic yet. Poor understanding of the action mechanisms and lack of rational design principles have been the two major obstacles that have slowed progress. Technological developments are now enabling multidisciplinary approaches including molecular dynamics simulations combined with biophysics and microbiology toward providing valuable insights into the interactions of AMPs with membranes at atomic level. This has led to increasingly robust models of the mechanisms of action of AMPs and has begun to contribute meaningfully toward the discovery of new AMPs. This review discusses the detailed action mechanisms that have been put forward, with detailed atomistic insights into how the AMPs interact with bacterial membranes. The review further discusses how this knowledge is exploited toward developing design principles for novel AMPs. Finally, the current status, associated challenges, and future directions for the development of AMP therapeutics are discussed. PMID:28261050

  20. Antimicrobial activity of essential oils of Physalis angulata. L.

    PubMed

    Osho, A; Adetunji, T; Fayemi, S O; Moronkola, D O

    2010-01-01

    The need for a reduction in drug resistance led to the investigation of Argemone Mexicana L. as an agent against Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Candida stellatoidea and Candida torulopsis, using well diffusion and minimum inhibitory concentrations methods. The sensitivity of Bacillus Subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus to the essential oils of both the aerial and root parts were determined. Pseudomonas aeruginosa was resistant to the essential oil from both the aerial and root part of the plant. C. torulopsis, C. stellatoidea and C. albicans were susceptible to the essential oils from the aerial and root part of the plant. The minimum inhibitory concentrations ranging between 3.75 mg/ml and 4.0 mg/ml were recorded for Bacillus subtilis, Klebsiella pneumoniae by the aerial and the root extracts, but P. aeruginosa and S. aureus were not susceptible to the aerial and root extracts. The observed inhibition of selected bacteria and fungi by oils of Physalis angulata makes it a promising antimicrobial agent. This study justifies its uses for treatment of sores, cuts, intestinal and digestive problems and some skin-diseases often reported in folkloric medicine.

  1. Antimicrobial activity of essential oils against Staphylococcus aureus biofilms.

    PubMed

    Vázquez-Sánchez, Daniel; Cabo, Marta L; Rodríguez-Herrera, Juan J

    2015-12-01

    The present study was aimed to evaluate the potential of essential oils to remove the foodborne pathogen Staphylococcus aureus from food-processing facilities. The effectiveness of 19 essential oils against planktonic cells of S. aureus was firstly assessed by minimal inhibitory concentration. Planktonic cells showed a wide variability in resistance to essential oils, with thyme oil as the most effective, followed by lemongrass oil and then vetiver oil. The eight essential oils most effective against planktonic cells were subsequently tested against 48-h-old biofilms formed on stainless steel. All essential oils reduced significantly (p < 0.01) the number of viable biofilm cells, but none of them could remove biofilms completely. Thyme and patchouli oils were the most effective, but high concentrations were needed to achieve logarithmic reductions over 4 log CFU/cm(2) after 30 min exposure. Alternatively, the use of sub-lethal doses of thyme oil allowed to slow down biofilm formation and to enhance the efficiency of thyme oil and benzalkonium chloride against biofilms. However, some cellular adaptation to thyme oil was detected. Therefore, essential oil-based treatments should be based on the rotation and combination of different essential oils or with other biocides to prevent the emergence of antimicrobial-resistant strains.

  2. Membrane Active Antimicrobial Peptides: Translating Mechanistic Insights to Design.

    PubMed

    Li, Jianguo; Koh, Jun-Jie; Liu, Shouping; Lakshminarayanan, Rajamani; Verma, Chandra S; Beuerman, Roger W

    2017-01-01

    Antimicrobial peptides (AMPs) are promising next generation antibiotics that hold great potential for combating bacterial resistance. AMPs can be both bacteriostatic and bactericidal, induce rapid killing and display a lower propensity to develop resistance than do conventional antibiotics. Despite significant progress in the past 30 years, no peptide antibiotic has reached the clinic yet. Poor understanding of the action mechanisms and lack of rational design principles have been the two major obstacles that have slowed progress. Technological developments are now enabling multidisciplinary approaches including molecular dynamics simulations combined with biophysics and microbiology toward providing valuable insights into the interactions of AMPs with membranes at atomic level. This has led to increasingly robust models of the mechanisms of action of AMPs and has begun to contribute meaningfully toward the discovery of new AMPs. This review discusses the detailed action mechanisms that have been put forward, with detailed atomistic insights into how the AMPs interact with bacterial membranes. The review further discusses how this knowledge is exploited toward developing design principles for novel AMPs. Finally, the current status, associated challenges, and future directions for the development of AMP therapeutics are discussed.

  3. Antimicrobial activity and genetic profile of Enteroccoci isolated from hoopoes uropygial gland.

    PubMed

    Ruiz-Rodríguez, Magdalena; Valdivia, Eva; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M; Martínez-Bueno, Manuel; Méndez, María; Peralta-Sánchez, Juan M; Soler, Juan J

    2012-01-01

    Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection.

  4. Antimicrobial Activity and Genetic Profile of Enteroccoci Isolated from Hoopoes Uropygial Gland

    PubMed Central

    Ruiz-Rodríguez, Magdalena; Valdivia, Eva; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M.; Martínez-Bueno, Manuel; Méndez, María; Peralta-Sánchez, Juan M.; Soler, Juan J.

    2012-01-01

    Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection. PMID:22911858

  5. Antimicrobial activity of the scolopendrasin V peptide identified from the centipede, Scolopendra subspinipes mutilans.

    PubMed

    Lee, Joon Ha; Kim, In-Woo; Kim, Mi-Ae; Ahn, Mi-Young; Yun, Eun-Young; Hwang, Jae Sam

    2016-10-25

    In a previous study, we analyzed the transcriptome of Scolopendra subspinipes mutilans using next generation sequencing technology and identified several antimicrobial peptide candidates. One of peptides, scolopendrasin V, was selected based on the physicochemical properties of antimicrobial peptides using a bioinformatics strategy. In this study, we assessed the antimicrobial activities of scolopendrasin V by using radial diffusion assay and colony count assay. We also investigated the mode of action of scolopendrasin V using flow cytometry. We found that scolopendrasin V's mechanism of action involved binding to the surface of microorganisms via a specific interaction with lipopolysaccharides, lipoteichoic acid, and peptidoglycans, which are components of the bacterial membrane. These results provide a basis for developing peptide antibiotics.

  6. Gemini alkyldeoxy-D-glucitolammonium salts as modern surfactants and microbiocides: synthesis, antimicrobial and surface activity, biodegradation.

    PubMed

    Brycki, Bogumił; Szulc, Adrianna

    2014-01-01

    Dimeric quaternary alkylammonium salts possess a favourable surface and antimicrobial activity. In this paper we describe synthesis, spectroscopic analysis, surface and antimicrobial activity as well as biodegradability of polymethylene-α,ω-bis(N,N-dialkyl-N-deoxy-D-glucitolammonium iodides), a new group of dimeric quaternary ammonium salts. This new group of gemini surfactants can be produced from chemicals which come from renewable sources. The structure of products has been determined by the FTIR and (1)H and (13)C NMR spectroscopy. The biodegradability, surface activity and antimicrobial efficacy against Escherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger and Penicillium chrysogenum were determined. The influence of the number of alkyl chains and their lengths on surface and antimicrobial properties has been shown. In general, dimeric quaternary alkyldeoxy-D-glucitolammonium salts with long alkyl substituents show favourable surface properties and an excellent antimicrobial activity.

  7. Artichoke and milk thistle pills and syrups as sources of phenolic compounds with antimicrobial activity.

    PubMed

    Pereira, Carla; Barros, Lillian; José Alves, Maria; Santos-Buelga, Celestino; Ferreira, Isabel C F R

    2016-07-13

    Dietary supplements based on hepatoprotective plants have been increasingly used in the prevention of liver injuries. In the present work, the aim was to study the phenolic profile and possibly relate it to the in vitro antimicrobial activity of two different formulations (pills and syrups) of artichoke and milk thistle, the antioxidant and anti-hepatocellular carcinoma activities of which were previously reported by our research group. The phenolic profiles were obtained by HPLC-DAD-ESI/MS, and the antimicrobial activity evaluation was performed with the clinical isolates of multiresistant bacteria (Escherichia coli, extended spectrum β-lactamases (ESBL) producing Escherichia coli, Proteus mirabilis, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa). Artichoke syrup revealed the presence of vanillic acid and luteolin-7-O-glucoside while the pills possessed higher concentrations of 4-O-caffeoylquinic, 5-O-caffeoylquinic and 1,3-O-dica