Science.gov

Sample records for activities including antibacterial

  1. Antibacterial activity of amphiphilic tobramycin.

    PubMed

    Dhondikubeer, Ramesh; Bera, Smritilekha; Zhanel, George G; Schweizer, Frank

    2012-10-01

    Amphiphilic aminoglycoside antimicrobials are an emerging class of new antibacterial agents with novel modes of action. Previous studies have shown that amphiphilic neomycin-B and kanamycin-A analogs restore potent antibacterial activity against Gram-positive neomycin-B- and kanamycin-A-resistant organisms. In this paper, we investigated the antibacterial properties of a series of amphiphilic tobramycin analogs. We prepared tobramycin-lipid conjugates, as well as tobramycin-peptide triazole conjugates, and studied their antibacterial activities against a panel of Gram-positive and Gram-negative bacterial strains, including isolates obtained from Canadian hospitals. Our results demonstrate that the antibacterial activity of amphiphilic tobramycin is greatly affected by the length and nature of the hydrophobic lipid tail, whereas the nature of the polycationic headgroup or the number of cationic charges appear to be less important. Replacement of the hydrophobic tail by a fluorinated lipid confers good activity against two Pseudomonas strains and reduces hemolytic activity. However, susceptibility studies in the presence of bovine serum albumin indicate that all amphiphilic tobramycin analogs are strongly protein-bound, leading to a typical four- to eight-fold increase in MIC.

  2. Antibacterial activity of Leonurus sibiricus aerial parts.

    PubMed

    Ahmed, Firoj; Islam, M Amirul; Rahman, M Mustafizur

    2006-06-01

    Different solvent extracts (carbon tetrachloride, chloroform, acetone and methanol) of Leonurus sibiricus were studied for their antibacterial activity. Carbon tetrachloride and chloroform extracts showed a broad spectrum of antibacterial activity.

  3. Antibacterial activity of Artocarpus heterophyllus.

    PubMed

    Khan, M R; Omoloso, A D; Kihara, M

    2003-07-01

    The crude methanolic extracts of the stem and root barks, stem and root heart-wood, leaves, fruits and seeds of Artocarpus heterophyllus and their subsequent partitioning with petrol, dichloromethane, ethyl acetate and butanol gave fractions that exhibited a broad spectrum of antibacterial activity. The butanol fractions of the root bark and fruits were found to be the most active. None of the fractions were active against the fungi tested.

  4. Antibacterial activity of novel benzopolycyclic amines.

    PubMed

    Barniol-Xicota, Marta; Escandell, Alex; Valverde, Elena; Julián, Esther; Torrents, Eduard; Vázquez, Santiago

    2015-01-15

    Staphylococcus aureus, especially strains resistant to multiple antibiotics, is a major pathogen for humans and animals. In this paper we have synthesized and evaluated the antibacterial activity of a new series of benzopolycyclic amines. Some of them exhibited μM MIC values against Staphylococcus aureus and other bacteria, including methicillin-resistant S. aureus MRSA. Compound 8 that displayed a good selectivity index, showed to be active in eliminating bacterial cells forming a preexisting biofilm. PMID:25515953

  5. Antibacterial activity of baking soda.

    PubMed

    Drake, D

    1996-01-01

    The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque. PMID:11524862

  6. Antibacterial activity of baking soda.

    PubMed

    Drake, D

    1997-01-01

    The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque. PMID:12017929

  7. Antibacterial activity of baking soda.

    PubMed

    Drake, D

    1997-01-01

    The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque.

  8. Antibacterial activity of baking soda.

    PubMed

    Drake, D

    1996-01-01

    The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque.

  9. Antibacterial activity on Citrullus colocynthis Leaf extract

    PubMed Central

    gowri, S. Shyamala; Priyavardhini, S.; Vasantha, K.; Umadevi, M.

    2009-01-01

    Studies on the antibacterial activities of the leaf extract of Citrullus colocynthis (Cucurbitaceae), a medicinal plant used for the treatment of various ailments was carried out using agar disc diffusion technique. The results revealed that the crude acetone extract exhibited antibacterial activities against Pseudomonas aeruginosa with zones of inhibition measuring 14.0mm. The chloroform leaf extract exhibited no antibacterial activity against Staphylococcus aureus. The minimum inhibitory concentration for the chloroform extract was 4.0mm for Escherichia coli. PMID:22557336

  10. [Antibacterial activity of natural compounds - essential oils].

    PubMed

    Hassan, Sherif T S; Majerová, Michaela; Šudomová, Miroslava; Berchová, Kateřina

    2015-12-01

    Since the problem of bacterial resistance has become a serious problem worldwide, it was necessary to search for new active substances that can overcome the problem and enhance the treatment efficacy of bacterial infections. Numerous plant-derived essential oils exhibited significant antibacterial activities. This review aimed to summarize the most promising essential oils that exhibited remarkable antibacterial activities against various bacterial infections, including staphylococcal infections, Helicobacter pylori infections, skin infections, tuberculosis infection and dental bacterial infection. The synergy effect of essential oils in combination with antibiotics, as well as their role in the treatment of bacterial infections have been discussed. Essential oils can be used as models for further studies in vivo and clinical trials.

  11. Optical control of antibacterial activity

    NASA Astrophysics Data System (ADS)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  12. Antibacterial Activity of Polyphenols of Garcinia Indica

    PubMed Central

    Lakshmi, C.; Kumar, K. Akshaya; Dennis, T. J.; Kumar, T. S. S. P. N. S. Sanath

    2011-01-01

    The aim of present work is to study the antibacterial activity of polyphenols isolated from the ethyl acetate soluble of methanol extract of stem bark of Garcinia indica against Staphylococcus aureus, Salmonella typhi and Escherichia coli by paper disc method. The results showed good antibacterial activity against S. aureus at higher concentrations, moderate at lower concentrations, against S. typhi moderate at higher concentrations but no activity against E. coli even at higher concentration for flavononylflavone. With proauthocyanin S. Aureus, S. Typhi and E. coli showed good antibacterial activity at higher concentration only. PMID:22707838

  13. Antibacterial Activity of Geminized Amphiphilic Cationic Homopolymers.

    PubMed

    Wang, Hui; Shi, Xuefeng; Yu, Danfeng; Zhang, Jian; Yang, Guang; Cui, Yingxian; Sun, Keji; Wang, Jinben; Yan, Haike

    2015-12-22

    The current study is aimed at investigating the effect of cationic charge density and hydrophobicity on the antibacterial and hemolytic activities. Two kinds of cationic surfmers, containing single or double hydrophobic tails (octyl chains or benzyl groups), and the corresponding homopolymers were synthesized. The antimicrobial activity of these candidate antibacterials was studied by microbial growth inhibition assays against Escherichia coli, and hemolysis activity was carried out using human red blood cells. It was interestingly found that the homopolymers were much more effective in antibacterial property than their corresponding monomers. Furthermore, the geminized homopolymers had significantly higher antibacterial activity than that of their counterparts but with single amphiphilic side chains in each repeated unit. Geminized homopolymers, with high positive charge density and moderate hydrophobicity (such as benzyl groups), combine both advantages of efficient antibacterial property and prominently high selectivity. To further explain the antibacterial performance of the novel polymer series, the molecular interaction mechanism is proposed according to experimental data which shows that these specimens are likely to kill microbes by disrupting bacterial membranes, leading them unlikely to induce resistance.

  14. Antibacterial activity of human natural killer cells

    PubMed Central

    1989-01-01

    The in vitro effects of human NK cells on viability of Gram-negative and Gram-positive bacteria was investigated. PBLs depleted of glass- adherent cells showed a significant antibacterial activity that was increased as the concentration of NK cells became higher. Leu-11- enriched cells exhibited the most efficient bactericidal activity. Stimulation of NK cells with staphylococcal enterotoxin B for 16 h produced a significant increase in the antibacterial activity of all NK cells tested. The antibacterial activity of monocyte-depleted cells and Leu-11-enriched cells was also enhanced after culturing in vitro for 16- 24 h without exogenous cytokines. Dependence of the antibacterial activity on the presence of serum in the culture medium was not found. Ultrastructural studies revealed close contact between NK cell membranes and bacteria, no evidence of phagocytosis, and extracellular bacterial ghosts, after incubation at 37 degrees C. Supernatants from purified NK cells exhibited potent bactericidal activity with kinetics and target specificity similar to that of effector cells. These results document the potent antibacterial activity of purified NK cells and suggest an extracellular mechanism of killing. PMID:2642532

  15. Tunable, antibacterial activity of silicone polyether surfactants.

    PubMed

    Khan, Madiha F; Zepeda-Velazquez, Laura; Brook, Michael A

    2015-08-01

    Silicone surfactants are used in a variety of applications, however, limited data is available on the relationship between surfactant structure and biological activity. A series of seven nonionic, silicone polyether surfactants with known structures was tested for in vitro antibacterial activity against Escherichia coli BL21. The compounds varied in their hydrophobic head, comprised of branched silicone structures with 3-10 siloxane linkages and, in two cases, phenyl substitution, and hydrophilic tail of 8-44 poly(ethylene glycol) units. The surfactants were tested at three concentrations: below, at, and above their Critical Micelle Concentrations (CMC) against 5 concentrations of E. coli BL21 in a three-step assay comprised of a 14-24h turbidometric screen, a live-dead stain and viable colony counts. The bacterial concentration had little effect on antibacterial activity. For most of the surfactants, antibacterial activity was higher at concentrations above the CMC. Surfactants with smaller silicone head groups had as much as 4 times the bioactivity of surfactants with larger groups, with the smallest hydrophobe exhibiting potency equivalent to sodium dodecyl sulfate (SDS). Smaller PEG chains were similarly associated with higher potency. These data link lower micelle stability and enhanced permeability of smaller silicone head groups to antibacterial activity. The results demonstrate that simple manipulation of nonionic silicone polyether structure leads to significant changes in antibacterial activity.

  16. Tunable, antibacterial activity of silicone polyether surfactants.

    PubMed

    Khan, Madiha F; Zepeda-Velazquez, Laura; Brook, Michael A

    2015-08-01

    Silicone surfactants are used in a variety of applications, however, limited data is available on the relationship between surfactant structure and biological activity. A series of seven nonionic, silicone polyether surfactants with known structures was tested for in vitro antibacterial activity against Escherichia coli BL21. The compounds varied in their hydrophobic head, comprised of branched silicone structures with 3-10 siloxane linkages and, in two cases, phenyl substitution, and hydrophilic tail of 8-44 poly(ethylene glycol) units. The surfactants were tested at three concentrations: below, at, and above their Critical Micelle Concentrations (CMC) against 5 concentrations of E. coli BL21 in a three-step assay comprised of a 14-24h turbidometric screen, a live-dead stain and viable colony counts. The bacterial concentration had little effect on antibacterial activity. For most of the surfactants, antibacterial activity was higher at concentrations above the CMC. Surfactants with smaller silicone head groups had as much as 4 times the bioactivity of surfactants with larger groups, with the smallest hydrophobe exhibiting potency equivalent to sodium dodecyl sulfate (SDS). Smaller PEG chains were similarly associated with higher potency. These data link lower micelle stability and enhanced permeability of smaller silicone head groups to antibacterial activity. The results demonstrate that simple manipulation of nonionic silicone polyether structure leads to significant changes in antibacterial activity. PMID:26057244

  17. Antibacterial activity of eight Brazilian annonaceae plants.

    PubMed

    Takahashi, Jacqueline A; Pereira, Cássia R; Pimenta, Lúcia P S; Boaventura, Maria Amélia D; Silva, Luiz G F E

    2006-01-01

    Sixteen extracts, obtained from eight Brazilian plants of Annonaceae family, were screened for their antibacterial activity: Xylopia frutescens, X. aromatica, X. amazonica, X. benthamii, Annona ambotay, A. crassiflora, A. muricata and A. cherimolia. Amongst the investigated extracts, six showed antibacterial activity against at least one of the tested organisms at the concentration of 100 microg/mL. The most active extracts were those prepared from X. frutescens, X. amazonica, and A. ambotay. A phytochemical screening showed the presence of anonaceus acetogenins in some active extracts. Eleven diterpenoids were also tested for comparison purposes. Six were natural products, previously isolated from Xylopia sp. (kaurenoic, frutoic, xylopic, 15beta-hydroxy-kaurenoic and trachylobanic acids plus kaurenol) and five were derivatives of such compounds, obtained by esterification or reduction reactions. Trachylobanic acid showed antibacterial activity against B. subtilis and S. aureus.

  18. Antibacterial activity of Pulicaria dysenterica extracts.

    PubMed

    Nickavar, Bahman; Mojab, Faraz

    2003-06-01

    Aqueous, methanolic and chloroformic extracts of Pulicaria dysenterica aerial parts were tested for their antibacterial activity using the disc-diffusion assay technique. The methanolic extract was found to be the most effective extract against three out of six tested bacteria. All of the extracts were active against Vibrio cholera.

  19. Antibacterial activity of aquatic gliding bacteria.

    PubMed

    Sangnoi, Yutthapong; Anantapong, Theerasak; Kanjana-Opas, Akkharawit

    2016-01-01

    The study aimed to screen and isolate strains of freshwater aquatic gliding bacteria, and to investigate their antibacterial activity against seven common pathogenic bacteria. Submerged specimens were collected and isolated for aquatic gliding bacteria using four different isolation media (DW, MA, SAP2, and Vy/2). Gliding bacteria identification was performed by 16S rRNA gene sequencing and phylogenetic analysis. Crude extracts were obtained by methanol extraction. Antibacterial activity against seven pathogenic bacteria was examined by agar-well diffusion assay. Five strains of aquatic gliding bacteria including RPD001, RPD008, RPD018, RPD027 and RPD049 were isolated. Each submerged biofilm and plastic specimen provided two isolates of gliding bacteria, whereas plant debris gave only one isolate. Two strains of gliding bacteria were obtained from each DW and Vy/2 isolation medium, while one strain was obtained from the SAP2 medium. Gliding bacteria strains RPD001, RPD008 and RPD018 were identified as Flavobacterium anhuiense with 96, 82 and 96 % similarity, respectively. Strains RPD049 and RPD027 were identified as F. johnsoniae and Lysobacter brunescens, respectively, with similarity equal to 96 %. Only crude extract obtained from RPD001 inhibited growth of Listeria monocytogenes (MIC 150 µg/ml), Staphylococcus aureus (MIC 75 µg/ml) and Vibrio cholerae (MIC 300 µg/ml), but showed weak inhibitory effect on Salmonella typhimurium (MIC > 300 µg/ml). Gliding bacterium strain RPD008 should be considered to a novel genus separate from Flavobacterium due to its low similarity value. Crude extract produced by RPD001 showed potential for development as a broad antibiotic agent. PMID:26885469

  20. Antibacterial activity of ribostamycin on Enterobacteriaceae.

    PubMed

    Yourassowsky, E; Vander Linden, M P

    1976-02-01

    The study of the inhibitory activity of ribostamvcin (Vistamycin), an antibiotic derived from Streptomyces ribosidificus, on 161 strains of Gram-negative bacilli shows that the antibacterial spectrum of this antibiotic is identical to that of kanamycin. If controlled clinical studies confirm that ribostamycin is less toxic than kanamycin on the otovestibular system, this antibiotic will constitute a real therapeutic advance.

  1. Antibacterial activity of graphene supported FeAg bimetallic nanocomposites.

    PubMed

    Ahmad, Ayyaz; Qureshi, Abdul Sattar; Li, Li; Bao, Jie; Jia, Xin; Xu, Yisheng; Guo, Xuhong

    2016-07-01

    We report the simple one pot synthesis of iron-silver (FeAg) bimetallic nanoparticles with different compositions on graphene support. The nanoparticles are well dispersed on the graphene sheet as revealed by the TEM, XRD, and Raman spectra. The antibacterial activity of graphene-FeAg nanocomposite (NC) towards Bacillus subtilis, Escherichia coli, and Staphylococcus aureus was investigated by colony counting method. Graphene-FeAg NC demonstrates excellent antibacterial activity as compared to FeAg bimetallic without graphene. To understand the antibacterial mechanism of the NC, oxidative stress caused by reactive oxygen species (ROS) and the glutathione (GSH) oxidation were investigated in the system. It has been observed that ROS production and GSH oxidation are concentration dependent while the increase in silver content up to 50% generally enhances the ROS production while ROS decreases on further increase in silver content. Graphene loaded FeAg NC demonstrates higher GSH oxidation capacity than bare FeAg bimetallic nanocomposite. The mechanism study suggests that the antibacterial activity is probably due to membrane and oxidative stress produced by the nanocomposites. The possible antibacterial pathway mainly includes the non-ROS oxidative stress (GSH oxidation) while ROS play minor role. PMID:27038914

  2. Antibacterial activity of nanosilver ions and particles.

    PubMed

    Sotiriou, Georgios A; Pratsinis, Sotiris E

    2010-07-15

    The antibacterial activity of nanosilver against Gram negative Escherichia coli bacteria is investigated by immobilizing nanosilver on nanostructured silica particles and closely controlling Ag content and size. These Ag/SiO(2) nanoparticles were characterized by S/TEM, EDX spectroscopy, X-ray diffraction the exposed Ag surface area was measured qualitatively by O(2) chemisorption. Furthermore, the fraction of dissolved nanosilver was determined by measuring the released (leached) Ag(+) ion concentration in aqueous suspensions of such Ag/SiO(2) particles. The antibacterial effect of Ag(+) ions was distinguished from that of nanosilver particles by monitoring the growth of E. coli populations in the presence and absence of Ag/SiO(2) particles. The antibacterial activity of nanosilver was dominated by Ag(+) ions when fine Ag nanoparticles (less than about 10 nm in average diameter) were employed that release high concentrations of Ag(+) ions. In contrast, when relatively larger Ag nanoparticles were used, the concentration of the released Ag(+) ions was lower. Then the antibacterial activity of the released Ag(+) ions and nanosilver particles was comparable.

  3. Antibacterial activity of resin rich plant extracts

    PubMed Central

    Shuaib, Mohd; Ali, Abuzer; Ali, Mohd; Panda, Bibhu Prasad; Ahmad, Mohd Imtiyaz

    2013-01-01

    Background: The in vitro antibacterial activity of resin rich methanolic extracts (RRMEs) of Commiphora myrrha, Operculina turpethum, and Pinus roxburghii. Materials and Methods: Different concentration were studied by agar-well diffusion method against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Enterococcus faecalis) and Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysenteriae). Results: Among all the bacterial strains tested, E. faecalis was most sensitive and S. typhi was resistant to C. myrrha and P. roxburghii. The extracts of O. turpethum were active against all tested strains in which B. subtilis and S. aureus were the most sensitive. Conclusion: This suggested that the antibacterial activity of RRMEs of O. turpethum was more than C. myrrha and P. roxburghii. This probably explains the potential of these plants against a number of infections caused by bacterial strains tested. PMID:24302834

  4. Fabrication of SWCNT-Ag nanoparticle hybrid included self-assemblies for antibacterial applications.

    PubMed

    Brahmachari, Sayanti; Mandal, Subhra Kanti; Das, Prasanta Kumar

    2014-01-01

    The present article reports the development of soft nanohybrids comprising of single walled carbon nanotube (SWCNT) included silver nanoparticles (AgNPs) having superior antibacterial property. In this regard aqueous dispersing agent of carbon nanotube (CNT) containing a silver ion reducing unit was synthesised by the inclusion of tryptophan and tyrosine within the backbone of the amphiphile. The dispersions were characterized spectroscopically and microscopically using TEM, AFM and Raman spectroscopy. The nanotube-nanoparticle conjugates were prepared by the in situ photoreduction of AgNO3. The phenolate residue and the indole moieties of tyrosine and tryptophan, respectively reduces the sliver ion as well as acts as stabilizing agents for the synthesized AgNPs. The nanohybrids were characterized using TEM and AFM. The antibacterial activity of the nanohybrids was studied against Gram-positive (Bacillus subtilis and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli and Klebsiella aerogenes). The SWCNT dispersions showed moderate killing ability (40-60%) against Gram-positive bacteria however no antibacterial activity was observed against the Gram negative ones. Interestingly, the developed SWCNT-amphiphile-AgNP nanohybrids exhibited significant killing ability (∼90%) against all bacteria. Importantly, the cell viability of these newly developed self-assemblies was checked towards chinese hamster ovarian cells and high cell viability was observed after 24 h of incubation. This specific killing of bacterial cells may have been achieved due to the presence of higher -SH containing proteins in the cell walls of the bacteria. The developed nanohybrids were subsequently infused into tissue engineering scaffold agar-gelatin films and the films similarly showed bactericidal activity towards both kinds of bacterial strains while allowing normal growth of eukaryotic cells on the surface of the films. PMID:25191756

  5. Flavones with antibacterial activity against cariogenic bacteria.

    PubMed

    Sato, M; Fujiwara, S; Tsuchiya, H; Fujii, T; Iinuma, M; Tosa, H; Ohkawa, Y

    1996-11-01

    Methanolic extracts obtained from 13 plants were studied for their antibacterial activity against cariogenic bacteria. Among them, the extract from Artocarpus heterophyllus showed the most intensive activity. Serial chromatographic purifications offered two active compounds which were identified as 6-(3-methyl-1-butenyl)-5,2',4'-trihydroxy-3-isoprenyl-7-methoxy flavone and 5,7,2',4'-tetrahydroxy-6-isoprenylflavone. Both isolates completely inhibited the growth of primary cariogenic bacteria at 3.13-12.5 micrograms/ml. They also exhibited the growth inhibitory effects on plaque-forming streptococci. These phytochemical isoprenylflavones would be potent compounds for the prevention of dental caries.

  6. Anti-bacterial activity of some Brazilian medicinal plants.

    PubMed

    de Lima, Maria Raquel Ferreira; de Souza Luna, Josiane; dos Santos, Aldenir Feitosa; de Andrade, Maria Cristina Caño; Sant'Ana, Antônio Euzébio Goulart; Genet, Jean-Pierre; Marquez, Béatrice; Neuville, Luc; Moreau, Nicole

    2006-04-21

    Extracts from various organs of 25 plants of Brazilian traditional medicine were assayed with respect to their anti-bacterial activities against Escherichia coli, a susceptible strain of Staphylococcus aureus and two resistant strains of Staphylococcus aureus harbouring the efflux pumps NorA and MsrA. Amongst the 49 extracts studied, 14 presented anti-bacterial activity against Staphylococcus aureus, including the ethanolic extracts from the rhizome of Jatropha elliptica, from the stem barks of Schinus terebinthifolius and Erythrina mulungu, from the stems and leaves of Caesalpinia pyramidalis and Serjania lethalis, and from the stem bark and leaves of Lafoensia pacari. The classes of compounds present in the active extracts were determined as a preliminary step towards their bioactivity-guided separation. No extracts were active against Escherichia coli.

  7. Antibacterial and Cytotoxic Activity of Compounds Isolated from Flourensia oolepis.

    PubMed

    Joray, Mariana Belén; Trucco, Lucas Daniel; González, María Laura; Napal, Georgina Natalia Díaz; Palacios, Sara María; Bocco, José Luis; Carpinella, María Cecilia

    2015-01-01

    The antibacterial and cytotoxic effects of metabolites isolated from an antibacterial extract of Flourensia oolepis were evaluated. Bioguided fractionation led to five flavonoids, identified as 2',4'-dihydroxychalcone (1), isoliquiritigenin (2), pinocembrin (3), 7-hydroxyflavanone (4), and 7,4'-dihydroxy-3'-methoxyflavanone (5). Compound 1 showed the highest antibacterial effect, with minimum inhibitory concentration (MIC) values ranging from 31 to 62 and 62 to 250 μg/mL, against Gram-positive and Gram-negative bacteria, respectively. On further assays, the cytotoxic effect of compounds 1-5 was determined by MTT assay on acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia (CML) cell lines including their multidrug resistant (MDR) phenotypes. Compound 1 induced a remarkable cytotoxic activity toward ALL cells (IC50 = 6.6-9.9 μM) and a lower effect against CML cells (IC50 = 27.5-30.0 μM). Flow cytometry was used to analyze cell cycle distribution and cell death by PI-labeled cells and by Annexin V/PI staining, respectively. Upon treatment, 1 induced cell cycle arrest in the G2/M phase accompanied by a strong induction of apoptosis. These results describe for the first time the antibacterial metabolites of F. oolepis extract, with 1 being the most effective. This chalcone also emerges as a selective cytotoxic agent against sensitive and resistant leukemic cells, highlighting its potential as a lead compound. PMID:26819623

  8. Antibacterial and Cytotoxic Activity of Compounds Isolated from Flourensia oolepis

    PubMed Central

    Joray, Mariana Belén; Trucco, Lucas Daniel; González, María Laura; Napal, Georgina Natalia Díaz; Palacios, Sara María; Bocco, José Luis; Carpinella, María Cecilia

    2015-01-01

    The antibacterial and cytotoxic effects of metabolites isolated from an antibacterial extract of Flourensia oolepis were evaluated. Bioguided fractionation led to five flavonoids, identified as 2′,4′-dihydroxychalcone (1), isoliquiritigenin (2), pinocembrin (3), 7-hydroxyflavanone (4), and 7,4′-dihydroxy-3′-methoxyflavanone (5). Compound 1 showed the highest antibacterial effect, with minimum inhibitory concentration (MIC) values ranging from 31 to 62 and 62 to 250 μg/mL, against Gram-positive and Gram-negative bacteria, respectively. On further assays, the cytotoxic effect of compounds 1–5 was determined by MTT assay on acute lymphoblastic leukemia (ALL) and chronic myeloid leukemia (CML) cell lines including their multidrug resistant (MDR) phenotypes. Compound 1 induced a remarkable cytotoxic activity toward ALL cells (IC50 = 6.6–9.9 μM) and a lower effect against CML cells (IC50 = 27.5–30.0 μM). Flow cytometry was used to analyze cell cycle distribution and cell death by PI-labeled cells and by Annexin V/PI staining, respectively. Upon treatment, 1 induced cell cycle arrest in the G2/M phase accompanied by a strong induction of apoptosis. These results describe for the first time the antibacterial metabolites of F. oolepis extract, with 1 being the most effective. This chalcone also emerges as a selective cytotoxic agent against sensitive and resistant leukemic cells, highlighting its potential as a lead compound. PMID:26819623

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

    PubMed

    Vucić, Dragana M; Petković, Miroslav R; Rodić-Grabovac, Branka B; Stefanović, Olgica D; Vasić, Sava M; Comić, Ljiljana R

    2013-01-01

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

  10. Evaluation of Parmotrema reticulatum Taylor for Antibacterial and Antiinflammatory Activities

    PubMed Central

    Jain, A. P.; Bhandarkar, S.; Rai, G.; Yadav, A. K.; Lodhi, S.

    2016-01-01

    Lichens produce variety of secondary metabolites including depsides, depsidones and dibenzofurans having multifunctional activity in response to external environmental condition. Present study provides evidence for in vitro antibacterial and in vivo antiinflammatory activity of acetone and ethanol extracts of Parmotrema reticulatum. In vitro antibacterial activity was investigated against gram positive and gram negative bacteria. Cotton pellet-induced granuloma, xylene-induced ear swelling, carragennan-induced edema, histamine-induced and carboxymethylcellulose sodium-induced leukocyte emigration in mice models were used to quantify the antiinflammatory activity. Acetone and ethanol extracts were showed antibacterial activity against Bacillus subtilis (minimal inhibitory concentration: 100 and 150 μg/ml) and Staphylococcus aureus (minimal inhibitory concentration: 100 and 200 μg/ml), Escherichia coli (minimal inhibitory concentration: 200 and 250 μg/ml), and Pseudomonasa eruginosa (minimal inhibitory concentration: 200 and 300 μg/ml). Acetone extract was inhibited edema significantly at 200 mg/kg with xylene, cotton pellet, carragennan and histamine induced edema in vivo models. Ethanol extract was found effective at dose of 300 mg/kg with all in vivo antiinflammatory models. The results showed significant (P<0.01) antiinflammatory effects at 200 and 300 mg/kg dose of acetone and ethanol extracts, respectively, which can be concluded that significant activity may be due to presence of flavanoids in ethanol extract and usnic acid in acetone extract. PMID:27168687

  11. Antibacterial activity against Porphyromonas gingivalis and biological characteristics of antibacterial stainless steel.

    PubMed

    Zhang, Dan; Ren, Ling; Zhang, Yang; Xue, Nan; Yang, Ke; Zhong, Ming

    2013-05-01

    To evaluate the possibility of an alternative to the traditional orthodontic stainless steel implants, the antibacterial activity against Porphyromonas gingivalis (P. gingivalis) and the related cytotoxicity of a type 304 Cu bearing antibacterial stainless steel were studied. The results indicated that the antibacterial stainless steel showed excellent antibacterial property against P. gingivalis, compared with the control steel (a purchased medical grade 304 stainless steel). Compared to the control steel, there were fewer bacteria on the surface of the antibacterial stainless steel, with significant difference in morphology. The cytotoxicities of the antibacterial stainless steel to both MG-63 and KB cells were all grade 1, the same as those of the control steel. There were no significant differences in the apoptosis rates on MG-63 and KB cells between the antibacterial stainless steel and the control steel. This study demonstrates that the antibacterial stainless steel is possible to reduce the incidence of implant-related infections and can be a more suitable material for the micro-implant than the conventional stainless steel in orthodontic treatment.

  12. Antibacterial activity of clarithromycin loaded PLGA nanoparticles.

    PubMed

    Valizadeh, H; Mohammadi, G; Ehyaei, R; Milani, M; Azhdarzadeh, M; Zakeri-Milani, P; Lotfipour, F

    2012-01-01

    Novel drug delivery systems such as nanoparticles (NPs) have been proved to enhance the effectiveness of many drugs. Clarithromycin is a broad spectrum macrolide antibiotic, used in many infectious conditions like upper and lower respiratory tract infections, and skin and other soft tissue infections. This paper describes the preparation and enhanced in vitro antibacterial activities of clarithromycin loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles. A modified quasi-emulsion solvent diffusion (MQESD) method was used to prepare clarithromycin (CLR) NPs. The antibacterial activity of the NPs was evaluated using the agar well diffusion method against Escherichia coli (PTCC 1330), Haemophilus influenzae (PTCC 1623), Salmonella typhi (PTCC 1609), Staphylococcus aureus (PTCC 1112) and Streptococcus pneumoniae (PTCC 1240). The inhibition zone diameters related to each nano formulation were compared with those for untreated CLR at the same concentrations. The results indicated that the mean inhibition zone diameters of NPs against all the bacteria tested were significantly higher than those of untreated CLR, particularly in the case of S. aureus. The increased potency of CLR NPs may be related to some physicochemical properties of NPs like modified surface characteristics, lower drug degradation, and increased drug adsorption and uptake.

  13. The antibacterial activity of fragrance ingredients against Legionella pneumophila.

    PubMed

    Shimizu, Ikuko; Isshiki, Yasunori; Nomura, Harue; Sakuda, Keisuke; Sakuma, Katsuya; Kondo, Seiichi

    2009-06-01

    In the current study we investigated the antibacterial activity of fragrance ingredients against Legionella pneumophila, a causative agent of severe pneumonia. Among the 41 different fragrance ingredients tested, we found that the natural fragrance ingredients oakmoss (OM) and birch tar oil (BT), which contain many components, exhibit potent antibacterial activity. The minimum inhibitory concentration (MIC, % (v/v)) of OM and BT were 0.0020 and 0.0024, respectively and were lower than that of cinnamic aldehyde (0.0078), which has been previously shown to possess high antimicrobial activity. In a time-kill assay of OM and BT at MIC and two times MIC, the colony forming units (CFU) of the microbe were reduced to between 10(-3) to 10(-4) of the original CFU after 1 h co-incubation. After this time, the CFU gradually decreased in number, but remained above detection levels even after a 48-h co-incubation, except for BT at two times MIC. In contrast, at a concentration of 0.1% OM and BT (approximately 50 times MIC), CFU were not detected after co-incubation for 1 h. Another 18 fragrance ingredients including ketone, aldehyde, lactone, acid, phenol derivative, aliphatic alcohol and quinoline also exhibited a lesser degree of antibacterial activity against L. pneumophila at a MIC of less than 0.10.

  14. Antibacterial activity of silver nanoparticles with different morphologies as well as their possible antibacterial mechanism

    NASA Astrophysics Data System (ADS)

    Hu, Guansong; Jin, Wenxiu; Chen, Qingyuan; Cai, Yuchun; Zhu, Qiuhua; Zhang, Wanzhong

    2016-10-01

    Silver nanoparticles (AgNPs) have good antibacterial activity and their morphologies have important influence on their activity. The relationship between their bactericidal property and morphology has not been studied thoroughly. Silver triangular nanoplates have basic {111} surface, nanospheres and nanocubes mainly have {100} planes, and nanorods have {100} side surfaces and {111} end facets. It was said that {111} crystal plane of AgNPs may play a prime role in antibacterial progress. Moreover, the antibacterial activity of nanocubes is not very clear when compared to nanoparticles with other morphologies. In this paper, we studied the antibacterial activity of nanocubes and attempted to confirm whether nanoparticles with {111} crystal facet truly had stronger antibacterial activity than other nanoparticles. We prepared four kinds of AgNPs and found silver triangle nanoplates had the best antibacterial activity, while nanospheres, nanocubes and short nanorods showed similar efficacy. It may provide a reference for safe application of AgNPs with different morphologies in the medical field.

  15. In Vitro Antibacterial Activity of Essential Oils against Streptococcus pyogenes

    PubMed Central

    Sfeir, Julien; Lefrançois, Corinne; Baudoux, Dominique; Derbré, Séverine; Licznar, Patricia

    2013-01-01

    Streptococcus pyogenes plays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate the in vitro antibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants against S. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity against S. pyogenes. Among them Cinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, and Satureja montana essential oils exhibited significant antibacterial activity. The in vitro results reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred. PMID:23662123

  16. Antibacterial Activity of Hawaiian Corals: Possible Protection from Disease?

    NASA Astrophysics Data System (ADS)

    Gochfeld, D. J.; Aeby, G. S.; Miller, J. D.

    2006-12-01

    Reports of coral diseases in the Caribbean have appeared with increasing frequency over the past two decades; however, records of coral diseases in the Pacific have lagged far behind. Recent surveys of coral disease in the Hawaiian Islands indicate relatively low, but consistent, levels of disease throughout the inhabited Main and uninhabited Northwestern Hawaiian Islands, and demonstrate variation in levels of disease among the major genera of Hawaiian corals. Although little is known about immune defense to disease in corals, one potential mechanism of defense is the production of antimicrobial compounds that protect corals from pathogens. A preliminary survey of antibacterial chemical defenses among three dominant species of Hawaiian corals was undertaken. Crude aqueous extracts of Porites lobata, Pocillopora meandrina and Montipora capitata were tested against nine strains of bacteria in a growth inhibition assay. Inhibitory extracts were further tested to determine whether their effects were cytostatic or cytotoxic. The bacteria selected included known coral pathogens, potential marine pathogens found in human waste and strains previously identified from the surfaces of Hawaiian corals. Extracts from all three species of coral exhibited a high degree of antibacterial activity, but also a high degree of selectivity against different bacterial strains. In addition, some extracts were stimulatory to some bacteria. In addition to interspecific variability, extracts also exhibited intraspecific variability, both within and between sites. Hawaiian corals have significant antibacterial activity, which may explain the relatively low prevalence of disease in these corals; however, further characterization of pathogens specifically responsible for disease in Hawaiian corals is necessary before we can conclude that antibacterial activity protects Hawaiian corals from disease.

  17. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    PubMed Central

    Nijampatnam, Bhavitavya; Nadkarni, Dwayaja H.; Wu, Hui; Velu, Sadanandan E.

    2015-01-01

    Streptococcus mutans is a key etiological agent in the formation of dental caries. The major virulence factor is its ability to form biofilms. Inhibition of S. mutans biofilms offers therapeutic prospects for the treatment and the prevention of dental caries. In this study, 14 analogs of makaluvamine, a marine alkaloid, were evaluated for their antibacterial activity against S. mutans and for their ability to inhibit S. mutans biofilm formation. All analogs contained the tricyclic pyrroloiminoquinone core of makaluvamines. The structural variations of the analogs are on the amino substituents at the 7-position of the ring and the inclusion of a tosyl group on the pyrrole ring N of the makaluvamine core. The makaluvamine analogs displayed biofilm inhibition with IC50 values ranging from 0.4 μM to 88 μM. Further, the observed bactericidal activity of the majority of the analogs was found to be consistent with the anti-biofilm activity, leading to the conclusion that the anti-biofilm activity of these analogs stems from their ability to kill S. mutans. However, three of the most potent N-tosyl analogs showed biofilm IC50 values at least an order of magnitude lower than that of bactericidal activity, indicating that the biofilm activity of these analogs is more selective and perhaps independent of bactericidal activity. PMID:25767719

  18. Rugulactone and its analogues exert antibacterial effects through multiple mechanisms including inhibition of thiamine biosynthesis.

    PubMed

    Nodwell, Matthew B; Menz, Helge; Kirsch, Stefan F; Sieber, Stephan A

    2012-07-01

    Rugulactone is a dihydro-α-pyrone isolated from the plant Cryptocarya rugulosa in 2009. It has been reported to display IkB kinase (IKK) inhibitory activity, as well as antibiotic activity in several strains of pathogenic bacteria. However, its biological targets and mode of action in bacteria have not yet been explored. Here we present enantioselective syntheses of rugulactone and of some corresponding activity-based protein profiling (ABPP) probes. We found that the ABPP probes in this study are more potent than rugulactone against Staphyloccocus aureus NCTC 8325, S. aureus Mu50, Listeria welshimeri SLCC 5334 and Listeria monocytogenes EGD-e, and that molecules of this class probably exert their antibacterial effect through a combination of targets. These targets include covalent inhibition of 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate (HMPP) kinase (ThiD), which is an essential component of the thiamine biosynthesis pathway in bacteria. This represents the first example of a small-molecule inhibitor of ThiD.

  19. Phytochemical constituents and antibacterial activity of some green leafy vegetables

    PubMed Central

    Bhat, Ramesa Shafi; Al-Daihan, Sooad

    2014-01-01

    Objective To investigate the antibacterial activity and photochemicals of five green leafy vegetables against a panel of five bacteria strains. Methods Disc diffusion method was used to determine the antibacterial activity, while kanamycin was used as a reference antibiotic. The phytochemical screening of the extracts was performed using standard methods. Results All methanol extracts were found active against all the test bacterial strains. Overall maximum extracts shows antibacterial activity which range from 6 to 15 mm. Proteins and carbohydrates was found in all the green leaves, whereas alkaloid, steroids, saponins, flavonoids, tannins were found in most of the test samples. Conclusions The obtain result suggests that green leafy vegetables have moderate antibacterial activity and contain various pharmacologically active compounds and thus provide the scientific basis for the traditional uses of the studied vegetables in the treatment of bacterial infections. PMID:25182436

  20. Antibacterial activity and bonding ability of an adhesive incorporating an antibacterial monomer DMAE-CB.

    PubMed

    Xiao, Yu-Hong; Ma, Sai; Chen, Ji-Hua; Chai, Zhi-Guo; Li, Fang; Wang, Ying-Jie

    2009-08-01

    This study evaluated the antibacterial effect and microtensile bond strength of a resin-based adhesive containing an antibacterial monomer DMAE-CB (methacryloxylethyl cetyl dimethyl ammonium chloride). Cured specimens of 1, 2, and 3% DMAE-CB-containing Single Bond 2 (crosslinking monomer: Bis-GMA, dimethacrylates; functional monomer: HEMA) were prepared, and their antibacterial effects on Streptococcus mutans ATCC 25175 were investigated. Antibacterial property after 0, 30, 90, and 180 days of aging was also tested. Bonding ability of the experimental adhesive incorporating 3% DMAE-CB was evaluated by microtensile bond strength test. The cured experimental adhesive exhibited an inhibitory effect on S. mutans growth, and the adhesive containing 3% DMAE-CB showed higher antibacterial efficiency compared with those incorporating 1 or 2% anibacterial monomer. Antibacterial activities of the specimens lasted for at least 180 days. Microtensile bond strength test revealed that the bonding ability of the experimental adhesive was not significantly adversely affected by the incorporation of DMAE-CB. Therefore, dental adhesives with strong and long-lasting bacteriostatic property could be achieved by incorporating DMAE-CB without negatively influencing bonding ability.

  1. Evaluation of antibacterial activity of synthetic aliphatic and aromatic monoacylglycerols.

    PubMed

    Batovska, Daniela; Todorova, Iva; Parushev, Stoyan; Tsvetkova, Iva; Najdenski, Hristo; Ubukata, Makoto

    2008-01-01

    The antibacterial activity of synthetic aliphatic and aromatic monoacylglycerols (MAGs) was studied against two human pathogens: Staphylococcus aureus and Escherichia coli. The active compounds inhibited selectively S. aureus. The most active compounds amongst them were those with medium size aliphatic chain and aromatic MAGs with electron withdrawing substituents at the aryl ring. The introduction of one or two-carbon spacer between the aryl ring and the carboxylic function did not influence antibacterial effectiveness. PMID:19004249

  2. ANTIBACTERIAL ACTIVITY OF LEAF EXTRACT OF Abutilon indicum

    PubMed Central

    Poonkothai, M.

    2006-01-01

    Chloroform, ethanol and aqueous extracts of the leaves of Abutilon indicum were investigated for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among the various extracts, maximum antibacterial activity was exhibited by ethanol extract (14, 25, 14, 25, 17, 18 mm) followed by chloroform extract (13, 17, 8, 15, 15, 20 mm) while aqueous extract, showed no activity. PMID:22557222

  3. ANTIBACTERIAL ACTIVITY OF LEAF EXTRACT OF Abutilon indicum.

    PubMed

    Poonkothai, M

    2006-07-01

    Chloroform, ethanol and aqueous extracts of the leaves of Abutilon indicum were investigated for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among the various extracts, maximum antibacterial activity was exhibited by ethanol extract (14, 25, 14, 25, 17, 18 mm) followed by chloroform extract (13, 17, 8, 15, 15, 20 mm) while aqueous extract, showed no activity. PMID:22557222

  4. Polybrominated Diphenyl Ethers: Structure Determination and Trends in Antibacterial Activity.

    PubMed

    Liu, Hongbing; Lohith, Katheryn; Rosario, Margaret; Pulliam, Thomas H; O'Connor, Robert D; Bell, Lori J; Bewley, Carole A

    2016-07-22

    Antibacterial-guided fractionation of the Dictyoceratid sponges Lamellodysidea sp. and two samples of Dysidea granulosa yielded 14 polybrominated, diphenyl ethers including one new methoxy-containing compound (8). Their structures were elucidated by interpretation of spectroscopic data of the natural product and their methoxy derivatives. Most of the compounds showed strong antimicrobial activity with low- to sub-microgram mL(-1) minimum inhibitory concentrations against drug-susceptible and drug-resistant strains of Staphylococcus aureus and Enterococcus faecium, and two compounds inhibited Escherichia coli in a structure-dependent manner. PMID:27399938

  5. [Influence of Polycations on Antibacterial Activity of Lysostaphin].

    PubMed

    Kulikov, S N; Khairullin, R Z; Varlamov, V P

    2015-01-01

    The synergistic antibacterial activity of lysostaphin and polycations of different chemical structures against Staphylococcus aureus has been shown. Polycations improved the lytic activity of lysostaphin against the peptidoglycan of staphylococci. It is proposed that this resulted in decreased binding of positively charged lysostaphin with S. aureus cell-wall teichoic acids. These data provide an opportunity to search for polycations that would amplify the synergistic effect of lysostaphin or other antibacterial proteins against staphylococci. PMID:26859963

  6. Zn or O? An Atomic Level Comparison on Antibacterial Activities of Zinc Oxides.

    PubMed

    Yu, Fen; Fang, Xuan; Jia, Huimin; Liu, Miaoxing; Shi, Xiaotong; Xue, Chaowen; Chen, Tingtao; Wei, Zhipeng; Fang, Fang; Zhu, Hui; Xin, Hongbo; Feng, Jing; Wang, Xiaolei

    2016-06-01

    For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D-printing-manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram-positive or gram-negative bacterial species. Zinc atoms as outermost layer (ZnO-Zn) showed a more pronounced antibacterial effect towards gram-negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO-O) showed a stronger antibacterial activity against gram-positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn(2+) concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species.

  7. Zn or O? An Atomic Level Comparison on Antibacterial Activities of Zinc Oxides.

    PubMed

    Yu, Fen; Fang, Xuan; Jia, Huimin; Liu, Miaoxing; Shi, Xiaotong; Xue, Chaowen; Chen, Tingtao; Wei, Zhipeng; Fang, Fang; Zhu, Hui; Xin, Hongbo; Feng, Jing; Wang, Xiaolei

    2016-06-01

    For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D-printing-manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram-positive or gram-negative bacterial species. Zinc atoms as outermost layer (ZnO-Zn) showed a more pronounced antibacterial effect towards gram-negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO-O) showed a stronger antibacterial activity against gram-positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn(2+) concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species. PMID:27124263

  8. Distribution and significance of heterotrophic marine bacteria with antibacterial activity.

    PubMed Central

    Nair, S; Simidu, U

    1987-01-01

    Bacteria with antibacterial activity were isolated from seawater, sediments, phytoplankton, and zooplankton of Suruga, Sagami, and Tokyo Bays and from soft corals and sponges collected from the Taiwan coast. Of the 726 strains isolated, 37 showed antibacterial activity against either Vibrio parahaemolyticus (ATCC 17802) or Staphylococcus aureus (P209). Sediment harbored the lowest number of these forms of bacteria, and those from Tokyo Bay did not show any activity. Attached isolates showed greater activity compared with free-living forms. Relatively high numbers of strains with antibacterial activity were associated with phytoplankton. Among the zooplankton isolates, cladocerans harbored the maximum number of antibacterial strains. Isolates were more inhibitory to gram-positive test cultures. Autoinhibition was observed only among 8% of the isolates. Marine nonproducers were more susceptible. Pseudomonas/Alteromonas species made up 81.0% of isolates, of which 30% were pigmented strains. The absence or reduction in number of bacteria with antibacterial activity in Tokyo Bay is attributed to its eutrophic nature, which may tend to moderate the production of antibacterial compounds. PMID:3435149

  9. Investigation of antibacterial activity of aspidin BB against Propionibacterium acnes.

    PubMed

    Gao, Chang; Guo, Na; Li, Na; Peng, Xiao; Wang, Peng; Wang, Wei; Luo, Meng; Fu, Yu-Jie

    2016-03-01

    In the present study, antibacterial activity of four kinds of phloroglucinol derivatives extracted from Dryopteris fragrans (L.) Schott against S. aureus, S. epidermidis and P. acnes has been tested. Aspidin BB exerted the strongest antibacterial activity with minimal inhibition concentration (MIC) values ranging from 7.81 to 15.63 μg/mL. The time-kill assay indicated that aspidin BB could kill P. acnes completely at 2 MIC (MBC) within 4 h. By using AFM, we demonstrated extensive cell surface alterations of aspidin BB-treated P. acnes. SDS-PAGE of supernatant proteins and lipid peroxidation results showed that aspidin BB dose-dependently affected membrane permeability of P. acnes. DNA damage and protein degradation of P. acnes were also verified. SDS-PAGE of precipitated proteins revealed possible targets of aspidin BB, i.e., heat shock proteins (26 kDa) and lipase (33 kDa) which could all cause inflammation. Aspidin BB also seriously increased the inhibition rate of lipase activity from 10.20 to 65.20 % to possibly inhibit the inflammation. In conclusions, the effective constituents of D. fragrans (L.) Schott to treat acne might be phloroglucinol derivatives including aspidin BB, aspidin PB, aspidinol and dryofragin. Among this, aspidin BB inhibited the growth of P. acnes by disrupting their membrane, DNA and proteins and finally leaded to the cell death. The obtained data highlighted the potential of using aspidin BB as an alternative treatment for acne vulgaris. PMID:26596576

  10. Antibacterial Activity of Nanocomposites of Copper and Cellulose

    PubMed Central

    Pinto, Ricardo J. B.; Daina, Sara; Neto, Carlos Pascoal; Trindade, Tito

    2013-01-01

    The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared by in situ and ex situ methods. Two cellulose matrices (vegetable and bacterial) were investigated together with morphological distinct copper particulates (nanoparticles and nanowires). A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus and Klebsiella pneumoniae, as pathogen microorganisms. The results showed that the chemical nature and morphology of the nanofillers have great effect on the antibacterial activity, with an increase in the antibacterial activity with increasing copper content in the composites. The cellulosic matrices also show an effect on the antibacterial efficiency of the nanocomposites, with vegetal cellulose fibers acting as the most effective substrate. Regarding the results obtained, we anticipate the development of new approaches to prepare cellulose/copper based nanocomposites thereby producing a wide range of interesting antibacterial materials with potential use in diverse applications such as packaging or paper coatings. PMID:24455681

  11. Antibacterial activity of nanocomposites of copper and cellulose.

    PubMed

    Pinto, Ricardo J B; Daina, Sara; Sadocco, Patrizia; Pascoal Neto, Carlos; Trindade, Tito

    2013-01-01

    The design of cheap and safe antibacterial materials for widespread use has been a challenge in materials science. The use of copper nanostructures combined with abundant biopolymers such as cellulose offers a potential approach to achieve such materials though this has been less investigated as compared to other composites. Here, nanocomposites comprising copper nanofillers in cellulose matrices have been prepared by in situ and ex situ methods. Two cellulose matrices (vegetable and bacterial) were investigated together with morphological distinct copper particulates (nanoparticles and nanowires). A study on the antibacterial activity of these nanocomposites was carried out for Staphylococcus aureus and Klebsiella pneumoniae, as pathogen microorganisms. The results showed that the chemical nature and morphology of the nanofillers have great effect on the antibacterial activity, with an increase in the antibacterial activity with increasing copper content in the composites. The cellulosic matrices also show an effect on the antibacterial efficiency of the nanocomposites, with vegetal cellulose fibers acting as the most effective substrate. Regarding the results obtained, we anticipate the development of new approaches to prepare cellulose/copper based nanocomposites thereby producing a wide range of interesting antibacterial materials with potential use in diverse applications such as packaging or paper coatings. PMID:24455681

  12. In vitro and in vivo antibacterial activity of AT-2266.

    PubMed

    Kouno, K; Inoue, M; Mitsuhashi, S

    1983-07-01

    AT-2266 [1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-1,8-naphthyridine-3-carbo xylic acid] showed a broad spectrum of antibacterial activity against gram-positive and gram-negative microorganisms, including Pseudomonas aeruginosa. The in vitro antibacterial activity of AT-2266 was in general comparable to that of norfloxacin, but much higher than that of pipemidic or nalidixic acid. The 90% minimal inhibitory concentrations (MIC90s) of AT-2266 for P. aeruginosa resistant to gentamicin (MIC range, 25 to greater than 200 microgram/ml) and Enterobacteriaceae resistant to nalidixic acid (25 to greater than 1,600 micrograms/ml) were 3.13 and 12.5 micrograms/ml, respectively. The to nalidixic acid (25 to 1,600 micrograms/ml) were 3.13 and 12.5 micrograms/ml, respectively. The MICs of AT-2266 were only slightly affected by the addition of horse serum or sodium cholate, by the pH of the medium, and by inoculum size. AT-2266 was sodium cholate, by the pH of the medium, and by inoculum size. AT-2266 was bactericidal at concentrations near its MIC value. The 50% effective doses of AT-2266 after oral administration against systemic infections in mice were about 1/2 those of norfloxacin, about 1/10 those of pipemidic acid, and between 1/20 and 1/40 those of nalidixic acid.

  13. Antibacterial activity of alimentary plants against Staphylococcus aureus growth.

    PubMed

    Pérez, C; Anesini, C

    1994-01-01

    Alimentary plants were screened for antibacterial activity against a penicillin G resistant strain of Staphylococcus aureus. Twenty-five samples of plant material corresponding to 21 species from 13 families were used. Both aqueous and ethanol extracts were obtained from them. Antibacterial activity was determined by the agar-well diffusion method, using cephazolin as a standard antibiotic. Seventeen ethanol extracts were found active. Eugenia caryophyllata (clavo de olor*) flowers, Myristica fragans (nuez moscada*) seeds, Theobroma cacao (cacao*) seed bark, Triticum sp (trigo*) fruit, Zea mays (maíz*) fruit and Piper nigrum (pimienta*) ripe fruit produced some of the more active extracts (* = Argentine vulgar names).

  14. Nanosilver on nanostructured silica: Antibacterial activity and Ag surface area.

    PubMed

    Sotiriou, Georgios A; Teleki, Alexandra; Camenzind, Adrian; Krumeich, Frank; Meyer, Andreas; Panke, Sven; Pratsinis, Sotiris E

    2011-06-01

    Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immobilized on nanostructured silica facilitates such investigations as the SiO2 support hinders the growth of nanosilver during its synthesis and, most importantly, its flocculation in bacterial suspensions. Here, such composite Ag/silica nanoparticles were made by flame spray pyrolysis of appropriate solutions of Ag-acetate or Ag-nitrate and hexamethyldisiloxane or tetraethylorthosilicate in ethanol, propanol, diethylene glucolmonobutyl ether, acetonitrile or ethylhexanoic acid. The effect of solution composition on nanosilver characteristics and antibacterial activity against the Gram negative Escherichia coli was investigated by monitoring their recombinantly synthesized green fluorescent protein. Suspensions with identical Ag mass concentration exhibited drastically different antibacterial activity pointing out that the nanosilver surface area concentration rather than its mass or molar or number concentration determine best its antibacterial activity. Nanosilver made from Ag-acetate showed a unimodal size distribution, while that made from inexpensive Ag-nitrate exhibited a bimodal one. Regardless of precursor composition or nanosilver size distribution, the antibacterial activity of nanosilver was correlated best with its surface area concentration in solution. PMID:23730198

  15. Nanosilver on nanostructured silica: Antibacterial activity and Ag surface area.

    PubMed

    Sotiriou, Georgios A; Teleki, Alexandra; Camenzind, Adrian; Krumeich, Frank; Meyer, Andreas; Panke, Sven; Pratsinis, Sotiris E

    2011-06-01

    Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immobilized on nanostructured silica facilitates such investigations as the SiO2 support hinders the growth of nanosilver during its synthesis and, most importantly, its flocculation in bacterial suspensions. Here, such composite Ag/silica nanoparticles were made by flame spray pyrolysis of appropriate solutions of Ag-acetate or Ag-nitrate and hexamethyldisiloxane or tetraethylorthosilicate in ethanol, propanol, diethylene glucolmonobutyl ether, acetonitrile or ethylhexanoic acid. The effect of solution composition on nanosilver characteristics and antibacterial activity against the Gram negative Escherichia coli was investigated by monitoring their recombinantly synthesized green fluorescent protein. Suspensions with identical Ag mass concentration exhibited drastically different antibacterial activity pointing out that the nanosilver surface area concentration rather than its mass or molar or number concentration determine best its antibacterial activity. Nanosilver made from Ag-acetate showed a unimodal size distribution, while that made from inexpensive Ag-nitrate exhibited a bimodal one. Regardless of precursor composition or nanosilver size distribution, the antibacterial activity of nanosilver was correlated best with its surface area concentration in solution.

  16. Antibacterial activity and cytocompatibility of Cu-Ti-O nanotubes.

    PubMed

    Hang, Ruiqiang; Gao, Ang; Huang, Xiaobo; Wang, Xiaoguang; Zhang, Xiangyu; Qin, Lin; Tang, Bin

    2014-06-01

    TiO2 nanotubes (NTs) have favorable biological properties, but the poor antibacterial activity limits their application especially in orthopedics fields. In this article, Cu-Ti-O nanotubes with different Cu contents are fabricated on sputtered TiCu films. Scanning electron microscopy reveals the NTs can be formed on sputtered TiCu films when the Cu content is less than 14.6 at %. X-ray photoelectron spectroscopy results indicate the NTs are consist of CuO mixed with TiO2 and the Cu content in NTs decreases dramatically compared with that in TiCu films. Biological experiments show that although these NTs have poor release antibacterial activity, their contact antibacterial activity has proven to be excellent, indicating the NT surface can effectively inhibit biomaterial-associated infections. The cytocompatibility of the NTs is closely related to the Cu content and when its content is relatively low (1.01 at %), there is no appreciable cytotoxicity. So Cu-Ti-O NTs with 1 at % Cu may be suitable to achieve proper antibacterial activity and desired cytocompatibility. The Cu-Ti-O NTs integrate the favorable antibacterial activity of Cu and excellent biological properties of TiO2 NTs therefore have potential applications in orthopedics, dentistry, and other biomedical fields.

  17. Synthesis and Antibacterial Activities of Antibacterial Peptides with a Spiropyran Fluorescence Probe

    PubMed Central

    Chen, Lei; Zhu, Yu; Yang, Danling; Zou, Rongfeng; Wu, Junchen; Tian, He

    2014-01-01

    In this report, antibacterial peptides1-3 were prepared with a spiropyran fluorescence probe. The probe exhibits a change in fluorescence when isomerized from a colorless spiro-form (spiropyran, Sp) to a colored open-form (merocyanine, Mc) under different chemical environments, which can be used to study the mechanism of antimicrobial activity. Peptides 1-3 exhibit a marked decrease in antimicrobial activity with increasing alkyl chain length. This is likely due to the Sp-Mc isomers in different polar environments forming different aggregate sizes in TBS, as demonstrated by time-dependent dynamic light scattering (DLS). Moreover, peptides 1-3 exhibited low cytotoxicity and hemolytic activity. These probe-modified peptides may provide a novel approach to study the effect of structural changes on antibacterial activity, thus facilitating the design of new antimicrobial agents to combat bacterial infection. PMID:25358905

  18. Acylated flavonol glycosides from Tagetes minuta with antibacterial activity.

    PubMed

    Shahzadi, Irum; Shah, Mohammad M

    2015-01-01

    Wild marigold (Tagetes minuta), a flowering plant of the family Asteraceae contains compounds of pharmaceutical and nutritional importance especially essential oils and flavonols. Identification, characterization of flavonols and determination of their antibacterial activity were major objectives of the current study. The isolation and purification of flavonols was accomplished using chromatographic techniques while structural elucidation was completed by LC-MS and NMR spectroscopy. The extracts and purified compounds were tested against various bacterial strains for antibacterial activity. A total of 19 flavonols were isolated from this species. Of these, 17 were of butanol and two of ethyl acetate extracts. Based on the concentration and purity, eight potential flavonols were selected and structurally elucidated. Four flavonols, 6-hydroxyquercetin 7-O-β-(6''-galloylglucopyranoside; 2), 6-hydroxykaempferol 7-O-β-glucopyranoside (5), 6-hydroxykaempferol 7-O-β-(6''-galloylglucopyranoside; 7), 6-hydroxyquercetin 7-O-β-(6''-caffeoylglucopyranoside; 9), were identified for the first time from T. minuta. Butanol and ethyl acetate extracts of flowers and seeds showed significant antibacterial activity against Micrococcus leteus, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas pikettii. Among the isolated flavonols only 1, 2, and 18 were found to possess significant antibacterial activity against M. luteus. The extracts and purified flavonols from T. minuta can be potential candidates for antibacterial drug discovery and support to ethnopharmacological use. PMID:26441652

  19. Acylated flavonol glycosides from Tagetes minuta with antibacterial activity

    PubMed Central

    Shahzadi, Irum; Shah, Mohammad M.

    2015-01-01

    Wild marigold (Tagetes minuta), a flowering plant of the family Asteraceae contains compounds of pharmaceutical and nutritional importance especially essential oils and flavonols. Identification, characterization of flavonols and determination of their antibacterial activity were major objectives of the current study. The isolation and purification of flavonols was accomplished using chromatographic techniques while structural elucidation was completed by LC–MS and NMR spectroscopy. The extracts and purified compounds were tested against various bacterial strains for antibacterial activity. A total of 19 flavonols were isolated from this species. Of these, 17 were of butanol and two of ethyl acetate extracts. Based on the concentration and purity, eight potential flavonols were selected and structurally elucidated. Four flavonols, 6-hydroxyquercetin 7-O-β-(6′′-galloylglucopyranoside; 2), 6-hydroxykaempferol 7-O-β-glucopyranoside (5), 6-hydroxykaempferol 7-O-β-(6′′-galloylglucopyranoside; 7), 6-hydroxyquercetin 7-O-β-(6′′-caffeoylglucopyranoside; 9), were identified for the first time from T. minuta. Butanol and ethyl acetate extracts of flowers and seeds showed significant antibacterial activity against Micrococcus leteus, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas pikettii. Among the isolated flavonols only 1, 2, and 18 were found to possess significant antibacterial activity against M. luteus. The extracts and purified flavonols from T. minuta can be potential candidates for antibacterial drug discovery and support to ethnopharmacological use. PMID:26441652

  20. Is the use o f Gunnera perpensa extracts in endometritis related to antibacterial activity?

    PubMed

    McGaw, L J; Gehring, R; Katsoulis, L; Eloff, J N

    2005-06-01

    Rhizome extracts of Gunnera perpensa are used in traditional remedies in South Africa to treat endometritis both in humans and animals. An investigation was undertaken to determine whether this plant possesses antibacterial activity, which may explain its efficacy. Gunnera perpensa rhizome extracts were prepared serially with solvents of increasing polarity and tested for antibacterial activity. Test bacteria included the Gram-positive Enterococcus faecalis and Staphylococcus aureus and the Gram-negative Escherichia coli and Pseudomonas aeruginosa. A moderate to weak level of antibacterial activity in most of the extracts resulted, with the best minimal inhibitory concentration (MIC) value of 2.61 mg ml(-1) shown by the acetone extract against S. aureus. The extracts were also submitted to the brine shrimp assay to detect possible toxic or pharmacological effects. All the extracts were lethal to the brine shrimp larvae at a concentration of 5 mg ml(-1). The acetone extract was extremely toxic at 1 mg ml(-1), with some toxicity evident at 0.1 mg ml(-1). The remainder of the extracts generally displayed little activity at concentrations lower than 5 mg ml(-1). In summary, the results indicate that although the extracts demonstrated a level of pharmacological activity, the relatively weak antibacterial activity is unlikely to justify the use of G. perpensa rhizomes in the traditional treatment of endometritis. Rather, the slightly antibacterial nature of the rhizomes may contribute to an additive effect, along with their known uterotonic activity, to the overall efficacy of the preparation. PMID:16137130

  1. Antibacterial and Antitumor Activities of Biscoumarin and Dihydropyran Derivatives.

    PubMed

    Sui, Yun-Peng; Huo, Hai-Ru; Xin, Jia-Jia; Li, Jing; Li, Xiao-Jun; Du, Xin-Liang; Ma, Hai; Zhou, Hai-Yu; Zhan, Hong-Dan; Wang, Zhu-Ju; Li, Chun; Sui, Feng; Li, Ming-Kai

    2015-09-23

    A novel series of biscoumarin (1-4) and dihydropyran (5-13) derivatives were synthesized via a one-pot multicomponent condensation reaction and evaluated for antibacterial and antitumor activity in vitro. The X-ray crystal structure analysis of four representative compounds, 3, 7, 9 and 11, confirmed the structures of these compounds. Compounds 1-4 showed the most potent antitumor activity among the total 13 derivatives; especially for compounds 1 and 2, they also emerged as promising antibacterial members with better antibacterial activity. In addition, the results of density functional theory (DFT) showed that compared with compounds 3 and 4, biscoumarins 1 and 2 had lower intramolecular hydrogen bonds (HB) energy in their structures.

  2. Synthesis, characterization and antibacterial activities of some new ferrocene-containing penems.

    PubMed

    Long, Bohua; He, Chunlian; Yang, Yingbin; Xiang, Jiannan

    2010-03-01

    The synthesis and structure-activity relationships of a series of new penems bearing ferrocenyl group attached to the C-2 position of the penem nucleus were described. The beta-lactanic derivatives obtained had been characterized as sodium salts, through (1)H NMR and IR, as well as through element analysis. Their in vitro antibacterial activities against both Gram-positive including meticillin-resistant Staphylococcus aureus (MRSA) and Gram-negative bacteria were tested. Most of the penems exhibited superior or equivalent efficacy of antibacterial activity as well as high stability to renal dehydropeptidase-I (DHP-I) compared with faropenem. In particular, the compound 14h having a heterocyclic group showed the most potent antibacterial activity. PMID:20053481

  3. Free-radical scavenging activity and antibacterial impact of Greek oregano isolates obtained by SFE.

    PubMed

    Stamenic, Marko; Vulic, Jelena; Djilas, Sonja; Misic, Dusan; Tadic, Vanja; Petrovic, Slobodan; Zizovic, Irena

    2014-12-15

    The antioxidant and antibacterial properties of Greek oregano extracts obtained by fractional supercritical fluid extraction (SFE) with carbon dioxide were investigated and compared with the properties of essential oil obtained by hydrodistillation. According to DPPH, hydroxyl radical and superoxide anion radical scavenging activity assays, the supercritical extracts expressed stronger antioxidant activity comparing to the essential oil. The most effective was the supercritical extract obtained by fractional extraction at 30 MPa and 100°C after the volatile fraction had been extracted at lower pressure. At the same time this extract showed strong antibacterial activity against staphylococci, including MRSA strain, but did not affect Escherichia coli of normal intestinal flora. The essential oil obtained by hydrodistillation showed stronger antibacterial activity against E. coli, Salmonella and Klebsiella pneumoniae, comparing to the supercritical extracts but at the same affected the normal gut flora.

  4. Preparation and antibacterial activity of oligosaccharides derived from dandelion.

    PubMed

    Qian, Li; Zhou, Yan; Teng, Zhaolin; Du, Chun-Ling; Tian, Changrong

    2014-03-01

    In this study, we prepared oligosaccharides from dandelion (Taraxacum officinale) by hydrolysis with hydrogen peroxide (H2O2) and investigated their antibacterial activity. The optimum hydrolysis conditions, as determined using the response surface methodology, were as follows: reaction time, 5.12h; reaction temperature, 65.53 °C and H2O2 concentration, 3.16%. Under these conditions, the maximum yield of the oligosaccharides reached 25.43%. The sugar content in the sample was 96.8%, and the average degree of polymerisation was approximately 9. The oligosaccharides showed high antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, indicating that dandelion-derived oligosaccharides have the potential to be used as antibacterial agents.

  5. Antibacterial activity of four dentin bonding systems.

    PubMed

    Herrera, M; Carrión, P; Bravo, M; Castillo, A

    2000-08-01

    The antibacterial action of bonding systems Gluma 2000, Syntac, Prisma Universal Bond 3, Scotchbond Multipurpose and Prime-Bond was tested against 32 strains of the caries-producing bacteria Streptococcus spp., Lactobacillus spp., Actinomyces spp., Porphyromonas spp. and Clostridium spp. An agar plate diffusion method was used with chlorhexidine as the positive control. Assays were performed in triplicate for each component (primer and adhesive) of the bonding systems. All the adhesives were found to inhibit bacterial growth but with differences in their spectra of action. The sum action of the Scotchbond Multipurpose components were most inhibitory and Prime-Bond was found to be the least effective system.

  6. Developing of a novel antibacterial agent by functionalization of graphene oxide with guanidine polymer with enhanced antibacterial activity

    NASA Astrophysics Data System (ADS)

    Li, Ping; Sun, Shiyu; Dong, Alideertu; Hao, Yanping; Shi, Shuangqiang; Sun, Zijia; Gao, Ge; Chen, Yuxin

    2015-11-01

    New materials with excellent antibacterial activity attract numerous research interests. Herein, a facile synthetic method of polyethylene glycol (PEG) and polyhexamethylene guanidine hydrochloride (PHGC) dual-polymer-functionalized graphene oxide (GO) (GO-PEG-PHGC), a novel antibacterial material, was reported. The as-prepared products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray pattern (XRD) and elemental analysis. The antibacterial effect on the bacterial strain was investigated by incubating both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). The results show that GO-PEG-PHGC has enhanced antibacterial activity when compared to GO, GO-PEG or GO-PHGC alone. The improved antibacterial activity was described to be related to a better dispersion of GO-PEG-PHGC in the presence of PEG. This better dispersion leads to a greater contact between the bacteria membrane and nanomaterials, therefore leading to greater cell damage. Not only Gram-negative bacteria but also Gram-positive bacteria are greatly inhibited by this antibacterial agent. With the powerful antibacterial activity as well as its low cost and facile preparation, the GO-PEG-PHGC as a novel antibacterial agent can find potential application in the areas of healthcare and environmental engineering.

  7. Antibacterial activity of cerium colloids against opportunistic microorganisms in vitro.

    PubMed

    Babenko, L P; Zholobak, N M; Shcherbakov, A B; Voychuk, S I; Lazarenko, L M; Spivak, M Ya

    2012-01-01

    The CeO2 sol with the size of nanoparticles 2-4 nm has been synthesized. It has been determined that the synthesized nanocrystalline cerium has antibacterial activity in vitro against different groups of opportunistic microorganisms: clinical strains of Escherichia coli, Staphylococcus aureus and Candida albicans. The rate of viability depression of test-cultures depends on the concentration of cerium dioxide nanoparticles and time of incubation. It is shown that the sol interacts with the bacterial cell surface. It is suggested that the observed differences of antibacterial action of nanocrystalline cerium dioxide can be related to the structural characteristics of the cell surface.

  8. Screening of antibacterial activities of twenty-one oxygenated monoterpenes.

    PubMed

    Kotan, Recep; Kordali, Saban; Cakir, Ahmet

    2007-01-01

    Plant essential oils are widely used as fragrances and flavours in the cosmetic, perfume, drug and food industries. Oxygenated monoterpenes are widespread components of the essential oils, usually occurring in high amount. In this paper, the antibacterial activities of twenty-one oxygenated monoterpenes (borneol, borneol acetate, camphor, carvone, 1,8-cineole, citronellal, beta-citronellol, dihydrocarvone, fenchol, fenchone, geraniol acetate, isomenthol, limonene oxide, linalool, linalool acetate, nerol, nerol acetate, terpinen-4-ol, alpha-terpineol, menthol and menthone) and penicillin (standard antibiotic) were determined using a disc diffusion method (in vitro) against 63 bacterial strains, belonging to 37 different genera and 54 species (plant, food and clinic origins). The results showed that the oxygenated monoterpenes exhibited a variable degree of antibacterial activities. These compounds also inhibited the growth of bacterial strains by producing a weak zone of inhibition from 7 to 11 mm in diameter, depending on the susceptibility of the tested bacteria. Among the tested compounds, nerol, linalool alpha-terpineol, fenchol and terpinen-4-ol showed antibacterial activity at a broad spectrum. However, their antibacterial activities were lower than those of penicillin. In contrast to these compounds, camphor and 1,8-cineole exhibited no inhibition effects on the growth of all tested bacteria.

  9. Antibacterial Activity of Polymer Coated Cerium Oxide Nanoparticles

    PubMed Central

    Shah, Vishal; Shah, Shreya; Shah, Hirsh; Rispoli, Fred J.; McDonnell, Kevin T.; Workeneh, Selam; Karakoti, Ajay; Kumar, Amit; Seal, Sudipta

    2012-01-01

    Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO4, CaCl2, KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to understand the collective influence of the tested parameters on the anti-bacterial activity and subsequently a computer-based, interactive visualization tool was developed. The visualization allows us to elucidate the effect of each of the parameters in combination with other parameters, on the antibacterial activity of nanoparticles. The results indicate that the toxicity of CeO2 NPs depend on the physical and chemical environment; and in a majority of the possible combinations of the nine parameters, non-lethal to the bacteria. In fact, the cerium oxide nanoparticles can decrease the anti-bacterial activity exerted by magnesium and potassium salts. PMID:23110109

  10. Enhanced antibacterial activities of leonuri herba extracts containing silver nanoparticles.

    PubMed

    Im, A-Rang; Han, Lina; Kim, E Ray; Kim, Jinwoong; Kim, Yeong Shik; Park, Youmie

    2012-08-01

    We report an efficient and powerful green process to enhance the antibacterial activities of the Leonuri herba extract. Plant sources, especially leaves and herbs, are precious for the generation of gold and silver nanoparticles. Various kinds of polyphenols and hydroxyl groups are capable of processing a reduction reaction to generate metals from its corresponding salts. We have prepared gold and silver nanoparticles with 70% ethanol and water extracts. No other toxic chemicals were utilized and the extracts played dual roles as reducing and stabilizing agents. For the generation of nanoparticles, both oven incubation and autoclaving methods were applied and the reaction conditions were optimized. Surface plasmon resonance band indicated that the formation of nanoparticles was successful. Images of high-resolution transmission electron microscopy revealed mostly spherical nanoparticles ranging from 9.9 to 13.0 nm in size. A water extract containing silver nanoparticles exhibited remarkable (approximately 127-fold) enhancement in antibacterial activities against Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae when compared with the water extract alone. In addition, antibacterial activity towards Gram-negative bacteria was greater than that against Gram-positive bacteria. The process reported here has the potential to be a new approach to improve the antibacterial activities of plant extracts.

  11. Highly selective antibacterial activities of silver nanoparticles against Bacillus subtilis.

    PubMed

    Li, Ju; Rong, Kaifeng; Zhao, Huiping; Li, Fei; Lu, Zhong; Chen, Rong

    2013-10-01

    Silver nanoparticles (AgNPs) with different sizes (5, 15 and 55 nm) were synthesized via simple method, and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray microanalysis (EDX) and ultraviolet-visible absorption spectroscopy (UV-Vis). The antibacterial activities of the prepared AgNPs against Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) were evaluated by inhibition zone, inhibition curve, and colony counting methods. The results showed that the AgNPs exhibited obvious bacterium-selective and size-dependent antibacterial activities. The Gram-positive bacteria S. aureus and B. subtilis were more sensitive to AgNPs than Gram-negative bacterium E. coli. Interestingly, AgNPs displayed remarkably antibacterial activities against B. subtilis among Gram-positive bacteria, regardless of whether in separately or cocultured bacteria. It also showed that AgNPs with 5 nm in size presented the highest antibacterial activity against both Gram-negative and Gram-positive bacteria. The effects of AgNPs on the membrane leakage of the reducing sugars from three bacteria were also measured by 3,5-dinitrosalicylic acid method. The leakage amount of reducing sugars from B. subtilis was the highest among the tested bacteria, indicating that AgNPs could damage the structure of bacteria cell membrane and resulted in the leakage of reducing sugars, leading to the death of bacteria.

  12. Antibacterial activity in Actinidia chinensis, Feijoa sellowiana and Aberia caffra.

    PubMed

    Basile, A; Vuotto, M L; Violante, U; Sorbo, S; Martone, G; Castaldo-Cobianchi, R

    1997-01-01

    The antibacterial activity of extracts from various parts of plants (leaves, fruits and stems) was studied in Actinidia chinensis, Feijoa sellowiana and Aberia caffra. These are tropical plants used for food. The fruits (subdivided into skin, pulp and seeds), leaves and stems were separately extracted and tested, in triplicate, against eight Gram positive and Gram negative bacterial strains. All the extracts, except from the leaves of A. caffra, showed activity against all the strains employed. Inhibition of bacterial growth was tested against Na-cefotaxime, benzyl penicillin and tetracycline. The antibiotic activity of fruit resides essentially in the seeds. The antibacterial activity of extracts from vegetative plant parts was generally less active that from fruit extracts. The minimum inhibiting concentration (MIC) and minimum bactericidal concentration (MBC) were determined for all the extracts and showed exclusively bacteriostatic activity.

  13. Benzotriazole-Mediated Synthesis and Antibacterial Activity of Novel N-Acylcephalexins

    PubMed Central

    Agha, Khalid A.; Abo-Dya, Nader E.; Ibrahim, Tarek S.; Abdel-Aal, Eatedal H.; Hegazy, Wael A.

    2016-01-01

    Cephalexin (1) was acylated using N-acylbenzotriazoles (3a–k′) derived from various carboxylic acids including aromatic, heterocyclic and N-Pg-α-amino acid to afford N-acylcephalexins in excellent yields (82%–96%). Antibacterial screening of the novel cephalosporins revealed that all targets (4a–j) retained the antibacterial activity of cephalexin against Staphylococcus aureus (ATCC 6538). N-Nicotinylcephalexin (4c) and N-(3,4,5-trimethoxybenzoyl)cephalexin (4g) exhibited a broader spectrum of antibacterial activity towards standard strains of Staphylococcus aureus (ATCC 6538), Paenibacillus polymyxa (ATCC 842), and Escherichia coli (ATCC 10536) as well as a resistant strain of Pseudomonas aeruginosa (ATCC 27853).

  14. Antibacterial Activity of Ti₃C₂Tx MXene.

    PubMed

    Rasool, Kashif; Helal, Mohamed; Ali, Adnan; Ren, Chang E; Gogotsi, Yury; Mahmoud, Khaled A

    2016-03-22

    MXenes are a family of atomically thin, two-dimensional (2D) transition metal carbides and carbonitrides with many attractive properties. Two-dimensional Ti3C2Tx (MXene) has been recently explored for applications in water desalination/purification membranes. A major success indicator for any water treatment membrane is the resistance to biofouling. To validate this and to understand better the health and environmental impacts of the new 2D carbides, we investigated the antibacterial properties of single- and few-layer Ti3C2Tx MXene flakes in colloidal solution. The antibacterial properties of Ti3C2Tx were tested against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) by using bacterial growth curves based on optical densities (OD) and colonies growth on agar nutritive plates. Ti3C2Tx shows a higher antibacterial efficiency toward both Gram-negative E. coli and Gram-positive B. subtilis compared with graphene oxide (GO), which has been widely reported as an antibacterial agent. Concentration dependent antibacterial activity was observed and more than 98% bacterial cell viability loss was found at 200 μg/mL Ti3C2Tx for both bacterial cells within 4 h of exposure, as confirmed by colony forming unit (CFU) and regrowth curve. Antibacterial mechanism investigation by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) coupled with lactate dehydrogenase (LDH) release assay indicated the damage to the cell membrane, which resulted in release of cytoplasmic materials from the bacterial cells. Reactive oxygen species (ROS) dependent and independent stress induction by Ti3C2Tx was investigated in two separate abiotic assays. MXenes are expected to be resistant to biofouling and offer bactericidal properties.

  15. Evaluation of the Antibacterial Activity of Patchouli Oil

    PubMed Central

    Yang, Xian; Zhang, Xue; Yang, Shui-Ping; Liu, Wei-Qi

    2013-01-01

    In the present study, the antimicrobial tests of patchouli oil were studied by using molecular docking technology and antimicrobial test in vitro. Five biological macromolecule enzymes, required by the bacteria in the process of biosynthesis were selected as target molecules. Five antibiotics benzylpenicillin, sulfadiazine, trimethoprim, rifampicin and ciprofloxacin, which are generally acknowledged as antibacterial drugs, were selected as reference compounds. The 3 three-dimensional (3D) structures of the 5 reference compounds and 26 compounds from patchouli oil were established by using surflex-dock software (8.1). And the 3D structures of five biological macromolecule enzymes derived from Protein Data Bank (PDB). Molecular docking was carried out between the 31 chemical compounds (ligands) and the 5 enzymes (receptors) by using surflex-dock function. Furthermore, the antibacterial effects of 31 chemical compounds were investigated by the scoring function after molecular docking was completed. By comparing the scoring result of 26 compounds in patchouli oil with 5 compared components, we inferred antibacterial activity in about 26 compounds in patchouli oil. On the other hand, six frequently-used pathogenic bacteria were selected for antimicrobial test in vitro, patchouli oil and its two major compounds: (-)-patchouli alcohol and pogostone, which their contents exceeded 60% in patchouli oil samples, were selected antibacterial agents. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) were also determined. Molecular docking technology and antimicrobial test in vitro proved that patchouli oil had strong antimicrobial effects. Particularly, pogostone and (-)-patchouli alcohol have potent antimicrobial activity. PMID:24250637

  16. Antibacterial activity of Nymphaea nouchali (Burm. f) flower

    PubMed Central

    2013-01-01

    Background The present work aimed to find out the antibacterial activity of Nymphaea nouchali flower on human and plant pathogenic bacteria. Methods Antibacterial potency of methanol, acetone, ethyl acetate and petroleum spirit extracts of Nymphaea nouchali flower has been tested against four human pathogenic bacteria Bacillus subtilis (FO 3026) Escherichia coli (IFO 3007), Klebsiella pneumonia (ATTC 10031) and Sarcina lutea (IFO 3232) and one plant pathogenic bacterium Xanthomonas campestris (IAM 1671) by disc diffusion assay. Zone of inhibition produced by different extracts against the test bacteria was measured and compared with standard antibiotic disc. Results Methanol extract possessed better antibacterial activity against two pathogenic bacteria, B. subtilis (FO 3026) and S. lutea (IFO 3232) than commercial antibiotic nalidixic acid. Acetone extract showed moderate sensitivity whereas B. subtilis (FO 3026), S. lutea (IFO 3232) and X. campestris (IAM 1671) showed resistance to ethyl acetate and petroleum spirit extracts. The minimum inhibitory concentrations of various extracts were ranged between 128–2048 μgml-1. Conclusions Nymphaea nouchali flower could be a potential candidate for future development of novel broad spectrum antibacterial herbal formulation. PMID:24099586

  17. Antibacterial activity of plant extracts from Brazil against fish pathogenic bacteria

    PubMed Central

    Castro, S.B.R.; Leal, C.A.G.; Freire, F.R.; Carvalho, D.A.; Oliveira, D.F.; Figueiredo, H.C.P.

    2008-01-01

    The aim of this work was to evaluate the antibacterial activity of Brazilian plants extracts against fish pathogenic bacteria. Forty six methanolic extracts were screened to identify their antibacterial properties against Streptococcus agalactiae, Flavobacterium columnare and Aeromonas hydrophila. Thirty one extracts showed antibacterial activity. PMID:24031303

  18. Antibacterial activity and probiotic potential of Lactobacillus plantarum HKN01: a new insight into the morphological changes of antibacterial compound-treated Escherichia coli by electron microscopy.

    PubMed

    Sharafi, Hakimeh; Maleki, Hadi; Ahmadian, Gholamreza; Shahbani Zahiri, Hossein; Sajedinejad, Neda; Houshmand, Behzad; Vali, Hojatollah; Akbari Noghabi, Kambiz

    2013-02-01

    Among several bacteria examined, an antibacterial-producing Lactobacillus strain with probiotic characteristics was selected and identified based on 16S rRNA gene sequencing. Subsequent purification and mode of action of the antibacterial compounds on target cells including E. coli were investigated. Maximum production of the antibacterial compound was recorded at 18 h incubation at 30 degrees C. Interestingly, antibacterial activity remained unchanged after heating at 121 degrees C for 45 min, 24 h storage in temperature range of 70 degrees C to room temperature, and 15 min exposure to UV light, and it was stable in the pH of range 2-10. The active compounds were inactivated by proteolytic enzymes, indicating their proteinaceous nature, and, therefore, referred to as bacteriocin-like inhibitory substances. Isolation and partial purification of the effective agent was done by performing ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the GFC-purified active compound (~3 kDa) was determined by Tris-Tricine SDS-PAGE. To predict the mechanisms of action, transmission electron microscopy (TEM) analysis of ultrathin sections of E. coli before and after antibacterial treatment was carried out. TEM analysis of antibacterial compounds-treated E. coli demonstrated that the completely altered bacteria appear much darker compared with the less altered bacteria, suggesting a change in the cytoplasmic composition. There were also some membrane-bound convoluted structures visible within the completely altered bacteria, which could be attributed to the response of the E. coli to the treatment with the antibacterial compound. According to the in vivo experiments oral administration of L. plantarum HKN01 resulted in recovery of infected BALB/c mice with Salmonella enterica ser. Typhimurium. PMID:23412066

  19. Mechanism of antibacterial activity of copper nanoparticles

    NASA Astrophysics Data System (ADS)

    Chatterjee, Arijit Kumar; Chakraborty, Ruchira; Basu, Tarakdas

    2014-04-01

    In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu2+ ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously.

  20. Mechanism of antibacterial activity of copper nanoparticles.

    PubMed

    Chatterjee, Arijit Kumar; Chakraborty, Ruchira; Basu, Tarakdas

    2014-04-01

    In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu(2+) ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously. PMID:24584282

  1. Synthesis, antibacterial and cytotoxic activity evaluation of hydroxyurea derivatives.

    PubMed

    Kos, Ivan; Jadrijević-Mladar, Milena; Butula, Ivan; Biruš, Mladen; Maravić-Vlahoviček, Gordana; Dabelić, Sanja

    2013-06-01

    5 Synthesis and biological evaluation of a series (N = 16) of cyclic and acyclic hydroxyurea derivatives, including benzotriazole-, isocyanuric acid- and biuret-containing compounds, are disclosed. 1-N-(benzyloxycarbamoyl)benzotriazole was used as a benzyloxyisocyanate donor, a useful intermediate in the preparation of substituted hydroxyurea. Antibacterial activities of synthesized hydroxyurea derivatives were tested on three E. coli strains, i.e., a strain susceptible to antibiotics, a strain resistant to macrolide antibiotics and a strain resistant to aminoglycoside antibiotics. Six compounds (three acyclic and three cyclic hydroxyureas) showed growth inhibition of the tested E. coli strains, with different specificity toward each strain. Results of the cytotoxic activity evaluation revealed that twelve out of sixteen test compounds were cytotoxic to human acute monocytic leukemia THP-1 and/or human acute T cell leukemia Jurkat cell line. 1-(N-hydroxycarbamoyl) benzotriazole () increased the metabolic activity of both cell lines. Two compounds, 1-(N-hydroxycarbamoyl) benzotriazole (5) and N,N',N''-trihydroxybiuret (15), were identified as potential NO donors.

  2. Antimycobacterial and Antibacterial Activity of Allium sativum Bulbs.

    PubMed

    Viswanathan, V; Phadatare, A G; Mukne, Alka

    2014-05-01

    Tuberculosis is one of the major public health problems faced globally. Resistance of Mycobacterium tuberculosis to antitubercular agents has called for an urgent need to investigate newer drugs to combat tuberculosis. Garlic (Allium sativum) is an edible plant which has generated a lot of curiosity throughout human history as a medicinal plant. Garlic contains sulfur compounds like allicin, ajoene, allylmethyltrisulfide, diallyltrisulfide, diallyldisulphide and others which exhibit various biological properties like antimicrobial, anticancer, antioxidant, immunomodulatory, antiinflammatory, hypoglycemic, and cardiovascular effects. According to various traditional systems of medicine, garlic is one of the established remedies for tuberculosis. The objective of the current study was to investigate in vitro antimycobacterial activity as well as anti-bacterial activity of various extracts rich in specific phytoconstituents from garlic. Preparation of garlic extracts was done based on the chemistry of the constituents and their stability. The estimation of in vitro antimycobacterial activity of different garlic extracts was done using Resazurin microtire plate assay technique whereas activity of garlic oil was evaluated by colony count method. The antibacterial activity of extracts and oil was estimated by zone of inhibition method. Extracts of garlic rich in allicin and ajoene showed appreciable antimycobacterial activity as compared to standard drugs. Garlic oil demonstrated significant antibacterial activity, particularly against methicillin-resistant Staphylococcus aureus.

  3. Antimycobacterial and Antibacterial Activity of Allium sativum Bulbs

    PubMed Central

    Viswanathan, V.; Phadatare, A. G.; Mukne, Alka

    2014-01-01

    Tuberculosis is one of the major public health problems faced globally. Resistance of Mycobacterium tuberculosis to antitubercular agents has called for an urgent need to investigate newer drugs to combat tuberculosis. Garlic (Allium sativum) is an edible plant which has generated a lot of curiosity throughout human history as a medicinal plant. Garlic contains sulfur compounds like allicin, ajoene, allylmethyltrisulfide, diallyltrisulfide, diallyldisulphide and others which exhibit various biological properties like antimicrobial, anticancer, antioxidant, immunomodulatory, antiinflammatory, hypoglycemic, and cardiovascular effects. According to various traditional systems of medicine, garlic is one of the established remedies for tuberculosis. The objective of the current study was to investigate in vitro antimycobacterial activity as well as anti-bacterial activity of various extracts rich in specific phytoconstituents from garlic. Preparation of garlic extracts was done based on the chemistry of the constituents and their stability. The estimation of in vitro antimycobacterial activity of different garlic extracts was done using Resazurin microtire plate assay technique whereas activity of garlic oil was evaluated by colony count method. The antibacterial activity of extracts and oil was estimated by zone of inhibition method. Extracts of garlic rich in allicin and ajoene showed appreciable antimycobacterial activity as compared to standard drugs. Garlic oil demonstrated significant antibacterial activity, particularly against methicillin-resistant Staphylococcus aureus. PMID:25035540

  4. Synthesis, antifungal and antibacterial activity of novel 1,2,4-triazole derivatives

    PubMed Central

    Gupta, Deepa; Jain, D. K.

    2015-01-01

    A large number of 1,2,4-triazole-containing ring system have been incorporated into a wide variety of therapeutically interesting drug candidates including anti-inflammatory, central nervous system stimulants, antianxiety, and antimicrobial agents. To overcome the rapid development of drug resistance, new agents should preferably have chemical characteristics that clearly differ from those of existing agents. Thus led to the design and synthesize the new antimicrobial agents. A novel series of Schiff bases based on of 4-(benzylideneamino)-5-phenyl-4H-1,2,4-triazole-3-thiol scaffold was prepared by heating thiocarbohydrazide and substituted benzoic acid and subsequently, treating with substituted benzaldehydes. Seventeen derivatives were synthesized and were biologically screened for antifungal and antibacterial activity. The newly synthesized derivatives of triazole showed antifungal activity against fungal species, Microsporum gypseum; and antibacterial activity against bacterial species, Staphylococcus aureus. It was observed that none of the compounds tested showed positive results for fungi Candida albicans fungi Aspergillus niger, nor against bacterial strain Escherichia coli. Strong antifungal effects were obtained for the synthesized compounds against M. gypseum and were superior or comparable to standard drug ketoconazole. Similarly, all of the synthesized compounds exhibit strong antibacterial activity against S. aureus and were superior or comparable to standard drug streptomycin. It was found that among the triazole derivatives so synthesized, six of them, showed antifungal activity superior to ketoconazole while one of them, showed antibacterial activity superior to streptomycin. Thus, these can be the potential new molecule as an antimicrobial agent. PMID:26317080

  5. [Antioxidant and antibacterial activities of dimeric phenol compounds].

    PubMed

    Ogata, Masahiro

    2008-08-01

    We studied the antioxidant and antibacterial activities of monomeric and dimeric phenol compounds. Dimeric compounds had higher antioxidant activities than monomeric compounds. Electron spin resonance spin-trapping experiments showed that phenol compounds with an allyl substituent on their aromatic rings directly scavenged superoxide, and that only eugenol trapped hydroxyl radicals. We developed a generation system of the hydroxyl radical without using any metals by adding L-DOPA and DMPO to PBS or MiliQ water in vitro. We found that eugenol trapped hydroxyl radicals directly and is metabolized to a dimer. On the other hand, dipropofol, a dimer of propofol, has strong antibacterial activity against Gram-positive bacteria. However, it lacks solubility in water and this property is assumed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water with the addition of a monosaccharide or ascorbic acid.

  6. Synthesis and antibacterial activity of sulfonamides. SAR and DFT studies

    NASA Astrophysics Data System (ADS)

    Boufas, Wahida; Dupont, Nathalie; Berredjem, Malika; Berrezag, Kamel; Becheker, Imène; Berredjem, Hajira; Aouf, Nour-Eddine

    2014-09-01

    A series of substituted sulfonamide derivatives were synthesized from chlorosulfonyl isocyanate (CSI) in tree steps (carbamoylation, sulfamoylation and deprotection). Antibacterial activity in vitro of some newly formed compounds investigated against clinical strains Gram-positive and Gram-negative: Escherichia coli and Staphylococcus aureus applying the method of dilution and minimal inhibition concentration (MIC) methods. These compounds have significant bacteriostatic activity with totalities of bacterial strains used. DFT calculations with B3LYP/6-31G(d) level have been used to analyze the electronic and geometric characteristics deduced for the stable structure of three compounds presenting conjugation between a nitrogen atom N through its lone pair and an aromatic ring next to it. The principal quantum chemical descriptors have been correlated with the antibacterial activity.

  7. Antibacterial and allelopathic activity of extract from Castanea sativa leaves.

    PubMed

    Basile, A; Sorbo, S; Giordano, S; Ricciardi, L; Ferrara, S; Montesano, D; Castaldo Cobianchi, R; Vuotto, M L; Ferrara, L

    2000-08-01

    Following the extraction of Castanea sativa with an aqueous solution of sulfuric acid (pH 3.0), the ethyl acetate soluble fraction was tested for its antibacterial and allelopathic activity. The extract was shown to have pronounced antibacterial effects against seven of the eight strains of Gram-positive and Gram-negative bacteria used (MIC in the range of 64-256 microg/ml and MBC in the range of 256-512 microg/ml). The active fraction was analyzed by TLC and HPLC showing the presence of rutin, hesperidin, quercetin, apigenin, morin, naringin, galangin and kaempferol. Standards of the identified flavonoids were tested against the same bacterial strains. The highest activity was shown by quercetin, rutin and apigenin. The allelopathic effect was tested against Raphanus sativus seed germination. The extract, quercetin, rutin and apigenin caused a decrease in the percentage of seed germination and root and epicotyl growth.

  8. Effect of surfactants on the antibacterial activity of preservatives.

    PubMed

    Kurup, T R; Wan, L S; Chan, L W

    1991-01-01

    Antibacterial activities of methyl-p-hydroxybenzoate, phenoxyethanol and chlorocresol against Pseudomonas aeruginosa were evaluated in the presence of varying concentrations of Tween 80. Below cmc level, the bactericidal activities increased with decrease in the surface tension values of Tween 80 solutions and with interfacial tension values of Tween 80 solution/liquid paraffin systems. Linear relationships were found to exist between the concentrations of each preservative required to reduce the microbial population by a factor 10(3) within 48 hours and the values of surface tension and interfacial tension respectively. Reduction in surface tension and interfacial tension would have increased the adsorption and uptake of preservatives by bacterial cells thereby killing the cells at a faster rate. Concentrations of Tween 80 above cmc also enhanced the antibacterial activities of these preservatives. This was attributed to the increase in the permeability of bacterial membranes to preservatives.

  9. In vitro antibacterial activity of different pulp capping materials

    PubMed Central

    Beltrami, Riccardo; Colombo, Marco; Ceci, Matteo; Dagna, Alberto; Chiesa, Marco

    2015-01-01

    Background Direct pulp capping involves the application of a dental material to seal communications between the exposed pulp and the oral cavity (mechanical and carious pulp exposures) in an attempt to act as a barrier, protect the dental pulp complex and preserve its vitality. The aim of this study was to evaluate and compare, by the agar disc diffusion test, the antimicrobial activity of six different pulp-capping materials: Dycal (Dentsply), Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), Biodentine (Septodont). Material and Methods Streptococcus salivarius, Streptococcus sanguis and Streptococcus mutans strains were selected to evaluate the antimicrobial activity by the agar disc diffusion test of different pulp capping materials. Paper disks were impregnated whit each pulp capping materials and placed onto culture agar-plates pre-adsorbed with bacterial cells and further incubated for 24 h at 37°C. The growth inhibition zones around each pulp capping materials were recorded and compared for each bacterial strain. Results For the investigation of the antibacterial properties the ANOVA showed the presence of significant differences among the various materials. Tukey test showed that MTA-based materials induced lower growth inhibition zones. Conclusions MTA-based products show a discrete antibacterial activity varying from calcium hydroxide-based materials which present an higher antibacterial activity. Key words:Agar disc diffusion test, antimicrobial activity, calcium hydroxide, MTA, pulp capping materials. PMID:26644833

  10. Antibacterial cannabinoids from Cannabis sativa: a structure-activity study.

    PubMed

    Appendino, Giovanni; Gibbons, Simon; Giana, Anna; Pagani, Alberto; Grassi, Gianpaolo; Stavri, Michael; Smith, Eileen; Rahman, M Mukhlesur

    2008-08-01

    Marijuana (Cannabis sativa) has long been known to contain antibacterial cannabinoids, whose potential to address antibiotic resistance has not yet been investigated. All five major cannabinoids (cannabidiol (1b), cannabichromene (2), cannabigerol (3b), Delta (9)-tetrahydrocannabinol (4b), and cannabinol (5)) showed potent activity against a variety of methicillin-resistant Staphylococcus aureus (MRSA) strains of current clinical relevance. Activity was remarkably tolerant to the nature of the prenyl moiety, to its relative position compared to the n-pentyl moiety (abnormal cannabinoids), and to carboxylation of the resorcinyl moiety (pre-cannabinoids). Conversely, methylation and acetylation of the phenolic hydroxyls, esterification of the carboxylic group of pre-cannabinoids, and introduction of a second prenyl moiety were all detrimental for antibacterial activity. Taken together, these observations suggest that the prenyl moiety of cannabinoids serves mainly as a modulator of lipid affinity for the olivetol core, a per se poorly active antibacterial pharmacophore, while their high potency definitely suggests a specific, but yet elusive, mechanism of activity.

  11. Antibacterial activity and inhibition of adherence of Streptococcus mutans by propolis electrospun fibers.

    PubMed

    Asawahame, Chawalinee; Sutjarittangtham, Krit; Eitssayeam, Sukum; Tragoolpua, Yingmanee; Sirithunyalug, Busaban; Sirithunyalug, Jakkapan

    2015-02-01

    Mouth-dissolving fibers with antibacterial activity for the oral cavity were prepared by an electrospinning technique. Propolis extract was used as an active ingredient and polyvinylpyrrolidone (PVP) K90 as the polymer matrix. The morphology and diameter of the fibers were characterized by scanning electron microscopy. Antibacterial activity against Streptococcus mutans and the inhibition of S. mutans adhesion on a smooth glass surface during the biofilm formation were tested. Propolis, 5% (w/v), was combined with a PVP K90 solution, 8% (w/v), with or without Tween 80 including flavor additives and electrospun with an applied voltage of 15 kV. Uniform and smooth fibers of propolis-PVP K90 were obtained. The results showed that electrospun fibers with propolis extract can dissolve and release the propolis in water. Propolis-PVP electrospun fibers showed better antibacterial activity by reduction of bacteria adhesion on a smooth glass surface when compared to some commercial mouthwash products. These results indicated the potential of electrospun fibers to be used as mouth-dissolving fibers for effective antibacterial activity in the oral cavity.

  12. Chicken cathelicidin-2-derived peptides with enhanced immunomodulatory and antibacterial activities against biological warfare agents.

    PubMed

    Molhoek, E Margo; van Dijk, Albert; Veldhuizen, Edwin J A; Dijk-Knijnenburg, Helma; Mars-Groenendijk, Roos H; Boele, Linda C L; Kaman-van Zanten, Wendy E; Haagsman, Henk P; Bikker, Floris J

    2010-09-01

    Host defence peptides (HDPs) are considered to be excellent candidates for the development of novel therapeutic agents. Recently, it was demonstrated that the peptide C1-15, an N-terminal segment of chicken HDP cathelicidin-2, exhibits potent antibacterial activity while lacking cytotoxicity towards eukaryotic cells. In the present study, we report that C1-15 is active against bacteria such as Bacillus anthracis and Yersinia pestis that may potentially be used by bioterrorists. Substitution of single and multiple phenylalanine (Phe) residues to tryptophan (Trp) in C1-15 resulted in variants with improved antibacterial activity against B. anthracis and Y. pestis as well as decreased salt sensitivity. In addition, these peptides exhibited enhanced neutralisation of lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines in human peripheral blood mononuclear cells (PBMCs). The antibacterial and LPS-neutralising activities of these C1-15-derived peptides are exerted at concentrations far below the concentrations that are toxic to human PBMCs. Taken together, we show that Phe-->Trp substitutions in C1-15 variants enhances the antibacterial and LPS-neutralising activities against pathogenic bacteria, including those that may potentially be used as biological warfare agents.

  13. Antibacterial Activity of a Cardanol from Thai Apis mellifera Propolis

    PubMed Central

    Boonsai, Pattaraporn; Phuwapraisirisan, Preecha; Chanchao, Chanpen

    2014-01-01

    Background: Propolis is a sticky, dark brown resinous residue made by bees that is derived from plant resins. It is used to construct and repair the nest, and in addition possesses several diverse bioactivities. Here, propolis from Apis mellifera from Nan province, Thailand, was tested for antibacterial activity against Gram+ve (Staphylococcus aureus and Paenibacillus larvae) and Gram-ve (Escherichia coli) bacteria. Materials and methods: The three bacterial isolates were confirmed for species designation by Gram staining and analysis of the partial sequence of 16S rDNA. Propolis was sequentially extracted by methanol, dichloromethane and hexane. The antibacterial activity was determined by agar well diffusion and microbroth dilution assays using streptomycin as a positive control. The most active crude extract was further purified by quick column and adsorption chromatography. The apparent purity of each bioactive fraction was tested by thin layer chromatography. The chemical structure of the isolated bioactive compound was analyzed by nuclear magnetic resonance (NMR). Results: Crude methanol extract of propolis showed the best antibacterial activity with a minimum inhibition concentration (MIC) value of 5 mg/mL for S. aureus and E. coli and 6.25 mg/mL for P. larvae. After quick column chromatography, only three active fractions were inhibitory to the growth of S. aureus and E. coli with MIC values of 6.25 and 31.3 µg/mL, respectively. Further adsorption chromatography yielded one pure bioactive fraction (A1A) with an IC50 value of 0.175 µg/mL for E. coli and 0.683 µg/mL for P. larvae, and was determined to be cardanol by NMR analysis. Scanning and transmission electron microscopy analysis revealed unusual shaped (especially in dividing cells), damaged and dead cells in cardanol-treated E. coli. Conclusion: Thai propolis contains a promising antibacterial agent. PMID:24578609

  14. A highly acid-resistant novel strain of Lactobacillus johnsonii No. 1088 has antibacterial activity, including that against Helicobacter pylori, and inhibits gastrin-mediated acid production in mice

    PubMed Central

    Aiba, Yuji; Nakano, Yasuhiro; Koga, Yasuhiro; Takahashi, Kenji; Komatsu, Yasuhiko

    2015-01-01

    A novel strain of Lactobacillus johnsonii No. 1088 was isolated from the gastric juice of a healthy Japanese male volunteer, and characterized for its effectiveness in the stomach environment. Lactobacillus johnsonii No. 1088 was found to have the strongest acid resistance among several lactobacilli examined (>10% of cells survived at pH 1.0 after 2 h), and such a high acid resistance property was a specific characteristic of this strain of L. johnsonii. When cultured with various virulent bacteria, L. johnsonii No. 1088 inhibited the growth of Helicobacter pylori,Escherichia coli O-157, Salmonella Typhimurium, and Clostridium difficile, in which case its effectiveness was more potent than that of a type strain of L. johnsonii,JCM2012. In addition to its effect in vitro, L. johnsonii No. 1088 inhibited the growth of H. pylori in human intestinal microbiota-associated mice in both its live and lyophilized forms. Moreover, L. johnsonii No. 1088 suppressed gastric acid secretion in mice via decreasing the number of gastrin-positive cells in the stomach. These results taken together suggest that L. johnsonii No. 1088 is a unique lactobacillus having properties beneficial for supporting H. pylori eradication by triple therapy including the use of a proton pump inhibitor (PPI) and also for prophylaxis of gastroesophageal reflux disease possibly caused after H. pylori eradication as a side effect of PPI. PMID:25771812

  15. A highly acid-resistant novel strain of Lactobacillus johnsonii No. 1088 has antibacterial activity, including that against Helicobacter pylori, and inhibits gastrin-mediated acid production in mice.

    PubMed

    Aiba, Yuji; Nakano, Yasuhiro; Koga, Yasuhiro; Takahashi, Kenji; Komatsu, Yasuhiko

    2015-06-01

    A novel strain of Lactobacillus johnsonii No. 1088 was isolated from the gastric juice of a healthy Japanese male volunteer, and characterized for its effectiveness in the stomach environment. Lactobacillus johnsonii No. 1088 was found to have the strongest acid resistance among several lactobacilli examined (>10% of cells survived at pH 1.0 after 2 h), and such a high acid resistance property was a specific characteristic of this strain of L. johnsonii. When cultured with various virulent bacteria, L. johnsonii No. 1088 inhibited the growth of Helicobacter pylori, Escherichia coli O-157, Salmonella Typhimurium, and Clostridium difficile, in which case its effectiveness was more potent than that of a type strain of L. johnsonii, JCM2012. In addition to its effect in vitro, L. johnsonii No. 1088 inhibited the growth of H. pylori in human intestinal microbiota-associated mice in both its live and lyophilized forms. Moreover, L. johnsonii No. 1088 suppressed gastric acid secretion in mice via decreasing the number of gastrin-positive cells in the stomach. These results taken together suggest that L. johnsonii No. 1088 is a unique lactobacillus having properties beneficial for supporting H. pylori eradication by triple therapy including the use of a proton pump inhibitor (PPI) and also for prophylaxis of gastroesophageal reflux disease possibly caused after H. pylori eradication as a side effect of PPI.

  16. Antibacterial activity of different natural honeys from Transylvania, Romania.

    PubMed

    Vica, Mihaela Laura; Glevitzky, Mirel; Dumitrel, Gabriela-Alina; Junie, Lia Monica; Popa, Maria

    2014-01-01

    Honey is used in food industry and medicine due to its nutritive, therapeutic and dietetic qualities. The microbiological characteristics of 10 unpasteurized honey samples of known origin, collected from Transylvania beekeepers (Romania) were determined. The antibacterial activity of these types of honey against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Salmonella enteritidis, Salmonella anatum, Salmonella choleraesuis, Bacillus cereus, Bacillus subtilis subsp. spizizenii and Listeria monocytogenes strains was studied. The most sensitive to the antibacterial activity were the two staphylococus strains (the largest diameter of inhibition zone was 18 mm) and B. subtilis strains (13.5 mm). The strains of B. cereus, E. coli, L. monocytogenes and Salmonella spp. were found to present resistance to some of the honey samples. Manna, sunflower and polyfloral honeys presented high antibacterial activity while acacia and linden honeys had a lower activity in terms of the number of sensible strains. Statistical analysis shows that the type of strains and the type of honey have influence on the diameter of inhibition. PMID:24380618

  17. Antibacterial activity of Citrus limonum fruit juice extract.

    PubMed

    Okeke, Malachy Ifeanyi; Okoli, Arinze Stanley; Eze, Edith Nneka; Ekwume, Grace Chinwe; Okosa, Evangelin Uchena; Iroegbu, Christian Ukwuoma

    2015-09-01

    The fruit juice extract of Citrus limonum was investigated for antibacterial activity. The antibacterial activity of the extract on ten strains of bacteria was determined by both agar well diffusion and macro-broth dilution methods. The extract was variously bacteriostatic and bactericidal against Bacillussubtilis ATCC 6051, Staphylococcus aureus ATCC 12600, Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC 10145 as well as locally isolated clinical strains of the above bacteria and Salmonella kintambo (Human: 13, 23: mt:-), Salmonella typhi and Proteus sp. The MICs ranged from 0.78 mg/ml to 50mg/ml; MBCs, 25.0mg/ml to >100mg/ml and MBC/MIC ratios 2.0 to >16.0. These results provide scientific justification for the medicinal use of Citrus limonum fruit juice by Nigerian herbalists in the treatment of diseases in which strains of the test organisms have been implicated as etiologic agents. PMID:26408878

  18. Synergistic effect of starch on the antibacterial activity of honey.

    PubMed

    Boukraâ, Laïd; Amara, Karim

    2008-03-01

    The role of amylase present in honey in enhancing its antibacterial activity was evaluated in the presence and absence of starch. Two strains of pathogenic bacteria have been used: Staphylococcus aureus and Escherichia coli. For S. aureus, the minimum inhibitory concentration (MIC) for the three varieties of honey tested without starch was 11%, 24%, and 29% (vol/vol), respectively. When starch was added with honey to the media the MIC obtained was 5%, 19%, and 25% (vol/vol), respectively. For E. coli, the MIC for the three varieties without starch was 23%, 28%, and 25% (vol/vol), respectively. When starch was added with honey to media, the MIC was 19%, 26%, and 23% (vol/vol), respectively. It is speculated that the amylase present in honey hydrolyzed the starch chains to randomly produce dextrin and maltose and that this increased the osmotic effect of the media, which consequently increased the antibacterial activity. PMID:18361758

  19. Antibacterial activity of Citrus limonum fruit juice extract.

    PubMed

    Okeke, Malachy Ifeanyi; Okoli, Arinze Stanley; Eze, Edith Nneka; Ekwume, Grace Chinwe; Okosa, Evangelin Uchena; Iroegbu, Christian Ukwuoma

    2015-09-01

    The fruit juice extract of Citrus limonum was investigated for antibacterial activity. The antibacterial activity of the extract on ten strains of bacteria was determined by both agar well diffusion and macro-broth dilution methods. The extract was variously bacteriostatic and bactericidal against Bacillussubtilis ATCC 6051, Staphylococcus aureus ATCC 12600, Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC 10145 as well as locally isolated clinical strains of the above bacteria and Salmonella kintambo (Human: 13, 23: mt:-), Salmonella typhi and Proteus sp. The MICs ranged from 0.78 mg/ml to 50mg/ml; MBCs, 25.0mg/ml to >100mg/ml and MBC/MIC ratios 2.0 to >16.0. These results provide scientific justification for the medicinal use of Citrus limonum fruit juice by Nigerian herbalists in the treatment of diseases in which strains of the test organisms have been implicated as etiologic agents.

  20. Gallic acid conjugated with gold nanoparticles: antibacterial activity and mechanism of action on foodborne pathogens

    PubMed Central

    Rattanata, Narintorn; Klaynongsruang, Sompong; Leelayuwat, Chanvit; Limpaiboon, Temduang; Lulitanond, Aroonlug; Boonsiri, Patcharee; Chio-Srichan, Sirinart; Soontaranon, Siriwat; Rugmai, Supagorn; Daduang, Jureerut

    2016-01-01

    Foodborne pathogens, including Plesiomonas shigelloides and Shigella flexneri B, are the major cause of diarrheal endemics worldwide. Antibiotic drug resistance is increasing. Therefore, bioactive compounds with antibacterial activity, such as gallic acid (GA), are needed. Gold nanoparticles (AuNPs) are used as drug delivery agents. This study aimed to conjugate and characterize AuNP–GA and to evaluate the antibacterial activity. AuNP was conjugated with GA, and the core–shell structures were characterized by small-angle X-ray scattering and transmission electron microscopy. Antibacterial activity of AuNP–GA against P. shigelloides and S. flexneri B was evaluated by well diffusion method. AuNP–GA bactericidal mechanism was elucidated by Fourier transform infrared microspectroscopic analysis. The results of small-angle X-ray scattering showed that AuNP–GA conjugation was successful. Antibacterial activity of GA against both bacteria was improved by conjugation with AuNP because the minimum inhibitory concentration value of AuNP–GA was significantly decreased (P<0.0001) compared to that of GA. Fourier transform infrared analysis revealed that AuNP–GA resulted in alterations of lipids, proteins, and nucleic acids at the bacterial cell membrane. Our findings show that AuNP–GA has potential for further application in biomedical sciences. PMID:27555764

  1. In Vitro Study to Evaluate Antibacterial and Non-haemolytic Activities of Four Iranian Medicinal Plants

    PubMed Central

    Sepahi, S; Ghorani-Azam, A; Sepahi, S; Asoodeh, A; Rostami, S

    2014-01-01

    Objective: Aqueous extracts of four medicinal plants including Ferula gummosa, Echinophora orientalis, Nasturtium microphyllum and Verbascum thapsus were used to determine their antibacterial activities and minimum inhibitory concentration (MIC). The aim of this study was to assess antibacterial activity of extracts of four medicinal plants against a Gram-positive and a Gram-negative bacteria (Staphylococcus aureus PTCC1431, and Escherichia coli HP101BA 7601c). Methods: Radial diffusion assay was used to assess the antibacterial activity of extracted samples. Haemolysis assay was also used to examine their nontoxic effects on human red blood cells. Results: This study showed that all the mentioned plants have satisfactory antibacterial effects against both Gram-positive and Gram-negative bacteria. Minimum inhibitory concentration values of these samples were less than 750 μg/mL. In addition, no significant haemolytic activity was observed at their MIC values. Conclusion: The results of this study showed that all these studied plants have good potential for further studies for drug discovery. PMID:25429470

  2. Gallic acid conjugated with gold nanoparticles: antibacterial activity and mechanism of action on foodborne pathogens.

    PubMed

    Rattanata, Narintorn; Klaynongsruang, Sompong; Leelayuwat, Chanvit; Limpaiboon, Temduang; Lulitanond, Aroonlug; Boonsiri, Patcharee; Chio-Srichan, Sirinart; Soontaranon, Siriwat; Rugmai, Supagorn; Daduang, Jureerut

    2016-01-01

    Foodborne pathogens, including Plesiomonas shigelloides and Shigella flexneri B, are the major cause of diarrheal endemics worldwide. Antibiotic drug resistance is increasing. Therefore, bioactive compounds with antibacterial activity, such as gallic acid (GA), are needed. Gold nanoparticles (AuNPs) are used as drug delivery agents. This study aimed to conjugate and characterize AuNP-GA and to evaluate the antibacterial activity. AuNP was conjugated with GA, and the core-shell structures were characterized by small-angle X-ray scattering and transmission electron microscopy. Antibacterial activity of AuNP-GA against P. shigelloides and S. flexneri B was evaluated by well diffusion method. AuNP-GA bactericidal mechanism was elucidated by Fourier transform infrared microspectroscopic analysis. The results of small-angle X-ray scattering showed that AuNP-GA conjugation was successful. Antibacterial activity of GA against both bacteria was improved by conjugation with AuNP because the minimum inhibitory concentration value of AuNP-GA was significantly decreased (P<0.0001) compared to that of GA. Fourier transform infrared analysis revealed that AuNP-GA resulted in alterations of lipids, proteins, and nucleic acids at the bacterial cell membrane. Our findings show that AuNP-GA has potential for further application in biomedical sciences. PMID:27555764

  3. Screening of solvent dependent antibacterial activity of Prunus domestica.

    PubMed

    Yaqeen, Zahra; Naqvi, Naim-ul-Hasan; Sohail, Tehmina; Rehman, Zakir-ur; Fatima, Nudrat; Imran, Hina; Rehman, Atiqur

    2013-03-01

    Fruit of Prunus domestica was extracted in ethanol. The ethanol extract was further extracted with two solvents ethyl acetate and chloroform. The crude ethanol extract and two fractions (ethyl acetate and chloroform) were screened for their antibacterial activity using the agar well diffusion method .They were tested against nine bacteria; five Gram positive bacteria (Staphylococcus aureus, Streptococcuc intermedius, Bacillus cereus, Bacillus pumilus) and four Gram negative bacteria (Eschrichia coli, Proteus mirabilis Shigella flexneri, Salmonella typhi and Klebsiela pneumoniae). The susceptibility of microorganisms to all three fractions was compared with each other and with standard antibiotic (Ampicillin) Among all fractions ethyl acetate exhibited highest antibacterial activity (average zone of inhibition 34.57mm ± 1.3) while ethyl alcohol exhibited least antibacterial activity (average zone of inhibition 17.42mm ± 3.3). Minimum inhibitory concentration of ethanol, ethyl acetate and chloroform fractions was found in the range of 78 μ g/ml to 2500 μ gl/ml against gram positive and gram negative bacteria.

  4. Antibacterial Activity of Copaiba Oil Gel on Dental Biofilm

    PubMed Central

    Simões, Cláudia A.C.G.; Conde, Nikeila C. de Oliveira; Venâncio, Gisely N.; Milério, Patrícia S.L.L.; Bandeira, Maria F.C.L.; da Veiga Júnior, Valdir F.

    2016-01-01

    Amazonian biodiversity products that have been used for years in folk medicine, have emerged as feasible and promising alternatives for the inhibition of microorganisms in dental biofilm. Copaiba oil, a phytotherapic agent widely used by the Amazonian populations, is known for its antibacterial, anti-inflammatory, anesthetic, healing and antitumor medicinal properties. Objective: The aim of this study was to evaluate the in vitro antibacterial activity of copaiba oil (Copaifera multijuga) gel against strains of Streptococcus sp present in dental biofilm. Materials and Methods: The copaiba oil was obtained and the chemical components were identified. The oil emulsions were formulated and used with the Brain Heart Infusion agar diffusion method with strains of Streptococcus mitis, Streptococcus constellatus and Streptococcus salivarius isolated from patients as well as standard strains of S. mitis (ATCC903), S. mutans (ATCC10449), S. sanguinis (ATCC15300) and S. oralis (ATCC10557). The study groups were as follows: experimental copaiba oil gel, 1% chlorhexidine gel (positive control) and base gel (negative control). The seeded plates were incubated at 37ºC for 12, 24 and 48 hours, respectively. The results obtained were analyzed by Shapiro-Wilk and Friedman Tests (p<0.05) for non parametric data and the Tukey test was used for pH values with 5% level of significance. Results: The experimental copaiba oil gel and 1% chlorhexidine gel showed antibacterial activity against the tested microorganisms. Conclusion: The copaiba oil gel demonstrated antibacterial activity against all the strains of Streptococcus sp tested, suggesting that it can be used for dental biofilm control. PMID:27386004

  5. Contact-active antibacterial aerogels from cellulose nanofibrils.

    PubMed

    Henschen, Jonatan; Illergård, Josefin; Larsson, Per A; Ek, Monica; Wågberg, Lars

    2016-10-01

    The use of cellulose aerogels as antibacterial materials has been investigated by applying a contact-active layer-by-layer modification to the aerogel surface. Studying the adsorption of multilayers of polyvinylamine (PVAm) and polyacrylic acid to aerogels comprising crosslinked cellulose nanofibrils and monitoring the subsequent bacterial adhesion revealed that up to 26mgPVAmgaerogel(-1) was adsorbed without noticeably affecting the aerogel structure. The antibacterial effect was tested by measuring the reduction of viable bacteria in solution when the aerogels were present. The results show that >99.9% of the bacteria adhered to the surface of the aerogels. Microscopy further showed adherence of bacteria to the surfaces of the modified aerogels. These results indicate that it is possible to create materials with three-dimensional cellulose structures that adsorb bacteria with very high efficiency utilizing the high specific surface area of the aerogels in combination with their open structure. PMID:27391038

  6. Contact-active antibacterial aerogels from cellulose nanofibrils.

    PubMed

    Henschen, Jonatan; Illergård, Josefin; Larsson, Per A; Ek, Monica; Wågberg, Lars

    2016-10-01

    The use of cellulose aerogels as antibacterial materials has been investigated by applying a contact-active layer-by-layer modification to the aerogel surface. Studying the adsorption of multilayers of polyvinylamine (PVAm) and polyacrylic acid to aerogels comprising crosslinked cellulose nanofibrils and monitoring the subsequent bacterial adhesion revealed that up to 26mgPVAmgaerogel(-1) was adsorbed without noticeably affecting the aerogel structure. The antibacterial effect was tested by measuring the reduction of viable bacteria in solution when the aerogels were present. The results show that >99.9% of the bacteria adhered to the surface of the aerogels. Microscopy further showed adherence of bacteria to the surfaces of the modified aerogels. These results indicate that it is possible to create materials with three-dimensional cellulose structures that adsorb bacteria with very high efficiency utilizing the high specific surface area of the aerogels in combination with their open structure.

  7. An adamantyl amino acid containing gramicidin S analogue with broad spectrum antibacterial activity and reduced hemolytic activity.

    PubMed

    Kapoerchan, Varsha V; Knijnenburg, Annemiek D; Niamat, Miquel; Spalburg, Emile; de Neeling, Albert J; Nibbering, Peter H; Mars-Groenendijk, Roos H; Noort, Daan; Otero, José M; Llamas-Saiz, Antonio L; van Raaij, Mark J; van der Marel, Gijs A; Overkleeft, Herman S; Overhand, Mark

    2010-10-25

    The cyclic cationic antimicrobial peptide gramicidin S (GS) is an effective topical antibacterial agent that is toxic for human red blood cells (hemolysis). Herein, we present a series of amphiphilic derivatives of GS with either two or four positive charges and characteristics ranging between very polar and very hydrophobic. Screening of this series of peptide derivatives identified a compound that combines effective antibacterial activity with virtually no toxicity within the same concentration range. This peptide acts against both Gram-negative and Gram-positive bacteria, including several MRSA strains, and represents an interesting lead for the development of a broadly applicable antibiotic.

  8. Antibacterial activity and toxicity of silver - nanosilver versus ionic silver

    NASA Astrophysics Data System (ADS)

    Kvitek, L.; Panacek, A.; Prucek, R.; Soukupova, J.; Vanickova, M.; Kolar, M.; Zboril, R.

    2011-07-01

    The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells - this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.

  9. Antibacterial activity of Thai herbal extracts on acne involved microorganism.

    PubMed

    Niyomkam, P; Kaewbumrung, S; Kaewnpparat, S; Panichayupakaranant, P

    2010-04-01

    Ethyl acetate and methanol extracts of 18 Thai medicinal plants were investigated for their antibacterial activity against Propionibacterium acnes, Stapylococcus aureus, and S. epidermidis. Thirteen plant extracts were capable of inhibiting the growth of P. acnes and S. epidermidis, while 14 plant extracts exhibited an inhibitory effect on S. aureus. Based on the broth dilution method, the ethyl acetate extract of Alpinia galanga (L.) Wild. (Zingiberaceae) rhizome showed the strongest antibacterial effect against P. acnes, with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 156.0 and 312.0 microg/mL, respectively. On the basis of bioassay-guided purification, the ethyl acetate extract was isolated to afford the antibacterial active compound, which was identified as 1'-acetoxychavicol acetate (1'-ACA). 1'-ACA had a strong inhibitory effect on P. acnes with MIC and MBC values of 62.0 and 250.0 microg/mL, respectively. Thus, 1'-ACA was used as an indicative marker for standardization of A. galanga extract using high performance liquid chromatography. These results suggest that A. galanga extract could be an interesting agent for further studies on an alternative treatment of acne.

  10. Antibacterial activity of papain and bromelain on Alicyclobacillus spp.

    PubMed

    dos Anjos, Márcia Maria; da Silva, Angela Aparecida; de Pascoli, Isabela Carolini; Mikcha, Jane Martha Graton; Machinski, Miguel; Peralta, Rosane Marina; de Abreu Filho, Benício Alves

    2016-01-01

    Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived frompapaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aimof this studywas to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98 μg/mL and the MBC was 3.91 μg/mL, while theMIC of bromelain was 62.5 μg/mL and the MBCwas 250 μg/mL. The concentration of 4 ×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24 h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, butmay be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both

  11. Antibacterial activity of papain and bromelain on Alicyclobacillus spp.

    PubMed

    dos Anjos, Márcia Maria; da Silva, Angela Aparecida; de Pascoli, Isabela Carolini; Mikcha, Jane Martha Graton; Machinski, Miguel; Peralta, Rosane Marina; de Abreu Filho, Benício Alves

    2016-01-01

    Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived frompapaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aimof this studywas to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98 μg/mL and the MBC was 3.91 μg/mL, while theMIC of bromelain was 62.5 μg/mL and the MBCwas 250 μg/mL. The concentration of 4 ×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24 h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, butmay be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both

  12. Antifungal and antibacterial activity of marine microorganisms.

    PubMed

    El Amraoui, B; El Amraoui, M; Cohen, N; Fassouane, A

    2014-03-01

    In order to explore marine microorganisms with pharmaceutical potential, marine bacteria, collected from different coastal areas of the Moroccan Atlantic Ocean, were previously isolated from seawater, sediment, marine invertebrates and seaweeds. The antimicrobial activities of these microorganisms were investigated against the pathogens involved in human pathologies. Whole cultures of 34 marine microorganisms were screened for antimicrobial activities using the method of agar diffusion against three Gram-positive bacteria, two Gram-negative bacteria, and against yeast. The results showed that among the 34 isolates studied, 28 (82%) strains have antimicrobial activity against at least one pathogen studied, 11 (32%) strains have antifungal activity and 24 (76%) strains are active against Gram-positive bacteria, while 21 (62%) strains are active against Gram-negative bacteria. Among isolates having antimicrobial activity, 14 were identified and were assigned to the genera Acinetobacter, Aeromonas, Alcaligenes, Bacillus, Chromobacterium, Enterococcus, Pantoea and Pseudomonas. Due to a competitive role for space and nutrient, the marine microorganisms can produce antibiotic substance; therefore, these marine microorganisms were expected to be potential resources of natural antibiotic products.

  13. Preparation, characterization, and antibacterial activity studies of silver-loaded poly(styrene-co-acrylic acid) nanocomposites.

    PubMed

    Song, Cunfeng; Chang, Ying; Cheng, Ling; Xu, Yiting; Chen, Xiaoling; Zhang, Long; Zhong, Lina; Dai, Lizong

    2014-03-01

    A simple method for preparing a new type of stable antibacterial agent was presented. Monodisperse poly(styrene-co-acrylic acid) (PSA) nanospheres, serving as matrices, were synthesized via soap-free emulsion polymerization. Field-emission scanning electron microscopy micrographs indicated that PSA nanospheres have interesting surface microstructures and well-controlled particle size distributions. Silver-loaded poly(styrene-co-acrylic acid) (PSA/Ag-NPs) nanocomposites were prepared in situ through interfacial reduction of silver nitrate with sodium borohydride, and further characterized by transmission electron microscopy and X-ray diffraction. Their effects on antibacterial activity including inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetics were evaluated. In the tests, PSA/Ag-NPs nanocomposites showed excellent antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. These nanocomposites are considered to have potential application in antibacterial coatings on biomedical devices to reduce nosocomial infection rates. PMID:24433897

  14. Mycosynthesis of silver nanoparticles bearing antibacterial activity.

    PubMed

    Azmath, Pasha; Baker, Syed; Rakshith, Devaraju; Satish, Sreedharamurthy

    2016-03-01

    Mycosynthesis of silver nanoparticles was achieved by endophytic Colletotrichum sp. ALF2-6 inhabiting Andrographis paniculata. Well dispersed nanoparticles were characterized using UV-Visible spectrometry with maximum absorption conferring at 420 nm. FTIR analysis revealed possible biomolecules reducing the metal salt and stabilization of nanoparticles. XRD analysis depicted the diffraction intensities exhibiting between 20 and 80 °C at 2theta angle thus conferring the crystalline nature of nanoparticles. Morphological characteristic using TEM revealed the polydispersity of nanoparticles with size ranging from 20 to 50 nm. Synthesized nanoparticles exhibited bactericidal activity against selected human pathogens. Nanoparticles mode of action was carried out to reveal DNA damage activity. Thus the present investigation reports facile fabrication of silver nanoparticles from endophytic fungi. PMID:27013906

  15. Synthesis and antibacterial activity of pyridinium-tailored aromatic amphiphiles.

    PubMed

    Wang, Peiyi; Gao, Manni; Zhou, Lei; Wu, Zhibing; Hu, Deyu; Hu, Jun; Yang, Song

    2016-02-15

    In this Letter, the antibacterial activities of pyridinium-tailored aromatic amphiphiles were evaluated by turbidimeter tests in vitro. The bioassays revealed that most of the target compounds exhibit appreciable inhibition activities against the plant pathogenic bacteria Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Xanthomonas axonopodis pv. citri. The half-maximal effective concentrations (EC50) of 2-NP-10, 9-AP-10, and 9-AP-7 against these three bacteria were relatively high, which may be ascribed to the favourable hydrophobicity/hydrophilicity balance in these compounds. Our results suggest that pyridinium-tailored aromatic amphiphiles are promising bactericide candidates against plant bacterial diseases. PMID:26832217

  16. Surfaces of Fluorinated Pyridinium Block Copolymers with Enhanced Antibacterial Activity

    SciTech Connect

    Krishnan,S.; Ward, R.; Hexemer, A.; Sohn, K.; Lee, K.; Angert, E.; Fischer, D.; Kramer, E.; Ober, C.

    2006-01-01

    Polystyrene-b-poly(4-vinylpyridine) copolymers were quaternized with 1-bromohexane and 6-perfluorooctyl-1-bromohexane. Surfaces prepared from these polymers were characterized by contact angle measurements, near-edge X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy. The fluorinated pyridinium surfaces showed enhanced antibacterial activity compared to their nonfluorinated counterparts. Even a polymer with a relatively low molecular weight pyridinium block showed high antimicrobial activity. The bactericidal effect was found to be related to the molecular composition and organization in the top 2-3 nm of the surface and increased with increasing hydrophilicity and pyridinium concentration of the surface.

  17. Synthesis and antibacterial activity of pyridinium-tailored aromatic amphiphiles.

    PubMed

    Wang, Peiyi; Gao, Manni; Zhou, Lei; Wu, Zhibing; Hu, Deyu; Hu, Jun; Yang, Song

    2016-02-15

    In this Letter, the antibacterial activities of pyridinium-tailored aromatic amphiphiles were evaluated by turbidimeter tests in vitro. The bioassays revealed that most of the target compounds exhibit appreciable inhibition activities against the plant pathogenic bacteria Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Xanthomonas axonopodis pv. citri. The half-maximal effective concentrations (EC50) of 2-NP-10, 9-AP-10, and 9-AP-7 against these three bacteria were relatively high, which may be ascribed to the favourable hydrophobicity/hydrophilicity balance in these compounds. Our results suggest that pyridinium-tailored aromatic amphiphiles are promising bactericide candidates against plant bacterial diseases.

  18. Antibacterial Activity of Barringtonia acutangula against Selected Urinary Tract Pathogens.

    PubMed

    Sahoo, S; Panda, P K; Mishra, S R; Parida, R K; Ellaiah, P; Dash, S K

    2008-09-01

    Barringtonia acutangula (L.) Gaertn belonging to family Barringtoniaceae was investigated to evaluate In vitro antibacterial activity of aqueous, ethanolic, petroleum ether and chloroform extracts against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis and Escherichia coli the major urinary tract infection causing pathogens were tested by disc diffusion assay method and the minimum inhibitory concentration was evaluated. Ethanol (95%) extract exhibited broader spectrum of inhibition followed by chloroform, petroleum ether and aqueous extracts against the urinary tract pathogens under test. An attempt has been made to compare the activity of extracts with standard antibiotics against selected urinary tract infection causing pathogens. PMID:21394275

  19. Antibacterial Activity of Barringtonia acutangula against Selected Urinary Tract Pathogens

    PubMed Central

    Sahoo, S.; Panda, P. K.; Mishra, S. R.; Parida, R. K.; Ellaiah, P.; Dash, S. K.

    2008-01-01

    Barringtonia acutangula (L.) Gaertn belonging to family Barringtoniaceae was investigated to evaluate In vitro antibacterial activity of aqueous, ethanolic, petroleum ether and chloroform extracts against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus faecalis and Escherichia coli the major urinary tract infection causing pathogens were tested by disc diffusion assay method and the minimum inhibitory concentration was evaluated. Ethanol (95%) extract exhibited broader spectrum of inhibition followed by chloroform, petroleum ether and aqueous extracts against the urinary tract pathogens under test. An attempt has been made to compare the activity of extracts with standard antibiotics against selected urinary tract infection causing pathogens. PMID:21394275

  20. The characterization of the antibacterial efficacy of an electrically activated silver ion-based surface system

    NASA Astrophysics Data System (ADS)

    Shirwaiker, Rohan A.

    There have been growing concerns in the global healthcare system about the eradication of pathogens in hospitals and other health-critical environments. The problem has been aggravated by the overuse of antibiotics and antimicrobial agents leading to the emergence of antibiotic-resistant superbugs such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) which are difficult to kill. Lower immunity of sick patients coupled with the escalating concurrent problem of antibiotic-resistant pathogens has resulted in increasing incidences of hospital acquired (nosocomial) infections. There is an immediate need to control the transmission of such infections, primarily in healthcare environments, by creating touch-contact and work surfaces (e.g., door knobs, push plates, countertops) that utilize alternative antibacterial materials like the heavy metal, silver. Recent research has shown that it is silver in its ionic (Ag+ ) and not elemental form that is antibacterial. Thus, silver-based antibacterial surfaces have to release silver ions directly into the pathogenic environment (generally, an aqueous media) in order to be effective. This dissertation presents the study and analysis of a new silver-based surface system that utilizes low intensity direct electric current (LIDC) for generation of silver ions to primarily inhibit indirect contact transmission of infections. The broader objective of this research is to understand the design, and characterization of the electrically activated silver ion-based antibacterial surface system. The specific objectives of this dissertation include: (1) Developing a comprehensive system design, and identifying and studying its critical design parameters and functional mechanisms. (2) Evaluating effects of the critical design parameters on the antibacterial efficacy of the proposed surface system. (3) Developing a response surface model for the surface system performance. These objectives are

  1. Antibacterial activities of persimmon extracts relate with their hydrogen peroxide concentration.

    PubMed

    Arakawa, Hidetoshi; Takasaki, Makiko; Tajima, Noriko; Fukamachi, Haruka; Igarashi, Takeshi

    2014-01-01

    Persimmon, a deciduous tree of the family Ebenaceae, is found throughout East Asia and contains high levels of tannins. This class of natural compounds exhibit favorable toxicity profiles along with bactericidal activity without the emergence of resistant bacteria, suggesting potential medical applications. Consistent with these observations, persimmon leaves show antibacterial activity. However, the mechanism of persimmon antibacterial activity remains unknown. In the present work, we demonstrate that the antibacterial activity of persimmon reflects the generation of reactive oxygen from tannins. The identification and quantification of reactive oxygen generated from persimmon and the level of antibacterial activity were determined.

  2. Antibacterial, Antifungal and antioxidant activities of some medicinal plants.

    PubMed

    Wazir, Asma; Mehjabeen, -; Jahan, Noor; Sherwani, Sikander Khan; Ahmad, Mansoor

    2014-11-01

    The purpose of this study was to evaluate the antibacterial, antifungal and antioxidant activities of medicinal plants. The antibacterial activity of methanolic extracts of three medicinal plants (Swertia chirata, Terminalia bellerica and Zanthoxylum armatum) were tested against Gentamicin (standard drug) on eleven gram positive and seventeen gram negative bacteria by agar well method. It was revealed that seven-gram negative and six gram positive bacterial species were inhibited by these plant extracts. Minimum inhibitory concentrations (MIC) of the extracts were determined by broth micro-dilution method. The significant MIC value of Swertia chirata was 20mg/ml against Serratia marcesens, Zanthoxylum armatum was 10 mg/ml against Aeromonas hydrophila and Terminali bellerica was 20mg/ml against Acinetobacter baumanii as well as Serratia marcesens. Antifungal screening was done for methanolic extracts of these plants by agar well method with the 6 saprophytic, 5 dermatophytic and 6 yeasts. In this case Griseofulvin was used as a standard. All saprophytes and dermatophytes were showed resistance by these plants extracts except Microsporum canis, which was inhibited by Z. armatum and S. chirata extracts. The significant MIC value of Zanthoxylum armatum was 10mg/ml against Microsporum canis and Swertia chirata was 10mg/ml against Candida tropicalis. The anti-oxidant study was performed by DPPH free radical scavenging assay using ascorbic acid as a reference standard. Significant antioxidant activities were observed by Swertia chirata and Zanthoxylum armatum at concentration 200μg/ml was 70% DPPH scavenging activity (EC50=937.5μg/ml) while Terminalia bellerica showed 55.6% DPPH scavenging activity (EC50=100μg/ml). This study has shown that these plants could provide potent antibacterial compounds and may possible preventive agents in ROS related ailments.

  3. Effect of various capping agents on photocatalytic, antibacterial and antibiofilm activities of ZnO nanoparticles.

    PubMed

    Akhil, K; Jayakumar, J; Gayathri, G; Khan, S Sudheer

    2016-07-01

    Zinc oxide nanoparticles (ZnO NPs) are extensively used in a wide variety of commercial products including sunscreens, textiles and paints It is a known fact that ZnO NPs are not stable when dispersed in water, therefore manufacturers use several surface modifying agents to increase the stability of ZnO NPs. In the present study, ZnO NPs were synthesized via chemical co-precipitation with and without the use of surface modifying agents including ethylene glycol (EG), gelatin, polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP). Preliminary characterization was done by UV-Visible spectroscopy. Electron microscopic analysis showed that the particles were hexagonal in shape. The hydrodynamic size distribution was analyzed by using dynamic light scattering method and crystalline nature was determined by X-ray diffraction method. The study evaluated the photocatalytic, antibacterial and antibiofilm activities of the particles with and without the addition of surface modifying agents. The capping of the particle was confirmed by FT-IR spectroscopy. The photocatalytic activity was checked against methylene blue. Capping of the particles reduced the photocatalytic activity of the particles. The antibacterial and antibiofilm activities were checked against Staphylococcus aureus (MTCC 3160) and Pseudomonas aeruginosa (MTCC 1688). Antibacterial activity was analyzed by simple plate count method both under dark as well as light condition. Antibiofilm activity was checked in both pre- and post-biofilm formation period under both dark as well as light condition. The activity was evaluated via crystal violet staining method. All the particles showed good antibacterial and antibiofilm activities. PMID:27088507

  4. Antibacterial activity of extracellular compounds produced by a Pseudomonas strain against methicillin-resistant Staphylococcus aureus (MRSA) strains

    PubMed Central

    2013-01-01

    Background The emergence of multidrug-resistant bacteria is a world health problem. Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) strains, is one of the most important human pathogens associated with hospital and community-acquired infections. The aim of this work was to evaluate the antibacterial activity of a Pseudomonas aeruginosa-derived compound against MRSA strains. Methods Thirty clinical MRSA strains were isolated, and three standard MRSA strains were evaluated. The extracellular compounds were purified by vacuum liquid chromatography. Evaluation of antibacterial activity was performed by agar diffusion technique, determination of the minimal inhibitory concentration, curve of growth and viability and scanning electron microscopy. Interaction of an extracellular compound with silver nanoparticle was studied to evaluate antibacterial effect. Results The F3 (ethyl acetate) and F3d (dichloromethane- ethyl acetate) fractions demonstrated antibacterial activity against the MRSA strains. Phenazine-1-carboxamide was identified and purified from the F3d fraction and demonstrated slight antibacterial activity against MRSA, and synergic effect when combined with silver nanoparticles produced by Fusarium oxysporum. Organohalogen compound was purified from this fraction showing high antibacterial effect. Using scanning electron microscopy, we show that the F3d fraction caused morphological changes to the cell wall of the MRSA strains. Conclusions These results suggest that P. aeruginosa-produced compounds such as phenazines have inhibitory effects against MRSA and may be a good alternative treatment to control infections caused by MRSA. PMID:23773484

  5. Antibacterial activity of ordered gold nanorod arrays.

    PubMed

    Zhu, Yuejing; Ramasamy, Mohankandhasamy; Yi, Dong Kee

    2014-09-10

    Well-packed two- and three-dimensional (2D and 3D) gold nanorod (AuNR) arrays were fabricated using confined convective arraying techniques. The array density could be controlled by changing the concentration of the gold nanorods solution, the velocity of the moving substrate, and the environment air-temperature. The hydrophilic behavior of glass substrates before and after surface modification was studied through contact angle measurements. The affinity and alignment of the AuNR arrays with varying nanorod concentrations and the resulting different array densities were studied using field emission scanning electron microscopy (FE-SEM). Under stable laser intensity irradiation, the photothermal response of the prepared arrays was measured using a thermocouple and the results were analyzed quantitatively. Synthesized AuNR arrays were added to Escherichia coli (E. coli) suspensions and evaluated for photothermal bactericidal activity before and after laser irradiation. The results showed promising bactericidal effect. The severity of pathogen destruction was measured and quantified using fluorescence microscopy, bioatomic force microscopy (Bio-AFM) and flow cytometry techniques. These results indicated that the fabricated AuNR arrays at higher concentrations were highly capable of complete bacterial destruction by photothermal effect compared to the low concentration AuNR arrays. Subsequent laser irradiation of the AuNR arrays resulted in rapid photoheating with remarkable bactericidal activity, which could be used for water treatment to produce microbe-free water. PMID:25148531

  6. Synthesis and antibacterial activity of nisin-containing block copolymers.

    PubMed

    Joshi, Pranav R; McGuire, Joseph; Neff, Jennifer A

    2009-10-01

    Nisin, an antibacterial peptide proven to be an effective inhibitor of Gram-positive bacteria, was incorporated into novel block copolymer constructs and tested for retained antibacterial activity. Covalent coupling was achieved by chemical modification of the N-terminal isoleucine to introduce a thiol group. Thiolated-nisin derivatives were then linked to poly[ethylene oxide]-poly[propylene oxide]-poly[ethylene oxide] (PEO-PPO-PEO) triblocks that had been end-activated such that terminal hydroxyl groups of the PEO chains were replaced with pyridyl disulfide moieties. The nisin-containing block copolymers were separated from free nisin by dialysis and showed antimicrobial activity against the Gram-positive indicator strain Pediococcus pentosaceus. The contribution to antimicrobial activity from nisin that was covalently linked was not distinguished from the contribution of nisin that had associated with the PEO-PPO-PEO triblocks through noncovalent interactions. However, nisin that was covalently linked showed activity upon reduction of the disulfide bond and release from the end-activated PEO. PMID:19358262

  7. Antibacterial Activities of Metabolites from Platanus occidentalis (American sycamore) against Fish Pathogenic Bacteria

    PubMed Central

    Schrader, Kevin K; Hamann, Mark T; McChesney, James D; Rodenburg, Douglas L; Ibrahim, Mohamed A

    2016-01-01

    One approach to the management of common fish diseases in aquaculture is the use of antibiotic-laden feed. However, there are public concerns about the use of antibiotics in agriculture and the potential development of antibiotic resistant bacteria. Therefore, the discovery of other environmentally safe natural compounds as alternatives to antibiotics would benefit the aquaculture industries. Four natural compounds, commonly called platanosides, [kaempferol 3-O-α-L-(2″,3″-di-E-p-coumaroyl)rhamnoside (1), kaempferol 3-O-α-L-(2″-E-p-coumaroyl-3″-Z-p-coumaroyl)rhamnoside (2), kaempferol 3-O-α-L-(2″-Z-p-coumaroyl-3″-E-p-coumaroyl)rhamnoside (3), and kaempferol 3-O-α-L-(2″,3″-di-Z-p-coumaroyl)rhamnoside (4)] isolated from the leaves of the American sycamore (Platanus occidentalis) tree were evaluated using a rapid bioassay for their antibacterial activities against common fish pathogenic bacteria including Flavobacterium columnare, Edwardsiella ictaluri, Aeromonas hydrophila, and Streptococcus iniae. The four isomers and a mixture of all four isomers were strongly antibacterial against isolates of F. columnare and S. iniae. Against F. columnare ALM-00-173, 3 and 4 showed the strongest antibacterial activities, with 24-h 50% inhibition concentration (IC50) values of 2.13 ± 0.11 and 2.62 ± 0.23 mg/L, respectively. Against S. iniae LA94-426, 4 had the strongest antibacterial activity, with 24-h IC50 of 1.87 ± 0.23 mg/L. Neither a mixture of the isomers nor any of the individual isomers were antibacterial against isolates of E. ictaluri and A. hydrophila at the test concentrations used in the study. Several of the isomers appear promising for the potential management of columnaris disease and streptococcosis in fish.

  8. Antibacterial and Anti-inflammatory Activities of Ppc-1, Active Principle of the Cellular Slime Mold Polysphondylium pseudo-candidum.

    PubMed

    Azelmat, Jabrane; Fiorito, Serena; Genovese, Salvatore; Epifano, Francesco; Grenier, Daniel

    2015-01-01

    The diisopentenyloxy quinolobactin derivative 3-methylbut-2-enyl-4-methoxy-8-[(3-methylbut-2-enyl)oxy] quinoline-2-carboxylate, also named as Ppc-1, has been initially isolated from the fruiting bodies of the cellular slime mold Polysphondylium pseudo-candidum. Given that few data are available in the literature concerning the biological properties of this compound, this study was undertaken to evaluate its antibacterial and anti-inflammatory properties. Ppc-1 exerted antibacterial activity on the Gram negative periodontopathogen Porphyromonas gingivalis, while it had no such effect on the other bacterial species tested. The antibacterial activity of Ppc-1 appeared to result from its ability to permeate the cell membrane. Using the U937-3xκB-LUC human monocytic cell line, Ppc-1 was found to dose-dependently inhibit the lipopolysaccharide-induced NF-κB activation, a signaling pathway that has been associated with inflammatory mediator secretion. In conclusion, Ppc-1, by exhibiting a dual mode of action including antibacterial and anti-inflammatory activities, may represent a promising targeted therapeutic agent for periodontal diseases.

  9. Antibacterial and Anti-inflammatory Activities of Ppc-1, Active Principle of the Cellular Slime Mold Polysphondylium pseudo-candidum.

    PubMed

    Azelmat, Jabrane; Fiorito, Serena; Genovese, Salvatore; Epifano, Francesco; Grenier, Daniel

    2015-01-01

    The diisopentenyloxy quinolobactin derivative 3-methylbut-2-enyl-4-methoxy-8-[(3-methylbut-2-enyl)oxy] quinoline-2-carboxylate, also named as Ppc-1, has been initially isolated from the fruiting bodies of the cellular slime mold Polysphondylium pseudo-candidum. Given that few data are available in the literature concerning the biological properties of this compound, this study was undertaken to evaluate its antibacterial and anti-inflammatory properties. Ppc-1 exerted antibacterial activity on the Gram negative periodontopathogen Porphyromonas gingivalis, while it had no such effect on the other bacterial species tested. The antibacterial activity of Ppc-1 appeared to result from its ability to permeate the cell membrane. Using the U937-3xκB-LUC human monocytic cell line, Ppc-1 was found to dose-dependently inhibit the lipopolysaccharide-induced NF-κB activation, a signaling pathway that has been associated with inflammatory mediator secretion. In conclusion, Ppc-1, by exhibiting a dual mode of action including antibacterial and anti-inflammatory activities, may represent a promising targeted therapeutic agent for periodontal diseases. PMID:25925558

  10. [Investigation of the antibacterial activity of faropenem against Streptococcus pneumoniae].

    PubMed

    Hanaki, H; Inaba, Y; Hiramatsu, K

    1999-09-01

    We evaluated the antibacterial activity of faropenem against penicillin-susceptible Streptococcus pneumoniae (PSSP) and penicillin-resistant S. pneumoniae (PRSP). It was shown that the minimum inhibitory concentrations against 90% of the clinically isolated strains (MIC90) of faropenem, penicillin G, cefaclor, cefcapene, and cefditoren against PSSP were 0.032, 0.063, 2, 0.25, and 0.125 micrograms/ml, respectively. While those against PRSP were 0.5, 2, > 128, 1, and 1 micrograms/ml, respectively. Furthermore, we evaluated the bactericidal activity, at the level of 1/4, 1, and 4 MIC, of faropenem and the above four reference antibacterial agents against PSSP and PRSP. Against PSSP No. 127, a sensitive strain to both penicillin G and cefcapene, faropenem showed almost the same bactericidal activity as those of reference agents. Against PSSP No. 108, a penicillin-susceptible and cephem-resistant strain, and PRSP No. 57, a resistant strain to both of penicillin and cephem, faropenem of 1 MIC showed bactericidal activity, but reference agents needed 4 MIC to show bactericidal activity. PMID:10746191

  11. Antibacterial Activity of Myristica fragrans against Oral Pathogens.

    PubMed

    Shafiei, Zaleha; Shuhairi, Nadia Najwa; Md Fazly Shah Yap, Nordiyana; Harry Sibungkil, Carrie-Anne; Latip, Jalifah

    2012-01-01

    Myristica fragrans Houtt is mostly cultivated for spices in Penang Island, Malaysia. The ethyl acetate and ethanol extracts of flesh, mace and seed of Myristica fragrans was evaluated the bactericidal potential against three Gram-positive cariogenic bacteria (Streptococcus mutans ATCC 25175, Streptococcus mitis ATCC 6249, and Streptococcus salivarius ATCC 13419) and three Gram-negative periodontopathic bacteria (Aggregatibacter actinomycetemcomitans ATCC 29522, Porphyromonas gingivalis ATCC 33277, and Fusobacterium nucleatum ATCC 25586). Antibacterial activities of the extracts was determined by twofold serial microdilution, with minimum inhibitory concentrations (MIC) ranging from 1.25 to 640 mg/mL and 0.075 to 40 mg/mL. The minimum bactericidal concentration (MBC) was obtained by subculturing method. Among all extracts tested, ethyl acetate extract of flesh has the highest significant inhibitory effects against Gram-positive and Gram-negative bacteria with mean MIC value ranging from 0.625 to 1.25 ± 0.00 (SD) mg/mL; P = 0.017) and highest bactericidal effects at mean MBC value ranging from 0.625 mg/mL to 20 ± 0.00 (SD) mg/mL. While for seed and mace of Myristica fragrans, their ethanol extracts exhibited good antibacterial activity against both groups of test pathogens compared to its ethyl acetate extracts. All of the extracts of Myristica fragrans did not show any antibacterial activities against Fusobacterium nucleatum ATCC 25586. Thus, our study showed the potential effect of ethyl acetate and ethanol extracts from flesh, seed and mace of Myristica fragrans to be new natural agent that can be incorporated in oral care products.

  12. Air surface microdischarge-photon synergy in antibacterial plasma-activated water

    NASA Astrophysics Data System (ADS)

    Graves, David; Pavlovich, Mathew; Chang, Hung-Wen; Sakiyama, Yuki; Clark, Douglas

    2013-09-01

    We show that the antibacterial effects of air plasma on water can be amplified by synergy with ultraviolet (UV) photons. We use the surface microdischarge configuration (SMD) in atmospheric air adjacent to bacteria-laden water coupled with UVA (360 nm) photons from a light emitting diode (LED) to demonstrate this synergy. Air SMD, especially if operated in a confined space, can operate in different modes: low power mode (<0.1 W/cm2) generates primarily O3 whereas higher powers generate mainly nitrogen oxides; we focus here on the latter. The nitrogen oxide mode creates a powerful antibacterial mixture in water, including NO2-, NO3- and H2O2. Although these species alone can be strongly antibacterial, especially at low pH, we show that addition of UVA photons greatly amplifies the antibacterial effect. We first measured log reductions with only photons and then only plasma. Only when UVA exposes water after plasma does the synergy appear. Synergy appears to be due to UVA photolysis of plasma-generated NO2- to form NO and OH. We conclude that combining plasma-generated chemical species with activating photons can amplify and strengthen plasma effectiveness in many biological and other applications. Supported by Department of Energy, Office of Fusion Science Plasma Science Center.

  13. Antibacterial activities of the methanol extracts of seven Cameroonian dietary plants against bacteria expressing MDR phenotypes.

    PubMed

    Seukep, Jackson A; Fankam, Aimé G; Djeussi, Doriane E; Voukeng, Igor K; Tankeo, Simplice B; Noumdem, Jaurès Ak; Kuete, Antoine Hln; Kuete, Victor

    2013-01-01

    The morbidity and mortality caused by bacterial infections significantly increased with resistance to commonly used antibiotics. This is partially due to the activation of efflux pumps in Gram-negative bacteria. The present work designed to assess the in vitro antibacterial activities of seven Cameroonian dietary plants (Sesamum indicum, Sesamum radiatum, Cinnamomum zeylanicum, Corchous olitorius, Cyperus esculentus, Adansonia digitata, Aframomum kayserianum), against multidrug resistant (MDR) Gram-negative bacteria over expressing active efflux pumps. The standard phytochemical methods were used to detect the main classes of secondary metabolites in the extracts. The antibacterial activities of the studied extracts in the absence or presence of an efflux pump inhibitor (PAβN) were evaluated using liquid microbroth dilution method. The results obtained indicated that apart from the extract of C. esculentus, all other samples contained alkaloids, phenols and polyphenols meanwhile other classes of chemicals were selectively present. The studied extracts displayed antibacterial activities with minimal inhibitory concentrations (MICs) values ranged from 64 to 1024 μg/mL on the majority of the 27 tested microbial strains. The extract of S. indicum was active against 77.77% of the tested microorganisms whilst the lowest MIC value (64 μg/mL) was recorded with that of A. kayserianum against E. aerogenes EA294. The results of the present work provide baseline information on the possible used of the tested Cameroonian dietary plants in the treatment of bacterial infections including multi-drug resistant phenotypes. PMID:23961425

  14. In Vitro antibacterial and in Vivo cytotoxic activities of Grewia paniculata

    PubMed Central

    Nasrin, Mahmuda; Dash, Pritesh Ranjan; Ali, Mohammad Shawkat

    2015-01-01

    Objectives: Grewia paniculata (Family: Malvaceae) has been used to treat inflammation, respiratory disorders and fever. It is additionally employed for other health conditions including colds, diarrhea and as an insecticide in Bangladesh. The aim of the present study was to investigate the antibacterial and cytotoxic activities of different extracts of Grewia paniculata. Materials and Methods: The antibacterial activity was evaluated against both gram negative and gram positive bacteria using disc diffusion method by determination of the diameter of zone of inhibition. Cytotoxic activity was performed by brine shrimp (Artemia salina) lethality bioassay. Results: In disc diffusion method, all the natural products (400 μg/disc) showed moderate to potent activity against all the tested bacteria. The ethanol extract of bark (EEB) and ethanol fraction of bark (EFB) (400 μg/disc) exhibited highest activity against Shigella dysenteriae with a zone of inhibition of 23±1.63 mm and 23±1.77 mm respectively. In the brine shrimp lethality bioassay all the extracts showed moderate cytotoxic activity when compared with the standard drug vincristin sulphate. For example, LC50 value of the ethanol fraction of bark (EFB) was 3.01 μg/ml while the LC50 of vincristine sulphate was 0.52 μg/ml. Conclusions: The results suggest that all the natural products possess potent antibacterial and moderate cytotoxic. PMID:25949950

  15. Cinobufagin Modulates Human Innate Immune Responses and Triggers Antibacterial Activity

    PubMed Central

    Xie, Shanshan; Spelmink, Laura; Codemo, Mario; Subramanian, Karthik; Pütsep, Katrin

    2016-01-01

    The traditional Chinese medicine Chan-Su is widely used for treatment of cancer and cardiovascular diseases, but also as a remedy for infections such as furunculosis, tonsillitis and acute pharyngitis. The clinical use of Chan-Su suggests that it has anti-infective effects, however, the mechanism of action is incompletely understood. In particular, the effect on the human immune system is poorly defined. Here, we describe previously unrecognized immunomodulatory activities of cinobufagin (CBG), a major bioactive component of Chan-Su. Using human monocyte-derived dendritic cells (DCs), we show that LPS-induced maturation and production of a number of cytokines was potently inhibited by CBG, which also had a pro-apoptotic effect, associated with activation of caspase-3. Interestingly, CBG triggered caspase-1 activation and significantly enhanced IL-1β production in LPS-stimulated cells. Finally, we demonstrate that CBG upregulates gene expression of the antimicrobial peptides (AMPs) hBD-2 and hBD-3 in DCs, and induces secretion of HNP1-3 and hCAP-18/LL-37 from neutrophils, potentiating neutrophil antibacterial activity. Taken together, our data indicate that CBG modulates the inflammatory phenotype of DCs in response to LPS, and triggers an antibacterial innate immune response, thus proposing possible mechanisms for the clinical effects of Chan-Su in anti-infective therapy. PMID:27529866

  16. A biotemplated nickel nanostructure: Synthesis, characterization and antibacterial activity

    SciTech Connect

    Ashtari, Khadijeh; Fasihi, Javad; Mollania, Nasrin; Khajeh, Khosro

    2014-02-01

    Highlights: • Nickel nanostructure-encapsulated bacteria were prepared using electroless deposition. • Bacterium surface was activated by red-ox reaction of its surface amino acids. • Interfacial changes at cell surfaces were investigated using fluorescence spectroscopy. • TEM and AFM depicted morphological changes. • Antibacterial activity of nanostructure was examined against different bacteria strains. - Abstract: Nickel nanostructure-encapsulated bacteria were prepared using the electroless deposition procedure and activation of bacterium cell surface by red-ox reaction of surface amino acids. The electroless deposition step occurred in the presence of Ni(II) and dimethyl amine boran (DMAB). Interfacial changes at bacteria cell surfaces during the coating process were investigated using fluorescence spectroscopy. Fluorescence of tryptophan residues was completely quenched after the deposition of nickel onto bacteria surfaces. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) depicted morphological changes on the surface of the bacterium. It was found that the Ni coated nanostructure was mechanically stable after ultrasonication for 20 min. Significant increase in surface roughness of bacteria was also observed after deposition of Ni clusters. The amount of coated Ni on the bacteria surface was calculated as 36% w/w. The antibacterial activity of fabricated nanostructure in culture media was examined against three different bacteria strains; Escherichia coli, Bacillus subtilis and Xantomonas campestris. The minimum inhibitory concentrations (MIC) were determined as 500 mg/L, 350 mg/L and 200 mg/L against bacteria, respectively.

  17. Cinobufagin Modulates Human Innate Immune Responses and Triggers Antibacterial Activity.

    PubMed

    Xie, Shanshan; Spelmink, Laura; Codemo, Mario; Subramanian, Karthik; Pütsep, Katrin; Henriques-Normark, Birgitta; Olliver, Marie

    2016-01-01

    The traditional Chinese medicine Chan-Su is widely used for treatment of cancer and cardiovascular diseases, but also as a remedy for infections such as furunculosis, tonsillitis and acute pharyngitis. The clinical use of Chan-Su suggests that it has anti-infective effects, however, the mechanism of action is incompletely understood. In particular, the effect on the human immune system is poorly defined. Here, we describe previously unrecognized immunomodulatory activities of cinobufagin (CBG), a major bioactive component of Chan-Su. Using human monocyte-derived dendritic cells (DCs), we show that LPS-induced maturation and production of a number of cytokines was potently inhibited by CBG, which also had a pro-apoptotic effect, associated with activation of caspase-3. Interestingly, CBG triggered caspase-1 activation and significantly enhanced IL-1β production in LPS-stimulated cells. Finally, we demonstrate that CBG upregulates gene expression of the antimicrobial peptides (AMPs) hBD-2 and hBD-3 in DCs, and induces secretion of HNP1-3 and hCAP-18/LL-37 from neutrophils, potentiating neutrophil antibacterial activity. Taken together, our data indicate that CBG modulates the inflammatory phenotype of DCs in response to LPS, and triggers an antibacterial innate immune response, thus proposing possible mechanisms for the clinical effects of Chan-Su in anti-infective therapy. PMID:27529866

  18. Composition and antibacterial activity of Abies balsamea essential oil.

    PubMed

    Pichette, André; Larouche, Pierre-Luc; Lebrun, Maxime; Legault, Jean

    2006-05-01

    The antibacterial activity of the essential oil of Abies balsamea (balsam fir) was evaluated against Escherichia coli and Staphylococcus aureus. The essential oil of A. balsamea was found to be inactive against E. coli (>100 microg/mL) and active against S. aureus, with an MIC of 56 microg/mL. The oil composition was analysed by GC-MS and the antibacterial activity of each oil constituent was determined. The essential oil of A. balsamea is essentially constituted of monoterpenes (>96%) and some sesquiterpenes. beta-pinene (29.9%), delta-3-carene (19.6%) and alpha-pinene (14.6%) were the major components. beta-pinene and delta-3-carene were found inactive against both bacteria strains. However, three constituents of the essential oil were active against S. aureus: alpha-pinene, beta-caryophyllene (0.4%) and alpha-humulene (0.2%) with MIC values of 13.6 microg/mL, 5.1 microg/mL and 2.6 microg/mL, respectively. PMID:16619365

  19. Antibacterial activity of Pseudoalteromonas in the coral holobiont.

    PubMed

    Shnit-Orland, Maya; Sivan, Alex; Kushmaro, Ariel

    2012-11-01

    Corals harbor diverse and abundant prokaryotic populations. Bacterial communities residing in the coral mucus layer may be either pathogenic or symbiotic. Some species may produce antibiotics as a method of controlling populations of competing microbial species. The present study characterizes cultivable Pseudoalteromonas sp. isolated from the mucus layer of different coral species from the northern Gulf of Eilat, Red Sea, Israel. Six mucus-associated Pseudoalteromonas spp. obtained from different coral species were screened for antibacterial activity against 23 tester strains. Five of the six Pseudoalteromonas strains demonstrated extracellular antibacterial activity against Gram-positive-but not Gram-negative-tester strains. Active substances secreted into the cell-free supernatant are heat-tolerant and inhibit growth of Bacillus cereus, Staphylococcus aureus, and of ten endogenous Gram-positive marine bacteria isolated from corals. The Pseudoalteromonas spp. isolated from Red sea corals aligned in a phylogenetic tree with previously isolated Pseudoalteromonas spp. of marine origin that demonstrated antimicrobial activity. These results suggest that coral mucus-associated Pseudoalteromonas may play a protective role in the coral holobiont's defense against potential Gram-positive coral pathogens. PMID:22767125

  20. Antibacterial activity of silver-killed bacteria: the "zombies" effect

    NASA Astrophysics Data System (ADS)

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  1. Antibacterial activity of silver-killed bacteria: the "zombies" effect.

    PubMed

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-04-23

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism.

  2. Interconverting flavonostilbenes with antibacterial activity from Sophora alopecuroides.

    PubMed

    Wan, Chuan-Xing; Luo, Jian-Guang; Ren, Xiao-Pu; Kong, Ling-Yi

    2015-08-01

    Five flavonostilbenes (alopecurones H, I, J, K and L) and five known ones were isolated from roots of Sophora alopecuroides, in addition to ten other phenolic compounds. A non-enzymatic interconversion of the lavandulyl-substituted flavonostilbenes was observed among alopecurones A, H, I, and K through a Wessely-Moser rearrangement reaction; this was proven by 1D and 2D NMR, HPLC-CD-PDA and HRMS analyses. Bioassay results suggested that flavonostilbenes exhibit significant antibacterial and anti-biofilm formation activities against Staphylococcus epidermidis with MIC values ranging from 3.1 to 12.5μg/mL. PMID:25813880

  3. Interconverting flavonostilbenes with antibacterial activity from Sophora alopecuroides.

    PubMed

    Wan, Chuan-Xing; Luo, Jian-Guang; Ren, Xiao-Pu; Kong, Ling-Yi

    2015-08-01

    Five flavonostilbenes (alopecurones H, I, J, K and L) and five known ones were isolated from roots of Sophora alopecuroides, in addition to ten other phenolic compounds. A non-enzymatic interconversion of the lavandulyl-substituted flavonostilbenes was observed among alopecurones A, H, I, and K through a Wessely-Moser rearrangement reaction; this was proven by 1D and 2D NMR, HPLC-CD-PDA and HRMS analyses. Bioassay results suggested that flavonostilbenes exhibit significant antibacterial and anti-biofilm formation activities against Staphylococcus epidermidis with MIC values ranging from 3.1 to 12.5μg/mL.

  4. Antibacterial activity of THAM Trisphenylguanide against methicillin-resistant Staphylococcus aureus.

    PubMed

    Weaver, Alan J; Shepard, Joyce B; Wilkinson, Royce A; Watkins, Robert L; Walton, Sarah K; Radke, Amanda R; Wright, Thomas J; Awel, Milat B; Cooper, Catherine; Erikson, Elizabeth; Labib, Mohamed E; Voyich, Jovanka M; Teintze, Martin

    2014-01-01

    This study investigated the potential antibacterial activity of three series of compounds synthesized from 12 linear and branched polyamines with 2-8 amino groups, which were substituted to produce the corresponding guanides, biguanides, or phenylguanides, against Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Antibacterial activity was measured for each compound by determining the minimum inhibitory concentration against the bacteria, and the toxicity towards mammalian cells was determined. The most effective compound, THAM trisphenylguanide, was studied in time-to-kill and cytoplasmic leakage assays against methicillin-resistant Staphylococcus aureus (MRSA, USA300) in comparison to chlorhexidine. Preliminary toxicity and MRSA challenge studies in mice were also conducted on this compound. THAM trisphenylguanide showed significant antibacterial activity (MIC ∼1 mg/L) and selectivity against MRSA relative to all the other bacteria examined. In time-to-kill assays it showed increased antimicrobial activity against MRSA versus chlorhexidine. It induced leakage of cytoplasmic content at concentrations that did not reduce cell viability, suggesting the mechanism of action may involve membrane disruption. Using an intraperitoneal mouse model of invasive MRSA disease, THAM trisphenylguanide reduced bacterial burden locally and in deeper tissues. This study has identified a novel guanide compound with selective microbicidal activity against Staphylococcus aureus, including a methicillin-resistant (MRSA) strain.

  5. Rational Design of Berberine-Based FtsZ Inhibitors with Broad-Spectrum Antibacterial Activity

    PubMed Central

    Sun, Ning; Chan, Fung-Yi; Lu, Yu-Jing; Neves, Marco A. C.; Lui, Hok-Kiu; Wang, Yong; Chow, Ka-Yan; Chan, Kin-Fai; Yan, Siu-Cheong; Leung, Yun-Chung; Abagyan, Ruben; Chan, Tak-Hang; Wong, Kwok-Yin

    2014-01-01

    Inhibition of the functional activity of Filamenting temperature-sensitive mutant Z (FtsZ) protein, an essential and highly conserved bacterial cytokinesis protein, is a promising approach for the development of a new class of antibacterial agents. Berberine, a benzylisoquinoline alkaloid widely used in traditional Chinese and native American medicines for its antimicrobial properties, has been recently reported to inhibit FtsZ. Using a combination of in silico structure-based design and in vitro biological assays, 9-phenoxyalkyl berberine derivatives were identified as potent FtsZ inhibitors. Compared to the parent compound berberine, the derivatives showed a significant enhancement of antibacterial activity against clinically relevant bacteria, and an improved potency against the GTPase activity and polymerization of FtsZ. The most potent compound 2 strongly inhibited the proliferation of Gram-positive bacteria, including methicillin-resistant S. aureus and vancomycin-resistant E. faecium, with MIC values between 2 and 4 µg/mL, and was active against the Gram-negative E. coli and K. pneumoniae, with MIC values of 32 and 64 µg/mL respectively. The compound perturbed the formation of cytokinetic Z-ring in E. coli. Also, the compound interfered with in vitro polymerization of S. aureus FtsZ. Taken together, the chemical modification of berberine with 9-phenoxyalkyl substituent groups greatly improved the antibacterial activity via targeting FtsZ. PMID:24824618

  6. Effect of an Antibacterial Monomer on the Antibacterial Activity of a Pit-and-Fissure Sealant

    PubMed Central

    Dong, Yan; Zhang, Ling; Sun, Xiang; Liu, Zhengya; Guo, Huihui; Huang, Li; Chen, Jihua

    2016-01-01

    Resin-based pit-and-fissure sealants are often used to form a barrier on the occlusal surface of molars to treat caries lesions; however, bacteria can remain in the pit and fissures without detection, increasing the risk of secondary caries. Sealants with antimicrobial properties or microbial repellent actions might be advantageous. The aim of this study was to assess the inhibitory effect of a 2-methacryloxylethyl dodecyl methyl ammonium bromide (MAE-DB)-incorporated sealant against Streptococcus mutans. MAE-DB (4% wt) was incorporated into a commercially available sealant, Eco-S resin-based pit-and-fissure sealant (Vericom Co., Ltd., Korea); a sealant without MAE-DB served as a negative control, and Clinpro™ Sealant (3M™ ESPE™), a fluoride-releasing resin, was used as a commercial control. The effects of the cured sealants and their eluents on the growth of S. mutans were determined according to colony-forming unit counts and metabolic tests. The effects of the cured sealants on the adherence and membrane integrity of S. mutans were investigated using confocal laser-scanning microscopy (CLSM) in conjunction with fluorescent indicators. Compared with the negative control and commercial control, the cured MAE-DB-incorporated pit-and-fissure sealant exhibited a significant inhibitory effect on the growth of S. mutans (P < 0.05), whereas the eluents did not show any detectable antibacterial activity. The commercial control also showed no detectable bactericidal activity. Moreover, the aged experimental material retained its property of contact inhibition of biofilm formation. The fluorescence analysis of CLSM images demonstrated that the cured MAE-DB-incorporated sealant could hamper the adherence of S. mutans and exert a detrimental effect on bacterial membrane integrity. The incorporation of MAE-DB can render a pit-and-fissure sealant with contact antibacterial activity after polymerization via influencing the growth, adherence, and membrane integrity of S

  7. Evaluation of antibacterial and anti-biofilm activities of cinchona alkaloid derivatives against Staphylococcus aureus.

    PubMed

    Skogman, Malena E; Kujala, Janni; Busygin, Igor; Leinob, Reko; Vuorela, Pia M; Fallarero, Adyary

    2012-09-01

    Bacterial biofilms are resistant to most of the commonly available antibacterial chemotherapies. Thus, an enormous need exists to meet the demands of effective anti-biofilm therapy. In this study, a small library of cinchona alkaloids, including the naturally occurring compounds cinchonidine and cinchonine, as well as various synthetic derivatives and analogues was screened for antibacterial and anti-biofilm activity against the Staphylococcus aureus biofilm producing strain ATCC 25923. Two methods were used to evaluate activity against biofilms, namely crystal violet staining to measure biomass and resazurin assay to measure biofilms viability. Cinchonidine was found to be inactive, whereas a synthetic derivative, 11-triphenylsilyl-10,11-dihydrocinchonidine (11-TPSCD), was effective against planktonic bacteria as well as in preventing biofilm formation at low micromolar concentrations. Higher concentrations were required to eradicate mature biofilms.

  8. Synthesis and Antibacterial Activity of Quaternary Ammonium 4-Deoxypyridoxine Derivatives

    PubMed Central

    Shtyrlin, Nikita V.; Sapozhnikov, Sergey V.; Galiullina, Albina S.; Kayumov, Airat R.; Bondar, Oksana V.; Mirchink, Elena P.; Isakova, Elena B.; Firsov, Alexander A.; Balakin, Konstantin V.

    2016-01-01

    A series of novel quaternary ammonium 4-deoxypyridoxine derivatives was synthesized. Two compounds demonstrated excellent activity against a panel of Gram-positive methicillin-resistant S. aureus strains with MICs in the range of 0.5–2 μg/mL, exceeding the activity of miramistin. At the same time, both compounds were inactive against the Gram-negative E. coli and P. aeruginosa strains. Cytotoxicity studies on human skin fibroblasts and embryonic kidney cells demonstrated that the active compounds possessed similar toxicity with benzalkonium chloride but were slightly more toxic than miramistin. SOS-chromotest in S. typhimurium showed the lack of DNA-damage activity of both compounds; meanwhile, one compound showed some mutagenic potential in the Ames test. The obtained results make the described chemotype a promising starting point for the development of new antibacterial therapies. PMID:27800491

  9. Antibacterial activity and mechanism of action of auranofin against multi-drug resistant bacterial pathogens

    PubMed Central

    Thangamani, Shankar; Mohammad, Haroon; Abushahba, Mostafa F. N.; Sobreira, Tiago J. P.; Hedrick, Victoria E.; Paul, Lake N.; Seleem, Mohamed N.

    2016-01-01

    Traditional methods employed to discover new antibiotics are both a time-consuming and financially-taxing venture. This has led researchers to mine existing libraries of clinical molecules in order to repurpose old drugs for new applications (as antimicrobials). Such an effort led to the discovery of auranofin, a drug initially approved as an anti-rheumatic agent, which also possesses potent antibacterial activity in a clinically achievable range. The present study demonstrates auranofin’s antibacterial activity is a complex process that involves inhibition of multiple biosynthetic pathways including cell wall, DNA, and bacterial protein synthesis. We also confirmed that the lack of activity of auranofin observed against Gram-negative bacteria is due to the permeability barrier conferred by the outer membrane. Auranofin’s ability to suppress bacterial protein synthesis leads to significant reduction in the production of key methicillin-resistant Staphylococcus aureus (MRSA) toxins. Additionally, auranofin is capable of eradicating intracellular MRSA present inside infected macrophage cells. Furthermore, auranofin is efficacious in a mouse model of MRSA systemic infection and significantly reduces the bacterial load in murine organs including the spleen and liver. Collectively, this study provides valuable evidence that auranofin has significant promise to be repurposed as a novel antibacterial for treatment of invasive bacterial infections. PMID:26936660

  10. Apolipophorin III from honeybees (Apis cerana) exhibits antibacterial activity.

    PubMed

    Kim, Bo Yeon; Jin, Byung Rae

    2015-04-01

    Apolipophorin III (apoLp-III) is involved in lipid transport and innate immunity in insects. In this study, an apoLp-III protein that exhibits antibacterial activity was identified in honeybees (Apis cerana). A. cerana apoLp-III cDNA encodes a 193 amino acid sequence that shares high identity with other members of the hymenopteran insect apoLp-III family. A. cerana apoLp-III is expressed constitutively in the fat body, epidermis, and venom gland and is detected as a 23-kDa protein. A. cerana apoLp-III expression is induced in the fat body after injection with Escherichia coli, Bacillus thuringiensis, or Beauveria bassiana. However, recombinant A. cerana apoLp-III (expressed in baculovirus-infected insect cells) binds directly to E. coli and B. thuringiensis but not to B. bassiana. Consistent with these findings, A. cerana apoLp-III exhibited antibacterial activity against both Gram-negative and Gram-positive bacteria. These results provide insight into the role of A. cerana apoLp-III during the innate immune response following bacterial infection.

  11. Study of the antibacterial activity of ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Surti, Arjuman; Radha, S.; Garje, S. S.

    2013-02-01

    This study focuses on the antibacterial activity of the ZnO nanoparticles against organisms causing skin and wound infections. The nanoparticles were synthesized by a wet chemical route. The method was quick and nanoparticles were obtained in 3 days of incubation in dark. Characterization of the nanoparticles was done by X-Ray Diffraction and UV-Visible Spectrophotometry. It was observed that the UV-Visible spectrum peak was obtained at 357 nm corresponding to the Plasmon absorbance of Zinc oxide. X-Ray diffraction exhibited the 2θ values corresponding to Zinc oxide and the particle size was estimated to be 20 nm. The antibacterial effect of nanoparticles was observed against Staphylococcus spp and Bacillus spp. The significance of the bactericidal activity of the nanoparticles lies in the reduction of using antibiotics against nosocomial infections, especially in prolonged treatments. The bandage material used in wound dressing was coated with ZnO nanoparticles by adsorption method. The textile was found to be efficient in inhibiting the growth of these organisms. The effect of adverse storage conditions on the coated bandage material was also studied. On comparing the results obtained at extreme pH and temperature and those obtained at optimum conditions, it was seen that the nanoparticles were less effective at these extreme conditions.

  12. Antibacterial activity of xanthones from Garcinia mangostana (L.) and their structure-activity relationship studies.

    PubMed

    Dharmaratne, H R W; Sakagami, Yoshikazu; Piyasena, K G P; Thevanesam, Vasanthi

    2013-01-01

    Antibacterial activities of prenylated xanthones from Garcinia mangostana and their synthetic analogues were investigated, and their structure-activity relationships have been studied. γ-Mangostin has shown antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-sensitive Enterococcus (VSE) strains at MICs 3.13, 6.25, 6.25 and 6.25 µg mL(-1), respectively. In these experiments, gentamicin was used as the positive control. Further, some analogues of γ-mangostin and α-mangostin were synthesised and their activity was tested against MRSA and VRE strains. The analysis of the bioassay results above indicated that, the combination of C-6 and C-3 hydroxyl groups along with the prenyl side chain at C-2 in the 1,3,6,7-tetraoxygenated xanthones from G. mangostana is essential to have a high antibacterial activity.

  13. The construction of hierarchical structure on Ti substrate with superior osteogenic activity and intrinsic antibacterial capability

    PubMed Central

    Huang, Ying; Zha, Guangyu; Luo, Qiaojie; Zhang, Jianxiang; Zhang, Feng; Li, Xiaohui; Zhao, Shifang; Zhu, Weipu; Li, Xiaodong

    2014-01-01

    The deficient osseointegration and implant-associated infections are pivotal issues for the long-term clinical success of endosteal Ti implants, while development of functional surfaces that can simultaneously overcome these problems remains highly challenging. This study aimed to fabricate sophisticated Ti implant surface with both osteogenic inducing activity and inherent antibacterial ability simply via tailoring surface topographical features. Micro/submciro/nano-scale structure was constructed on Ti by three cumulative subtractive methods, including sequentially conducted sandblasting as well as primary and secondary acid etching treatment. Topographical features of this hierarchical structure can be well tuned by the time of the secondary acid treatment. Ti substrate with mere micro/submicro-scale structure (MS0-Ti) served as a control to examine the influence of hierarchical structures on surface properties and biological activities. Surface analysis indicated that all hierarchically structured surfaces possessed exactly the same surface chemistry as that of MS0-Ti, and all of them showed super-amphiphilicity, high surface free energy, and high protein adsorption capability. Biological evaluations revealed surprisingly antibacterial ability and excellent osteogenic activity for samples with optimized hierarchical structure (MS30-Ti) when compared with MS0-Ti. Consequently, for the first time, a hierarchically structured Ti surface with topography-induced inherent antibacterial capability and excellent osteogenic activity was constructed. PMID:25146099

  14. Alkaloids: an overview of their antibacterial, antibiotic-enhancing and antivirulence activities.

    PubMed

    Cushnie, T P Tim; Cushnie, Benjamart; Lamb, Andrew J

    2014-11-01

    With reports of pandrug-resistant bacteria causing untreatable infections, the need for new antibacterial therapies is more pressing than ever. Alkaloids are a large and structurally diverse group of compounds that have served as scaffolds for important antibacterial drugs such as metronidazole and the quinolones. In this review, we highlight other alkaloids with development potential. Natural, semisynthetic and synthetic alkaloids of all classes are considered, looking first at those with direct antibacterial activity and those with antibiotic-enhancing activity. Potent examples include CJ-13,136, a novel actinomycete-derived quinolone alkaloid with a minimum inhibitory concentration of 0.1 ng/mL against Helicobacter pylori, and squalamine, a polyamine alkaloid from the dogfish shark that renders Gram-negative pathogens 16- to >32-fold more susceptible to ciprofloxacin. Where available, information on toxicity, structure-activity relationships, mechanisms of action and in vivo activity is presented. The effects of alkaloids on virulence gene regulatory systems such as quorum sensing and virulence factors such as sortases, adhesins and secretion systems are also described. The synthetic isoquinoline alkaloid virstatin, for example, inhibits the transcriptional regulator ToxT in Vibrio cholerae, preventing expression of cholera toxin and fimbriae and conferring in vivo protection against intestinal colonisation. The review concludes with implications and limitations of the described research and directions for future research.

  15. Alkaloids: an overview of their antibacterial, antibiotic-enhancing and antivirulence activities.

    PubMed

    Cushnie, T P Tim; Cushnie, Benjamart; Lamb, Andrew J

    2014-11-01

    With reports of pandrug-resistant bacteria causing untreatable infections, the need for new antibacterial therapies is more pressing than ever. Alkaloids are a large and structurally diverse group of compounds that have served as scaffolds for important antibacterial drugs such as metronidazole and the quinolones. In this review, we highlight other alkaloids with development potential. Natural, semisynthetic and synthetic alkaloids of all classes are considered, looking first at those with direct antibacterial activity and those with antibiotic-enhancing activity. Potent examples include CJ-13,136, a novel actinomycete-derived quinolone alkaloid with a minimum inhibitory concentration of 0.1 ng/mL against Helicobacter pylori, and squalamine, a polyamine alkaloid from the dogfish shark that renders Gram-negative pathogens 16- to >32-fold more susceptible to ciprofloxacin. Where available, information on toxicity, structure-activity relationships, mechanisms of action and in vivo activity is presented. The effects of alkaloids on virulence gene regulatory systems such as quorum sensing and virulence factors such as sortases, adhesins and secretion systems are also described. The synthetic isoquinoline alkaloid virstatin, for example, inhibits the transcriptional regulator ToxT in Vibrio cholerae, preventing expression of cholera toxin and fimbriae and conferring in vivo protection against intestinal colonisation. The review concludes with implications and limitations of the described research and directions for future research. PMID:25130096

  16. Potent Antibacterial Activity of Copper Embedded into Silicone and Polyurethane.

    PubMed

    Sehmi, Sandeep K; Noimark, Sacha; Weiner, Jonathan; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan P

    2015-10-21

    A simple, easily up-scalable swell-encapsulation-shrink technique was used to incorporate small 2.5 nm copper nanoparticles (CuNPs) into two widely used medical grade polymers, polyurethane, and silicone, with no significant impact on polymer coloration. Both medical grade polymers with incorporated CuNPs demonstrated potent antimicrobial activity against the clinically relevant bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. CuNP-incorporated silicone samples displayed potent antibacterial activity against both bacteria within 6 h. CuNP-incorporated polyurethane exhibited more efficacious antimicrobial activity, resulting in a 99.9% reduction in the numbers of both bacteria within just 2 h. With the high prevalence of hospital-acquired infections, the use of antimicrobial materials such as these CuNP-incorporated polymers could contribute to reducing microbial contamination associated with frequently touched surfaces in and around hospital wards (e.g., bed rails, overbed tables, push plates, etc.).

  17. Facile synthesis and antibacterial activity of naturally occurring 5-methoxyfuroflavone.

    PubMed

    Alam, Mohammad Sayed; Lee, Dong-Ung

    2010-12-01

    A convenient synthesis of 5-methoxyfuroflavone (6, pongaglabol methyl ether), a constituent of some Pongamia or Millettia genus, was achieved by starting from 2,4-dihydroxy-6-methoxyacetophenone via a chalcone precursor, followed by treatment with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). This five-step reaction (total yield: 21.6%) is more facile with that of previously utilized procedures using each different starting material. Antibacterial activities of the above compound and its precursor chalcones, which also belongs to the class of furoflavonoids, were tested by the disc diffusion method against Shigella dysenteriae, Salmonella typhi, Streptococcus-β-haemolyticus, and Staphylococcus aureus. 5-Methoxyfuroflavone showed moderate bactericidal activity against all tested bacterial strains, whereas its corresponding chalcone compound revealed a selective activity. PMID:21139271

  18. Characterization of Antibacterial Activities of Eastern Subterranean Termite, Reticulitermes flavipes, against Human Pathogens

    PubMed Central

    Zeng, Yuan; Hu, Xing Ping

    2016-01-01

    The emergence and dissemination of multidrug resistant bacterial pathogens necessitate research to find new antimicrobials against these organisms. We investigated antimicrobial production by eastern subterranean termites, Reticulitermes flavipes, against a panel of bacteria including three multidrug resistant (MDR) and four non-MDR human pathogens. We determined that the crude extract of naïve termites had a broad-spectrum activity against the non-MDR bacteria but it was ineffective against the three MDR pathogens Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii. Heat or trypsin treatment resulted in a complete loss of activity suggesting that antibacterial activity was proteinaceous in nature. The antimicrobial activity changed dramatically when the termites were fed with either heat-killed P. aeruginosa or MRSA. Heat-killed P. aeruginosa induced activity against P. aeruginosa and MRSA while maintaining or slightly increasing activity against non-MDR bacteria. Heat-killed MRSA induced activity specifically against MRSA, altered the activity against two other Gram-positive bacteria, and inhibited activity against three Gram-negative bacteria. Neither the naïve termites nor the termites challenged with heat-killed pathogens produced antibacterial activity against A. baumannii. Further investigation demonstrated that hemolymph, not the hindgut, was the primary source of antibiotic activity. This suggests that the termite produces these antibacterial activities and not the hindgut microbiota. Two-dimensional gel electrophoretic analyses of 493 hemolymph protein spots indicated that a total of 38 and 65 proteins were differentially expressed at least 2.5-fold upon being fed with P. aeruginosa and MRSA, respectively. Our results provide the first evidence of constitutive and inducible activities produced by R. flavipes against human bacterial pathogens. PMID:27611223

  19. Characterization of Antibacterial Activities of Eastern Subterranean Termite, Reticulitermes flavipes, against Human Pathogens.

    PubMed

    Zeng, Yuan; Hu, Xing Ping; Suh, Sang-Jin

    2016-01-01

    The emergence and dissemination of multidrug resistant bacterial pathogens necessitate research to find new antimicrobials against these organisms. We investigated antimicrobial production by eastern subterranean termites, Reticulitermes flavipes, against a panel of bacteria including three multidrug resistant (MDR) and four non-MDR human pathogens. We determined that the crude extract of naïve termites had a broad-spectrum activity against the non-MDR bacteria but it was ineffective against the three MDR pathogens Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii. Heat or trypsin treatment resulted in a complete loss of activity suggesting that antibacterial activity was proteinaceous in nature. The antimicrobial activity changed dramatically when the termites were fed with either heat-killed P. aeruginosa or MRSA. Heat-killed P. aeruginosa induced activity against P. aeruginosa and MRSA while maintaining or slightly increasing activity against non-MDR bacteria. Heat-killed MRSA induced activity specifically against MRSA, altered the activity against two other Gram-positive bacteria, and inhibited activity against three Gram-negative bacteria. Neither the naïve termites nor the termites challenged with heat-killed pathogens produced antibacterial activity against A. baumannii. Further investigation demonstrated that hemolymph, not the hindgut, was the primary source of antibiotic activity. This suggests that the termite produces these antibacterial activities and not the hindgut microbiota. Two-dimensional gel electrophoretic analyses of 493 hemolymph protein spots indicated that a total of 38 and 65 proteins were differentially expressed at least 2.5-fold upon being fed with P. aeruginosa and MRSA, respectively. Our results provide the first evidence of constitutive and inducible activities produced by R. flavipes against human bacterial pathogens. PMID:27611223

  20. Synthesis and antibacterial activity of alaremycin derivatives for the porphobilinogen synthase.

    PubMed

    Iwai, Noritaka; Nakayama, Kyosuke; Oku, Jumpei; Kitazume, Tomoya

    2011-05-15

    The preparation and the antibacterial activity of alaremycin derivatives such as their CF(3)-derivatives and (R)- and (S)-4-oxo-5-acetylaminohexanoic acid for the porphobilinogen synthase (PBGS), were described. The IC(50) values of the antibacterial activity of the prepared materials for the inhibitor of PBGS, were determined using PBGS assay. PMID:21514151

  1. QSAR study on the antibacterial activity of some sulfa drugs: building blockers of Mannich bases.

    PubMed

    Mandloi, Dheeraj; Joshi, Sheela; Khadikar, Padmakar V; Khosla, Navita

    2005-01-17

    Sulfa drugs are building blockers of several types of Mannich bases. Consequently, the antibacterial activities of sulfa drugs are reported in this paper, which will help in explaining and understanding antibacterial activities of Mannich bases. Reported QSAR is carried out using distance-based topological indices and discussed critically on the basis of statistical parameters.

  2. Acylprolinamides: a new class of peptide deformylase inhibitors with in vivo antibacterial activity.

    PubMed

    Axten, Jeffrey M; Medina, Jesús R; Blackledge, Charles W; Duquenne, Céline; Grant, Seth W; Bobko, Mark A; Peng, Tony; Miller, William H; Pinckney, Theresa; Gallagher, Timothy F; Kulkarni, Swarupa; Lewandowski, Thomas; Van Aller, Glenn S; Zonis, Rimma; Ward, Paris; Campobasso, Nino

    2012-06-15

    A new class of PDF inhibitor with potent, broad spectrum antibacterial activity is described. Optimization of blood stability and potency provided compounds with improved pharmacokinetics that were suitable for in vivo experiments. Compound 5c, which has robust antibacterial activity, demonstrated efficacy in two respiratory tract infection models.

  3. Antibacterial activity of caffeine against plant pathogenic bacteria.

    PubMed

    Sledz, Wojciech; Los, Emilia; Paczek, Agnieszka; Rischka, Jacek; Motyka, Agata; Zoledowska, Sabina; Piosik, Jacek; Lojkowska, Ewa

    2015-01-01

    The objective of the present study was to evaluate the antibacterial properties of a plant secondary metabolite - caffeine. Caffeine is present in over 100 plant species. Antibacterial activity of caffeine was examined against the following plant-pathogenic bacteria: Ralstonia solanacearum (Rsol), Clavibacter michiganesis subsp. sepedonicus (Cms), Dickeya solani (Dsol), Pectobacterium atrosepticum (Pba), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pseudomonas syringae pv. tomato (Pst), and Xanthomonas campestris subsp. campestris (Xcc). MIC and MBC values ranged from 5 to 20 mM and from 43 to 100 mM, respectively. Caffeine increased the bacterial generation time of all tested species and caused changes in cell morphology. The influence of caffeine on the synthesis of DNA, RNA and proteins was investigated in cultures of plant pathogenic bacteria with labelled precursors: [(3)H]thymidine, [(3)H]uridine or (14)C leucine, respectively. RNA biosynthesis was more affected than DNA or protein biosynthesis in bacterial cells treated with caffeine. Treatment of Pba with caffeine for 336 h did not induce resistance to this compound. Caffeine application reduced disease symptoms caused by Dsol on chicory leaves, potato slices, and whole potato tubers. The data presented indicate caffeine as a potential tool for the control of diseases caused by plant-pathogenic bacteria, especially under storage conditions. PMID:26307771

  4. Antibacterial activity and mechanism of berberine against Streptococcus agalactiae

    PubMed Central

    Peng, Lianci; Kang, Shuai; Yin, Zhongqiong; Jia, Renyong; Song, Xu; Li, Li; Li, Zhengwen; Zou, Yuanfeng; Liang, Xiaoxia; Li, Lixia; He, Changliang; Ye, Gang; Yin, Lizi; Shi, Fei; Lv, Cheng; Jing, Bo

    2015-01-01

    The antibacterial activity and mechanism of berberine against Streptococcus agalactiae were investigated in this study by analyzing the growth, morphology and protein of the S. agalactiae cells treated with berberine. The antibacterial susceptibility test result indicated minimum inhibition concentration (MIC) of berberine against Streptococcus agalactiae was 78 μg/mL and the time-kill curves showed the correlation of concentration-time. After the bacteria was exposed to 78 μg/mL berberine, the fragmentary cell membrane and cells unequal division were observed by the transmission electron microscopy (TEM), indicating the bacterial cells were severely damaged. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) study demonstrated that berberine could damage bacterial cells through destroying cellular proteins. Meanwhile, Fluorescence microscope revealed that berberine could affect the synthesis of DNA. In conclusion, these results strongly suggested that berberine may damage the structure of bacterial cell membrane and inhibit synthesis of protein and DNA, which cause Streptococcus agalactiae bacteria to die eventually. PMID:26191220

  5. Antibacterial activity and mechanism of berberine against Streptococcus agalactiae.

    PubMed

    Peng, Lianci; Kang, Shuai; Yin, Zhongqiong; Jia, Renyong; Song, Xu; Li, Li; Li, Zhengwen; Zou, Yuanfeng; Liang, Xiaoxia; Li, Lixia; He, Changliang; Ye, Gang; Yin, Lizi; Shi, Fei; Lv, Cheng; Jing, Bo

    2015-01-01

    The antibacterial activity and mechanism of berberine against Streptococcus agalactiae were investigated in this study by analyzing the growth, morphology and protein of the S. agalactiae cells treated with berberine. The antibacterial susceptibility test result indicated minimum inhibition concentration (MIC) of berberine against Streptococcus agalactiae was 78 μg/mL and the time-kill curves showed the correlation of concentration-time. After the bacteria was exposed to 78 μg/mL berberine, the fragmentary cell membrane and cells unequal division were observed by the transmission electron microscopy (TEM), indicating the bacterial cells were severely damaged. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) study demonstrated that berberine could damage bacterial cells through destroying cellular proteins. Meanwhile, Fluorescence microscope revealed that berberine could affect the synthesis of DNA. In conclusion, these results strongly suggested that berberine may damage the structure of bacterial cell membrane and inhibit synthesis of protein and DNA, which cause Streptococcus agalactiae bacteria to die eventually.

  6. Antibacterial activity of silver nanoparticles synthesized from serine.

    PubMed

    Jayaprakash, N; Judith Vijaya, J; John Kennedy, L; Priadharsini, K; Palani, P

    2015-04-01

    Silver nanoparticles (Ag NPs) were synthesized by a simple microwave irradiation method using polyvinyl pyrrolidone (PVP) as a capping agent and serine as a reducing agent. UV-Visible spectra were used to confirm the formation of Ag NPs by observing the surface plasmon resonance (SPR) band at 443nm. The emission spectrum of Ag NPs showed an emission band at 484nm. In the presence of microwave radiation, serine acts as a reducing agent, which was confirmed by Fourier transformed infrared (FT-IR) spectrum. High-resolution transmission electron microscopy (HR-TEM) and high-resolution scanning electron microscopy (HR-SEM) were used to investigate the morphology of the synthesized sample. These images showed the sphere-like morphology. The elemental composition of the sample was determined by the energy dispersive X-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NPs. The electrochemical behavior of the synthesized Ag NPs was analyzed by the cyclic voltammetry (CV). Antibacterial experiments showed that the prepared Ag NPs showed relatively similar antibacterial activities, when compared with AgNO3 against Gram-positive and Gram-negative bacteria.

  7. Nanostructured Ag(4)O(4) films with enhanced antibacterial activity.

    PubMed

    Dellasega, D; Facibeni, A; Di Fonzo, F; Bogana, M; Polissi, A; Conti, C; Ducati, C; Casari, C S; Li Bassi, A; Bottani, C E

    2008-11-26

    Ag(4)O(4) (i.e. silver(I)-silver(III) oxide) thin films with tailored structure and morphology at the nanoscale have been grown by reactive pulsed laser deposition (PLD) in an oxygen-containing atmosphere and they are shown to exhibit a very strong antibacterial activity towards Gram-negative bacteria (E. coli) and to completely inhibit the growth of Gram-positive bacteria (S. aureus). The formation of this particular high-valence silver oxide is explained in terms of the reactions occurring during the expansion of the ablated species in the reactive atmosphere, leading to the formation of low-stability Ag-O dimers and atomic oxygen, providing reactive species at the substrate where the film grows. PLD is shown to allow control of the structure (i.e. crystallinity and grain size) and of the morphology of the films, from compact and columnar to foam-like, thus allowing the deposition of nanocrystalline films with increased porosity and surface area. The antibacterial action towards E. coli is demonstrated and is shown to be superior to that of nanostructured Ag-based medical products. This can be related to the release of Ag ions with high oxidation number, which are known to be very reactive towards bacteria, and to the peculiar morphology at the nanoscale resulting in a large effective surface area.

  8. Antibacterial activity of caffeine against plant pathogenic bacteria.

    PubMed

    Sledz, Wojciech; Los, Emilia; Paczek, Agnieszka; Rischka, Jacek; Motyka, Agata; Zoledowska, Sabina; Piosik, Jacek; Lojkowska, Ewa

    2015-01-01

    The objective of the present study was to evaluate the antibacterial properties of a plant secondary metabolite - caffeine. Caffeine is present in over 100 plant species. Antibacterial activity of caffeine was examined against the following plant-pathogenic bacteria: Ralstonia solanacearum (Rsol), Clavibacter michiganesis subsp. sepedonicus (Cms), Dickeya solani (Dsol), Pectobacterium atrosepticum (Pba), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pseudomonas syringae pv. tomato (Pst), and Xanthomonas campestris subsp. campestris (Xcc). MIC and MBC values ranged from 5 to 20 mM and from 43 to 100 mM, respectively. Caffeine increased the bacterial generation time of all tested species and caused changes in cell morphology. The influence of caffeine on the synthesis of DNA, RNA and proteins was investigated in cultures of plant pathogenic bacteria with labelled precursors: [(3)H]thymidine, [(3)H]uridine or (14)C leucine, respectively. RNA biosynthesis was more affected than DNA or protein biosynthesis in bacterial cells treated with caffeine. Treatment of Pba with caffeine for 336 h did not induce resistance to this compound. Caffeine application reduced disease symptoms caused by Dsol on chicory leaves, potato slices, and whole potato tubers. The data presented indicate caffeine as a potential tool for the control of diseases caused by plant-pathogenic bacteria, especially under storage conditions.

  9. Colloidal polyaniline dispersions: antibacterial activity, cytotoxicity and neutrophil oxidative burst.

    PubMed

    Kucekova, Zdenka; Humpolicek, Petr; Kasparkova, Vera; Perecko, Tomas; Lehocký, Marián; Hauerlandová, Iva; Sáha, Petr; Stejskal, Jaroslav

    2014-04-01

    Polyaniline colloids rank among promising application forms of this conducting polymer. Cytotoxicity, antibacterial activity, and neutrophil oxidative burst tests were performed on cells treated with colloidal polyaniline dispersions. The antibacterial effect of colloidal polyaniline against gram-positive and gram-negative bacteria was most pronounced for Bacillus cereus and Escherichia coli, with a minimum inhibitory concentration of 3,500 μg mL(-1). The data recorded on human keratinocyte (HaCaT) and a mouse embryonic fibroblast (NIH/3T3) cell lines using an MTT assay and flow cytometry indicated a concentration-dependent cytotoxicity of colloid, with the absence of cytotoxic effect at around 150 μg mL(-1). The neutrophil oxidative burst test then showed that colloidal polyaniline, in concentrations <150 μg mL(-1), was not able to stimulate the production of reactive oxygen species in neutrophils and whole human blood. However, it worked efficiently as a scavenger of those already formed.

  10. Antibacterial activity of two-dimensional MoS2 sheets

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Li, Jie; Liang, Tao; Ma, Chunyan; Zhang, Yingying; Chen, Hongzheng; Hanagata, Nobutaka; Su, Huanxing; Xu, Mingsheng

    2014-08-01

    Graphene-like two-dimensional materials (2DMats) show application potential in optoelectronics and biomedicine due to their unique properties. However, environmental and biological influences of these 2DMats remain to be unveiled. Here we reported the antibacterial activity of two-dimensional (2D) chemically exfoliated MoS2 (ce-MoS2) sheets. We found that the antibacterial activity of ce-MoS2 sheets was much more potent than that of the raw MoS2 powders used for the synthesis of ce-MoS2 sheets possibly due to the 2D planar structure (high specific surface area) and higher conductivity of the ce-MoS2. We investigated the antibacterial mechanisms of the ce-MoS2 sheets and proposed their antibacterial pathways. We found that the ce-MoS2 sheets could produce reactive oxygen species (ROS), different from a previous report on graphene-based materials. Particularly, the oxidation capacity of the ce-MoS2 sheets toward glutathione oxidation showed a time and concentration dependent trend, which is fully consistent with the antibacterial behaviour of the ce-MoS2 sheets. The results suggest that antimicrobial behaviors were attributable to both membrane and oxidation stress. The antibacterial pathways include MoS2-bacteria contact induced membrane stress, superoxide anion (O2&z.rad;-) induced ROS production by the ce-MoS2, and the ensuing superoxide anion-independent oxidation. Our study thus indicates that the tailoring of the dimension of nanomaterials and their electronic properties would manipulate antibacterial activity.Graphene-like two-dimensional materials (2DMats) show application potential in optoelectronics and biomedicine due to their unique properties. However, environmental and biological influences of these 2DMats remain to be unveiled. Here we reported the antibacterial activity of two-dimensional (2D) chemically exfoliated MoS2 (ce-MoS2) sheets. We found that the antibacterial activity of ce-MoS2 sheets was much more potent than that of the raw MoS2 powders

  11. Human Urinary Composition Controls Antibacterial Activity of Siderocalin* ♦

    PubMed Central

    Shields-Cutler, Robin R.; Crowley, Jan R.; Hung, Chia S.; Stapleton, Ann E.; Aldrich, Courtney C.; Marschall, Jonas; Henderson, Jeffrey P.

    2015-01-01

    During Escherichia coli urinary tract infections, cells in the human urinary tract release the antimicrobial protein siderocalin (SCN; also known as lipocalin 2, neutrophil gelatinase-associated lipocalin/NGAL, or 24p3). SCN can interfere with E. coli iron acquisition by sequestering ferric iron complexes with enterobactin, the conserved E. coli siderophore. Here, we find that human urinary constituents can reverse this relationship, instead making enterobactin critical for overcoming SCN-mediated growth restriction. Urinary control of SCN activity exhibits wide ranging individual differences. We used these differences to identify elevated urinary pH and aryl metabolites as key biochemical host factors controlling urinary SCN activity. These aryl metabolites are well known products of intestinal microbial metabolism. Together, these results identify an innate antibacterial immune interaction that is critically dependent upon individualistic chemical features of human urine. PMID:25861985

  12. Influence of glucosamine on oligochitosan solubility and antibacterial activity.

    PubMed

    Blagodatskikh, Inesa V; Kulikov, Sergey N; Vyshivannaya, Oxana V; Bezrodnykh, Evgeniya A; Yamskov, Igor A; Tikhonov, Vladimir E

    2013-11-15

    Light scattering studies indicate that oligochitosan (short-chain chitosan) solutions contain aggregates at pH values below the critical pH of phase separation, while at or above this point the gel phase coexists with the aggregate solution. This work demonstrates for the first time that the presence of D-glucosamine in an oligochitosan solution shifts the critical pH to a higher value and improves the oligochitosan antibacterial activity against Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermis in neutral and slightly alkaline aqueous media. By comparing the results of light scattering studies and antimicrobial assays one can conclude that the antimicrobial activity of oligochitosan is dependent on its unimolecular form, not its supramolecular structures. The widening of the homogeneity region of an oligochitosan solution could lead to promising biomedical applications. PMID:24056011

  13. Structure-activity relationship of buffalo antibacterial hepcidin analogs.

    PubMed

    Chanu, Khangembam Victoria; Kumar, Ashok; Kumar, Satish

    2011-10-01

    Hepcidin is an anti-microbial peptide expressed predominantly in the liver of many species. Based on the amino acid sequence deduced from buffalo (Bubalus bubalis) hepcidin cDNA (Accession no. EU399814), six peptides Hepc(1-25), Hepc(6-25), Hepc(7-25), Hepc(9-25), Hepc(11-25) and Hepc(15-25) were synthesized using solid-phase fluorenylmethoxycarbonyl (Fmoc) chemistry. CD spectroscopy revealed different spectra of the peptides in different solvents and in all the cases beta-structure was found to be dominant with less alpha-helix as predicted. Quantitation of secondary structure indicated the highest beta-structure for all the six peptides in SDS solution, when used as mimetic for membrane-like environment. The CD spectra of all the peptides taken in water showed that degree of randomness decreased with increase in chain length of the peptide. Out of the six peptides, only Hepc(1-25), Hepc(6-25) and Hepc(7-25) showed antibacterial activity against Staphylococcus aureus (Gram-positive bacteria). The peptides did not show any sensitivity toward E. coli (Gram-negative bacteria). Minimum inhibitory concentration (MIC) showed the lowest value for Hepc(7-25) as an antibacterial agent, followed by Hepc(6-25) and Hepc(1-25). The peptides Hepc(9-25), Hepc(11-25) and Hepc(15-25) with more random structure did not show any antimicrobial activity The study demonstrated that 5 amino acids at N-terminal in buffalo hepcidin can be truncated without loss of antimicrobial activity and further reduction of length of the analog from 20 to 19 amino acids resulted increase in the activity because of increase in beta-structure of the peptide shown by CD spectroscopy.

  14. Larvicidal activity of synthetic disinfectants and antibacterial soaps against mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Xue, Rui-De; Qualls, Whitney A

    2013-01-01

    Seven commercial synthetic disinfectant and antibacterial soap products were evaluated as mosquito larvicides against Culex quinquefasciatus Say in the laboratory. Three aerosol disinfectant products, at 0.01% concentration resulted in 58-76% mortality of laboratory-reared fourth instar mosquito larvae at 24 h posttreatment. Four antibacterial soap products at 0.0001% concentration resulted in 88-100% larval mortality at 24 h posttreatment. The active ingredient of the antibacterial soap products, triclosan (0.1%) resulted in 74% larval mortality. One of the antibacterial soap products, Equate caused the highest mosquito larval mortality in the laboratory. Equate antibacterial soap at the application rate of 0.000053 ppm resulted in 90% mortality of the introduced fourth instar larvae of Cx. quinquesfasicatus in the outdoor pools. In laboratory and field bioassays, the antibacterial soap resulted in significant larval mosquito mortality.

  15. Larvicidal activity of synthetic disinfectants and antibacterial soaps against mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Xue, Rui-De; Qualls, Whitney A

    2013-01-01

    Seven commercial synthetic disinfectant and antibacterial soap products were evaluated as mosquito larvicides against Culex quinquefasciatus Say in the laboratory. Three aerosol disinfectant products, at 0.01% concentration resulted in 58-76% mortality of laboratory-reared fourth instar mosquito larvae at 24 h posttreatment. Four antibacterial soap products at 0.0001% concentration resulted in 88-100% larval mortality at 24 h posttreatment. The active ingredient of the antibacterial soap products, triclosan (0.1%) resulted in 74% larval mortality. One of the antibacterial soap products, Equate caused the highest mosquito larval mortality in the laboratory. Equate antibacterial soap at the application rate of 0.000053 ppm resulted in 90% mortality of the introduced fourth instar larvae of Cx. quinquesfasicatus in the outdoor pools. In laboratory and field bioassays, the antibacterial soap resulted in significant larval mosquito mortality. PMID:23427662

  16. Dual mode antibacterial activity of ion substituted calcium phosphate nanocarriers for bone infections.

    PubMed

    Sampath Kumar, T S; Madhumathi, K; Rubaiya, Y; Doble, Mukesh

    2015-01-01

    Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25-0.75, and 2.5-7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40-50 nm and width 5-6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent drug

  17. Short communication: an in vitro assessment of the antibacterial activity of plant-derived oils.

    PubMed

    Mullen, K A E; Lee, A R; Lyman, R L; Mason, S E; Washburn, S P; Anderson, K L

    2014-09-01

    Nonantibiotic treatments for mastitis are needed in organic dairy herds. Plant-derived oils may be useful but efficacy and potential mechanisms of action of such oils in mastitis therapy have not been well documented. The objective of the current study was to evaluate the antibacterial activity of the plant-derived oil components of Phyto-Mast (Bovinity Health LLC, Narvon, PA), an herbal intramammary product, against 3 mastitis-causing pathogens: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Plant-derived oils evaluated were Thymus vulgaris (thyme), Gaultheria procumbens (wintergreen), Glycyrrhiza uralensis (Chinese licorice), Angelica sinensis, and Angelica dahurica. Broth dilution testing according to standard protocol was performed using ultrapasteurized whole milk instead of broth. Controls included milk only (negative control), milk + bacteria (positive control), and milk + bacteria + penicillin-streptomycin (antibiotic control, at 1 and 5% concentrations). Essential oil of thyme was tested by itself and not in combination with other oils because of its known antibacterial activity. The other plant-derived oils were tested alone and in combination for a total of 15 treatments, each replicated 3 times and tested at 0.5, 1, 2, and 4% to simulate concentrations potentially achievable in the milk within the pre-dry-off udder quarter. Thyme oil at concentrations ≥2% completely inhibited bacterial growth in all replications. Other plant-derived oils tested alone or in various combinations were not consistently antibacterial and did not show typical dose-response effects. Only thyme essential oil had consistent antibacterial activity against the 3 mastitis-causing organisms tested in vitro. Further evaluation of physiological effects of thyme oil in various preparations on mammary tissue is recommended to determine potential suitability for mastitis therapy.

  18. Short communication: an in vitro assessment of the antibacterial activity of plant-derived oils.

    PubMed

    Mullen, K A E; Lee, A R; Lyman, R L; Mason, S E; Washburn, S P; Anderson, K L

    2014-09-01

    Nonantibiotic treatments for mastitis are needed in organic dairy herds. Plant-derived oils may be useful but efficacy and potential mechanisms of action of such oils in mastitis therapy have not been well documented. The objective of the current study was to evaluate the antibacterial activity of the plant-derived oil components of Phyto-Mast (Bovinity Health LLC, Narvon, PA), an herbal intramammary product, against 3 mastitis-causing pathogens: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Plant-derived oils evaluated were Thymus vulgaris (thyme), Gaultheria procumbens (wintergreen), Glycyrrhiza uralensis (Chinese licorice), Angelica sinensis, and Angelica dahurica. Broth dilution testing according to standard protocol was performed using ultrapasteurized whole milk instead of broth. Controls included milk only (negative control), milk + bacteria (positive control), and milk + bacteria + penicillin-streptomycin (antibiotic control, at 1 and 5% concentrations). Essential oil of thyme was tested by itself and not in combination with other oils because of its known antibacterial activity. The other plant-derived oils were tested alone and in combination for a total of 15 treatments, each replicated 3 times and tested at 0.5, 1, 2, and 4% to simulate concentrations potentially achievable in the milk within the pre-dry-off udder quarter. Thyme oil at concentrations ≥2% completely inhibited bacterial growth in all replications. Other plant-derived oils tested alone or in various combinations were not consistently antibacterial and did not show typical dose-response effects. Only thyme essential oil had consistent antibacterial activity against the 3 mastitis-causing organisms tested in vitro. Further evaluation of physiological effects of thyme oil in various preparations on mammary tissue is recommended to determine potential suitability for mastitis therapy. PMID:25022682

  19. Influence of metallocene substitution on the antibacterial activity of multivalent peptide conjugates.

    PubMed

    Hoffknecht, Barbara C; Prochnow, Pascal; Bandow, Julia E; Metzler-Nolte, Nils

    2016-07-01

    Peptide dendrimers and derivatisation of peptides with metallocenes showed promising results in the search for new antibacterial agents. The two concepts are combined in this work leading to multivalent, metallocene-containing peptide derivates. These new peptides were synthesised utilising microwave assisted, copper(I) catalyzed alkyne-azide cycloaddition (CuAAC, "click" chemistry). Twelve new peptide conjugates, containing either a ferrocenoyl group or a ruthenocenoyl group on so-called ultrashort (i.e. < 5 amino acids) peptides, and ranging from monovalent to trivalent conjugates, were synthesised and their antibacterial activity was investigated by minimal inhibitory concentration (MIC) assays on five different bacterial strains. The antibacterial activity was compared to the same peptide conjugates without metallocenes. The resulting MIC values showed a significant enhancement of the antibacterial activity of these peptide conjugates against Gram-positive bacteria by the metallocenoyl groups. Additionally, the compounds with two metallocenoyl groups presented the best antibacterial activities overall. PMID:26988572

  20. Effect of salivary pellicle on antibacterial activity of novel antibacterial dental adhesives using a dental plaque microcosm biofilm model

    PubMed Central

    Li, Fang; Weir, Michael D.; Fouad, Ashraf F.; Xu, Hockin H.K.

    2014-01-01

    Objectives Antibacterial primer and adhesive are promising to inhibit biofilms and caries. Since restorations in vivo are exposed to saliva, one concern is the attenuation of antibacterial activity due to salivary pellicles. The objective of this study was to investigate the effects of salivary pellicles on bonding agents containing a new monomer dimethylaminododecyl methacrylate (DMADDM) or nanoparticles of silver (NAg) against biofilms for the first time. Methods DMADDM and NAg were synthesized and incorporated into Scotchbond Multi-Purpose adhesive and primer. Specimens were either coated or not coated with salivary pellicles. A microcosm biofilm model was used with mixed saliva from ten donors. Two types of culture medium were used: an artificial saliva medium (McBain), and Brain Heart Infusion (BHI) medium without salivary proteins. Metabolic activity, colony-forming units (CFU), and lactic acid production of plaque microcosm biofilms were measured (n = 6). Results Bonding agents containing DMADDM and NAg greatly inhibited biofilm activities, even with salivary pellicles. When using BHI, the pre-coating of salivary pellicles on resin surfaces significantly decreased the antibacterial effect (p < 0.05). When using artificial saliva medium, pre-coating of salivary pellicles on resin did not decrease the antibacterial effect. These results suggest that artificial saliva yielded medium-derived pellicles on resin surfaces, which provided attenuating effects on biofilms similar to salivary pellicles. Compared with the commercial control, the DMADDM-containing bonding agent reduced biofilm CFU by about two orders of magnitude. Significance Novel DMADDM- and NAg-containing bonding agents substantially reduced biofilm growth even with salivary pellicle coating on surfaces, indicating a promising usage in saliva-rich environment. DMADDM and NAg may be useful in a wide range of primers, adhesives and other restoratives to achieve antibacterial and anti

  1. A Comparison between Antibacterial Activity of Propolis and Aloe vera on Enterococcus faecalis (an In Vitro Study).

    PubMed

    Ehsani, Maryam; Amin Marashi, Mahmood; Zabihi, Ebrahim; Issazadeh, Maryam; Khafri, Soraya

    2013-01-01

    Removing the bacteria, including Enterococcus faecalis, from the root canal is one of the important aims in endodontic treatment.We aimed to compare the antibacterial activity of Chlorhexidine with two natural drugs. The antibacterial activities of three different propolis extracts (alcohol concentrations: 0, 15, 40%) and Aloe vera gel on E. faecalis were compared using three methods: disk diffusion, microdilution and direct contact test. In addition to the above bacterium, the Aloe vera gel effect on Staphylococcus aureus and Streptococcus mutans was evaluated. Disk diffusion test revealed that propolis ethanolic extracts (the alcohol concentration of 15 and 40%) and Aloe vera gel have antibacterial activities but aqueous extract of propolis did not show any effect in this test. The MICs for propolis ethanolic extracts, Aloe vera gel and aqueous extract of propolis (0% alcohol) were 313 µg/ml, 750 µg/ml, 2250 µg/ml, and ≥ 500 µg/ml respectively, much higher than the Chlorhexidine one. In direct contact test, contrary to Aloe vera, all three propolis extracts showed antibacterial effects on E. faecalis. The Aloe vera gel also showed significant antibacterial effect on S.aureus and S.mutans. The hydroalcoholic extracts of propolis and Aloe vera gel had antibacterial effects on E. faecalis, however, propolis is more potent than Aloe vera. The antibacterial effect of Aloe vera on S. aureus and S. mutans is low (MIC ≥ 2250 µg/ml). Appropriate concentrations of alcoholic extracts of propolis and some fractions of Aloe vera gel might be good choices for disinfecting the root canal in endodontic treatments.

  2. Development and Characterization of Polyphenon 60 and Caffeine Microemulsion for Enhanced Antibacterial Activity

    PubMed Central

    Gupta, Sonal; Bansal, Rakhi; Ali, Javed; Gabrani, Reema; Dang, Shweta

    2014-01-01

    Green tea catechins and caffeine have exhibited antibacterial activity; however, their use is limited by lack of stability and effective delivery systems. Polyphenon 60 (P60) and caffeine were encapsulated in a single microemulsion (ME) formulation with an objective to lower the minimum inhibitory concentrations (MICs) of the individual agents against selected pathogens (S. epidermidis and E. coli). Combination of two natural compounds would advocate two different mechanisms on the bacterial growth thereby providing for better antibacterial activity. Thermodynamically stable ME was developed and characterized with an average particle size of 17.58 nm, further confirmed by TEM analysis. Antibacterial studies included chequerboard microdilution assay to determine the MIC and fractional inhibitory concentration (FIC) of both the natural compounds individually and in combination. MIC and FIC results indicated that the combination of the above two natural compounds was proficient in lowering the MICs of individual agents. Results of DPPH assay indicated that ME system preserved the long term antioxidative potential of P60 and caffeine. The cytotoxicity of the optimized formulation on Vero cell line by MTT assay was found to be nontoxic to mammalian cells. PMID:25050379

  3. Ciprofloxacin-Induced Antibacterial Activity Is Atteneuated by Pretreatment with Antioxidant Agents

    PubMed Central

    Masadeh, Majed M.; Alzoubi, Karem H.; Al-azzam, Sayer I.; Khabour, Omar F.; Al-buhairan, Ahlam M.

    2016-01-01

    Ciprofloxacin works through interfering with replication and transcription of bacterial DNA, which leads to increased oxidative stress, and death of bacterial cells. Drugs with strong antioxidant such as tempol, melatonin and pentoxifylline might interfere with the antibacterial activity of ciprofloxacin. In the current study, the effect of these drugs on the cytotoxicity of ciprofloxacin was investigated against several reference bacteria. Standard bacterial strains included Escherichia coli ATCC 35218, Staphylococcus aureus ATCC29213, Pseudomonas aeruginosa ATCC 9027, Staphylococcus epidermidis ATCC 12228, Acinetobacter baumannii ATCC 17978, Proteus mirabilis ATCC 12459, Klebsiella pneumoniae ATCC 13883, methicillin-resistant Staphylococcus aureus (MRSA) (ATCC 43300), and Streptococcus pneumoniae (ATCC 25923). The antibacterial activity of ciprofloxacin with or without treatment of bacterial cells by tempol, melatonin or pentoxifylline was assessed using the disc diffusion method and by measuring the minimum inhibitory concentration (MIC) and zones of inhibition of bacterial growth. All of the tested bacterial strains were sensitive to ciprofloxacin. When treated with tempol, melatonin or pentoxifylline, all bacterial strains showed significantly smaller zones of inhibition and larger MIC values compared ciprofloxacin alone. In correlation, reactive oxygen species (ROS) generation induced by ciprofloxacin antibacterial action was diminished by treatment of bacterial cells with tempol, melatonin or pentoxifylline. In conclusion, results indicate the possible antagonistic properties for agents with antioxidant properties such as tempol, melatonin and pentoxifylline when they are used concurrently with flouroquinolones. This could be related to the ability of these agents to inhibit oxidative stress in bacterial cells. PMID:27005666

  4. Antibacterial mechanism and activities of black pepper chloroform extract.

    PubMed

    Zou, Lan; Hu, Yue-Ying; Chen, Wen-Xue

    2015-12-01

    Black pepper extracts reportedly inhibit food spoilage and food pathogenic bacteria. This study explored the antimicrobial activity of black pepper chloroform extract (BPCE) against Escherichia coli and Staphylococcus aureus. The antibacterial mechanism of BPCE was elucidated by analyzing the cell morphology, respiratory metabolism, pyruvic acid content, and ATP levels of the target bacteria. Scanning electron micrographs showed that the bacterial cells were destroyed and that plasmolysis was induced. BPCE inhibited the tricarboxylic acid pathway of the bacteria. The extract significantly increased pyruvic acid concentration in bacterial solutions and reduced ATP level in bacterial cells. BPCE destroyed the permeability of the cell membrane, which consequently caused metabolic dysfunction, inhibited energy synthesis, and triggered cell death. PMID:26604394

  5. Antibacterial activity of a lectin-like Burkholderia cenocepacia protein.

    PubMed

    Ghequire, Maarten G K; De Canck, Evelien; Wattiau, Pierre; Van Winge, Iris; Loris, Remy; Coenye, Tom; De Mot, René

    2013-08-01

    Bacteriocins of the LlpA family have previously been characterized in the γ-proteobacteria Pseudomonas and Xanthomonas. These proteins are composed of two MMBL (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. Genes encoding four different types of LlpA-like proteins were identified in genomes from strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. A selected recombinant LlpA-like protein from the human isolate Burkholderia cenocepacia AU1054 displayed narrow-spectrum genus-specific antibacterial activity, thus representing the first functionally characterized bacteriocin within this β-proteobacterial genus. Strain-specific killing was confined to other members of the Bcc, with mostly Burkholderia ambifaria strains being susceptible. In addition to killing planktonic cells, this bacteriocin also acted as an antibiofilm agent.

  6. Synergistic antibacterial activity of Curcumin with antibiotics against Staphylococcus aureus.

    PubMed

    Teow, Sin-Yeang; Ali, Syed Atif

    2015-11-01

    This study evaluated the synergistic antibacterial activity of Curcumin with 8 different antibiotic groups. Two reference, one clinical and ten environmental strains of Staphylococcus aureus (S. aureus) were tested. Disc diffusion assay with 25 μg/mL Curcumin demonstrated synergism in combination with a majority of tested antibiotics against S. aureus. However, checkerboard micro dilution assay only showed synergism, fractional inhibitory concentration index (FICI) <0.5 in three antibiotics i.e. Gentamicin, Amikacin, and Ciprofloxacin. Other antibiotics showed indifferent interactions but no antagonism was observed. In time-kill curve, appreciable reduction of bacterial cells was also observed in combination therapy (Curcumin + antibiotics) compared to monotherapy (Curcumin or antibiotic(s) alone). The antibiotics with higher synergistic interaction with Curcumin are arranged in a decreasing order: Amikacin > Gentamicin > Ciprofloxacin.

  7. Antibacterial activity of silver-killed bacteria: the "zombies" effect.

    PubMed

    Wakshlak, Racheli Ben-Knaz; Pedahzur, Rami; Avnir, David

    2015-01-01

    We report a previously unrecognized mechanism for the prolonged action of biocidal agents, which we denote as the zombies effect: biocidally-killed bacteria are capable of killing living bacteria. The concept is demonstrated by first killing Pseudomonas aeruginosa PAO1 with silver nitrate and then challenging, with the dead bacteria, a viable culture of the same bacterium: Efficient antibacterial activity of the killed bacteria is observed. A mechanism is suggested in terms of the action of the dead bacteria as a reservoir of silver, which, due to Le-Chatelier's principle, is re-targeted to the living bacteria. Langmuirian behavior, as well as deviations from it, support the proposed mechanism. PMID:25906433

  8. Antibacterial activity of a lectin-like Burkholderia cenocepacia protein.

    PubMed

    Ghequire, Maarten G K; De Canck, Evelien; Wattiau, Pierre; Van Winge, Iris; Loris, Remy; Coenye, Tom; De Mot, René

    2013-08-01

    Bacteriocins of the LlpA family have previously been characterized in the γ-proteobacteria Pseudomonas and Xanthomonas. These proteins are composed of two MMBL (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. Genes encoding four different types of LlpA-like proteins were identified in genomes from strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. A selected recombinant LlpA-like protein from the human isolate Burkholderia cenocepacia AU1054 displayed narrow-spectrum genus-specific antibacterial activity, thus representing the first functionally characterized bacteriocin within this β-proteobacterial genus. Strain-specific killing was confined to other members of the Bcc, with mostly Burkholderia ambifaria strains being susceptible. In addition to killing planktonic cells, this bacteriocin also acted as an antibiofilm agent. PMID:23737242

  9. Synthesis of Silver Polymer Nanocomposites and Their Antibacterial Activity

    NASA Astrophysics Data System (ADS)

    Gavade, Chaitali; Shah, Sunil; Singh, N. L.

    2011-07-01

    PVA (Polyvinyl Alcohol) silver nanocomposites of different sizes were prepared by chemical reduction method. Silver nitrate was taken as the metal precursor and amine hydrazine as a reducing agent. The formation of the silver nanoparticles was noticed using UV- visible absorption spectroscopy. The UV-visible spectroscopy revealed the formation of silver nanoparticles by exhibiting the surface plasmon resonance. The bactericidal activity due to silver release from the surface was determined by the modification of conventional diffusion method. Salmonella typhimurium, Serratia sps and Shigella sps were used as test bacteria which are gram-negative type bacteria. Effect of the different sizes of silver nano particles on antibacterial efficiency was discussed. Zones of inhibition were measured after 24 hours of incubation at 37 °C which gave 20 mm radius for high concentration of silver nanoparticles.

  10. Gramicidin D enhances the antibacterial activity of fluoride.

    PubMed

    Nelson, James W; Zhou, Zhiyuan; Breaker, Ronald R

    2014-07-01

    Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in Bacillus subtilis and that the antibacterial activity of this compound is potentiated by fluoride. Polymyxin B, another membrane-targeting antibiotic with a different mechanism of action, shows no such improvement. These results, along with previous findings, indicate that certain compounds that destabilize bacterial cell envelopes can enhance the toxicity of fluoride.

  11. [Antibacterial and antimycotic activity of the amniotic fluid against selected germs (author's transl)].

    PubMed

    Jankowski, R P; Rauskolb, R; Gupta, K G

    1977-03-01

    60 samples of amniotic fluid from 60 patients were obtained between 14 and 42 weeks gestation by dates and tested for their antibacterial activity against staphlococcus aureus strains and brucella abortus and their antimycotic activity against Candida albicans. The antibacterial and antimycotic activity of the amniotic fluid was confirmed. This activity increases steadily from the 15th week and reaches its maximum around term between 36 and 42 weeks. The amniotic samples obtained at 20 weeks gestation showed a weak antibacterial activity especially against staphlococcus aureus of human origin. The above results are important because of the increasing frequency of early and late diagnostic amniocentesis in pregnancy.

  12. Synthesis and antibacterial activities of acylide derivatives bearing an aryl-tetrazolyl chain

    PubMed Central

    Shan, Ling-Xing; Sun, Ping-Hua; Guo, Bao-Qin; Xu, Xing-Jun; Li, Zhi-Qiang; Sun, Jia-Zhi; Zhou, Shu-Feng; Chen, Wei-Min

    2014-01-01

    Seventeen acylides bearing an aryl-tetrazolyl alkyl-substituted side chain were synthesized, starting from clarithromycin, via several reactions including hydrolysis, acetylating, esterification, carbamylation, and Michael addition. The structures of all new compounds were confirmed by 1H nuclear magnetic resonance spectroscopy, 13C nuclear magnetic resonance spectroscopy, and mass spectrometry. All these synthesized acylides were evaluated for in vitro antimicrobial activities against gram-positive pathogens (Staphylococcus aureus, Staphylococcus epidermidis) and gram-negative pathogens (Pseudomonas aeruginosa, Escherichia coli), using the broth microdilution method. Results showed that compounds 10e, 10f, 10g, 10 h, 10o have good antibacterial activities. PMID:25284984

  13. Antibacterial and allelopathic activity of methanolic extract from Iris pseudopumila rhizomes.

    PubMed

    Rigano, Daniela; Grassia, Armando; Formisano, Carmen; Basile, Adriana; Sorbo, Sergio; Senatore, Felice

    2006-09-01

    The methanolic extract of rhizomes of Iris pseudopumila was tested for its antibacterial and allelopathic activity. The extract was shown to have antibacterial effects. The allelopathic effect was tested against Raphanus sativus seed germination. The extract caused a decrease in the percentage of seed germination and root and epicotyl growth.

  14. Antifungal and antibacterial activities of Petroselinum crispum essential oil.

    PubMed

    Linde, G A; Gazim, Z C; Cardoso, B K; Jorge, L F; Tešević, V; Glamoćlija, J; Soković, M; Colauto, N B

    2016-07-29

    Parsley [Petroselinum crispum (Mill.) Fuss] is regarded as an aromatic, culinary, and medicinal plant and is used in the cosmetic, food, and pharmaceutical industries. However, few studies with conflicting results have been conducted on the antimicrobial activity of parsley essential oil. In addition, there have been no reports of essential oil obtained from parsley aerial parts, except seeds, as an alternative natural antimicrobial agent. Also, microorganism resistance is still a challenge for health and food production. Based on the demand for natural products to control microorganisms, and the re-evaluation of potential medicinal plants for controlling diseases, the objective of this study was to determine the chemical composition and antibacterial and antifungal activities of parsley essential oil against foodborne diseases and opportunistic pathogens. Seven bacteria and eight fungi were tested. The essential oil major compounds were apiol, myristicin, and b-phellandrene. Parsley essential oil had bacteriostatic activity against all tested bacteria, mainly Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica, at similar or lower concentrations than at least one of the controls, and bactericidal activity against all tested bacteria, mainly S. aureus, at similar or lower concentrations than at least one of the controls. This essential oil also had fungistatic activity against all tested fungi, mainly, Penicillium ochrochloron and Trichoderma viride, at lower concentrations than the ketoconazole control and fungicidal activity against all tested fungi at higher concentrations than the controls. Parsley is used in cooking and medicine, and its essential oil is an effective antimicrobial agent.

  15. Antifungal and antibacterial activities of Petroselinum crispum essential oil.

    PubMed

    Linde, G A; Gazim, Z C; Cardoso, B K; Jorge, L F; Tešević, V; Glamoćlija, J; Soković, M; Colauto, N B

    2016-01-01

    Parsley [Petroselinum crispum (Mill.) Fuss] is regarded as an aromatic, culinary, and medicinal plant and is used in the cosmetic, food, and pharmaceutical industries. However, few studies with conflicting results have been conducted on the antimicrobial activity of parsley essential oil. In addition, there have been no reports of essential oil obtained from parsley aerial parts, except seeds, as an alternative natural antimicrobial agent. Also, microorganism resistance is still a challenge for health and food production. Based on the demand for natural products to control microorganisms, and the re-evaluation of potential medicinal plants for controlling diseases, the objective of this study was to determine the chemical composition and antibacterial and antifungal activities of parsley essential oil against foodborne diseases and opportunistic pathogens. Seven bacteria and eight fungi were tested. The essential oil major compounds were apiol, myristicin, and b-phellandrene. Parsley essential oil had bacteriostatic activity against all tested bacteria, mainly Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica, at similar or lower concentrations than at least one of the controls, and bactericidal activity against all tested bacteria, mainly S. aureus, at similar or lower concentrations than at least one of the controls. This essential oil also had fungistatic activity against all tested fungi, mainly, Penicillium ochrochloron and Trichoderma viride, at lower concentrations than the ketoconazole control and fungicidal activity against all tested fungi at higher concentrations than the controls. Parsley is used in cooking and medicine, and its essential oil is an effective antimicrobial agent. PMID:27525894

  16. Effect of Cu content on the antibacterial activity of titanium-copper sintered alloys.

    PubMed

    Liu, Jie; Li, Fangbing; Liu, Cong; Wang, Hongying; Ren, Baorui; Yang, Ke; Zhang, Erlin

    2014-02-01

    The phase constitution and the microstructure Ti-x Cu (x=2, 5, 10 and 25 wt.%) sintered alloys were investigated by XRD and SEM and the antibacterial activity was assessed in order to investigate the effect of the Cu content on the antibacterial activity. The results have shown that Ti2Cu was synthesized as a main secondary phase in all Ti-Cu alloys while Cu-rich phase was formed in the alloys with 5 wt.% or more copper. Antibacterial tests have showed that the Cu content influences the antibacterial rate seriously and only the alloys with 5 wt.% or high Cu have a strong and stable antibacterial rate, which indicates that the Cu content in Ti-Cu alloys must be at least 5 wt.% to obtain strong and stable antibacterial property. The Cu content also influenced the Cu ion release behavior. High Cu ion release concentration and high Cu ion release rate were observed for Ti-Cu alloys with high Cu content. It was concluded that the Cu content affects the Cu existence and the Cu ion release behavior, which in turn influences the antibacterial property. It was thought that the Cu-rich phase should play an important role in the strong antibacterial activity.

  17. Antioxidant and antibacterial activity of different parts of Leucas aspera

    PubMed Central

    Chew, Ai Lan; Jessica, Jeyanthi James Antony; Sasidharan, Sreenivasan

    2012-01-01

    Objective To evaluate antioxidant, antimicrobial and cytotoxic activity of different parts (root, flower, leaf and stem) of Leucas aspera (L. aspera) (Labiatae). Methods Different parts of L. aspera were extracted with 80% (v/v) methanol. The methanol extracts were subjected to antioxidant, antimicrobial and brine shrimp lethality assay. Results All the extracts showed moderate to potent antioxidant activity, among which the root extract demonstrated the strongest antioxidant activity with the IC50 value of 6.552 µg/mL. Methanol extract of root possessed antioxidant activity near the range of vitamin E and thus could be a potential rich source of natural antioxidant. In case of antimicrobial screening, crude extracts of root, flower, leaf and stem showed notable antibacterial activity against tested microorganisms. The root extract showed the highest mean zone of inhibition ranging from 9.0–11.0 mm against tested microorganisms, at a concentration of 100 mg/mL. In the brine shrimp lethality bioassay, it was evident that the methanol root extract did not show significant toxicity. The LC50 value for 12 h and 24 h observation was 2.890 mg/mL and 1.417 mg/mL, respectively. Conclusions The present finding suggests that the methanol root extract of L. aspera could be developed as pharmaceutical products. PMID:23569893

  18. Antibacterial activity of medicinal plant extracts against periodontopathic bacteria.

    PubMed

    Iauk, L; Lo Bue, A M; Milazzo, I; Rapisarda, A; Blandino, G

    2003-06-01

    This study was performed to evaluate the antibacterial activity of Althaea officinalis L. roots, Arnica montana L. flowers, Calendula officinalis L. flowers, Hamamelis virginiana L. leaves, Illicium verum Hook. fruits and Melissa officinalis L. leaves, against anaerobic and facultative aerobic periodontal bacteria: Porphyromonas gingivalis, Prevotella spp., Fusobacterium nucleatum, Capnocytophaga gingivalis, Veilonella parvula, Eikenella corrodens, Peptostreptococcus micros and Actinomyces odontolyticus. The methanol extracts of H. virginiana and A. montana and, to a lesser extent, A. officinalis were shown to possess an inhibiting activity (MIC < or = 2048 mg/L) against many of the species tested. In comparison, M. officinalis and C. officinalis extracts had a lower inhibiting activity (MIC > or = 2048 mg/L) against all the tested species with the exception of Prevotella sp. Illicium verum methanol extract was not very active though it had a particular good activity against E. corrodens. The results suggest the use of the alcohol extracts of H. virginiana, A. montana and A. officinalis for topical medications in periodontal prophylactics.

  19. Antibacterial performance of polypropylene nonwoven fabric wound dressing surfaces containing passive and active components

    NASA Astrophysics Data System (ADS)

    Xin, Zhirong; Du, Shanshan; Zhao, Chunyu; Chen, Hao; Sun, Miao; Yan, Shunjie; Luan, Shifang; Yin, Jinghua

    2016-03-01

    A growing number of wound dressing-related nosocomial infections necessitate the development of novel antibacterial strategies. Herein, polypropylene non-woven fabric (PPNWF) was facilely modified with passive and active antibacterial components, namely photografting polymerization both N-Vinyl-2-pyrrolidone (NVP) and glycidyl methacrylate (GMA) monomers, and the introduction of guanidine polymer through the reaction between active amino groups and epoxy groups. The modified samples were confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), respectively. Water contact angle measurement, antibacterial test, platelet and red blood cell adhesion were used to evaluate the hydrophilicity, antibacterial properties and hemocompatibility of the samples. It was found that the antibacterial properties were obviously enhanced, meanwhile significantly suppressing platelet and red blood cell adhesion after the above modification. This PPNWF samples that possess antifouling and antimicrobial properties, have great potential in wound dressing applications.

  20. Novel Synthesis of Kanamycin Conjugated Gold Nanoparticles with Potent Antibacterial Activity

    PubMed Central

    Payne, Jason N.; Waghwani, Hitesh K.; Connor, Michael G.; Hamilton, William; Tockstein, Sarah; Moolani, Harsh; Chavda, Fenil; Badwaik, Vivek; Lawrenz, Matthew B.; Dakshinamurthy, Rajalingam

    2016-01-01

    With a sharp increase in the cases of multi-drug resistant (MDR) bacteria all over the world, there is a huge demand to develop a new generation of antibiotic agents to fight them. As an alternative to the traditional drug discovery route, we have designed an effective antibacterial agent by modifying an existing commercial antibiotic, kanamycin, conjugated on the surface of gold nanoparticles (AuNPs). In this study, we report a single-step synthesis of kanamycin-capped AuNPs (Kan-AuNPs) utilizing the combined reducing and capping properties of kanamycin. While Kan-AuNPs have increased toxicity to a primate cell line (Vero 76), antibacterial assays showed dose-dependent broad spectrum activity of Kan-AuNPs against both Gram-positive and Gram-negative bacteria, including Kanamycin resistant bacteria. Further, a significant reduction in the minimum inhibitory concentration (MIC) of Kan-AuNPs was observed when compared to free kanamycin against all the bacterial strains tested. Mechanistic studies using transmission electron microscopy and fluorescence microscopy indicated that at least part of Kan-AuNPs increased efficacy may be through disrupting the bacterial envelope, resulting in the leakage of cytoplasmic content and the death of bacterial cells. Results of this study provide critical information about a novel method for the development of antibiotic capped AuNPs as potent next-generation antibacterial agents. PMID:27330535

  1. Antibacterial Activity of Essential Oils and Their Isolated Constituents against Cariogenic Bacteria: A Systematic Review.

    PubMed

    Freires, Irlan Almeida; Denny, Carina; Benso, Bruna; de Alencar, Severino Matias; Rosalen, Pedro Luiz

    2015-01-01

    Dental caries remains the most prevalent and costly oral infectious disease worldwide. Several methods have been employed to prevent this biofilm-dependent disease, including the use of essential oils (EOs). In this systematic review, we discuss the antibacterial activity of EOs and their isolated constituents in view of a potential applicability in novel dental formulations. Seven databases were systematically searched for clinical trials, in situ, in vivo and in vitro studies addressing the topic published up to date. Most of the knowledge in the literature is based on in vitro studies assessing the effects of EOs on caries-related streptococci (mainly Streptococcus mutans) and lactobacilli, and on a limited number of clinical trials. The most promising species with antibacterial potential against cariogenic bacteria are: Achillea ligustica, Baccharis dracunculifolia, Croton cajucara, Cryptomeria japonica, Coriandrum sativum, Eugenia caryophyllata, Lippia sidoides, Ocimum americanum, and Rosmarinus officinalis. In some cases, the major phytochemical compounds determine the biological properties of EOs. Menthol and eugenol were considered outstanding compounds demonstrating an antibacterial potential. Only L. sidoides mouthwash (1%) has shown clinical antimicrobial effects against oral pathogens thus far. This review suggests avenues for further non-clinical and clinical studies with the most promising EOs and their isolated constituents bioprospected worldwide. PMID:25911964

  2. Activity of antibacterial, antiviral, anti-inflammatory in compounds andrographolide salt.

    PubMed

    Wen, Li; Xia, Nan; Chen, Xianghong; Li, Yingxiu; Hong, Yi; Liu, YaJie; Wang, ZiZhen; Liu, YaJie

    2014-10-01

    Andrographolide sulfonic acid sodium salt (ASS) was synthesized to increase the the solubility of Andrographolide in aqueous solution. We have studied its pharmacological effect of antibiosis, anti-inflammatory and immunoregulation. Cylinder-plate method was used to study ASS׳s in vitro antibacterial activity, and its protection for mice infected by Staphylococcus aureus and Shigella dysenteriae. Various inflammation models, including the auricular edema induced by xylene in mice, CMC-Na induced air pounch model and the paw edema induced by albumen in rats were used to explore the characteristic of ASS׳s anti-inflammation effect. We built up the immune model by injecting chicken red cells in enter celiac of mice and study the effect of ASS on immunoregulation, taking andrographolide as the positive control. bacteriostasis in vivo and in vitro experiments show that ASS has a weak antibacterial effect and no bactericidal effect, but can reduce the mice mortality of Staphylococcus aureus infected. Anti-inflammatory experiments show that ASS can reduce the mouse ear swelling induced by xylene and rat paw swelling induced by egg albumin, and lessen leukocytes in air bag caused by CMCNa, and lower IL1 not ably in rat serum. Immune tests indicate that ASS can get spleen and thymus gain weight and increase rate of abdominal macrophage phagocytosis of mice. The result of bacteriostasis shows that ASS has weak in vitro antibacterial effect. ASS shows significant effects of anti-inflammation and improving immunity, thus enables the mice against bacteria better.

  3. Structure activity relationship study of Mezzettiasides natural products and their four new disaccharide analogues for anticancer/antibacterial activity

    PubMed Central

    Bajaj, Sumit O.; Shi, Pei

    2014-01-01

    Ten members of the mezzettiaside family of natural products were synthesized and evaluated for anticancer and antibacterial activity. Complete anticancer (H460) and antibacterial (B. subtilis) activities for the ten natural products and four new analogues were found. Comparison to the cleistrioside and cleistetroside classes of natural products were made. PMID:25729554

  4. Antibacterial activity in Strongylocentrotus droebachiensis (Echinoidea), Cucumaria frondosa (Holothuroidea), and Asterias rubens (Asteroidea).

    PubMed

    Haug, Tor; Kjuul, Anita K; Styrvold, Olaf B; Sandsdalen, Erling; Olsen, Ørjan M; Stensvåg, Klara

    2002-10-01

    A search for antibacterial activity in different body parts of the green sea urchin Strongylocentrotus droebachiensis, the common starfish Asterias rubens, and the sea cucumber Cucumaria frondosa was conducted. Antibacterial activity was detected in extracts from several tissues in all species tested, but mainly in the coelomocyte and body wall extracts. Relatively high antibacterial activity could also be detected in gastrointestinal organs and eggs from A. rubens and in eggs from C. frondosa. Differences between active extracts regarding hydrophobicity and sensitivity to heat and proteinase K treatment indicated that several different compounds were responsible for the antibacterial activities detected. Lysozyme-like activity could be detected in several tissues from A. rubens. Haemolytic activity could be detected in all species tested, especially in the body wall extracts. Results from the current study suggest that marine echinoderms are a potential source for the discovery of novel antibiotics. PMID:12445793

  5. Assessment of Tamarindus indica extracts for antibacterial activity.

    PubMed

    Nwodo, Uchechukwu U; Obiiyeke, Grace E; Chigor, Vincent N; Okoh, Anthony I

    2011-01-01

    Ethanolic and aqueous (hot and cold) extracts of the fruit pulp, stem bark and leaves of Tamarindus indica were evaluated for antibacterial activity, in vitro, against 13 Gram negative and 5 Gram positive bacterial strains using agar well diffusion and macro broth dilution techniques, simultaneously. The fruit pulp extracts exhibited a wide spectrum of activity; the cold water extract against 95.5% of the test bacterial strains; and the hot water and ethanolic extracts against 90.9% and 86.4%, respectively. In contrast the cold water extract of the leaves and stem bark, each was active against 16.7%; while the ethanolic extract of each was active against 75% of the test strains. The minimum inhibitory concentrations (MIC) ranged from 7.81 mg/mL against Bacillus subtilis ATCC 6051 to 31.25 mg/mL against Escherichia coli ATCC 11775; and the minimum bactericidal concentration (MBC) ranged from 125 mg/mL against Pseudomonas aeruginosa ATCC 10145 to 250 mg/mL against Bacillus subtilis ATCC 6051.

  6. Assessment of Tamarindus indica extracts for antibacterial activity.

    PubMed

    Nwodo, Uchechukwu U; Obiiyeke, Grace E; Chigor, Vincent N; Okoh, Anthony I

    2011-01-01

    Ethanolic and aqueous (hot and cold) extracts of the fruit pulp, stem bark and leaves of Tamarindus indica were evaluated for antibacterial activity, in vitro, against 13 Gram negative and 5 Gram positive bacterial strains using agar well diffusion and macro broth dilution techniques, simultaneously. The fruit pulp extracts exhibited a wide spectrum of activity; the cold water extract against 95.5% of the test bacterial strains; and the hot water and ethanolic extracts against 90.9% and 86.4%, respectively. In contrast the cold water extract of the leaves and stem bark, each was active against 16.7%; while the ethanolic extract of each was active against 75% of the test strains. The minimum inhibitory concentrations (MIC) ranged from 7.81 mg/mL against Bacillus subtilis ATCC 6051 to 31.25 mg/mL against Escherichia coli ATCC 11775; and the minimum bactericidal concentration (MBC) ranged from 125 mg/mL against Pseudomonas aeruginosa ATCC 10145 to 250 mg/mL against Bacillus subtilis ATCC 6051. PMID:22072893

  7. Phytochemical observation and antibacterial activity of Cyperus esculentus L.

    PubMed Central

    Prakash, N; Ragavan, B

    2009-01-01

    In the present study various extracts of Cyperus esculentus L. such as acetone, 50% ethanol, chloroform and petroleum ether were evaluated for their antibacterial activity against several human pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella sp, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa and Citrobacter freundii, by using disc diffusion method. The activity of the samples were compared with that of standard antibiotics. The qualitative phytochemical analysis was also carried out with all the extracts of the sample. Of all the extracts 50% ethanol and acetone extract were found to be rich in phytochemicals such as alkaloids, flavonoids, phenols, tannins, steroids, terpenoids and glycosides. Acetone extract showed highest inhibitory activity against S.aureus, ILpneumoniae and P.vulgaris. 50% ethanolic extract showed maximum activity against E.coli, S.aureus and Salmonella sp. Chloroform extract maximally inhibited the growth of S.aureus whereas, petroleum ether extract showed positive results against Salmonella sp respectively. All extracts were sensitive to C. freundii. PMID:22557327

  8. Phytochemical observation and antibacterial activity of Cyperus esculentus L.

    PubMed

    Prakash, N; Ragavan, B

    2009-04-01

    In the present study various extracts of Cyperus esculentus L. such as acetone, 50% ethanol, chloroform and petroleum ether were evaluated for their antibacterial activity against several human pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella sp, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa and Citrobacter freundii, by using disc diffusion method. The activity of the samples were compared with that of standard antibiotics. The qualitative phytochemical analysis was also carried out with all the extracts of the sample. Of all the extracts 50% ethanol and acetone extract were found to be rich in phytochemicals such as alkaloids, flavonoids, phenols, tannins, steroids, terpenoids and glycosides. Acetone extract showed highest inhibitory activity against S.aureus, ILpneumoniae and P.vulgaris. 50% ethanolic extract showed maximum activity against E.coli, S.aureus and Salmonella sp. Chloroform extract maximally inhibited the growth of S.aureus whereas, petroleum ether extract showed positive results against Salmonella sp respectively. All extracts were sensitive to C. freundii. PMID:22557327

  9. ZnO/graphite composites and its antibacterial activity at different conditions.

    PubMed

    Dědková, Kateřina; Janíková, Barbora; Matějová, Kateřina; Čabanová, Kristina; Váňa, Rostislav; Kalup, Aleš; Hundáková, Marianna; Kukutschová, Jana

    2015-10-01

    The paper reports laboratory preparation, characterization and in vitro evaluation of antibacterial activity of ZnO/graphite nanocomposites. Zinc chloride and sodium carbonate served as precursors for synthesis of zinc oxide, while micromilled and natural graphite were used as the matrix for ZnO nanoparticles anchoring. During the reaction of ZnCl2 with saturated aqueous solution of Na2CO3a new compound is created. During the calcination at the temperature of 500 °C this new precursors decomposes and ZnO nanoparticles are formed. Composites ZnO/graphite with 50 wt.% of ZnO particles were prepared. X-ray powder diffraction and Raman microspectroscopy served as phase-analytical methods. Scanning electron microscopy technique was used for morphology characterization of the prepared samples and EDS mapping for visualization of elemental distribution. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity and antibacterial activity at dark conditions. Common human pathogens served as microorganism for antibacterial assay. Antibacterial activity of ZnO/graphite composites could be based on photocatalytic reaction; however there is a role of Zn(2+) ions on the resulting antibacterial activity which proved the experiments in dark condition. There is synergistic effect between Zn(2+) caused and reactive oxygen species caused antibacterial activity. PMID:26318283

  10. Antibacterial activity of the body wall extracts of sea cucumber (Invertebrata; Echinodermata) on infectious oral streptococci.

    PubMed

    Kiani, Negin; Heidari, Behrooz; Rassa, Mehdi; Kadkhodazadeh, Mahdi; Heidari, Bijan

    2014-01-27

    Abstract Background: The present study was carried out to test the antibacterial effect of the body wall of the sea cucumber Holothuria leucospilota Brandt on Streptococcus mutans and Streptococcus salivarius. Methods: After sampling sea cucumbers from the Persian Gulf, different extractions were prepared. Then, aqueous, phosphate-buffered saline (PBS, pH 7.8), chloroform, hexane and methanolic extracts from sea cucumber body wall were screened for antibacterial activity against pathogenic bacteria S. mutans and S. salivarius using the disk diffusion method. Results: The PBS extract did not show any antibacterial or inhibitory activity; the chloroform extract, however, demonstrated high levels of antibacterial activity against S. salivarius while exhibiting low levels of activity against S. mutans. The hexane and methanolic extracts were found to show no antibacterial activity against S. mutans, but exhibited antibacterial activity against S. salivarius. Conclusions: In conclusion, the results demonstrated the possibility of utilizing sea cucumbers as a cheap source of potential antibacterial agents and for treating odontogenic diseases.

  11. Methanolic extracts of Withania somnifera leaves, fruits and roots possess antioxidant properties and antibacterial activities

    PubMed Central

    2012-01-01

    Background Withania somnifera, also known as ashwagandha, is an important herb in ayurvedic and indigenous medical systems. The present study was designed to evaluate the antioxidant and antibacterial activities of an 80% aqueous methanolic extract of W. somnifera roots (WSREt), fruits (WSFEt) and leaves (WSLEt). Methods Several assays were performed to determine the antioxidant properties of this herb including 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity, ferric reducing antioxidant power (FRAP), ferrous chelation and inhibition of β-carotene bleaching. Results The values for DPPH, FRAP, ferrous chelation and inhibition of β carotene bleaching for the three types of extracts ranged from 101.73-801.93 μg/ml, 2.26-3.29 mM Fe/kg, 0.22-0.65 mg/ml and 69.87-79.67%, respectively, indicating that W. somnifera, particularly the leaves, possesses significant antioxidant properties. The mean ascorbic acid content was 20.60-62.60 mg/100 g, and the mean anthocyanin content was 2.86-12.50 mg/100 g. Antibacterial activities were measured using the agar well diffusion method and five pathogenic Gram-negative bacteria: Escherichia coli, Salmonella typhi, Citrobacter freundii, Pseudomonas aeruginosa and Klebsiella pneumoniae. The leaf extracts displayed the highest activity against S. typhi (32.00 ± 0.75 mm zone of inhibition), whereas the lowest activity was against K. pneumoniae (19.00 ± 1.48 mm zone of inhibition). The lowest minimum inhibitory concentration value was 6.25 mg/ml, which was against S. typhi, followed by 12.5 mg/ml against E. coli. Conclusion In addition to its antioxidant properties, W. somnifera exhibited significant antibacterial activities against Gram-negative bacteria, particularly S. typhi. PMID:23039061

  12. Antibacterial activity of Lactobacillus strains isolated from dry fermented sausages.

    PubMed

    Vignolo, G M; Suriani, F; Pesce de Ruiz Holgado, A; Oliver, G

    1993-10-01

    One hundred strains of lactic acid bacteria isolated from dry cured sausages were tested for antagonistic activity against a set of test strains. Nine of 52 strains of Lactobacillus casei and three of 48 strains of Lact. plantarun produced inhibition zones against the indicator species. The substance excreted by Lact. casei CRL 705 was active against Lact. plantarum, Listeria monocytogenes, Staphylococcus aureus and a wide range of Gram-negative bacteria. The activity of the antibacterial compound from Lact. casei CRL 705 was destroyed by papain, trypsin and pepsin, but was resistant to heat (100 degrees C for 20 min), lysozyme and catalase. The agent was produced during the growth cycle and when the concentrated and neutralized supernatant fluid was added to a fresh culture of sensitive cells it produced a rapid inactivation. A decrease in optical density (O.D.) over time, indicative of cell lysis, was also observed. These characteristics allowed us to identify the inhibitory compound as a bacteriocin which we termed Lactocin 705. PMID:8226391

  13. Isolation of the Entomopathogenic Fungal Strain Cod-MK1201 from a Cicada Nymph and Assessment of Its Antibacterial Activities.

    PubMed

    Sangdee, Kusavadee; Nakbanpote, Woranan; Sangdee, Aphidech

    2015-01-01

    The entomopathogenic fungus Cod-MK1201 was isolated from a dead cicada nymph. Three regions of ribosomal nuclear DNA, the internal transcribed spacers of nuclear ribosomal DNA repeats (ITS), the partial small subunit of rDNA (nrSSU) , and the partial large subunit of rDNA (nrLSU), and two protein-coding regions, the elongation factor 1α (EF-1α), and the largest subunit of the RNA polymerase II (rpb1) gene, were sequenced and used for fungal identification. The phylogenetic analysis of the ITS and the combined data set of the five genes indicated that the fungal isolate Cod-MK1201 is a new strain of Cordyceps sp. that is closely related to Cordyceps nipponica and C. kanzashiana. Crude extracts of mycelium-cultured Cod-MK1201 were obtained using distilled water and 50% (v/v) ethanol, and the antibacterial activity of each was determined. Both extracts had activity against Gram-positive and Gram-negative bacteria, but the ethanol extract was the more potent of the two. The antibacterial activity of the protein fractions of these extracts was also determined. The protein fraction from the ethanol extract was more antibacterial than the protein fraction from the aqueous extract. Three antibacterial constituents including adenosine, the total phenolic content (TPC), and the total flavonoid content (TFC) was also determined. The results showed that the adenosine content, the TPC, and the TFC of the ethanol extract were more active than those of the aqueous extract. Moreover, synergism was detected between these antibacterial constituents. In conclusion, the entomopathogenic fungal isolate Cod-MK1201 represents a natural source of antibacterial agents. PMID:25746406

  14. Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

    PubMed Central

    Kıvanç, Sertaç Argun; Kıvanç, Merih; Yiğit, Tülay

    2016-01-01

    Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents. PMID:27602088

  15. Antibiotic susceptibility, antibacterial activity and characterisation of Enterococcus faecium strains isolated from breast milk

    PubMed Central

    Kıvanç, Sertaç Argun; Kıvanç, Merih; Yiğit, Tülay

    2016-01-01

    Enterococci, which have useful biotechnological applications, produce bacteriocins, including those that exert anti-Listerial activity. The present study aimed to determine the antibiotic susceptibility patterns and antimicrobial activity of Enterococcus faecium strains isolated from human breast milk. The strains were identified using carbohydrate fermentation tests and ribotyping. Subsequently, the antibacterial activity of the isolates was investigated, and the quantities of lactic acid and hydrogen peroxide produced, and the proteolytic activity of E. faecium, were determined. In addition, biofilm formation by E. faecium strains was assessed. E. faecium strains exhibited antimicrobial activity against food-borne and clinical bacterial isolates. Furthermore, following 24 h incubation, the tested strains exhibited resistance to a pH range of 2.0–9.5 and tolerance of bile acid, lysozyme activity and phenol. Supernatants of the E. faecium TM13, TM15, TM17 and TM18 strains were shown to be effective against Listeria monocytogenes, and were also resistant to heat. Further studies are required in order to determine whether certain strains of E. faecium may be used for the development of novel antibacterial agents.

  16. Elucidation of the Mode of Action of a New Antibacterial Compound Active against Staphylococcus aureus and Pseudomonas aeruginosa

    PubMed Central

    Gerits, Evelien; Blommaert, Eline; Lippell, Anna; O’Neill, Alex J.; Weytjens, Bram; De Maeyer, Dries; Fierro, Ana Carolina; Marchal, Kathleen; Marchand, Arnaud; Chaltin, Patrick; Spincemaille, Pieter; De Brucker, Katrijn; Thevissen, Karin; Cammue, Bruno P. A.; Swings, Toon; Liebens, Veerle; Fauvart, Maarten; Verstraeten, Natalie; Michiels, Jan

    2016-01-01

    Nosocomial and community-acquired infections caused by multidrug resistant bacteria represent a major human health problem. Thus, there is an urgent need for the development of antibiotics with new modes of action. In this study, we investigated the antibacterial characteristics and mode of action of a new antimicrobial compound, SPI031 (N-alkylated 3, 6-dihalogenocarbazol 1-(sec-butylamino)-3-(3,6-dichloro-9H-carbazol-9-yl)propan-2-ol), which was previously identified in our group. This compound exhibits broad-spectrum antibacterial activity, including activity against the human pathogens Staphylococcus aureus and Pseudomonas aeruginosa. We found that SPI031 has rapid bactericidal activity (7-log reduction within 30 min at 4x MIC) and that the frequency of resistance development against SPI031 is low. To elucidate the mode of action of SPI031, we performed a macromolecular synthesis assay, which showed that SPI031 causes non-specific inhibition of macromolecular biosynthesis pathways. Liposome leakage and membrane permeability studies revealed that SPI031 rapidly exerts membrane damage, which is likely the primary cause of its antibacterial activity. These findings were supported by a mutational analysis of SPI031-resistant mutants, a transcriptome analysis and the identification of transposon mutants with altered sensitivity to the compound. In conclusion, our results show that SPI031 exerts its antimicrobial activity by causing membrane damage, making it an interesting starting point for the development of new antibacterial therapies. PMID:27167126

  17. Elucidation of the Mode of Action of a New Antibacterial Compound Active against Staphylococcus aureus and Pseudomonas aeruginosa.

    PubMed

    Gerits, Evelien; Blommaert, Eline; Lippell, Anna; O'Neill, Alex J; Weytjens, Bram; De Maeyer, Dries; Fierro, Ana Carolina; Marchal, Kathleen; Marchand, Arnaud; Chaltin, Patrick; Spincemaille, Pieter; De Brucker, Katrijn; Thevissen, Karin; Cammue, Bruno P A; Swings, Toon; Liebens, Veerle; Fauvart, Maarten; Verstraeten, Natalie; Michiels, Jan

    2016-01-01

    Nosocomial and community-acquired infections caused by multidrug resistant bacteria represent a major human health problem. Thus, there is an urgent need for the development of antibiotics with new modes of action. In this study, we investigated the antibacterial characteristics and mode of action of a new antimicrobial compound, SPI031 (N-alkylated 3, 6-dihalogenocarbazol 1-(sec-butylamino)-3-(3,6-dichloro-9H-carbazol-9-yl)propan-2-ol), which was previously identified in our group. This compound exhibits broad-spectrum antibacterial activity, including activity against the human pathogens Staphylococcus aureus and Pseudomonas aeruginosa. We found that SPI031 has rapid bactericidal activity (7-log reduction within 30 min at 4x MIC) and that the frequency of resistance development against SPI031 is low. To elucidate the mode of action of SPI031, we performed a macromolecular synthesis assay, which showed that SPI031 causes non-specific inhibition of macromolecular biosynthesis pathways. Liposome leakage and membrane permeability studies revealed that SPI031 rapidly exerts membrane damage, which is likely the primary cause of its antibacterial activity. These findings were supported by a mutational analysis of SPI031-resistant mutants, a transcriptome analysis and the identification of transposon mutants with altered sensitivity to the compound. In conclusion, our results show that SPI031 exerts its antimicrobial activity by causing membrane damage, making it an interesting starting point for the development of new antibacterial therapies. PMID:27167126

  18. pH-Dependent Metal Ion Toxicity Influences the Antibacterial Activity of Two Natural Mineral Mixtures

    PubMed Central

    Cunningham, Tanya M.; Koehl, Jennifer L.; Summers, Jack S.; Haydel, Shelley E.

    2010-01-01

    Background Recent studies have demonstrated that several mineral products sold for medicinal purposes demonstrate antimicrobial activity, but little is known about the physicochemical properties involved in antibacterial activity. Methodology/Principal Findings Using in vitro mineral suspension testing, we have identified two natural mineral mixtures, arbitrarily designated BY07 and CB07, with antibacterial activity against a broad-spectrum of bacterial pathogens. Mineral-derived aqueous leachates also exhibited antibacterial activity, revealing that chemical, not physical, mineral characteristics were responsible for the observed activity. The chemical properties essential for bactericidal activity against Escherichia coli were probed by testing antibacterial activity in the presence of metal chelators, the hydroxyl radical scavenger, thiourea, and varying pH levels. Chelation of the BY07 minerals with EDTA or desferrioxamine eliminated or reduced BY07 toxicity, respectively, suggesting a role of an acid-soluble metal species, particularly Fe3+ or other sequestered metal cations, in mineral toxicity. This conclusion was supported by NMR relaxation data, which indicated that BY07 and CB07 leachates contained higher concentrations of chemically accessible metal ions than leachates from non-bactericidal mineral samples. Conclusions/Significance We conclude that the acidic environment of the hydrated minerals significantly contributes to antibacterial activity by increasing the availability and toxicity of metal ions. These findings provide impetus for further investigation of the physiological effects of mineral products and their applications in complementary antibacterial therapies. PMID:20209160

  19. Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

    PubMed

    Dědková, Kateřina; Lang, Jaroslav; Matějová, Kateřina; Peikertová, Pavlína; Holešinský, Jan; Vodárek, Vlastimil; Kukutschová, Jana

    2015-08-01

    The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation. PMID:26114221

  20. Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

    PubMed

    Dědková, Kateřina; Lang, Jaroslav; Matějová, Kateřina; Peikertová, Pavlína; Holešinský, Jan; Vodárek, Vlastimil; Kukutschová, Jana

    2015-08-01

    The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation.

  1. Antibacterial activity of Syzygium cumini and Syzygium travancoricum leaf essential oils.

    PubMed

    Shafi, P M; Rosamma, M K; Jamil, Kaiser; Reddy, P S

    2002-08-01

    The leaf essential oils of Syzygium cumini and Syzygium travancoricum were tested for their antibacterial property. The activity of S. cumini essential oil was found to be good, while that of S. travancoricum was moderate. PMID:12165339

  2. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Fou...

  3. Chemical composition and antibacterial activity of essential oils from different parts of Leonurus japonicus Houtt.

    PubMed

    Xiong, Liang; Peng, Cheng; Zhou, Qin-Mei; Wan, Feng; Xie, Xiao-Fang; Guo, Li; Li, Xiao-Hong; He, Cheng-Jun; Dai, Ou

    2013-01-01

    The herb and fruits of Leonurus japonicus Houtt., named "Yimucao" and "Chongweizi", respectively, in Chinese, have been widely used in China as gynecological medicines. The components of the essential oils obtained by hydrodistillation were investigated by GC-MS. The antibacterial activity of the essential oils was determined by micro-dilution assay. The results showed large variations in the chemical composition and antibacterial activity of the oils. The oil of "Yimucao" showed antibacterial activity against various Gram-positive bacteria and consisted mainly of sesquiterpenes and diterpenes, with phytone, phytol, caryophyllene oxide and β-caryophyllene being the most significant constituents, whereas the oil of "Chongweizi", mainly made up of bornyl acetate and aliphatic hydrocarbons, was inactive in the antibacterial assay. Further study of the main compounds in "Yimucao oil" showed that β-caryophyllene had wide-spectrum activity against Gram-positive bacteria. PMID:23344204

  4. Antibacterial activity of lichen Usnea rubrotincta, Ramalina dumeticola, and Cladonia verticillata

    NASA Astrophysics Data System (ADS)

    Gunasekaran, Saranyapiriya; Rajan, Vinoshene Pillai; Samsudin, Mohd. Wahid; Din, Laily; Ramanathan, Surash; Murugaiyah, Vikneswaran

    2015-09-01

    The present study was carried out to evaluate the antibacterial activity of extract and chemical constituents of Usnea rubrotincta, Ramalina dumeticola and Cladonia verticillata. Extracts of U. rubrotincta and R. dumeticola showed promising antibacterial activity against gram positive bacteria Staphylococcus aureus and Bacillus subtilis. The lowest value of MIC (15.63 μg/mL) was observed for the acetone extract of U. rubrotincta against B. subtilis. While extract of C. verticillata was neither active against gram positive nor gram negative bacteria at the highest tested concentration of 500 μg/m. This is the first evaluation of antibacterial activity of lichens found in Malaysia and to our knowledge, this is the first report of antibacterial

  5. Chemical composition and antibacterial activity of essential oils from different parts of Leonurus japonicus Houtt.

    PubMed

    Xiong, Liang; Peng, Cheng; Zhou, Qin-Mei; Wan, Feng; Xie, Xiao-Fang; Guo, Li; Li, Xiao-Hong; He, Cheng-Jun; Dai, Ou

    2013-01-01

    The herb and fruits of Leonurus japonicus Houtt., named "Yimucao" and "Chongweizi", respectively, in Chinese, have been widely used in China as gynecological medicines. The components of the essential oils obtained by hydrodistillation were investigated by GC-MS. The antibacterial activity of the essential oils was determined by micro-dilution assay. The results showed large variations in the chemical composition and antibacterial activity of the oils. The oil of "Yimucao" showed antibacterial activity against various Gram-positive bacteria and consisted mainly of sesquiterpenes and diterpenes, with phytone, phytol, caryophyllene oxide and β-caryophyllene being the most significant constituents, whereas the oil of "Chongweizi", mainly made up of bornyl acetate and aliphatic hydrocarbons, was inactive in the antibacterial assay. Further study of the main compounds in "Yimucao oil" showed that β-caryophyllene had wide-spectrum activity against Gram-positive bacteria.

  6. Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family.

    PubMed

    Tan, Joash Ban Lee; Yap, Wei Jin; Tan, Shen Yeng; Lim, Yau Yan; Lee, Sui Mae

    2014-01-01

    Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5-10 mg/mL based on the broth microdilution method. PMID:26785239

  7. Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family

    PubMed Central

    Tan, Joash Ban Lee; Yap, Wei Jin; Tan, Shen Yeng; Lim, Yau Yan; Lee, Sui Mae

    2014-01-01

    Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5–10 mg/mL based on the broth microdilution method. PMID:26785239

  8. Photogenerated charge carriers and reactive oxygen species in ZnO/Au hybrid nanostructures with enhanced photocatalytic and antibacterial activity.

    PubMed

    He, Weiwei; Kim, Hyun-Kyung; Wamer, Wayne G; Melka, David; Callahan, John H; Yin, Jun-Jie

    2014-01-15

    Semiconductor nanostructures with photocatalytic activity have the potential for many applications including remediation of environmental pollutants and use in antibacterial products. An effective way for promoting photocatalytic activity is depositing noble metal nanoparticles (NPs) on a semiconductor. In this paper, we demonstrated the successful deposition of Au NPs, having sizes smaller than 3 nm, onto ZnO NPs. ZnO/Au hybrid nanostructures having different molar ratios of Au to ZnO were synthesized. It was found that Au nanocomponents even at a very low Au/ZnO molar ratio of 0.2% can greatly enhance the photocatalytic and antibacterial activity of ZnO. Electron spin resonance spectroscopy with spin trapping and spin labeling was used to investigate the enhancing effect of Au NPs on the generation of reactive oxygen species and photoinduced charge carriers. Deposition of Au NPs onto ZnO resulted in a dramatic increase in light-induced generation of hydroxyl radical, superoxide and singlet oxygen, and production of holes and electrons. The enhancing effect of Au was dependent on the molar ratio of Au present in the ZnO/Au nanostructures. Consistent with these results from ESR measurements, ZnO/Au nanostructures also exhibited enhanced photocatalytic and antibacterial activity. These results unveiled the enhanced mechanism of Au on ZnO and these materials have great potential for use in water purification and antibacterial products.

  9. Propolis induced antibacterial activity and other technical properties of cotton textiles.

    PubMed

    Sharaf, S; Higazy, A; Hebeish, A

    2013-08-01

    Propolis is a gum gathered by honey bees from various plants; the honey bees use propolis to seal holes in their honey combs, smooth out the internal wall and protect the entrance against intruders. It is composed of 50% resin (flavonoids and related phenolic acid), 30% wax, 10% essential oils, 5% pollen and 5% various organic components. As a natural mixture, propolis is widely used in medicine, cosmetics and food. So far no attempts have been yet made to make use of propolis in the realm of textile finishing. Current work presents the first systemic study targeted to build up a scientific basis for production of cotton textiles having antibacterial activity and other useful properties by making use of propolis as eco-friendly finish within the scope of green strategy. Propolis extract solution (70/30 ethanol/water) of 10% concentration was prepared as the stock. Different amounts of the latter were used along with a crosslinking agent and catalyst for treatment of cotton fabrics as per pad-dry-cure technique. Antibacterial activity of the so treated fabrics was obtained through monitoring the efficiency of the interaction of propolis with cotton cellulose. This interaction was expressed as inhibition zone diameter after the treated fabrics were exposed to (G+ve) and (G-ve) bacteria. Other properties include crease recovery, tensile strength and elongation at break. Factors affecting these properties such as type, nature and concentration of the crosslinking agent, concentration of propolis, and conditions of curing were investigated. In addition characterization of the propolis containing modified cotton fabrics including demonstration of the antibacterial activity, SEM, FTIR, durability to washing, UV protection and water repellency were performed. Based on results obtained, it is concluded that application of propolis along with glyoxal and Al2(SO4)3catalyst using pad-dry (3min/80°C), cure (5/140°C) bring about cotton textile with superior antibacterial

  10. Essential oil composition and antibacterial activity of Monticalia greenmaniana (Asteraceae).

    PubMed

    Cárdenas, José; Rojas, Janne; Rojas-Fermin, Luís; Lucena, María; Buitrago, Alexis

    2012-02-01

    The essential oils from fresh aerial parts of Monticalia greenmaniana (Hieron) C. Jeffrey (Asteraceae) collected in March, were analyzed by GC/MS. Oil yields (w/v) of 0.1% (flowers), 0.07%, (stems) and 0.1% (leaves) were obtained by hydrodistillation. Thirteen, sixteen and eighteen components, respectively, were identified by comparison of their mass spectra with those in the Wiley GC-MS Library data base. The major components of the flower and stem oils were 1-nonane (38.8% flowers; 33.5% stems), alpha-pinene (29.0% flowers; 14.8% stems) and germacrene D (15.6% flowers; 18.6% stems). However, in the leaf oil, germacrene D was observed at 50.7%, followed by beta-cedrene at 8.4%. The leaf essential oil showed a broad spectrum of antibacterial activity against the important human pathogenic Gram-positive and Gram-negative bacteria Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 25955) with MIC values ranging from 75 to 6000 ppm.

  11. Antibacterial activity of a lectin-like Burkholderia cenocepacia protein

    PubMed Central

    Ghequire, Maarten G K; Canck, Evelien; Wattiau, Pierre; Winge, Iris; Loris, Remy; Coenye, Tom; Mot, René

    2013-01-01

    Abstract Bacteriocins of the LlpA family have previously been characterized in the γ-proteobacteria Pseudomonas and Xanthomonas. These proteins are composed of two MMBL (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. Genes encoding four different types of LlpA-like proteins were identified in genomes from strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. A selected recombinant LlpA-like protein from the human isolate Burkholderia cenocepacia AU1054 displayed narrow-spectrum genus-specific antibacterial activity, thus representing the first functionally characterized bacteriocin within this β-proteobacterial genus. Strain-specific killing was confined to other members of the Bcc, with mostly Burkholderia ambifaria strains being susceptible. In addition to killing planktonic cells, this bacteriocin also acted as an antibiofilm agent. Bacteriocins mediate highly selective antagonism among closely related bacteria but such antimicrobial proteins have not yet been reported in Burkholderia. We identified a lectin-like protein of the LlpA family in a Burkholderia cenocepacia human isolate that strain-specifically and selectively kills planktonic and biofilm cells of other Burkholderia cepacia complex members. PMID:23737242

  12. Antibacterial Activity of Various Plants Extracts Against Antibiotic-resistant Aeromonas hydrophila

    PubMed Central

    Al Laham, Shaza Anwar; Al Fadel, Frdoos Mohammad

    2014-01-01

    Background: Aeromonas hydrophila cause one of the most important diseases in fishes and lead to economic losses, and may be contaminated human beings. Objectives: The current research aimed to investigate the anti-bacterial activity shown by the extracts prepared from different parts of Olea europea, Myrtus communis, Thymus vulgaris, Rosmarinuis officinalis, and Achillea falcata that grow in Syria against A. hydrophila that causes the most dangerous bacterial diseases in fish. Materials and Methods: The study was performed in four stages: First of all, the presence of A. hydrophila was investigated in 450 Samples of Cyprinus Carpio fish using blood agar, Trypticase soya agar, and Analytical Profile Index (API20E). Secondly, the plants extract was obtained using water, absolute alcohol, then ether using Soxhlet extraction apparatus and rotary vacuum evaporator. Thirdly, the antibacterial activity of some antibiotics on these bacteria was evaluated by disk diffusion method. Finally, the antibacterial effect of the extracts was determined by disk diffusion method. Results: The studied antibiotics showed no antibacterial activity against these bacteria, except amikacin which had an acceptable effectiveness. However, the ethanol extracts of the studied plants revealed different antibacterial effects against A. hydrophila which showed antibiotic resistant. T. vulgaris extract had the strongest effect, whereas O. europea extract had the weakest activity. The water and ether petroleum extracts had no antibacterial activities. Conclusions: Ethanol extracts of the studied plants had different antibacterial effects against antibiotic-resistant A. hydrophila. T. vulgaris had the highest activity, R. officinalis had the second, and M. communis and A. falcate were in the third place, while the O. europea had the weakest antibacterial activity. PMID:25368797

  13. Report: Studies on antibacterial activity of some traditional medicinal plants used in folk medicine.

    PubMed

    Israr, Fozia; Hassan, Fouzia; Naqvi, Baqir Shyum; Azhar, Iqbal; Jabeen, Sabahat; Hasan, S M Farid

    2012-07-01

    Ethanolic extracts of eight medicinal plants commonly used in folk medicine were tested for their antibacterial activity against four Gram positive strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis and, Streptococcus pneumoniae) and six Gram negative strains (Escherichia coli, Proteus vulgaris, Proteus mirabilis. Salmonella typhi para A, Salmonella typhi para B and Shigella dysenteriae) that were obtained from different pathological laboratories located in Karachi, Pakistan. Disc diffusion method was used to analyze antibacterial activity. Out of eight, five medicinal plants showed antibacterial activity against two or more than two microbial species. The most effective antimicrobial plant found to be Punica granatum followed by Curcuma zedoaria Rosc, Grewia asiatica L and Carissa carandas L, Curcuma caesia Roxb respectively. From these results, it is evident that medicinal plants could be used as a potential source of new antibacterial agents.

  14. Chemical composition and in vitro antioxidant and antibacterial activity of Heracleum transcaucasicum and Heracleum anisactis roots essential oil

    PubMed Central

    Torbati, Mohammadali; Nazemiyeh, Hossein; Lotfipour, Farzaneh; Nemati, Mahboob; Asnaashari, Solmaz; Fathiazad, Fatemeh

    2014-01-01

    Introduction: In vitro antioxidant and antibacterial activity and volatile compositions of two Heracleum species (Apiaceae) including Heracleum transcaucasicum and Heracleum anisactis roots Essential Oil (EO) were investigated. Methods: The volatile compositions of EOs were analyzed by GC/Mass spectroscopy. To detect the antioxidant activity of essential oils TLC-bioautography and DPPH radical scavenging assay by spectrophotometry was performed. Additionally, the antibacterial activity of two essential oils were studied and compared against four pathogenic bacteria by agar disc diffusion method and MIC values of the EOs were determined using the broth dilution method. Results: Myristicin was the dominant component in both EOs. It was identified as 96.87% and 95.15% of the essential oil composition of H. transcaucasicum and H. anisactis roots, respectively. The TLC-bioautography showed antioxidant spots in both EOs and IC50 of H. anisactis and H. transcaucasicum EO was found to be 54 μg × ml (-1) and 77 μg × ml (-1), respectively. Regarding the antimicrobial assay, H. anisactis EO exhibited weak to moderate antibacterial activity against gram-positive bacteria and also Escherichia coli, whereas the essential oil from H. transcaucasicum was inactive. Conclusion: Based on the results from this study, both tested EOs mainly consist of myristicin. Despite the presence of myristicin with known antibacterial property, the EO from H. transcacausicum showed no antibacterial activity. Thus it is supposed that the biological activity of plants is remarkably linked to the extracts’ chemical profile and intercomponents’ synergistic or antagonistic effect could play a crucial role in bioactivity of EOs and other plant extracts. PMID:25035849

  15. Investigation of the chemical composition-antibacterial activity relationship of essential oils by chemometric methods.

    PubMed

    Miladinović, Dragoljub L; Ilić, Budimir S; Mihajilov-Krstev, Tatjana M; Nikolić, Nikola D; Miladinović, Ljiljana C; Cvetković, Olga G

    2012-05-01

    The antibacterial effects of Thymus vulgaris (Lamiaceae), Lavandula angustifolia (Lamiaceae), and Calamintha nepeta (Lamiaceae) Savi subsp. nepeta var. subisodonda (Borb.) Hayek essential oils on five different bacteria were estimated. Laboratory control strain and clinical isolates from different pathogenic media were researched by broth microdilution method, with an emphasis on a chemical composition-antibacterial activity relationship. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalool acetate (38.23%) and β-linalool (35.01%) were main compounds in lavender oil. C. nepeta essential oil was characterized by a high percentage of piperitone oxide (59.07%) and limonene (9.05%). Essential oils have been found to have antimicrobial activity against all tested microorganisms. Classification and comparison of essential oils on the basis of their chemical composition and antibacterial activity were made by utilization of appropriate chemometric methods. The chemical principal component analysis (PCA) and hierachical cluster analysis (HCA) separated essential oils into two groups and two sub-groups. Thyme essential oil forms separate chemical HCA group and exhibits highest antibacterial activity, similar to tetracycline. Essential oils of lavender and C. nepeta in the same chemical HCA group were classified in different groups, within antibacterial PCA and HCA analyses. Lavender oil exhibits higher antibacterial ability in comparison with C. nepeta essential oil, probably based on the concept of synergistic activity of essential oil components. PMID:22389175

  16. Screening for antibacterial activity of some Turkish plants against fish pathogens: a possible alternative in the treatment of bacterial infections

    PubMed Central

    Turker, Hakan; Yıldırım, Arzu Birinci

    2015-01-01

    The antibacterial activity of ethanolic and aqueous crude extracts from 36 plants in Turkey, including seven endemic species, against fish pathogens was studied using the disc diffusion assay. The extract that was most active against all microbial strains, except Aeromonas salmonicida, was that of Dorycnium pentaphyllum. Some of the extracts also showed a very broad spectrum of potent antimicrobial activity. The extract of Anemone nemorosa showed the highest antimicrobial activity against Vibrio anguillarum. V. anguillarum, a Gram-negative bacterium, appeared to be the most susceptible to the plant extracts used in this experiment. To the best of our knowledge, this is the first report on the antimicrobial activity of 11 of the studied plants. The preliminary screening assay indicated that some of the Turkish plants with antibacterial properties may offer alternative therapeutic agents against bacterial infections in aquaculture industry. PMID:26019642

  17. Antibacterial activities and structure-activity relationships of a panel of 48 compounds from Kenyan plants against multidrug resistant phenotypes.

    PubMed

    Omosa, Leonidah K; Midiwo, Jacob O; Mbaveng, Armelle T; Tankeo, Simplice B; Seukep, Jackson A; Voukeng, Igor K; Dzotam, Joachim K; Isemeki, John; Derese, Solomon; Omolle, Ruth A; Efferth, Thomas; Kuete, Victor

    2016-01-01

    In the current study forty eight compounds belonging to anthraquinones, naphthoquinones, benzoquinones, flavonoids (chalcones and polymethoxylated flavones) and diterpenoids (clerodanes and kauranes) were explored for their antimicrobial potential against a panel of sensitive and multi-drug resistant Gram-negative and Gram-positive bacteria. The minimal inhibitory concentration (MIC) determinations on the tested bacteria were conducted using modified rapid INT colorimetric assay. To evaluate the role of efflux pumps in the susceptibility of Gram-negative bacteria to the most active compounds, they were tested in the presence of phenylalanine arginine β-naphthylamide (PAβN) (at 30 µg/mL) against selected multidrug resistance (MDR) bacteria. The anthraquinone, emodin, naphthaquinone, plumbagin and the benzoquinone, rapanone were active against methicillin resistant Staphylococcus aureus (MRSA) strains of bacteria with MIC values ranging from 2 to 128 μg/mL. The structure activity relationships of benzoquinones against the MDR Gram-negative phenotype showed antibacterial activities increasing with increase in side chain length. In the chalcone series the presence of a hydroxyl group at C3' together with a methoxy group and a second hydroxyl group in meta orientation in ring B of the chalcone skeleton appeared to be necessary for minimal activities against MRSA. In most cases, the optimal potential of the active compounds were not attained as they were extruded by bacterial efflux pumps. However, the presence of the PAβN significantly increased the antibacterial activities of emodin against Gram-negative MDR E. coli AG102, 100ATet; K. pneumoniae KP55 and KP63 by >4-64 g/mL. The antibacterial activities were substantially enhanced and were higher than those of the standard drug, chloramphenicol. These data clearly demonstrate that the active compounds, having the necessary pharmacophores for antibacterial activities, including some quinones and chalcones are

  18. The drosomycin multigene family: three-disulfide variants from Drosophila takahashii possess antibacterial activity.

    PubMed

    Gao, Bin; Zhu, Shunyi

    2016-01-01

    Drosomycin (DRS) is a strictly antifungal peptide in Drosophila melanogaster, which contains four disulfide bridges (DBs) with three buried in molecular interior and one exposed on molecular surface to tie the amino- and carboxyl-termini of the molecule together (called wrapper disulfide bridge, WDB). Based on computational analysis of genomes of Drosophila species belonging to the Oriental lineage, we identified a new multigene family of DRS in Drosphila takahashii that includes a total of 11 DRS-encoding genes (termed DtDRS-1 to DtDRS-11) and a pseudogene. Phylogenetic tree and synteny analyses reveal orthologous relationship between DtDRSs and DRSs, indicating that orthologous genes of DRS-1, DRS-2, DRS-3 and DRS-6 have undergone duplication in D. takahashii and three amplifications (DtDRS-9 to DtDRS-11) of DRS-3 have lost WDB. Among the 11 genes, five are transcriptionally active in adult fruitflies. The ortholog of DRS (DtDRS-1) shows high structural and functional similarity to DRS while two WDB-deficient members display antibacterial activity accompanying complete loss or remarkable reduction of antifungal activity. To the best of our knowledge, this is the first report on the presence of three-disulfide antibacterial DRSs in a specific Drosophila species, suggesting a potential role of DB loss in neofunctionalization of a protein via structural adjustment. PMID:27562645

  19. The drosomycin multigene family: three-disulfide variants from Drosophila takahashii possess antibacterial activity

    PubMed Central

    Gao, Bin; Zhu, Shunyi

    2016-01-01

    Drosomycin (DRS) is a strictly antifungal peptide in Drosophila melanogaster, which contains four disulfide bridges (DBs) with three buried in molecular interior and one exposed on molecular surface to tie the amino- and carboxyl-termini of the molecule together (called wrapper disulfide bridge, WDB). Based on computational analysis of genomes of Drosophila species belonging to the Oriental lineage, we identified a new multigene family of DRS in Drosphila takahashii that includes a total of 11 DRS-encoding genes (termed DtDRS-1 to DtDRS-11) and a pseudogene. Phylogenetic tree and synteny analyses reveal orthologous relationship between DtDRSs and DRSs, indicating that orthologous genes of DRS-1, DRS-2, DRS-3 and DRS-6 have undergone duplication in D. takahashii and three amplifications (DtDRS-9 to DtDRS-11) of DRS-3 have lost WDB. Among the 11 genes, five are transcriptionally active in adult fruitflies. The ortholog of DRS (DtDRS-1) shows high structural and functional similarity to DRS while two WDB-deficient members display antibacterial activity accompanying complete loss or remarkable reduction of antifungal activity. To the best of our knowledge, this is the first report on the presence of three-disulfide antibacterial DRSs in a specific Drosophila species, suggesting a potential role of DB loss in neofunctionalization of a protein via structural adjustment. PMID:27562645

  20. In vitro effects on biofilm viability and antibacterial and antiadherent activities of silymarin.

    PubMed

    Evren, Ebru; Yurtcu, Erkan

    2015-07-01

    Limited treatment options in infectious diseases caused by resistant microorganisms created the need to search new approaches. Several herbal extracts are studied for their enormous therapeutic potential. Silymarin extract, from Silybum marianum (milk thistle), is an old and a new remedy for this goal. The purpose of this study is to evaluate the antibacterial and antiadherent effects of silymarin besides biofilm viability activity on standard bacterial strains. Minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), antiadherent/antibiofilm activity, and effects on biofilm viability of silymarin were evaluated against standard bacterial strains. MIC values were observed between 60 and >241 μg/mL (0.25->1 mmol/L). Gram-positive bacteria were inhibited at concentrations between 60 and 120 μg/mL. Gram-negative bacteria were not inhibited by the silymarin concentrations included in this study. MBC values for Gram-positive bacteria were greater than 241 μg/mL. Adherence/biofilm formations were decreased to 15 μg/mL silymarin concentration when compared with silymarin-untreated group. Silymarin reduced the biofilm viabilities to 13 and 46 % at 1 and 0.5 mmol/L concentrations, respectively. We demonstrated that silymarin shows antibacterial and antiadherent/antibiofilm activity against certain standard bacterial strains which may be beneficial when used as a dietary supplement or a drug. PMID:25937395

  1. Antibacterial activity of casein-derived peptides isolated from rabbit (Oryctolagus cuniculus) milk.

    PubMed

    Baranyi, Maria; Thomas, Ursula; Pellegrini, Antonio

    2003-05-01

    Acid-precipitated rabbit 'whole casein' was digested by trypsin, chymotrypsin, pepsin, and clostripain to screen for possible peptides with antibacterial properties. The peptide fragments were separated by reversed-phase chromatography. The collected fractions were pooled and their antibacterial properties tested against Escherichia coli, Bacillus subtilis and Staphylococcus lentus. Three antibacterial peptide fragments derived from tryptic digestion of rabbit casein were isolated and identified. Their sequences were found as follows: HVEQLLR (residues 50-56 of beta-casein), ILPFIQSLFPFAER (residues 64-77 of beta-casein), and FHLGHLK (residues 19-25 of alpha(s1)-casein). The three peptides were synthesized and found to exert antibacterial effect against gram positive bacteria only. Proteolytic digestion of rabbit casein by chymotrypsin, pepsin and clostripain yielded several peptide fragments with antibacterial activity. Since antibiotic peptides can be released from casein during the digestion of milk proteins, our results suggest a possible antibacterial function of rabbit caseins. It is conceivable that antibacterial peptides can be generated by endopeptidases of the mammalian gastrointestinal tract possibly providing protection for new-born rabbits against aggression of micro-organisms.

  2. The cellular responses and antibacterial activities of silver nanoparticles stabilized by different polymers

    NASA Astrophysics Data System (ADS)

    Lin, Jiang-Jen; Lin, Wen-Chun; Dong, Rui-Xuan; Hsu, Shan-hui

    2012-02-01

    Silver nanoparticles (AgNPs) are known for their excellent antibacterial activities. The possible toxicity, however, is a major concern for their applications. Three types of AgNPs were prepared in this study by chemical processes. Each was stabilized by a polymer surfactant, which was expected to reduce the exposure of cells to AgNPs and therefore their cytotoxicity. The polymer stabilizers included poly(oxyethylene)-segmented imide (POEM), poly(styrene-co-maleic anhydride)-grafting poly(oxyalkylene) (SMA) and poly(vinyl alcohol) (PVA). The cytotoxicity of these chemically produced AgNPs to mouse skin fibroblasts (L929), human hepatocarcinoma cells (HepG2), and mouse monocyte macrophages (J774A1) was compared to that of physically produced AgNPs and gold nanoparticles (AuNPs) as well as the standard reference material RM8011 AuNPs. Results showed that SMA-AgNPs were the least cytotoxic among all materials, but cytotoxicity was still observed at higher silver concentrations (>30 ppm). Macrophages demonstrated the inflammatory response with cell size increase and viability decrease upon exposure to 10 ppm of the chemically produced AgNPs. SMA-AgNPs did not induce hemolysis at a silver concentration below 1.5 ppm. Regarding the antibacterial activity, POEM-AgNPs and SMA-AgNPs at 1 ppm silver content showed 99.9% and 99.3% growth inhibition against E. coli, while PVA-AgNPs at the same silver concentration displayed 79.1% inhibition. Overall, SMA-AgNPs demonstrated better safety in vitro and greater antibacterial effects than POEM-AgNPs and PVA-AgNPs. This study suggested that polymer stabilizers may play an important role in determining the toxicity of AgNPs.

  3. Antibacterial, antioxidant and tyrosinase-inhibition activities of pomegranate fruit peel methanolic extract

    PubMed Central

    2012-01-01

    Background This study evaluated, using in vitro assays, the antibacterial, antioxidant, and tyrosinase-inhibition activities of methanolic extracts from peels of seven commercially grown pomegranate cultivars. Methods Antibacterial activity was tested on Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia) using a microdilution method. Several potential antioxidant activities, including radical-scavenging ability (RSA), ferrous ion chelating (FIC) and ferric ion reducing antioxidant power (FRAP), were evaluated. Tyrosinase enzyme inhibition was investigated against monophenolase (tyrosine) and diphenolase (DOPA), with arbutin and kojic acid as positive controls. Furthermore, phenolic contents including total flavonoid content (TFC), gallotannin content (GTC) and total anthocyanin content (TAC) were determined using colourimetric methods. HPLC-ESI/MSn analysis of phenolic composition of methanolic extracts was also performed. Results Methanolic peel extracts showed strong broad-spectrum activity against Gram-positive and Gram-negative bacteria, with the minimum inhibitory concentrations (MIC) ranging from 0.2 to 0.78 mg/ml. At the highest concentration tested (1000 μg/ml), radical scavenging activities were significantly higher in Arakta (83.54%), Ganesh (83.56%), and Ruby (83.34%) cultivars (P< 0.05). Dose dependent FIC and FRAP activities were exhibited by all the peel extracts. All extracts also exhibited high inhibition (>50%) against monophenolase and diphenolase activities at the highest screening concentration. The most active peel extract was the Bhagwa cultivar against monophenolase and the Arakta cultivar against diphenolase with IC50 values of 3.66 μg/ml and 15.88 μg/ml, respectively. High amounts of phenolic compounds were found in peel extracts with the highest and lowest total phenolic contents of 295.5 (Ganesh) and 179.3 mg/g dry extract (Molla de Elche), respectively

  4. Screening of Taiwanese crude drugs for antibacterial activity against Streptococcus mutans.

    PubMed

    Chen, C P; Lin, C C; Namba, T

    1989-12-01

    Preliminary antibacterial screening of local crude drugs was carried out using the cariogenic bacterium, Streptococcus mutans. Of 79 aqueous extracts tested, 6 crude drugs were shown to have significant antibacterial activity with minimal inhibitory concentration equal to or lower than 7.8 mg/ml (expressed in terms of dry starting material). Of these effective crude drugs, Morus australis, Ludwigia octovalvis and Thuja orientalis were very effective in inhibiting the growth of serotypes c and d of S. mutans (MIC less than or equal to 2.0-7.8 mg/ml). Elephantopus scaber, Artemisia vulgaris, Mosla chinensis and Orthosiphon aristatus also exhibited considerable antibacterial activity (MIC = 7.8-23.4 mg/ml) against both serotypes. In the presence of 5% sucrose, the antibacterial potency of the majority of the extracts did not change for type c, while the potency decreased about one-half for type d.

  5. Synthesis and structure-activity relationship of amidine derivatives of 3,4-ethylenedioxythiophene as novel antibacterial agents.

    PubMed

    Stolić, Ivana; Čipčić Paljetak, Hana; Perić, Mihaela; Matijašić, Mario; Stepanić, Višnja; Verbanac, Donatella; Bajić, Miroslav

    2015-01-27

    Current antibacterial chemotherapeutics are facing an alarming increase in bacterial resistance pressuring the search for novel agents that would expand the available therapeutic arsenal against resistant bacterial pathogens. In line with these efforts, a series of 9 amidine derivatives of 3,4-ethylenedioxythiophene were synthesized and, together with 18 previously synthesized analogs, evaluated for their relative DNA binding affinity, in vitro antibacterial activities and preliminary in vitro safety profile. Encouraging antibacterial activity of several subclasses of tested amidine derivatives against Gram-positive (including resistant MRSA, MRSE, VRE strains) and Gram-negative bacterial strains was observed. The bis-phenyl derivatives were the most antibacterially active, while compound 19 from bis-benzimidazole class exhibited the widest spectrum of activity (with MIC of 4, 2, 0.5 and ≤0.25 μg/ml against laboratory strains of Staphyloccocus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Moraxella catarrhalis, respectively and 4-32 μg/ml against clinical isolates of sensitive and resistant S. aureus, Staphylococcus epidermidis and Enterococcus faecium) and also demonstrated the strongest DNA binding affinity (ΔTm of 15.4 °C). Asymmetrically designed compounds and carboxamide-amidines were, in general, less active. Molecular docking indicated that the shape of the 3,4-ethylenedioxythiophene derivatives and their ability to form multiple electrostatic and hydrogen bonds with DNA, corresponds to the binding modes of other minor-groove binders. Herein reported results encourage further investigation of this class of compounds as novel antibacterial DNA binding agents.

  6. Phytochemical screening, cytotoxicity and antibacterial activities of two Bangladeshi medicinal plants.

    PubMed

    Roy, Ajoy; Biswas, Subrata Kumar; Chowdhury, Anusua; Shill, Manik Chandra; Raihan, Sheikh Zahir; Muhit, Md Abdul

    2011-10-01

    The objectives of the present study were to investigate phytochemical screening and to assay cytotoxicity and antibacterial activities of ethanolic extracts of leaves of two medicinal plants, Aglaonema hookerianum Schott (Family: Araceae) and Lannea grandis Engl. (Family: Anacardiaceae) available in Bangladesh. The brine shrimp lethality bioassay showed that the ethanolic extracts of Aglaonema hookerianum and Lannea grandis possessed cytotoxic activities with LC50 5.25 (microg mL(-1)) and 5.75 (microg mL(-1)) and LC90 10.47 (microg mL(-1)) and 9.55 (microg mL(-1)), respectively. Two extracts obtained from leaves were examined for their antibacterial activities against some gram positive bacteria such as Bacillus subtilis, Bacillus megaterium and Staphylococcus aureus, also gram negative strains of Pseudomonas aeruginosa, Escherichia coli, Shigella dysenteriae, Salmonella typhi, Salmonella paratyphi and Vibrio cholerae. Agar disc diffusion method was applied to observe the antibacterial efficacy of the extracts. Results indicated that both plant extracts (500 microg disc(-1)) displayed antibacterial activity against all of the tested microorganisms. These results were also compared with the zones of inhibition produced by commercially available standard antibiotic, Amoxicillin at concentration of 10 microg disc(-1). Observed antibacterial properties of the ethanolic extract of Aglaonema hookerianum Schott and Lannea grandis Engl. showed that both plants might be useful sources for the development of new potent antibacterial agents.

  7. Cytotoxic and antibacterial activity of the mixture of olive oil and lime cream in vitro conditions.

    PubMed

    Sumer, Zeynep; Yildirim, Gulay; Sumer, Haldun; Yildirim, Sahin

    2013-01-01

    The mixture of olive oil and lime cream has been traditionally used to treat external burns in the region of Hatay/Antakya and middle Anatolia. Olive oil and lime cream have been employed by many physicians to treat many ailments in the past. A limited number of studies have shown the antibacterial effect of olive oil and that it does not have any toxic effect on the skin. But we did not find any reported studies on the mixture of olive oil and lime cream. The aim of this paper is to investigate the cytotoxic and antibacterial activity of olive oil and lime cream individually or/and in combination in vitro conditions, by using disk-diffusion method and in cell culture. The main purpose in using this mixture is usually to clear burns without a trace. Agar overlay, MTT (Cytotoxicity assay) and antibacterial susceptibility tests were used to investigate the cytotoxic and antibacterial activity of olive oil and lime cream. We found that lime cream has an antibacterial activity but also cytotoxic on the fibroblasts. On the other hand olive oil has limited or no antibacterial effect and it has little or no cytotoxic on the fibroblasts. When we combined lime cream and olive oil, olive oil reduced its cytotoxic impact. These results suggest that mixture of olive oil and lime cream is not cytotoxic and has antimicrobial activity.

  8. Phenol content, antioxidant capacity and antibacterial activity of methanolic extracts derived from four Jordanian medicinal plants.

    PubMed

    Irshaid, Fawzi I; Tarawneh, Khalid A; Jacob, Jacob H; Alshdefat, Aisha M

    2014-02-01

    This study was performed to assess the antioxidant and antibacterial properties of methanolic extracts derived from aerial parts of four Jordanian medicinal plants (Artemisia sieberi, Peganum harmala, Rosmarinus officinalis (Green-Flowered) and Sarcopterium spinosium). The possible relationship between these biological properties and the total phenolic concentrations of these extracts were also be determined. The antioxidant capacity and total phenolic concentrations were assessed by the ABTS method and Folin-Ciocalteu method, respectively. The amount of the extract required to scavenge 50% of ABTS (IC50) was also measured. Broth dilution and disc diffusion assays were performed to measure the antibacterial activity of these extracts against available bacterial strains. Variations were observed among the examined plants in antioxidant and antibacterial activities as well as in their phenol contents. According to ABTS assay and IC50 value, the highest free radical scavenging potential was found in Sarcopterium spinosium, followed by Rosmarinus officinalis, Peganum harmala and Artemisia sieberi, respectively. Similarly, the results of antibacterial assays showed that Sarcopterium spinosium exhibited the highest antibacterial activity against all tested bacterial strains as compared to Rosmarinus officinalis, Peganum harmala and Artemisia sieberi. Moreover, Sarcopterium spinosium contained the highest amount of phenolic compounds followed by, Rosmarinus officinalis, Artemisia sieberi and Peganum harmala, respectively. In conclusion, these plants are not only interesting sources for antimicrobial agents but also have a considerable amount of antioxidants. In addition, these findings revealed that the antioxidant capacity and antibacterial activity of these plant extracts do not necessary be attributed to their total phenolic concentrations.

  9. Bifunctionalized mesoporous silica-supported gold nanoparticles: intrinsic oxidase and peroxidase catalytic activities for antibacterial applications.

    PubMed

    Tao, Yu; Ju, Enguo; Ren, Jinsong; Qu, Xiaogang

    2015-02-11

    Bifunctionalized mesoporous silica-supported gold nanoparticles as oxidase and peroxidase mimics for antibacterial applications are demonstrated. For the first time, these mesoporous silica-supported gold nanoparticles are applied as oxidase and peroxidase mimics. Taking advantage of their prominent enzyme activities, the MSN-AuNPs show excellent antibacterial properties against both Gram-negative and Gram-positive bacteria. Furthermore, MSN-AuNPs also exhibit outstanding performance in biofilm elimination . PMID:25655182

  10. Dual Mode Antibacterial Activity of Ion Substituted Calcium Phosphate Nanocarriers for Bone Infections

    PubMed Central

    Sampath Kumar, T. S.; Madhumathi, K.; Rubaiya, Y.; Doble, Mukesh

    2015-01-01

    Nanotechnology has tremendous potential for the management of infectious diseases caused by multi-drug resistant bacteria, through the development of newer antibacterial materials and efficient modes of antibiotic delivery. Calcium phosphate (CaP) bioceramics are commonly used as bone substitutes due to their similarity to bone mineral and are widely researched upon for the treatment of bone infections associated with bone loss. CaPs can be used as local antibiotic delivery agents for bone infections and can be substituted with antibacterial ions in their crystal structure to have a wide spectrum, sustained antibacterial activity even against drug resistant bacteria. In the present work, a dual mode antibiotic delivery system with antibacterial ion substituted calcium deficient hydroxyapatite (CDHA) nanoparticles has been developed. Antibacterial ions such as zinc, silver, and strontium have been incorporated into CDHA at concentrations of 6, 0.25–0.75, and 2.5–7.5 at. %, respectively. The samples were found to be phase pure, acicular nanoparticles of length 40–50 nm and width 5–6 nm approximately. The loading and release profile of doxycycline, a commonly used antibiotic, was studied from the nanocarriers. The drug release was studied for 5 days and the release profile was influenced by the ion concentrations. The release of antibacterial ions was studied over a period of 21 days. The ion substituted CDHA samples were tested for antibacterial efficacy on Staphylococcus aureus and Escherichia coli by MIC/MBC studies and time-kill assay. AgCDHA and ZnCDHA showed high antibacterial activity against both bacteria, while SrCDHA was weakly active against S. aureus. Present study shows that the antibiotic release can provide the initial high antibacterial activity, and the sustained ion release can provide a long-term antibacterial activity. Such dual mode antibiotic and antibacterial ion release offers an efficient and potent way to treat an incumbent

  11. Antifungal and antibacterial activities of Mexican tarragon (Tagetes lucida).

    PubMed

    Céspedes, Carlos L; Avila, J Guillermo; Martínez, Andrés; Serrato, Blanca; Calderón-Mugica, José C; Salgado-Garciglia, Rafael

    2006-05-17

    Mexican tarragon (Tagetes lucida Cv. Asteraceae: Campanulatae) is an important, nutritious plant and an effective herbal medicine. Seven coumarins, 7,8-dihydroxycoumarin (4), umbelliferone (7-hydroxycoumarin) (5), scoparone (6,7-dimethoxycoumarin) (7), esculetin (6,7-dihydroxycoumarin) (11), 6-hydroxy-7-methoxycoumarin (12), herniarin (7-methoxycoumarin) (13), and scopoletin (6-methoxy-7-hydroxycoumarin) (14), and three flavonoids, patuletin (18), quercetin (19), and quercetagetin (20), were isolated from CH2Cl2 and MeOH extracts from aerial parts of T. lucida. In addition, 6,7-diacetoxy coumarin (15), 6-methoxy-7-acetylcoumarin (16), and 6-acetoxy-7-methoxycoumarin (17) derivatives were synthesized. 8-Methoxypsoralen (1), 8-acetyl-7-hydroxycoumarin (2), 7,8-dihydroxy-6-meth-oxycoumarin (3), 6,7-dimethoxy-4-methylcoumarin (6), 5,7-dihydroxy-4-methylcoumarin (8), 4-hydroxycoumarin (9), 4-hydroxy-6,7-dimethylcoumarin (10), naringenin (21), glycoside-7-rhamnonaringin (22), and rutin (23) were commercially obtained (Sigma-Aldrich). All of these compounds and extracts (M1 and M2) were assayed against bacteria and fungi. The antibacterial activity was determined on Bacillus subtilis, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Salmonella typhi, Salmonella sp., Shigella boydii, Shigella sp., Enterobacter aerogenes, Enterobacter agglomerans, Sarcina lutea, Staphylococcus epidermidis, Staphylococcus aureus, Yersinia enterolitica, Vibrio cholerae (three El Tor strains, CDC-V12, clinic case, and INDRE-206, were obtained from contaminated water), and V. cholerae (NO-O1). The evaluated fungi were Aspergillus niger, Penicillium notatum, Fusarium moniliforme, Fusarium sporotrichum, Rhizoctonia solani, and Trichophyton mentagrophytes. The most active compounds against Gram-positive and -negative bacteria were the dihydroxylated coumarins 3 and 4. In addition, 2-4, 6, 7, and 11 showed an interesting activity against V. cholerae, a key bacterium in the contaminated

  12. Semisynthetic Lipopeptides Derived from Nisin Display Antibacterial Activity and Lipid II Binding on Par with That of the Parent Compound.

    PubMed

    Koopmans, Timo; Wood, Thomas M; 't Hart, Peter; Kleijn, Laurens H J; Hendrickx, Antoni P A; Willems, Rob J L; Breukink, Eefjan; Martin, Nathaniel I

    2015-07-29

    The lipid II-binding N-terminus of nisin, comprising the so-called A/B ring system, was synthetically modified to provide antibacterially active and proteolytically stable derivatives. A variety of lipids were coupled to the C-terminus of the nisin A/B ring system to generate semisynthetic constructs that display potent inhibition of bacterial growth, with activities approaching that of nisin itself. Most notable was the activity observed against clinically relevant bacterial strains including MRSA and VRE. Experiments with membrane models indicate that these constructs operate via a lipid II-mediated mode of action without causing pore formation. A lipid II-dependent mechanism of action is further supported by antagonization assays wherein the addition of lipid II was found to effectively block the antibacterial activity of the nisin-derived lipopeptides. PMID:26122963

  13. Semisynthetic Lipopeptides Derived from Nisin Display Antibacterial Activity and Lipid II Binding on Par with That of the Parent Compound.

    PubMed

    Koopmans, Timo; Wood, Thomas M; 't Hart, Peter; Kleijn, Laurens H J; Hendrickx, Antoni P A; Willems, Rob J L; Breukink, Eefjan; Martin, Nathaniel I

    2015-07-29

    The lipid II-binding N-terminus of nisin, comprising the so-called A/B ring system, was synthetically modified to provide antibacterially active and proteolytically stable derivatives. A variety of lipids were coupled to the C-terminus of the nisin A/B ring system to generate semisynthetic constructs that display potent inhibition of bacterial growth, with activities approaching that of nisin itself. Most notable was the activity observed against clinically relevant bacterial strains including MRSA and VRE. Experiments with membrane models indicate that these constructs operate via a lipid II-mediated mode of action without causing pore formation. A lipid II-dependent mechanism of action is further supported by antagonization assays wherein the addition of lipid II was found to effectively block the antibacterial activity of the nisin-derived lipopeptides.

  14. Antibacterial activity of Phyllantus emblica, Coriandrum sativum, Culinaris medic, Lawsonia alba and Cucumis sativus.

    PubMed

    Khan, Dawood Ali; Hassan, Fouzia; Ullah, Hanif; Karim, Sabiha; Baseer, Abdul; Abid, Mobasher Ali; Ubaidi, Muhammad; Khan, Shujaat Ali; Murtaza, Ghulam

    2013-01-01

    Present study deals with the demonstration of the antibacterial activity of very common medicinal plants of Pakistani origin i.e., Phyllantus emblica, Coriandrum sativum, Culinaris medic, Lawsonia alba and Cucumis sativus. The extracts were prepared in crude form by the use of hydro-alcoholic solution and were screened for antibacterial activity against various bacterial species by disk diffusion method. Assay was performed using clinical isolates of B. cereus, S. aureus, P. aeruginosa and E. coli. Crude extract of Phyllantus emblica fruit exhibited strong activity against standard cultures of all studied bacteria. Lawsonia alba showed good activity against standard cultures of all the used microorganisms. Coriandrum sativum was effective only against Bacillus cereus, while Cucumis sativus and Culinaris medic showed poor activity against Pseudomonas aeruginosa only. Hence, Phyllantus emblica exhibited strong antibacterial activity against a wide range of bacteria it means that Phyllantus emblica extract contains some compounds which have broad spectrum of bactericidal activity.

  15. Antibacterial activity and reusability of CNT-Ag and GO-Ag nanocomposites

    NASA Astrophysics Data System (ADS)

    Kim, Ji Dang; Yun, Hyosuk; Kim, Gwui Cheol; Lee, Chul Won; Choi, Hyun Chul

    2013-10-01

    A facile approach to the synthesis of novel CNT-Ag and GO-Ag antibacterial materials, in which thiol groups are utilized as linkers to secure silver (Ag) nanoparticles to the CNT and GO surfaces without agglomeration, is reported. The resulting CNT-Ag and GO-Ag samples were characterized by performing TEM, XRD, Auger, XPS, and Raman measurements, which revealed that in these antibacterial materials size-similar and quasi-spherical Ag nanoparticles are anchored to the CNT and GO surfaces. The Ag nanoparticles in CNT-Ag and GO-Ag have narrow size distributions with average diameters of 2.6 and 3.5 nm respectively. The antibacterial activities of CNT-Ag and GO-Ag against Escherichia coli were assessed with the paper-disk diffusion method and by determining the minimal inhibitory concentrations (MICs). CNT-Ag was found to have higher antibacterial activity than the reference Ag colloid. Moreover, both CNT-Ag and GO-Ag retain more than 50% of their original antibacterial activities after 20 washes with detergent, which indicates their potential as antibacterial materials for laboratory and medical purposes.

  16. Diversity and antibacterial activity of culturable actinobacteria isolated from five species of the South China Sea gorgonian corals.

    PubMed

    Zhang, Xiao-Yong; He, Fei; Wang, Guang-Hua; Bao, Jie; Xu, Xin-Ya; Qi, Shu-Hua

    2013-06-01

    This study describes the diversity and antibacterial activity of culturable actinobacteria isolated from five species of gorgonian corals (Echinogorgia aurantiaca, Melitodes squamata, Muricella flexuosa, Subergorgia suberosa, and Verrucella umbraculum) collected in shallow water of the South China Sea. A total of 123 actinobacterial isolates were recovered using ten different isolation media, and assigned to 11 genera, including Streptomyces and Micromonospora as the dominant genera, followed by Nocardia, Verrucosispora, Nocardiopsis, Rhodococcus, Pseudonocardia, Agrococcus, Saccharomonospora, Saccharopolyspora and Dietzia. Comparable analysis indicated that the numbers of actinobacterial genera and isolates from the five gorgonian coral species varied significantly. It was found that 72 isolates displayed antibacterial activity against at least one indicator bacterium, and the antibacterial strains isolated from different gorgonians had almost the same proportion (~50 %). These results provide direct evidence for the hypotheses that gorgonian coral species contain large and diverse communities of actinobacteria, and suggest that many gorgonian-associated actinobacteria could produce some antibacterial agents to protect their hosts against pathogens. To our knowledge, this is the first report about the diversity of culturable actinobacteria isolated from gorgonian corals.

  17. Antioxidant, Antibacterial, and Cytotoxic Activities of the Ethanolic Origanum vulgare Extract and Its Major Constituents.

    PubMed

    Coccimiglio, John; Alipour, Misagh; Jiang, Zi-Hua; Gottardo, Christine; Suntres, Zacharias

    2016-01-01

    Oregano is a perennial shrub that grows in the mountains of the Mediterranean and Euro/Irano-Siberian regions. This study was conducted to identify the major constituents of the ethanolic Origanum vulgare extract and examine the cytotoxic, antioxidant, and antibacterial properties of the extract but more importantly the contribution of its specific major constituent(s) or their combination to the overall extract biological activity. Gas chromatography/mass spectroscopy analysis showed that the extract contained monoterpene hydrocarbons and phenolic compounds, the major ones being carvacrol and thymol and to a lesser extent p-cymene, 1-octacosanol, creosol, and phytol. A549 epithelial cells challenged with the extract showed a concentration-dependent increase in cytotoxicity. A combination of thymol and carvacrol at equimolar concentrations to those present in the extract was less cytotoxic. The A549 cells pretreated with nonlethal extract concentrations protected against hydrogen-peroxide-induced cytotoxicity, an antioxidant effect more effective than the combination of equimolar concentrations of thymol/carvacrol. Inclusion of p-cymene and/or 1-octacosanol did not alter the synergistic antioxidant effects of the carvacrol/thymol mixture. The extract also exhibited antimicrobial properties against Gram-positive and Gram-negative bacterial strains including clinical isolates. In conclusion, the oregano extract has cytotoxic, antioxidant, and antibacterial activities mostly attributed to carvacrol and thymol. PMID:27051475

  18. Antioxidant, Antibacterial, and Cytotoxic Activities of the Ethanolic Origanum vulgare Extract and Its Major Constituents

    PubMed Central

    Coccimiglio, John; Alipour, Misagh; Jiang, Zi-Hua; Gottardo, Christine

    2016-01-01

    Oregano is a perennial shrub that grows in the mountains of the Mediterranean and Euro/Irano-Siberian regions. This study was conducted to identify the major constituents of the ethanolic Origanum vulgare extract and examine the cytotoxic, antioxidant, and antibacterial properties of the extract but more importantly the contribution of its specific major constituent(s) or their combination to the overall extract biological activity. Gas chromatography/mass spectroscopy analysis showed that the extract contained monoterpene hydrocarbons and phenolic compounds, the major ones being carvacrol and thymol and to a lesser extent p-cymene, 1-octacosanol, creosol, and phytol. A549 epithelial cells challenged with the extract showed a concentration-dependent increase in cytotoxicity. A combination of thymol and carvacrol at equimolar concentrations to those present in the extract was less cytotoxic. The A549 cells pretreated with nonlethal extract concentrations protected against hydrogen-peroxide-induced cytotoxicity, an antioxidant effect more effective than the combination of equimolar concentrations of thymol/carvacrol. Inclusion of p-cymene and/or 1-octacosanol did not alter the synergistic antioxidant effects of the carvacrol/thymol mixture. The extract also exhibited antimicrobial properties against Gram-positive and Gram-negative bacterial strains including clinical isolates. In conclusion, the oregano extract has cytotoxic, antioxidant, and antibacterial activities mostly attributed to carvacrol and thymol. PMID:27051475

  19. The Effect of Ultrafine Process on the Dissolution, Antibacterial Activity, and Cytotoxicity of Coptidis rhizoma

    PubMed Central

    Jiang, Zhen-Yu; Deng, Hai-Ying; Yu, Zhi-Jun; Ni, Jun-Yan; Kang, Si-He

    2016-01-01

    Background: The dosage of herb ultrafine particle (UFP) depended on the increased level of its dissolution, toxicity, and efficacy. Objective: The dissolution, antibacterial activity, and cytotoxicity of Coptidis rhizoma (CR) UFP were compared with those of traditional decoction (TD). Materials and Methods: The dissolution of berberine (BBR) of CR TD and UFP was determined by high-performance liquid chromatography. The antibacterial activity of CR extract was assayed by plate-hole diffusion and broth dilution method; the inhibitory effect of rat serums against bacteria growth was evaluated after orally given CR UFP or TD extract. The cytotoxicity of CR extract was evaluated by 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide assay. Results: The dissolution amount of BBR from CR UFP increased 6–8-folds in comparison to TD at 2 min, the accumulative amount of BBR in both UFP and TD group increased in a time-dependent manner. The minimal inhibitory concentrations and minimal bactericidal concentrations of CR UFP extract decreased to 1/2~1/4 of those of TD extract. The inhibitory effect of rat serums against bacteria growth decreased time-dependently, and no statistical difference was observed between two groups at each time point. The 50% cytotoxic concentrations of UFP extract increased 1.66~1.97 fold than those of TD. Conclusions: The antibacterial activity and cytotoxicity of CR UFP increased in a dissolution-effect manner in vitro, the increased level of cytotoxicity was lower than that of antibacterial activity, and the inhibitory effect of rat serums containing drugs of UFP group did not improve. SUMMARY Ultrafine grinding process caused a rapid increase of BBR dissolution from CR.The antibacterial activity and cytotoxicity of UFP extract in vitro increased in a dissolution-effect manner, but the cytotoxicity increased lower than the antibacterial activity.The antibacterial activity of rat serums of UFP group did not improve in comparison to that

  20. Antifungal and antibacterial activity of Haliclona sp. from the Persian Gulf, Iran.

    PubMed

    Nazemi, M; Alidoust Salimi, M; Alidoust Salimi, P; Motallebi, A; Tamadoni Jahromi, S; Ahmadzadeh, O

    2014-09-01

    In this study, antifungal and antibacterial activities of diethyl ether, methanol and aqueous extracts of Haliclona sp. were assessed (in vitro). The antibacterial activity of the extracts was determined by broth dilution methods against clinical Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa and Gram-positive bacteria: Staphylococcus aureus aureus, Bacillus subtilis spizizenii. The antifungal activity of the extracts was determined by using a broth microdilution test against clinical fungi Candida albicans and Aspergillus fumigatus. Our results showed diethyl ether extract of Haliclona sp. was active on Gram-positive bacteria. In addition, methanol extract in comparison with diethyl ether extract had better activity against C. albicans (MIC: 0.75 mg/mL, MFC: 1.5mg/mL) and A. fumigatus (MIC: 2mg/mL, MFC: 3mg/mL). Aqueous extract had neither antifungal nor antibacterial activities. Based our results, Haliclona sp. can be considered as a source of novel antibiotic and antifungal.

  1. Zinc Pyrithione Improves the Antibacterial Activity of Silver Sulfadiazine Ointment

    PubMed Central

    Blanchard, Catlyn; Brooks, Lauren; Ebsworth-Mojica, Katherine; Didione, Louis; Wucher, Benjamin; Dewhurst, Stephen; Krysan, Damian

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus are commonly associated with biofilm-associated wound infections that are recalcitrant to conventional antibiotics. As an initial means to identify agents that may have a greater propensity to improve clearance of wound-associated bacterial pathogens, we screened a Food and Drug Administration-approved drug library for members that display bactericidal activity toward 72-h-established P. aeruginosa biofilms using an adenylate kinase reporter assay for bacterial cell death. A total of 34 compounds displayed antibiofilm activity. Among these, zinc pyrithione was also shown to reduce levels of A. baumannii and S. aureus biofilm-associated bacteria and exhibited an additive effect in combination with silver sulfadiazine, a leading topical therapeutic for wound site infections. The improved antimicrobial activity of zinc pyrithione and silver sulfadiazine was maintained in an ointment formulation and led to improved clearance of P. aeruginosa, A. baumannii, and S. aureus in a murine model of wound infection. Taken together, these results suggest that topical zinc pyrithione and silver sulfadiazine combination formulations may mitigate wound-associated bacterial infections and disease progression. IMPORTANCE Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA

  2. Zinc Pyrithione Improves the Antibacterial Activity of Silver Sulfadiazine Ointment.

    PubMed

    Blanchard, Catlyn; Brooks, Lauren; Ebsworth-Mojica, Katherine; Didione, Louis; Wucher, Benjamin; Dewhurst, Stephen; Krysan, Damian; Dunman, Paul M; Wozniak, Rachel A F

    2016-01-01

    Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus are commonly associated with biofilm-associated wound infections that are recalcitrant to conventional antibiotics. As an initial means to identify agents that may have a greater propensity to improve clearance of wound-associated bacterial pathogens, we screened a Food and Drug Administration-approved drug library for members that display bactericidal activity toward 72-h-established P. aeruginosa biofilms using an adenylate kinase reporter assay for bacterial cell death. A total of 34 compounds displayed antibiofilm activity. Among these, zinc pyrithione was also shown to reduce levels of A. baumannii and S. aureus biofilm-associated bacteria and exhibited an additive effect in combination with silver sulfadiazine, a leading topical therapeutic for wound site infections. The improved antimicrobial activity of zinc pyrithione and silver sulfadiazine was maintained in an ointment formulation and led to improved clearance of P. aeruginosa, A. baumannii, and S. aureus in a murine model of wound infection. Taken together, these results suggest that topical zinc pyrithione and silver sulfadiazine combination formulations may mitigate wound-associated bacterial infections and disease progression. IMPORTANCE Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA

  3. Zinc Pyrithione Improves the Antibacterial Activity of Silver Sulfadiazine Ointment.

    PubMed

    Blanchard, Catlyn; Brooks, Lauren; Ebsworth-Mojica, Katherine; Didione, Louis; Wucher, Benjamin; Dewhurst, Stephen; Krysan, Damian; Dunman, Paul M; Wozniak, Rachel A F

    2016-01-01

    Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus are commonly associated with biofilm-associated wound infections that are recalcitrant to conventional antibiotics. As an initial means to identify agents that may have a greater propensity to improve clearance of wound-associated bacterial pathogens, we screened a Food and Drug Administration-approved drug library for members that display bactericidal activity toward 72-h-established P. aeruginosa biofilms using an adenylate kinase reporter assay for bacterial cell death. A total of 34 compounds displayed antibiofilm activity. Among these, zinc pyrithione was also shown to reduce levels of A. baumannii and S. aureus biofilm-associated bacteria and exhibited an additive effect in combination with silver sulfadiazine, a leading topical therapeutic for wound site infections. The improved antimicrobial activity of zinc pyrithione and silver sulfadiazine was maintained in an ointment formulation and led to improved clearance of P. aeruginosa, A. baumannii, and S. aureus in a murine model of wound infection. Taken together, these results suggest that topical zinc pyrithione and silver sulfadiazine combination formulations may mitigate wound-associated bacterial infections and disease progression. IMPORTANCE Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA

  4. Zinc Pyrithione Improves the Antibacterial Activity of Silver Sulfadiazine Ointment

    PubMed Central

    Blanchard, Catlyn; Brooks, Lauren; Ebsworth-Mojica, Katherine; Didione, Louis; Wucher, Benjamin; Dewhurst, Stephen; Krysan, Damian

    2016-01-01

    ABSTRACT Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus are commonly associated with biofilm-associated wound infections that are recalcitrant to conventional antibiotics. As an initial means to identify agents that may have a greater propensity to improve clearance of wound-associated bacterial pathogens, we screened a Food and Drug Administration-approved drug library for members that display bactericidal activity toward 72-h-established P. aeruginosa biofilms using an adenylate kinase reporter assay for bacterial cell death. A total of 34 compounds displayed antibiofilm activity. Among these, zinc pyrithione was also shown to reduce levels of A. baumannii and S. aureus biofilm-associated bacteria and exhibited an additive effect in combination with silver sulfadiazine, a leading topical therapeutic for wound site infections. The improved antimicrobial activity of zinc pyrithione and silver sulfadiazine was maintained in an ointment formulation and led to improved clearance of P. aeruginosa, A. baumannii, and S. aureus in a murine model of wound infection. Taken together, these results suggest that topical zinc pyrithione and silver sulfadiazine combination formulations may mitigate wound-associated bacterial infections and disease progression. IMPORTANCE Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA

  5. In Vitro Antibacterial Activity of Rhodanine Derivatives against Pathogenic Clinical Isolates

    PubMed Central

    AbdelKhalek, Ahmed; Ashby, Charles R.; Patel, Bhargav A.; Talele, Tanaji T.; Seleem, Mohamed N.

    2016-01-01

    Bacterial infections present a serious challenge to healthcare practitioners due to the emergence of resistance to numerous conventional antibacterial drugs. Therefore, new bacterial targets and new antimicrobials are unmet medical needs. Rhodanine derivatives have been shown to possess potent antimicrobial activity via a novel mechanism. However, their potential use as antibacterials has not been fully examined. In this study, we determined the spectrum of activity of seven rhodanine derivatives (compounds Rh 1–7) against clinical isolates of Gram-positive and Gram-negative bacterial strains and Candida albicans. We also synthesized and tested three additional compounds, ethyl ester and amide of rhodanine 2 (Rh 8 and Rh 10, respectively) and ethyl ester of rhodanine 3 (Rh 9) to determine the significance of the carboxyl group modification towards antibacterial activity and human serum albumin binding. A broth microdilution assay confirmed Rh 1–7 exhibit bactericidal activity against Gram-positive pathogens. Rh 2 had significant activity against various vancomycin-resistant (MIC90 = 4 μM) and methicillin-resistant (MIC90 = 4 μM) Staphylococcus aureus (VRSA and MRSA), Staphylococcus epidermidis (MIC = 4 μM) and vancomycin-resistant Enterococcus (VRE) strains (MIC90 = 8 μM). The rhodanine compounds exhibited potent activity against Bacillus spp., including Bacillus anthracis, with MIC range of 2–8 μM. In addition, they had potent activity against Clostridium difficile. The most potent compound, Rh 2, at 4 and 8 times its MIC, significantly decreased S. epidermidis biofilm mass by more than 35% and 45%, respectively. None of the rhodanine compounds showed antimicrobial activity (MIC > 128 μM) against various 1) Gram-negative pathogens (Acinetobacter baumannii, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, and Salmonella Typhimurium) or 2) strains of Candida albicans (MIC > 64 μM). The MTS assay confirmed that rhodanines were not toxic to

  6. Antibacterial Activity of MTA Fillapex and AH 26 Root Canal Sealers at Different Time Intervals

    PubMed Central

    Jafari, Farnaz; Samadi Kafil, Hossein; Jafari, Sanaz; Aghazadeh, Mohammad; Momeni, Tahereh

    2016-01-01

    Introduction: The main goal of endodontic treatment is elimination of bacteria and their by-products from infected root canals. This study compared the antibacterial effect of two different sealers, AH 26 and MTA Fillapex, on 4 microorganisms 24, 48 and 72 h and 7 days after mixing. Methods and Materials: The microorganisms used in this study consisted of Lactobacillus acidophilus (ATCC 4356), Lactobacillus casei (ATCC 39392), Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 29212). This test is based on the growth of bacteria and turbidity measurement technique using a spectrophotometer, and direct contact was conducted. Multiple comparisons were carried out using repeated-measures ANOVA followed by Tukey’s test and student’s t-test. The level of significance was set at 0.05. Results: The antibacterial activity in the indirect technique was more than the technique with both sealers. In the direct technique the antibacterial activity on all microorganisms were lower for MTA Fillapex sealer. In the indirect technique, both sealers exhibited similar antibacterial properties. Conclusion: The antibacterial effect of MTA Fillapex sealer was significantly less than that of AH 26 sealer in the direct technique. The antibacterial effects of both sealers were similar in the indirect technique. PMID:27471530

  7. ZnO nanoparticles enhanced antibacterial activity of ciprofloxacin against Staphylococcus aureus and Escherichia coli.

    PubMed

    Banoee, Maryam; Seif, Sepideh; Nazari, Zeinab E; Jafari-Fesharaki, Parisa; Shahverdi, Hamid R; Moballegh, Ali; Moghaddam, Kamyar M; Shahverdi, Ahmad R

    2010-05-01

    Nanoparticle metal oxides offer a wide variety of potential applications in medicine due to the unprecedented advances in nanobiotechnology research. In this work, the effect of zinc oxide (ZnO) nanoparticles prepared by mechano-chemical method on the antibacterial activity of different antibiotics was evaluated using disk diffusion method against Staphylococcus aureus and Escherichia coli. The average size of ZnO nanoparticles was between 20 nm and 45 nm. Although ZnO nanoparticles (500 microg/disk) decreased the antibacterial activity of amoxicillin, penicillin G, and nitrofurantoin in S. aureus, the antibacterial activity of ciprofloxacin increased in the presence of ZnO nanoparticles in both test strains. A total of 27% and 22% increase in inhibition zone areas was observed for ciprofloxacin in the presence of ZnO nanoparticles in S. aureus and E. coli, respectively. The enhancing effect of this nanomaterial on the antibacterial activity of ciprofloxacin was further investigated at three different contents (500, 1000, and 2000 microg/disk) against various clinical isolates of S. aureus and E. coli The enhancing effect of ZnO nanoparticles on the antibacterial activity of ciprofloxacin was concentration-dependent against all test strains. The most enhancing activities were observed in the contents of the 2000 microg/disk.

  8. Effects of Lactobacillus plantarum immobilization in alginate coated with chitosan and gelatin on antibacterial activity.

    PubMed

    Trabelsi, Imen; Ayadi, Dorra; Bejar, Wacim; Bejar, Samir; Chouayekh, Hichem; Ben Salah, Riadh

    2014-03-01

    The present study aimed to investigate and evaluate the efficiency of immobilizing the Lactobacillus plantarum TN9 strain in alginate using chitosan and gelatin as coating materials, in terms of viability and antibacterial activity. The results indicate that maximum concentrations of L. plantarum TN9 strain were produced with 2% sodium alginate, 10(8)UFC/ml, and 1M calcium chloride. The viability and antibacterial activity of the L. plantarum TN9 cultures before and after immobilization in alginate, chitosan-coated alginate, and gelatin-coated alginate, were studied. The findings revealed that the viability of encapsulated L. plantarum could be preserved more than 5.8 log CFU/ml after 35 day of incubation at 4 °C, and no effects were observed when gelatin was used. The antibacterial activity of encapsulated L. plantarum TN9 against Gram-positive and Gram-negative pathogenic bacteria was enhanced in the presence of chitosan coating materials, and no activity was observed in the presence of gelatin. The effects of catalase and proteolytic enzymes on the culture supernatant of L. plantarum TN9 were also investigated, and the results suggested that the antibacterial activity observed was due to the production of organic acids. Taken together, the findings indicated that immobilization in chitosan enhanced the antibacterial activity of L. plantarum TN9 against several pathogenic bacteria. This encapsulated strain could be considered as a potential strong candidate for future application as an additive in the food and animal feed industries.

  9. Comparative study on the antibacterial activity of some flavonoids and their sulfonic derivatives.

    PubMed

    Woźnicka, Elzbieta; Kuźniar, Anna; Nowak, Dorota; Nykiel, Elzbieta; Kopacz, Maria; Gruszecka, Jolanta; Golec, Krzysztof

    2013-01-01

    The antibacterial activity of quercetin, morin, sodium salt of quercetin-5'-sulfonic acid (NaQSA) and sodium salt of morin-5'-sulfonic acid (NaMSA) were tested against six bacterial strains: Escherichia coli (ATCC 25922 and clinical isolates--ESBL), Pseudomonas aeruginosa (ATCC 27853 and clinical isolates--carbapenem resistant), Staphylococcus aureus (ATCC 29213 and clinical isolats- MRSA). The most effective inhibitors against the model strain S. aureus are NaQSA and NaMSA (MIC = 3.9 microg/mL). Among polyhydroxyflavones used in this investigation, morin exhibits the highest antibacterial activity against tested strains. The structure-activity relationship indicates that 2',4'-dihydroxylation of the B ring in the flavanone structure is important for significant antibacterial activity and that substitution of the sulfo group at position 5' on the lateral phenyl ring enhances antistaphylococcal activity of flavonoids.

  10. Design, synthesis and antibacterial activity of isatin derivatives as FtsZ inhibitors

    NASA Astrophysics Data System (ADS)

    Lian, Zhi-Min; Sun, Juan; Zhu, Hai-Liang

    2016-08-01

    Seven isatin derivatives have been designed, and their chemical structures were characterized by single crystal X-ray diffraction studies, 1H NMR, MS, and elemental analysis. Structural stabilization followed by intramolecular as well as intermolecular H-bonds makes these molecules as perfect examples in molecular recognition with self-complementary donor and acceptor units within a single molecule. These compounds were evaluated for antimicrobial activities. Docking simulations have been performed to position compounds into the FtsZ active site to determine their probable binding models. All of the compounds exhibited better antibacterial activities. Interestingly, compound 5c and 5d exhibited better antibacterial activities with IC50 values of 0.03 and 0.05 μmol/mL against Staphylococcus aureus, respectively. Compound 5g displays antibacterial activity with IC50 values of 0.672 and 0.830 μmol/mL against Escherichia coli and Pseudomonas aeruginosa, respectively.

  11. In vitro assessment of antioxidant and antibacterial activities of six edible plants from Iran.

    PubMed

    Tabaraki, Reza; Nateghi, Ashraf; Ahmady-Asbchin, Salman

    2013-06-01

    The antioxidant and antibacterial activities of six edible plants were evaluated. The active constituents of the edible plants were extracted using boiling water or 80% methanol. Results demonstrated that extraction of antioxidants by boiling water was more efficient. Lycium depressum and Berula angustifolia had the highest antioxidant activities and, therefore, could be rich sources of natural antioxidants. The antibacterial activities of the extracts were tested against Staphylococcus aureus, Escherichia coli, Entrococcus faecalis and Proteus mirabilis. Further research is needed to isolate, characterize, and identify the bioactive compounds present in these plants.

  12. Hypervalent iodine compounds as potent antibacterial agents against ice nucleation active (INA) Pseudomonas syringae.

    PubMed

    Menkissoglu-Spiroudi, U; Karamanoli, K; Spyroudis, S; Constantinidou, H I

    2001-08-01

    Twenty-three hypervalent iodine compounds belonging to aryliodonium salts, 1, aryliodonium ylides, 2, and (diacyloxyiodo)arenes, 3, were tested for their antibacterial activities against ice nucleation active (INA) Pseudomonas syringae, and the MIC and EC(50) values were determined. All of the compounds examined caused a dose-dependent decrease in bacterial growth rates. Aryliodonium salts, especially those with electron-withdrawing groups, exhibit higher antibacterial activities with MIC = 8-16 ppm, whereas the nature of the anion does not seem to affect the activities of the diaryliodonium salts. PMID:11513659

  13. New Insights into the Antibacterial Activity of Hydroxycoumarins against Ralstonia solanacearum.

    PubMed

    Yang, Liang; Ding, Wei; Xu, Yuquan; Wu, Dousheng; Li, Shili; Chen, Juanni; Guo, Bing

    2016-01-01

    Coumarins are important plant-derived natural products with wide-ranging bioactivities and extensive applications. In this study, we evaluated for the first time the antibacterial activity and mechanisms of action of coumarins against the phytopathogen Ralstonia solanacearum, and investigated the effect of functional group substitution. We first tested the antibacterial activity of 18 plant-derived coumarins with different substitution patterns, and found that daphnetin, esculetin, xanthotol, and umbelliferone significantly inhibited the growth of R. solanacearum. Daphnetin showed the strongest antibacterial activity, followed by esculetin and umbelliferone, with MICs of 64, 192, and 256 mg/L, respectively, better than the archetypal coumarin with 384 mg/L. We further demonstrated that the hydroxylation of coumarins at the C-6, C-7 or C-8 position significantly enhanced the antibacterial activity against R. solanacearum. Transmission electron microscope (TEM) and fluorescence microscopy images showed that hydroxycoumarins may interact with the pathogen by mechanically destroying the cell membrane and inhibiting biofilm formation. The antibiofilm effect of hydroxycoumarins may relate to the repression of flagellar genes fliA and flhC. These physiological changes in R. solanacearum caused by hydroxycoumarins can provide information for integral pathogen control. The present findings demonstrated that hydroxycoumarins have superior antibacterial activity against the phytopathogen R. solanacearum, and thus have the potential to be applied for controlling plant bacterial wilt. PMID:27070570

  14. Superior antibacterial activity of nanoemulsion of Thymus daenensis essential oil against E. coli.

    PubMed

    Moghimi, Roya; Ghaderi, Lida; Rafati, Hasan; Aliahmadi, Atousa; McClements, David Julian

    2016-03-01

    Natural preservatives are being extensively investigated for their potential industrial applications in foods and other products. In this work, an essential oil (Thymus daenensis) was formulated as a water-dispersible nanoemulsion (diameter=143nm) using high-intensity ultrasound. The antibacterial activity of the essential oil in both pure and nanoemulsion forms was measured against an important food-borne pathogen bacterium, Escherichia coli. Antibacterial activity was determined by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibacterial activity of the essential oil against E. coli was enhanced considerably when it was converted into a nanoemulsion, which was attributed to easier access of the essential oils to the bacterial cells. The mechanism of antibacterial activity was investigated by measuring potassium, protein, and nucleic acid leakage from the cells, and electron microscopy. Evaluation of the kinetics of microbial deactivation showed that the nanoemulsion killed all the bacteria in about 5min, whereas only a 1-log reduction was observed for pure essential oil. The nanoemulsion appeared to amplify the antibacterial activity of essential oils against E. coli by increasing their ability to disrupt cell membrane integrity.

  15. Superior antibacterial activity of nanoemulsion of Thymus daenensis essential oil against E. coli.

    PubMed

    Moghimi, Roya; Ghaderi, Lida; Rafati, Hasan; Aliahmadi, Atousa; McClements, David Julian

    2016-03-01

    Natural preservatives are being extensively investigated for their potential industrial applications in foods and other products. In this work, an essential oil (Thymus daenensis) was formulated as a water-dispersible nanoemulsion (diameter=143nm) using high-intensity ultrasound. The antibacterial activity of the essential oil in both pure and nanoemulsion forms was measured against an important food-borne pathogen bacterium, Escherichia coli. Antibacterial activity was determined by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibacterial activity of the essential oil against E. coli was enhanced considerably when it was converted into a nanoemulsion, which was attributed to easier access of the essential oils to the bacterial cells. The mechanism of antibacterial activity was investigated by measuring potassium, protein, and nucleic acid leakage from the cells, and electron microscopy. Evaluation of the kinetics of microbial deactivation showed that the nanoemulsion killed all the bacteria in about 5min, whereas only a 1-log reduction was observed for pure essential oil. The nanoemulsion appeared to amplify the antibacterial activity of essential oils against E. coli by increasing their ability to disrupt cell membrane integrity. PMID:26471573

  16. Chemical composition and antibacterial activity of essential oils from the Tunisian Allium nigrum L.

    PubMed Central

    Rouis-Soussi, Lamia Sakka; Ayeb-Zakhama, Asma El; Mahjoub, Aouni; Flamini, Guido; Jannet, Hichem Ben; Harzallah-Skhiri, Fethia

    2014-01-01

    The chemical composition of the essential oils of different Allium nigrum L. organs and the antibacterial activity were evaluated. The study is particularly interesting because hitherto there are no reports on the antibacterial screening of this species with specific chemical composition. Therefore, essential oils from different organs (flowers, stems, leaves and bulbs) obtained separately by hydrodistillation were analyzed using gas chromatography–mass spectrometry (GC–MS). The antibacterial activity was evaluated using the disc and microdilution assays. In total, 39 compounds, representing 90.8-96.9 % of the total oil composition, were identified. The major component was hexadecanoic acid (synonym: palmitic acid) in all the A. nigrum organs oils (39.1-77.2 %). We also noted the presence of some sesquiterpenes, mainly germacrene D (12.8 %) in leaves oil) and some aliphatic compounds such as n-octadecane (30.5 %) in bulbs oil. Isopentyl isovalerate, 14-oxy-α-muurolene and germacrene D were identified for the first time in the genus Allium L. All the essential oils exhibited antimicrobial activity, especially against Enterococcus faecalis and Staphylococcus aureus. The oil obtained from the leaves exhibited an interesting antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 62.50 µg/mL against these two latter strains. The findings showed that the studied oils have antibacterial activity, and thus great potential for their application in food preservation and natural health products. PMID:26417280

  17. Antibacterial action of silver-doped activated carbon prepared by vacuum impregnation

    NASA Astrophysics Data System (ADS)

    Zhao, Ying; Wang, Zi-qiang; Zhao, Xin; Li, Wei; Liu, Shou-xin

    2013-02-01

    Silver-containing activated carbon (Ag/AC) exhibiting controlled release of silver and antibacterial action was prepared by vacuum impregnation using acetate silver as a precursor. The antibacterial activity toward E. coli and resistance to water erosion were investigated with the view of water purification. N2 adsorption at 77 K, scanning electron microscopy and X-ray diffraction were used to characterize the surface morphology and crystalline properties of the Ag/AC samples. As the concentration of CH3COOAg increased, the samples change from exhibiting no antibacterial activity to inhibition of bacteria growth and then to antibacterial activity because of the higher silver content and smaller size of the silver particles. The Ag/AC composites showed a lower release rate of silver than that of a composite prepared by a traditional AgNO3 impregnation method, which suggests a strong interaction between the silver particles and carbon. Because the Ag particles block the pores of AC, the BET surface area, total pore volume and average pore diameter of the Ag/AC samples decreased as the concentration of the CH3COOAg solution increased. The higher antibacterial activity and controlled release of silver by Ag/AC containing 1.65 wt % silver means that it shows promise for purification of drinking water.

  18. New Insights into the Antibacterial Activity of Hydroxycoumarins against Ralstonia solanacearum.

    PubMed

    Yang, Liang; Ding, Wei; Xu, Yuquan; Wu, Dousheng; Li, Shili; Chen, Juanni; Guo, Bing

    2016-01-01

    Coumarins are important plant-derived natural products with wide-ranging bioactivities and extensive applications. In this study, we evaluated for the first time the antibacterial activity and mechanisms of action of coumarins against the phytopathogen Ralstonia solanacearum, and investigated the effect of functional group substitution. We first tested the antibacterial activity of 18 plant-derived coumarins with different substitution patterns, and found that daphnetin, esculetin, xanthotol, and umbelliferone significantly inhibited the growth of R. solanacearum. Daphnetin showed the strongest antibacterial activity, followed by esculetin and umbelliferone, with MICs of 64, 192, and 256 mg/L, respectively, better than the archetypal coumarin with 384 mg/L. We further demonstrated that the hydroxylation of coumarins at the C-6, C-7 or C-8 position significantly enhanced the antibacterial activity against R. solanacearum. Transmission electron microscope (TEM) and fluorescence microscopy images showed that hydroxycoumarins may interact with the pathogen by mechanically destroying the cell membrane and inhibiting biofilm formation. The antibiofilm effect of hydroxycoumarins may relate to the repression of flagellar genes fliA and flhC. These physiological changes in R. solanacearum caused by hydroxycoumarins can provide information for integral pathogen control. The present findings demonstrated that hydroxycoumarins have superior antibacterial activity against the phytopathogen R. solanacearum, and thus have the potential to be applied for controlling plant bacterial wilt.

  19. Potent antibacterial activity of halogenated metabolites from Malaysian red algae, Laurencia majuscula (Rhodomelaceae, Ceramiales).

    PubMed

    Vairappan, Charles S

    2003-07-01

    Red algae genus Laurencia (Rhodomelaceae, Ceramiales) are known to produce a wide range of chemically interesting secondary halogenated metabolites. This investigation delves upon extraction, isolation, structural elucidation and antibacterial activity of inherently available secondary metabolites of Laurencia majuscula Harvey collected from two locations in waters of Sabah, Malaysia. Two major halogenated compounds, identified as elatol (1) and iso-obtusol (2) were isolated. Structures of these compounds were determined from their spectroscopic data such as IR, 1H-NMR, 13C-NMR and optical rotation. Antibacterial bioassay against human pathogenic bacteria was conducted using disc diffusion (Kirby-Bauer) method. Elatol (1) inhibited six species of bacteria, with significant antibacterial activities against Staphylococcus epidermis, Klebsiella pneumonia and Salmonella sp. while iso-obtusol (2) exhibited antibacterial activity against four bacterial species with significant activity against K. pneumonia and Salmonella sp. Elatol (1) showed equal and better antibacterial activity compared with tested commercial antibiotics while iso-obtusol (2) only equaled the potency of commercial antibiotics against K. pneumonia and Salmonella sp. Further tests conducted using dilution method showed both compounds as having bacteriostatic mode of action against the tested bacteria. PMID:12919806

  20. Microalgae mediated synthesis of silver nanoparticles and their antibacterial activity against pathogenic bacteria.

    PubMed

    Sudha, S S; Rajamanickam, Karthic; Rengaramanujam, J

    2013-05-01

    Silver nanoparticles is known to have antimicrobial affects. Cyanobacteria isolates from muthupet mangrove includes Aphanothece sp, Oscillatoria sp, Microcoleus sp, Aphanocapsa sp, Phormidium sp, Lyngbya sp, Gleocapsa sp, Synechococcus sp, Spirulina sp with were set in compliance with their cellular mechanism of nano silver creation, and were investigated by UV-VIS spectrophotometer, Energy-dispersive X-ray (EDX) and scanning electron microscopy (SEM). Silver nanoparticles were spherical shaped well distributed without aggregation in solution with an average size of about 40- 80 nm. Synthesised nano silver had antibacterial production on various organisms that provoked various diseases in humans. The cellular metabolites of Microcoleus sp. only created nano silver and it enhanced the antibacterial activity against test pathogenic bacteria from MTCC (Proteus vulgaris, Salmonella typhi, Vibrio cholera, Streptococcus sp., Bacillus subtilis, Staphylococcus aureus, Escherichia coli.) The antimicrobial assay was performed using 0.001 M concentration of nano silver in well diffusion method with positive control of appropriate standard antibiotic discs Cephotaxime, Ampicillin, Tetracyclin, Cephalexin etc. Synthesised silver nanoparticles acted as an effective antimicrobial agent and proved as an alternative for the development of new antimicrobial agents to combat the problem of resistance. PMID:23821828

  1. Chemical composition and antibacterial and cytotoxic activities of Allium hirtifolium Boiss.

    PubMed

    Ismail, Salmiah; Jalilian, Farid Azizi; Talebpour, Amir Hossein; Zargar, Mohsen; Shameli, Kamyar; Sekawi, Zamberi; Jahanshiri, Fatemeh

    2013-01-01

    Allium hirtifolium Boiss. known as Persian shallot, is a spice used as a traditional medicine in Iran and, Mediterranean region. In this study, the chemical composition of the hydromethanolic extract of this plant was analyzed using GC/MS. The result showed that 9-hexadecenoic acid, 11,14-eicosadienoic acid, and n-hexadecanoic acid are the main constituents. The antibacterial activity of the shallot extract was also examined by disk diffusion and microdilution broth assays. It was demonstrated that Persian shallot hydromethanolic extract was effective against 10 different species of pathogenic bacteria including methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Escherichia coli, Escherichia coli O157:H7, Salmonella typhimurium, Proteus mirabilis, and Klebsiella pneumoniae. Specifically, the minimum concentration of the extract which inhibited bacterial growth (MIC values) was 1.88 mg/mL for most of the gram-positive bacteria. This concentration was not much different from the concentration that was safe for mammalian cells (1.50 mg/mL) suggesting that the hydromethanolic extract of Persian shallot may be a safe and strong antibacterial agent.

  2. Chemical Composition and Antibacterial and Cytotoxic Activities of Allium hirtifolium Boiss

    PubMed Central

    Ismail, Salmiah; Jalilian, Farid Azizi; Talebpour, Amir Hossein; Zargar, Mohsen; Shameli, Kamyar; Sekawi, Zamberi; Jahanshiri, Fatemeh

    2013-01-01

    Allium hirtifolium Boiss. known as Persian shallot, is a spice used as a traditional medicine in Iran and, Mediterranean region. In this study, the chemical composition of the hydromethanolic extract of this plant was analyzed using GC/MS. The result showed that 9-hexadecenoic acid, 11,14-eicosadienoic acid, and n-hexadecanoic acid are the main constituents. The antibacterial activity of the shallot extract was also examined by disk diffusion and microdilution broth assays. It was demonstrated that Persian shallot hydromethanolic extract was effective against 10 different species of pathogenic bacteria including methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Escherichia coli, Escherichia coli O157:H7, Salmonella typhimurium, Proteus mirabilis, and Klebsiella pneumoniae. Specifically, the minimum concentration of the extract which inhibited bacterial growth (MIC values) was 1.88 mg/mL for most of the gram-positive bacteria. This concentration was not much different from the concentration that was safe for mammalian cells (1.50 mg/mL) suggesting that the hydromethanolic extract of Persian shallot may be a safe and strong antibacterial agent. PMID:23484141

  3. Chemical composition and antibacterial and cytotoxic activities of Allium hirtifolium Boiss.

    PubMed

    Ismail, Salmiah; Jalilian, Farid Azizi; Talebpour, Amir Hossein; Zargar, Mohsen; Shameli, Kamyar; Sekawi, Zamberi; Jahanshiri, Fatemeh

    2013-01-01

    Allium hirtifolium Boiss. known as Persian shallot, is a spice used as a traditional medicine in Iran and, Mediterranean region. In this study, the chemical composition of the hydromethanolic extract of this plant was analyzed using GC/MS. The result showed that 9-hexadecenoic acid, 11,14-eicosadienoic acid, and n-hexadecanoic acid are the main constituents. The antibacterial activity of the shallot extract was also examined by disk diffusion and microdilution broth assays. It was demonstrated that Persian shallot hydromethanolic extract was effective against 10 different species of pathogenic bacteria including methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Escherichia coli, Escherichia coli O157:H7, Salmonella typhimurium, Proteus mirabilis, and Klebsiella pneumoniae. Specifically, the minimum concentration of the extract which inhibited bacterial growth (MIC values) was 1.88 mg/mL for most of the gram-positive bacteria. This concentration was not much different from the concentration that was safe for mammalian cells (1.50 mg/mL) suggesting that the hydromethanolic extract of Persian shallot may be a safe and strong antibacterial agent. PMID:23484141

  4. The antibacterial activity and action mechanism of emodin from Polygonum cuspidatum against Haemophilus parasuis in vitro.

    PubMed

    Li, Li; Song, Xu; Yin, Zhongqiong; Jia, Renyong; Li, Zhengwen; Zhou, Xun; Zou, Yuanfeng; Li, Lixia; Yin, Lizi; Yue, Guizhou; Ye, Gang; Lv, Cheng; Shi, Wenjing; Fu, Yuping

    2016-01-01

    Haemophilus parasuis is the causative agent of Glässer's disease, which leads to serious economic loss to the swine industry. Although antibiotics are widely used to control infections, outbreaks of this disease repeatedly happen. In this study, emodin from Polygonum cuspidatum showed potent inhibitory effect against H. parasuis. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of emodin were 32 and 64μg/mL, respectively. The antibacterial kinetic curves indicated the antibacterial activity of emodin was in a concentration-dependent manner. Cell membrane permeability and flow cytometry assays proved that emodin could destroy cell membrane integrity and increase membrane permeability, and fluorescence spectra assay indicated emodin has influenced conformation of membrane protein. Under transmission electron microscopy, serious lesions of H. parasuis exposed to emodin (64μg/mL) were found, including irregular cell shape, plasmolysis, ruptured cell wall and membrane and cytoplasmic vacuolation. These results suggested that emodin could be used as candidate for treating Glässer's disease. PMID:27242151

  5. Antibacterial Activities of Actinomycete Isolates Collected from Soils of Rajshahi, Bangladesh

    PubMed Central

    Rahman, Md. Ajijur; Islam, Mohammad Zahidul; Islam, Md. Anwar Ul

    2011-01-01

    This study was performed to isolate actinomycete colonies having antibacterial activity from soil samples collected from different places around Rajshahi, Bangladesh. Thirty actinomycete colonies were isolated in pure culture from five soil samples using Starch-casein-nitrate-agar medium. The isolates were grouped in five color series based on their aerial mycelia color and screened for their antibacterial activity against a range of test bacteria. Sixteen isolates (53.3%) were found to have moderate to high activity against four gram-positive and four gram-negative bacteria. Since many isolates showed inhibitory activity against indicator bacteria, it is suggestive that Bangladeshi soil could be an interesting source to explore for antibacterial secondary metabolites. PMID:21904683

  6. Rapidly Probing Antibacterial Activity of Graphene Oxide by Mass Spectrometry-based Metabolite Fingerprinting

    PubMed Central

    Zhang, Ning; Hou, Jian; Chen, Suming; Xiong, Caiqiao; Liu, Huihui; Jin, Yulong; Wang, Jianing; He, Qing; Zhao, Rui; Nie, Zongxiu

    2016-01-01

    Application of nanomaterials as anti-bacteria agents has aroused great attention. To investigate the antibacterial activity and antibacterial mechanism of nanomaterials from a molecular perspective is important for efficient developing of nanomaterial antibiotics. In the current work, a new mass spectrometry-based method was established to investigate the bacterial cytotoxicity of graphene oxide (GO) by the metabolite fingerprinting of microbes. The mass spectra of extracted metabolites from two strains DH5α and ATCC25922 were obtained before and after the incubation with nanomaterials respectively. Then principal component analysis (PCA) of these spectra was performed to reveal the relationship between the metabolism disorder of microbes and bactericidal activity of GO. A parameter “D” obtained from PCA scores was proposed that is capable to quantitatively evaluate the antibacterial activity of GO in concentration and time-dependent experiments. Further annotation of the fingerprinting spectra shows the variabilities of important metabolites such as phosphatidylethanolamine, phosphatidylglycerol and glutathione. This metabolic perturbation of E. coli indicates cell membrane destruction and oxidative stress mechanisms for anti-bacteria activity of graphene oxide. It is anticipated that this mass spectrometry-based metabolite fingerprinting method will be applicable to other antibacterial nanomaterials and provide more clues as to their antibacterial mechanism at molecular level. PMID:27306507

  7. Effect of gamma irradiation on fluoride release and antibacterial activity of resin dental materials.

    PubMed

    Carvalho, Fabíola Galbiatti de; Fucio, Suzana Beatriz Portugal de; Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Correr-Sobrinho, Lourenço; Puppin-Rontani, Regina Maria

    2009-01-01

    This study evaluated the effect of gamma irradiation on fluoride release and antibacterial activity of FluroShield (FS) and Clearfil Protect Bond (CPB). Four groups were formed: G1-FS + gamma; G2-FS without gamma; G3-CPB + gamma; G4-CPB without gamma. For fluoride release analysis, 12 disks of each material were prepared and covered with nail polish, except for one side (50.4 mm(2) area). G1 and G3 were sterilized with a 14.5 KGy dose at 27 degrees C for 24 h, while G2 and G4 (controls) were not sterilized and were maintained under the same time and temperature conditions. Fluoride release measurements were made in duplicate (n=6) by an ion specific electrode. The antibacterial activity of the CPB and FS against Streptococcus mutans after gamma sterilization was evaluated by the agar-disc diffusion method. The diameter of the zones of microbial growth inhibition was recorded after 48 h. Data were analyzed statistically by ANOVA and Tukey's test (alpha=5%). Gamma sterilization decreased the fluoride release of FS by approximately 50%, while CPB was not affected. There was no statistically significant difference (p>0.05) in the antibacterial effect of CPB between gamma and non-gamma sterilization groups. FS presented no antibacterial activity. Gamma irradiation decreased the fluoride release of FS, but did not affect the antibacterial activity of the studied materials. PMID:19738944

  8. Changes in antibacterial activity of triclosan and sulfa drugs due to photochemical transformations.

    PubMed

    Wammer, Kristine H; Lapara, Timothy M; McNeill, Kristopher; Arnold, William A; Swackhamer, Deborah L

    2006-06-01

    Sulfa drugs and triclosan represent two classes of antibacterials that have been found in natural waters and for which photodegradation is anticipated to be a significant loss process. Parent antibacterial compounds and the products of photolysis reactions were compared for three sulfa drugs and triclosan to determine the extent to which photolysis affects their antibacterial potency on Escherichia coli DH5alpha. Sulfathiazole (median effective concentration [EC50] = 20.0 microM), sulfamethoxazole (EC50 = 12.3 microM), and sulfachloropyridazine (EC50 = 6.9 microM) inhibited bacterial growth but did not affect respiratory activity. Photolysis products of these sulfa drugs did not retain any measurable ability to inhibit growth. Triclosan inhibited both the growth (EC50 = 0.24 microM) and respiratory activity of E. coli DH5alpha. Triclosan photolysis products also exhibited no measurable effect on growth or respiratory activity. These experiments indicate that the products of triclosan and sulfa drug photolysis are unlikely to possess antibacterial activity in natural waters. The rapid screening method used for these two classes of compounds will be useful for helping to identify photolabile antibacterial compounds, for which photoproducts could require further investigation.

  9. Screening of Endophytic Fungi from Chlorophyta and Phaeophyta for Antibacterial Activity

    NASA Astrophysics Data System (ADS)

    Rahaweman, A. C.; Pamungkas, J.; Madduppa, H.; Thoms, C.; Tarman, K.

    2016-01-01

    Chlorophyta and Phaeophyta macroalgae are important sources of secondary metabolites with pharmaceutically relevant antibacterial, antifungal and antiviral bioactivities. Oftentimes, these algae-derived compounds are, in fact, produced by endophytic fungi living inside the macroalgal tissue. Numerous studies have shown that endophytic fungi can produce a broad range of active metabolites such as terpenes, alkaloids, and quinones. The aim of the present study was to screen fungal strains isolated from a variety of Caulerpa spp., Halimeda spp., and Sargassum spp. for antibacterial activity against Staphylococcus aureus and Escherichia coli. Thirteen morphologically different isolates were tested. Two of them showed pronounced activity against S. aureus in agar diffusion assays.

  10. Synthesis and Antibacterial Activity of Pentacyclines: A Novel Class of Tetracycline Analogs

    PubMed Central

    2011-01-01

    Employing a highly efficient total synthesis approach, we synthesized and evaluated for antibacterial activity diverse and novel pentacycline analogs with systematic variations at C7, C8, C9, and C10. Certain substitution groups, as well as substitution patterns at various positions, were found to be preferred for increased antibacterial activity. A number of pentacycline analogs displayed potent activity in vitro and in vivo, especially against Gram-positive organisms. Several analogs have also shown promising oral bioavailability in rats and cynomolgus monkey. PMID:21500832

  11. Chemical Composition, Antioxidant, and Antibacterial Activity of Wood Vinegar from Litchi chinensis.

    PubMed

    Yang, Jyh-Ferng; Yang, Cheng-Hong; Liang, Ming-Tsai; Gao, Zi-Jie; Wu, Yuh-Wern; Chuang, Li-Yeh

    2016-01-01

    The antioxidant and antibacterial activities of wood vinegar from Litchi chinensis, and its components have been studied. The chemical compositions of wood vinegar were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 17 chemical compounds were identified, representing 83.96% of the compositions in the wood vinegar. Three major components, included 2,6-dimethoxyphenol (syringol, 29.54%), 2-methoxyphenol (guaiacol, 12.36%), and 3,5-dimethoxy-4-hydroxytoluene (11.07%), were found in the wood vinegar. Antioxidant activities of the acids were investigated from the aspects of 1,1-Diphyl-2-picrylhydrazyl (DPPH) free radicals scavenging capacity, superoxide anion radical scavenging capacity, and reducing power. The pyroligneous acid exhibited high antioxidant activity which was comparable to the reference standards (vitamin C and butylated hydroxyl toluene) at the same dose with IC50 values of 36.5 ppm calculated by the DPPH radical scavenging assay, 38.38 g Trolox equivalent/100 g DW by the trolox equivalent antioxidant capacity (TEAC) assay, and 67.9 by the reducing power analysis. Antibacterial activity was evaluated using the disc diffusion and microdilution methods against a group of clinically antibiotic resistant isolates. The major components exhibited broad spectrum inhibition against all the bacterial strains with a range of disc inhibition zoon between 15-19 mm. The minimum inhibition concentration and minimum bactericide concentration against the test strains was ranging in 0.95-3.80 μL/100 μL and 1.90-3.80 μL/100 μL, respectively. Most of the antibiotic resistant strains were more susceptible to the wood vinegar than the non-antibiotic resistant strain except the strain of ornithine resistant Staphylococcus aureus. Based on the chemical profile, it was considered that the strongest antioxidant and antibacterial activity of Litchi chinensis wood vinegar was due to its highly phenolic compositions. This study revealed that the Litchi

  12. Loaded Ce-Ag organic-inorganic hybrids and their antibacterial activity.

    PubMed

    Truffault, Laurianne; Rodrigues, Danilo Fernando; Salgado, Hérida Regida Nunes; Santilli, Celso Valentim; Pulcinelli, Sandra Helena

    2016-11-01

    There are requirements for surfaces with antibacterial properties in various technological fields. U-PEO hybrids with antibacterial properties were synthesized by the sol-gel process, incorporating combinations of cerium and silver salts at different silver molar fractions (0, 0.02, 0.05, 0.10, and 1) relative to the total amount of doped cations. The loaded hybrids were characterized by TGA, XRD, and Raman spectroscopy. Release tests were performed using UV-vis spectroscopy, and the antibacterial properties of the hybrids were studied in agar tests and turbidimetry assays. The nanostructural evolution of the hybrids during the release of the antibacterial agents was investigated by in situ SAXS. XRD results showed the presence of the AgCl crystalline phase in the loaded hybrids from a silver molar fraction of 0.05. Raman spectroscopy evidenced the interaction of silver cations with the polymeric part of the hybrid. SAXS results confirmed these interactions and showed that cerium species interacted with both organic and inorganic parts of the hybrids. The loaded U-PEO hybrids were found to release all the incorporated cerium in 1h, while the hybrid containing 100% of silver released only 78% of the incorporated silver. All the loaded hybrids displayed antibacterial activity against the Pseudomonas aeruginosa bacterium. The antibacterial activity was found to increase with silver molar fraction. Due to its high antibacterial activity and low silver molar fraction, the loaded hybrid with silver molar fraction of 0.10 seemed to be a good compromise between efficiency, esthetic transparency, and photostability. PMID:27500358

  13. Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity.

    PubMed

    Ayaz Ahmed, Khan Behlol; Subramanian, Swetha; Sivasubramanian, Aravind; Veerappan, Ganapathy; Veerappan, Anbazhagan

    2014-09-15

    The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual.

  14. Trichoderma koningii assisted biogenic synthesis of silver nanoparticles and evaluation of their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Tripathi, R. M.; Gupta, Rohit Kumar; Shrivastav, Archana; Singh, M. P.; Shrivastav, B. R.; Singh, Priti

    2013-09-01

    The present study demonstrates the biosynthesis of silver nanoparticles using Trichoderma koningii and evaluation of their antibacterial activity. Trichoderma koningii secretes proteins and enzymes that act as reducing and capping agent. The biosynthesized silver nanoparticles (AgNPs) were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and x-ray diffraction (XRD). UV-Vis spectra showed absorbance peak at 413 nm corresponding to the surface plasmon resonance of silver nanoparticles. DLS was used to find out the size distribution profile. The size and morphology of the AgNPs was determined by TEM, which shows the formation of spherical nanoparticles in the size range of 8-24 nm. X-ray diffraction showed intense peaks corresponding to the crystalline silver. The antibacterial activity of biosynthesized AgNPs was evaluated by growth curve and inhibition zone and it was found that the AgNPs show potential effective antibacterial activity.

  15. Structure–Activity Relationship for the 4(3H)-Quinazolinone Antibacterials

    PubMed Central

    2016-01-01

    We recently reported on the discovery of a novel antibacterial (2) with a 4(3H)-quinazolinone core. This discovery was made by in silico screening of 1.2 million compounds for binding to a penicillin-binding protein and the subsequent demonstration of antibacterial activity against Staphylococcus aureus. The first structure–activity relationship for this antibacterial scaffold is explored in this report with evaluation of 77 variants of the structural class. Eleven promising compounds were further evaluated for in vitro toxicity, pharmacokinetics, and efficacy in a mouse peritonitis model of infection, which led to the discovery of compound 27. This new quinazolinone has potent activity against methicillin-resistant (MRSA) strains, low clearance, oral bioavailability and shows efficacy in a mouse neutropenic thigh infection model. PMID:27088777

  16. Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Ayaz Ahmed, Khan Behlol; Subramanian, Swetha; Sivasubramanian, Aravind; Veerappan, Ganapathy; Veerappan, Anbazhagan

    2014-09-01

    The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual.

  17. Synthesis, characterization and antibacterial activity of polyaniline/Pt-Pd nanocomposite.

    PubMed

    Boomi, Pandi; Prabu, Halliah Gurumallesh; Mathiyarasu, Jayaraman

    2014-01-24

    Pt colloid and Pt-Pd colloid, pristine polyaniline, polyaniline/Pt nanocomposite and polyaniline/Pt-Pd nanocomposite were synthesized by simple chemical method. They were characterized by UV-Vis, FT-IR, XRD, TGA, SEM, HR-SEM and HR-TEM with EDAX techniques. The results proved that there is a strong interaction between metal nanoparticles (Pt-Pd) and polyaniline chains. This interaction creates changes in the backbone chain of polyaniline/Pt-Pd nanocomposite when compared to pristine polyaniline. The synthesized materials were evaluated for antibacterial activity, minimal inhibitory concentration and minimal bactericidal concentration. The results indicated that the nanocomposites exhibited improved antibacterial activity when compared to pristine polyaniline and individual metal colloids. This is the first report on the chemical synthesis of polyaniline/Pt-Pd nanocomposite, which exhibits antibacterial activity at micro molar concentration levels.

  18. Silver/poly (lactic acid) nanocomposites: preparation, characterization, and antibacterial activity

    PubMed Central

    Shameli, Kamyar; Ahmad, Mansor Bin; Yunus, Wan Md Zin Wan; Ibrahim, Nor Azowa; Rahman, Russly Abdul; Jokar, Maryam; Darroudi, Majid

    2010-01-01

    In this study, antibacterial characteristic of silver/poly (lactic acid) nanocomposite (Ag/PLA-NC) films was investigated, while silver nanoparticles (Ag-NPs) were synthesized into biodegradable PLA via chemical reduction method in diphase solvent. Silver nitrate and sodium borohydride were respectively used as a silver precursor and reducing agent in the PLA, which acted as a polymeric matrix and stabilizer. Meanwhile, the properties of Ag/PLA-NCs were studied as a function of the Ag-NP weight percentages (8, 16, and 32 wt% respectively), in relation to the use of PLA. The morphology of the Ag/PLA-NC films and the distribution of the Ag-NPs were also characterized. The silver ions released from the Ag/PLA-NC films and their antibacterial activities were scrutinized. The antibacterial activities of the Ag/PLA-NC films were examined against Gram-negative bacteria (Escherichia coli and Vibrio parahaemolyticus) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using Muller–Hinton agar. The results indicated that Ag/PLA-NC films possessed a strong antibacterial activity with the increase in the percentage of Ag-NPs in the PLA. Thus, Ag/PLA-NC films can be used as an antibacterial scaffold for tissue engineering and medical application. PMID:20856832

  19. Silver doped nanomaterials and their possible use for antibacterial photodynamic activity

    NASA Astrophysics Data System (ADS)

    Wysocka-Król, Katarzyna; Wieliczko, Alina; Podbielska, Halina

    2011-10-01

    Bacteria, viruses and parasites elimination from human environment is one of the most important problem, extensively studied by many groups. The growing resistance to commonly used disinfection and/or sterilization methods and antibiotics, is one of the major problem in the health care sector. Nanomaterials with tailored antimicrobial features may find applications in this field. One of the promising application of nanomaterials is the possibility to enhance the antimicrobial photodynamic therapy (APDT), which combines a nontoxic photoactive dye - photosensitizer and nanomaterials properties. This paper focused on the examination of optical and antibacterial properties of silica- and titania-based nanopowders doped with silver and photosensitizer - Photolon. Various concentration of Photolon and nanomaterials have been prepared in order to examine the fluorescence enhancement and resulting better antibacterial activity. It was proved that the fluorescence intensity of Photolon increased, depending on silver concentration. Antibacterial study showed that silver doped silica and titania nanoparticles revealed antibacterial activity, but in the presence of Photolon, the antibacterial activity of materials is more effective.

  20. Bioinspired synthesis of polydopamine/Ag nanocomposite particles with antibacterial activities.

    PubMed

    Wu, Chengjiao; Zhang, Guoxing; Xia, Tian; Li, Zhenni; Zhao, Kai; Deng, Ziwei; Guo, Dingzong; Peng, Bo

    2015-10-01

    Mussel-inspired chemistry (polydopamine) offers great opportunities to develop inexpensive and efficient process for many types of materials with complex shapes and functions in a mild and friendly environment. This paper describes a facile, yet green approach to synthesize polydopamine/silver (PDA/Ag) nanocomposite particles with a combination use of polydopamine chemistry and electroless metallization of Ag. In this approach, monodisperse spherical polydopamine particles are first synthesized by the oxidation and self-polymerization of dopamine (monomer) in an alkaline water-ethanol solution at room temperature, which are served as the active templates for secondary reactions due to the abundant catechol and amine groups on the surface. Subsequently, the silver precursor-[Ag(NH3)2](+) ions introduced are easily absorbed onto the surface of the PDA particles, and are immediately in situ reduced to metallic Ag nanoparticles with the help of these active catechol and amine groups. During the preparation, no additional reductants, toxic reagents and intricate instruments are needed. These as-synthesized PDA/Ag nanocomposite particles are ideal candidates for antibacterial application because they do not show significant cytotoxicity against HEK293T human embryonic kidney cells in the in vitro cytotoxicity assay, whereas demonstrate enhanced antibacterial abilities against Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria) in the antibacterial assays. Owing to their excellent cytocompatibilities and antibacterial activities, these PDA/Ag nanocomposite particles can be considered as the promising antibacterial materials for future biomedical applications.

  1. Bacitracin-conjugated superparamagnetic iron oxide nanoparticles: synthesis, characterization and antibacterial activity.

    PubMed

    Zhang, Wenjing; Shi, Xinhao; Huang, Jing; Zhang, Yixuan; Wu, Zirong; Xian, Yuezhong

    2012-10-01

    Bacitracin-conjugated superparamagnetic iron oxide (Fe(3)O(4)) nanoparticles were prepared by click chemistry and their antibacterial activity was investigated. After functionalization with hydrophilic and biocompatible poly(acrylic acid), water-soluble Fe(3)O(4) nanoparticles were obtained. Propargylated Fe(3)O(4) nanoparticles were then synthesized by carbodiimide reaction of propargylamine with the carboxyl groups on the surface of the iron oxide nanoparticles. By further reaction with N(3)-bacitracin in a Cu(I)-catalyzed azide-alkyne cycloaddition, the magnetic Fe(3)O(4) nanoparticles were modified with the peptide bacitracin. The functionalized magnetic nanoparticles were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, TEM, zeta-potential analysis, FTIR spectroscopy and vibrating-sample magnetometry. Cell cytotoxicity tests indicate that bacitracin-conjugated Fe(3)O(4) nanoparticles show very low cytotoxicity to human fibroblast cells, even at relatively high concentrations. In view of the antibacterial activity of bacitracin, the biofunctionalized Fe(3)O(4) nanoparticles exhibit an antibacterial effect against both Gram-positive and Gram-negative organisms, which is even higher than that of bacitracin itself. The enhanced antibacterial activity of the magnetic nanocomposites allows the dosage and the side effects of the antibiotic to be reduced. Due to the antibacterial effect and magnetism, the bacitracin-functionalized magnetic nanoparticles have potential application in magnetic-targeting biomedical applications.

  2. Antibacterial, antifungal and cytotoxic activities of amblyone isolated from Amorphophallus campanulatus

    PubMed Central

    Khan, Alam; Rahman, Moizur; Islam, M.S.

    2008-01-01

    Objective: To assess the in vitro antibacterial, antifungal and cytotoxic activities of amblyone, a triterpenoid isolated from Amorphophallus campanulatus (Roxb). Methods: Disc diffusion technique was used for in vitro antibacterial and antifungal screening. Cytotoxicity was determined against brine shrimp nauplii. In addition, minimum inhibitory concentration (MIC) was determined using serial dilution technique to determine the antibacterial potency. Results: Large zones of inhibition were observed in disc diffusion antibacterial screening against four Gram-positive bacteria (Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus and Streptococcus pyogenes) and six Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella sonnei, Shigella flexneri, Pseudomonas aeruginosa and Salmonella typhi). The MIC values against these bacteria ranged from 8 to 64 μg/ml. In antifungal screening, the compound showed small zones of inhibition against Aspergillus flavus, Aspergillus niger and Rhizopus aryzae. Candida albicans was resistant against the compound. In the cytotoxicity determination, LC50 of the compound against brine shrimp nauplii was 13.25 μg/ml. Conclusions: These results suggest that the compound has good antibacterial activity against the tested bacteria, moderate cytotoxicity against brine shrimp nauplii and insignificant antifungal activity against the tested fungi. PMID:21264161

  3. Shape effect on the antibacterial activity of silver nanoparticles synthesized via a microwave-assisted method.

    PubMed

    Hong, Xuesen; Wen, Junjie; Xiong, Xuhua; Hu, Yongyou

    2016-03-01

    Silver nanoparticles (AgNPs) are used as sustained-release bactericidal agents for water treatment. Among the physicochemical characteristics of AgNPs, shape is an important parameter relevant to the antibacterial activity. Three typically shaped AgNPs, nanocubes, nanospheres, and nanowires, were prepared via a microwave-assisted method and characterized by TEM, UV-vis, and XRD. The antibacterial activity of AgNPs was determined by OD growth curves tests, MIC tests, and cell viability assay against Escherichia coli. The interaction between AgNPs and bacterial cells was observed by TEM. The results showed that the three differently shaped AgNPs were nanoscale, 55 ± 10 nm in edge length for nanocubes, 60 ± 15 nm in diameter for nanospheres, 60 ± 10 nm in diameter and 2-4 μm in length for nanowires. At the bacterial concentration of 10(4) CFU/mL, the MIC of nanocubes, nanospheres, and nanowires were 37.5, 75, and 100 μg/mL, respectively. Due to the worst contact with bacteria, silver nanowires exhibited the weakest antibacterial activity compared with silver nanocubes and silver nanospheres. Besides, silver nanocubes mainly covered by {100} facets showed stronger antibacterial activity than silver nanospheres covered by {111} facets. It suggests that the shape effect on the antibacterial activity of AgNPs is attributed to the specific surface areas and facets reactivity; AgNPs with larger effective contact areas and higher reactive facets exhibit stronger antibacterial activity.

  4. Antibacterial activity of graphene-modified anode on Shewanella oneidensis MR-1 biofilm in microbial fuel cell

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Deng, Feng; Hu, Yongyou; Sun, Jian; Yang, Yonggang

    2015-09-01

    To clearly illustrate the antibacterial activity of graphene on anodic exoelectrogen, the growth of a Shewanella oneidensis MR-1 biofilm on graphene-modified anodes (GMAs) and bare graphite anodes (BGs) were compared. The GMAs with different amounts of graphene were obtained by the cyclic voltammetric electrodeposition of 5, 20 and 40 potential cycles (5-G, 20-G and 40-G). Confocal scanning laser microscopy and cyclic voltammetry results demonstrated that graphene exhibited an obvious antibacterial effect for initial Shewanella MR biofilm growth. After 5 h of inoculation, 40-G, 20-G and 5-G had 6.3, 8.8 and 13.9% lower levels of biofilm viability, respectively, compared to BG, and all three exhibited approximately 70% lower electrochemical activity compared to BG. However, 18 h later, the biofilm on the GMAs exhibited much higher viability than that of the BG, and the electrochemical activity increased to a similar level. This study revealed the dual effect of graphene, including the antibacterial activity on biofilms and the enhancement of bacterial attachment and electron transfer.

  5. Phenolic Compounds and In Vitro Antibacterial and Antioxidant Activities of Three Tropic Fruits: Persimmon, Guava, and Sweetsop

    PubMed Central

    Lu, WenQing; Zhou, XiaoMin

    2016-01-01

    In our previous study, we have found that persimmon, guava, and sweetsop owned considerably high antioxidant activity and contained high total phenolic contents as well. In order to further supply information on the antibacterial and antioxidant activity of these three tropic fruits, they were extracted by 80% methanol. We then examined the extractions about their phenolic compounds and also studied the extractions and phenolic contents about their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against twelve targeted pathogens including 8 standard strains (Staphylococcus aureus, Bacillus cereus, Staphylococcus epidermidis, Monilia albican, Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Pseudomonas aeruginosa) and 4 multidrug-resistant strains (methicillin-resistant Staphylococcus aureus, ESBLs-producing Escherichia coli, carbapenems-resistant Pseudomonas aeruginosa, and multidrug-resistant Acinetobacter baumannii), which are common and comprehensive in clinic. We also employed two ways, that is, FRAP and TEAC, to evaluate their antioxidant activities, using ultraviolet and visible spectrophotometer. Our study indicated that the three tropical fruits possessed obvious antioxidant and antibacterial activity, which supported the possibility of developing the fruits into new natural resource food and functional food as well as new natural antimicrobial agent and food preservatives. Moreover, phenolic compounds detected in the fruits could be used as a potential natural antibacterial agent and antioxidant. PMID:27648444

  6. Phenolic Compounds and In Vitro Antibacterial and Antioxidant Activities of Three Tropic Fruits: Persimmon, Guava, and Sweetsop.

    PubMed

    Fu, Li; Lu, WenQing; Zhou, XiaoMin

    2016-01-01

    In our previous study, we have found that persimmon, guava, and sweetsop owned considerably high antioxidant activity and contained high total phenolic contents as well. In order to further supply information on the antibacterial and antioxidant activity of these three tropic fruits, they were extracted by 80% methanol. We then examined the extractions about their phenolic compounds and also studied the extractions and phenolic contents about their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against twelve targeted pathogens including 8 standard strains (Staphylococcus aureus, Bacillus cereus, Staphylococcus epidermidis, Monilia albican, Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Pseudomonas aeruginosa) and 4 multidrug-resistant strains (methicillin-resistant Staphylococcus aureus, ESBLs-producing Escherichia coli, carbapenems-resistant Pseudomonas aeruginosa, and multidrug-resistant Acinetobacter baumannii), which are common and comprehensive in clinic. We also employed two ways, that is, FRAP and TEAC, to evaluate their antioxidant activities, using ultraviolet and visible spectrophotometer. Our study indicated that the three tropical fruits possessed obvious antioxidant and antibacterial activity, which supported the possibility of developing the fruits into new natural resource food and functional food as well as new natural antimicrobial agent and food preservatives. Moreover, phenolic compounds detected in the fruits could be used as a potential natural antibacterial agent and antioxidant. PMID:27648444

  7. Phenolic Compounds and In Vitro Antibacterial and Antioxidant Activities of Three Tropic Fruits: Persimmon, Guava, and Sweetsop

    PubMed Central

    Lu, WenQing; Zhou, XiaoMin

    2016-01-01

    In our previous study, we have found that persimmon, guava, and sweetsop owned considerably high antioxidant activity and contained high total phenolic contents as well. In order to further supply information on the antibacterial and antioxidant activity of these three tropic fruits, they were extracted by 80% methanol. We then examined the extractions about their phenolic compounds and also studied the extractions and phenolic contents about their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against twelve targeted pathogens including 8 standard strains (Staphylococcus aureus, Bacillus cereus, Staphylococcus epidermidis, Monilia albican, Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Pseudomonas aeruginosa) and 4 multidrug-resistant strains (methicillin-resistant Staphylococcus aureus, ESBLs-producing Escherichia coli, carbapenems-resistant Pseudomonas aeruginosa, and multidrug-resistant Acinetobacter baumannii), which are common and comprehensive in clinic. We also employed two ways, that is, FRAP and TEAC, to evaluate their antioxidant activities, using ultraviolet and visible spectrophotometer. Our study indicated that the three tropical fruits possessed obvious antioxidant and antibacterial activity, which supported the possibility of developing the fruits into new natural resource food and functional food as well as new natural antimicrobial agent and food preservatives. Moreover, phenolic compounds detected in the fruits could be used as a potential natural antibacterial agent and antioxidant.

  8. Flavonoid glycosides from Prunus armeniaca and the antibacterial activity of a crude extract.

    PubMed

    Rashid, Fahima; Ahmed, Rehana; Mahmood, Azhar; Ahmad, Zaheer; Bibi, Nazia; Kazmi, Shahana Urooj

    2007-08-01

    Investigations on the chemical constituents of the fruits of Prunus armeniaca have led to the isolation of two new flavonoid glycosides, 4',5,7-trihydroxy flavone-7-O-[beta-D-mannopyranosyl (1'''-->2")]-beta-D-allopyranoside (1) and 3,4',5,7-tetrahydroxy-3',5'-di-methoxy flavone 3-O-[alpha-L-rhamnopyranosyl (1'''-->6")]-beta-D-galactopyranoside (2), from the butanolic fraction of the fruits. The butanolic extract exhibited antibacterial activity against both Gram positive and Gram negative bacteria. The structures of these compounds were elucidated through spectral studies, including 2D-NMR (COSY, NOESY, J-resolved), HMQC and HMBC experiments.

  9. Calixarene Assisted Rapid Synthesis of Silver-Graphene Nanocomposites with Enhanced Antibacterial Activity.

    PubMed

    Kellici, Suela; Acord, John; Vaughn, Arni; Power, Nicholas P; Morgan, David J; Heil, Tobias; Facq, Sébastien P; Lampronti, Giulio I

    2016-07-27

    Demonstrated herein is a single rapid approach employed for synthesis of Ag-graphene nanocomposites, with excellent antibacterial properties and low cytotoxicity, by utilizing a continuous hydrothermal flow synthesis (CHFS) process in combination with p-hexasulfonic acid calix[6]arene (SCX6) as an effective particle stabilizer. The nanocomposites showed high activity against E. coli (Gram-negative) and S. aureus (Gram-positive) bacteria. The materials were characterized using a range of techniques including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-vis spectrophotometry, FT-IR, and X-ray powder diffraction (XRD). This rapid, single step synthetic approach not only provides a facile means of enabling and controlling graphene reduction (under alkaline conditions) but also offers an optimal route for homogeneously producing and depositing highly crystalline Ag nanostructures into reduced graphene oxide substrate. PMID:27378104

  10. Preparation and characterization of quaternary ammonium chitosan hydrogel with significant antibacterial activity.

    PubMed

    Fan, Lihong; Yang, Jing; Wu, Huan; Hu, Zhihai; Yi, Jiayan; Tong, Jun; Zhu, Xiaoming

    2015-08-01

    Quaternary ammonium chitosan (HACC)/polyvinyl alcohol (PVA)/polyethylene oxide (PEO) hydrogels were prepared using gamma radiation. The chemical structure of the hydrogels was characterized using FT-IR. The results revealed that HACC, PVA and PEO were perfectly compatible and interacted via the hydrogen bonds. As revealed by SEM, scaffolds with a homogeneous interconnected pore structure were obtained after lyophilizing the hydrogels. The influence of different radiation doses and weight ratios on properties including gel content, swelling ability, water evaporation rate and mechanical properties were investigated. It indicated that the hydrogels had the good swelling ability, water evaporation rate and mechanical properties. In vitro antibacterial activity assessment, the hydrogels exhibited a pronounced inhibitory effect against two bacteria (Staphylococcus aureus and Escherichia coli). Therefore, the hydrogels showed a promising potential to be applied as wound dressing. PMID:25895959

  11. Antibacterial activity of essential oils of Pimenta racemosa var. terebinthina and Pimenta racemosa var. grisea.

    PubMed

    Saenz, M T; Tornos, M P; Alvarez, A; Fernandez, M A; García, M D

    2004-09-01

    The antibacterial activity of essential oils of Pimenta racemosa var. terebinthina and P. racemosa var. grisea was determined against Gram (+) and Gram (-) bacteria. P. racemosa var. grisea demonstrated a more pronounced activity. These data would indicate the potential usefulness of the variety grisea as a microbiostatic, antiseptic or disinfectant agent.

  12. Novel photocatalytic antibacterial activity of TiO2 microspheres exposing 100% reactive {111} facets.

    PubMed

    Sun, Liang; Qin, Ying; Cao, Qingqing; Hu, Bingqing; Huang, Zhiwei; Ye, Ling; Tang, Xingfu

    2011-12-21

    TiO(2) microspheres constructed by well-crystallized faceted nanorods with high aspect ratios expose 100% photocatalytic reactive {111} facets on the spherical surface. The microspheres demonstrated excellent photocatalytic antibacterial activity towards Staphylococcus aureus due to effective suppression of photoinduced electron-hole pair recombination and active TiO(2)@˙OH core-shell structure. PMID:22051605

  13. Synthesis, in vitro antibacterial activities of a series of 3-N-substituted canthin-6-ones.

    PubMed

    Dai, Jiang-Kun; Dan, Wen-Jia; Li, Na; Du, Hong-Tao; Zhang, Ji-Wen; Wang, Jun-Ru

    2016-01-15

    An improved synthetic route of canthin-6-one was accomplished. To further enhance the antibacterial potency and improve water solubility, a series of 3-N-alkylated and 3-N-benzylated canthin-6-ones were designed and synthesized, and their in vitro antibacterial activities were evaluated. A clear structure-activity relationship with peak minimal inhibitory concentration (MIC) values of 0.98 (μg·mL(-)(1)) was investigated. Particularly, compounds 6i-r and 6t were found to be the most potent compounds with minimal inhibitory concentration (MIC) values lower than 1.95 (μg·mL(-)(1)) against Staphylococcus aureus.

  14. Potential antibacterial activity of coumarin and coumarin-3-acetic acid derivatives.

    PubMed

    Chattha, Fauzia Anjum; Munawar, Munawar Ali; Nisa, Mehrun; Ashraf, Mohammad; Kousar, Samina; Arshad, Shafia

    2015-05-01

    Coumarin and coumarin-3-acetic acid derivatives were synthesized by reacting phenols with malic acid, ethyl acetoacetate and ethyl acetylsuccinate in appropriate reaction conditions. All synthesized compounds were subjected to test for their antimicrobial activities against variety of gram positive (Bacillus subtilis, Staphylococcus aureus) and gram negative bacterial stains (Shigella sonnei, Escherichia coli) by agar dilution method. Several of them exhibited appreciable good antibacterial activity against the different strains of gram positive and gram negative bacteria. These findings suggest a great potential of these compounds for screening and use as antibacterial agents for further studies with a battery of bacteria.

  15. Antibacterial structure–activity relationship studies of several tricyclic sulfur-containing flavonoids

    PubMed Central

    Bahrin, Lucian G; Hopf, Henning; Jones, Peter G; Sarbu, Laura G; Babii, Cornelia; Mihai, Alina C

    2016-01-01

    Summary A structure–activity relationship study concerning the antibacterial properties of several halogen-substituted tricyclic sulfur-containing flavonoids has been performed. The compounds have been synthesized by cyclocondensation of the corresponding 3-dithiocarbamic flavanones under acidic conditions. The influence of different halogen substituents on the antibacterial properties has been tested against Staphylococcus aureus and Escherichia coli. Amongst the N,N-dialkylamino-substituted flavonoids, those having an N,N-diethylamino moiety exhibited good to excellent antimicrobial properties against both pathogens. Fluorine-substituted flavonoids were found to be less active than those bearing other halogen atoms. PMID:27340492

  16. Antibacterial structure-activity relationship studies of several tricyclic sulfur-containing flavonoids.

    PubMed

    Bahrin, Lucian G; Hopf, Henning; Jones, Peter G; Sarbu, Laura G; Babii, Cornelia; Mihai, Alina C; Stefan, Marius; Birsa, Lucian M

    2016-01-01

    A structure-activity relationship study concerning the antibacterial properties of several halogen-substituted tricyclic sulfur-containing flavonoids has been performed. The compounds have been synthesized by cyclocondensation of the corresponding 3-dithiocarbamic flavanones under acidic conditions. The influence of different halogen substituents on the antibacterial properties has been tested against Staphylococcus aureus and Escherichia coli. Amongst the N,N-dialkylamino-substituted flavonoids, those having an N,N-diethylamino moiety exhibited good to excellent antimicrobial properties against both pathogens. Fluorine-substituted flavonoids were found to be less active than those bearing other halogen atoms. PMID:27340492

  17. Development and Antibacterial Activity of Cashew Gum-Based Silver Nanoparticles

    PubMed Central

    Quelemes, Patrick V.; Araruna, Felipe B.; de Faria, Bruna E. F.; Kuckelhaus, Selma A. S.; da Silva, Durcilene A.; Mendonça, Ronaldo Z.; Eiras, Carla; dos S. Soares, Maria José; Leite, José Roberto S. A.

    2013-01-01

    The present study describes the development of a green synthesis of silver nanoparticles reduced and stabilized by exuded gum from Anacardium occidentale L. and evaluates in vitro their antibacterial and cytotoxic activities. Characterization of cashew gum-based silver nanoparticles (AgNPs) was carried out based on UV–Vis spectroscopy, transmission electron microscopy and dynamic light scattering analysis which revealed that the synthesized silver nanoparticles were spherical in shape, measuring about 4 nm in size with a uniform dispersal. AgNPs presented antibacterial activity, especially against Gram-negative bacteria, in concentrations where no significant cytotoxicity was observed. PMID:23455467

  18. Combined Antibacterial and Anti-Inflammatory Activity of a Cationic Disubstituted Dexamethasone-Spermine Conjugate▿

    PubMed Central

    Bucki, Robert; Leszczyńska, Katarzyna; Byfield, Fitzroy J.; Fein, David E.; Won, Esther; Cruz, Katrina; Namiot, Andrzej; Kułakowska, Alina; Namiot, Zbigniew; Savage, Paul B.; Diamond, Scott L.; Janmey, Paul A.

    2010-01-01

    The rising number of antibiotic-resistant bacterial strains represents an emerging health problem that has motivated efforts to develop new antibacterial agents. Endogenous cationic antibacterial peptides (CAPs) that are produced in tissues exposed to the external environment are one model for the design of novel antibacterial compounds. Here, we report evidence that disubstituted dexamethasone-spermine (D2S), a cationic corticosteroid derivative initially identified as a by-product of synthesis of dexamethasone-spermine (DS) for the purpose of improving cellular gene delivery, functions as an antibacterial peptide-mimicking molecule. This moiety exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa present in cystic fibrosis (CF) sputa, and Pseudomonas aeruginosa biofilm. Although compromised in the presence of plasma, D2S antibacterial activity resists the proteolytic activity of pepsin and is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage (BAL) fluid. D2S also enhances S. aureus susceptibility to antibiotics, such as amoxicillin (AMC), tetracycline (T), and amikacin (AN). Inhibition of interleukin-6 (IL-6) and IL-8 release from lipopolysaccharide (LPS)- or lipoteichoic acid (LTA)-treated neutrophils in the presence of D2S suggests that this molecule might also prevent systemic inflammation caused by bacterial wall products. D2S-mediated translocation of green fluorescent protein (GFP)-labeled glucocorticoid receptor (GR) in bovine aorta endothelial cells (BAECs) suggests that some of its anti-inflammatory activities involve engagement of glucocorticoid receptors. The combined antibacterial and anti-inflammatory activities of D2S suggest its potential as an alternative to natural CAPs in the prevention and treatment of some bacterial infections. PMID:20308375

  19. Oligomerization of esculin improves its antibacterial activity and modulates antibiotic resistance.

    PubMed

    Mokdad-Bzeouich, Imen; Mustapha, Nadia; Chaabane, Fadwa; Ghedira, Zied; Ghedira, Kamel; Ghoul, Mohamed; Chebil, Latifa; Chekir-Ghedira, Leila

    2015-03-01

    In this particular study, the antibacterial activity of esculin and oligomer fractions was assessed. MIC values of esculin and its oligomer fractions as well as of some antibiotics against Gram-positive and Gram-negative strains and against Escherichia coli multiresistant variants were determined by the standard broth microdilution method. Both esculin and oligoesculin fractions exhibited antibacterial effect against reference strains; Staphylococcus aureus, Enterococcus faecalis, Salmonella enteritidis and Salmonella typhimurium. It appears that E3 oligomer fraction had the greatest antibacterial activity against these reference strains. Besides, as E2 and E3 revealed the best antibacterial effect against multiresistant variants of E. coli, we decided to test the effect of each, combined to the antibiotic against which the variants were resistant. In the interaction study, E2 and E3 oligoesculin fractions were found to be effective in reducing the resistance of E. coli 6574 to ofloxacin and the resistance of E. coli 6228 to amoxicillin. Only E3 oligoesculin fraction showed a synergetic interaction with amoxicillin and tetracyclin against E. coli 6708, but no interaction was found either with E2 or E3 fractions against E. coli 6234. Our study allowed us to conclude that oligomerization of esculin increases its antibacterial potential, according to the degree of polymerization.

  20. I-TiO2/PVC film with highly photocatalytic antibacterial activity under visible light.

    PubMed

    Deng, Weihua; Ning, Shangbo; Lin, Qianying; Zhang, Hualei; Zhou, Tanghua; Lin, Huaxiang; Long, Jinlin; Lin, Qun; Wang, Xuxu

    2016-08-01

    Iodine-modified TiO2(I-TiO2) film were coated on medical-grade PVC material by impregnation-deposition method and subsequently characterized by XRD, SEM, TEM, AFM, DRS and XPS. The photocatalytic anti-bacterial activity of I-TiO2/PVC was investigated both by in vitro anti-bacterial experiments and by clinical study. The results revealed that I-TiO2/PVC exhibit excellent photocatalytic antibacterial activity, which can destroy the propagation of the Escherichia coli and cause the deactivation and death of most E. coli bacteria within 30min visible light illumination. Clinical study on animals showed that I-TiO2 coated on PVC decrease the formation of biofilm on PVC surface in the mechanical ventilation. Furthermore, I-TiO2/PVC can effectively reduce inflammation of tracheal tissue of bam suckling pig and prevents the occurrence of VAP.

  1. Chemical Composition and Antibacterial Activity of Essential Oils of Two Species of Lamiaceae against Phytopathogenic Bacteria.

    PubMed

    Gormez, Arzu; Bozari, Sedat; Yanmis, Derya; Gulluce, Medine; Sahin, Fikrettin; Agar, Guleray

    2015-01-01

    In this study, we aimed to determine chemical composition and antibacterial activities of Satureja hortensis and Calamintha nepeta against to 20 phytopathogenic bacteria causing serious crop loss. The essential oils of S. hortensis and C. nepeta were isolated by the hydrodistillation method and the chemical composition of the essential oils were analyzed by GC-MS. The antibacterial properties of the essential oils were evaluated against 20 phytopathogenic bacteria through Disc diffusion assay and micro dilution assay. The results revealed that the essential oils of S. hortensis and C. nepeta have significant antibacterial activity. Furthermore, the findings of the study are valuable for future investigations focusing on the alternative natural compounds to control plant diseases. PMID:26373171

  2. In vitro evaluation of antibacterial activity of an herbal dentifrice against Streptococcus mutans and Lactobacillus acidophilus.

    PubMed

    Vyas, Yogesh Kumar; Bhatnagar, Maheep; Sharma, Kanika

    2008-01-01

    Antibacterial activity of a herbal dentifrice Arodent against Streptococcus mutans and Lactobacillus acidophilus was evaluated using Colgate as standard. Both bacterial strains were isolated from the oral cavity on selective media and identified by standard methods. The antibacterial activity was assayed by cup-well method. The bacterial lawn of facultative anaerobe S. mutans was established between two layers of agar under microaerophilic conditions. Five and a half millimeters and 10 mm zones of inhibition were produced by Arodent against S. mutans and L. acidophilus , respectively, under microaerophilic conditions. On the other hand, the standard dentifrice Colgate produced 5.83 mm and 10.17 mm zones of inhibition against S. mutans and L. acidophilus , respectively, under microaerophilic condition. The results suggest that Arodent is an effective antibacterial herbal dentifrice. PMID:18245920

  3. In vitro evaluation of antibacterial activity of an herbal dentifrice against Streptococcus mutans and Lactobacillus acidophilus.

    PubMed

    Vyas, Yogesh Kumar; Bhatnagar, Maheep; Sharma, Kanika

    2008-01-01

    Antibacterial activity of a herbal dentifrice Arodent against Streptococcus mutans and Lactobacillus acidophilus was evaluated using Colgate as standard. Both bacterial strains were isolated from the oral cavity on selective media and identified by standard methods. The antibacterial activity was assayed by cup-well method. The bacterial lawn of facultative anaerobe S. mutans was established between two layers of agar under microaerophilic conditions. Five and a half millimeters and 10 mm zones of inhibition were produced by Arodent against S. mutans and L. acidophilus , respectively, under microaerophilic conditions. On the other hand, the standard dentifrice Colgate produced 5.83 mm and 10.17 mm zones of inhibition against S. mutans and L. acidophilus , respectively, under microaerophilic condition. The results suggest that Arodent is an effective antibacterial herbal dentifrice.

  4. Biocompatibility and antibacterial activity of the Adathoda vasica Linn extract mediated silver nanoparticles.

    PubMed

    Latha, M; Priyanka, M; Rajasekar, P; Manikandan, R; Prabhu, N M

    2016-04-01

    The aim of this study is to investigate the biocompatibility and anti-Vibrio efficacy of green synthesized silver nanoparticles (AgNPs) using an aqueous leaf extract of Adathoda vasica (A. vasica). The green synthesized silver nanoparticles were characterized by UV-vis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). A. vasica AgNPs showed significant antibacterial activity against Vibrio parahaemolyticus in agar bioassay and well diffusion method. Further, nanoparticles interactions with bacteria and its antibacterial activity were confirmed by CLSM analysis. In vivo evaluation results confirmed that synthesized A. vasica AgNPs had good antibacterial efficacy and also nontoxic to the Artemia nauplii. PMID:26802519

  5. Antibacterial activities of peptides from the water-soluble extracts of Italian cheese varieties.

    PubMed

    Rizzello, C G; Losito, I; Gobbetti, M; Carbonara, T; De Bari, M D; Zambonin, P G

    2005-07-01

    Water-soluble extracts of 9 Italian cheese varieties that differed mainly for type of cheese milk, starter, technology, and time of ripening were fractionated by reversed-phase fast protein liquid chromatography, and the antimicrobial activity of each fraction was first assayed toward Lactobacillus sakei A15 by well-diffusion assay. Active fractions were further analyzed by HPLC coupled to electrospray ionization-ion trap mass spectrometry, and peptide sequences were identified by comparison with a proteomic database. Parmigiano Reggiano, Fossa, and Gorgonzola water-soluble extracts did not show antibacterial peptides. Fractions of Pecorino Romano, Canestrato Pugliese, Crescenza, and Caprino del Piemonte contained a mixture of peptides with a high degree of homology. Pasta filata cheeses (Caciocavallo and Mozzarella) also had antibacterial peptides. Peptides showed high levels of homology with N-terminal, C-terminal, or whole fragments of well known antimicrobial or multifunctional peptides reported in the literature: alphaS1-casokinin (e.g., sheep alphaS1-casein (CN) f22-30 of Pecorino Romano and cow alphaS1-CN f24-33 of Canestrato Pugliese); isracidin (e.g., sheep alphaS1-CN f10-21 of Pecorino Romano); kappacin and casoplatelin (e.g., cow kappa-CN f106-115 of Canestrato Pugliese and Crescenza); and beta-casomorphin-11 (e.g., goat beta-CN f60-68 of Caprino del Piemonte). As shown by the broth microdilution technique, most of the water-soluble fractions had a large spectrum of inhibition (minimal inhibitory concentration of 20 to 200 microg/mL) toward gram-positive and gram-negative bacterial species, including potentially pathogenic bacteria of clinical interest. Cheeses manufactured from different types of cheese milk (cow, sheep, and goat) have the potential to generate similar peptides with antimicrobial activity.

  6. 1-methyl malate from Berberis integerrima fruits enhances the antibacterial activity of ampicillin against Staphylococcus aureus.

    PubMed

    Alimirzaee, P; Gohari, A R; Hajiaghaee, R; Mirzaee, S; Jamalifar, H; Monsef-Esfahani, H R; Amin, Gh; Saeidnia, S; Shahverdi, A R

    2009-06-01

    The enhancement of the antibacterial activity of ampicillin by different extracts of Berberis integerrima fruits was evaluated against Staphylococcus aureus. Disk diffusion and agar dilution methods were used to determine the antibacterial activity of ampicillin in the absence and presence of different plant extracts or various fractions eluted by column chromatography. A clinical isolate of S. aureus was used as a test strain. The active component of B. integerrima fruits involved in the enhancement of ampicillin activity was purified and identified as 1-methyl malate using different spectroscopic methods. Both the ethanol extract of B. integerrima fruits and 1-methyl malate enhanced the antibacterial activity of ampicillin. The total extract as well as 1-methyl malate increased the antibacterial activity of ampicillin against the test strain. The potency of ampicillin against the test strain was increased 64-fold when tested with a sub-toxic concentration of total extract of B. integerrima fruits. Also, 1-methyl malate increased the bactericidal activity of ampicillin. In the presence of 2 mg/mL of 1-methyl malate the MIC of ampicillin for S. aureus decreased from 128 to 1 microg/mL (128-fold).

  7. Antibacterial and Anti-Inflammatory Activities of Physalis Alkekengi var. franchetii and Its Main Constituents

    PubMed Central

    Shu, Zunpeng; Xing, Na; Wang, Qiuhong; Li, Xinli; Xu, Bingqing; Li, Zhenyu; Kuang, Haixue

    2016-01-01

    This study was designed to determine whether the 50% EtOH fraction from AB-8 macroporous resin fractionation of a 70% EtOH extract of P. Alkekengi (50-EFP) has antibacterial and/or anti-inflammatory activity both in vivo and in vitro and to investigate the mechanism of 50-EFP anti-inflammatory activity. Additionally, this study sought to define the chemical composition of 50-EFP. Results indicated that 50-EFP showed significant antibacterial activity in vitro and efficacy in vivo. Moreover, 50-EFP significantly reduced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) production in lipopolysaccharide- (LPS-) stimulated THP-1 cells. Nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (examined at the protein level) in THP-1 cells were suppressed by 50-EFP, which inhibited nuclear translocation of p65. Consistent with this anti-inflammatory activity in vitro, 50-EFP reduced inflammation in both animal models. Finally, seventeen compounds (8 physalins and 9 flavones) were isolated as major components of 50-EFP. Our data demonstrate that 50-EFP has antibacterial and anti-inflammatory activities both in vitro and in vivo. The anti-inflammatory effect appears to occur, at least in part, through the inhibition of nuclear translocation of p65. Moreover, physalins and flavones are probably the active components in 50-EFP that exert antibacterial and anti-inflammatory activities. PMID:27057196

  8. Antibacterial activity of phenolic compounds and aromatic alcohols.

    PubMed

    Lucchini, J J; Corre, J; Cremieux, A

    1990-05-01

    The antibacterial properties of phenolic compounds and aromatic alcohols (growth inhibition, lethal effect and cytological damage) were investigated. The role of protein and RNA synthesis in the bactericidal action was also determined. All compounds tested demonstrated lethal properties and the ability to alter membranes, especially in Gram-negative bacteria. Efficacious concentrations, however, varied greatly among the compounds. These data corroborate previous findings which suggest that the mechanism of action of these compounds is related to their lipophilia. Moreover, since it was demonstrated that the lethal effect of two aromatic alcohols (phenethyl alcohol and benzyl alcohol) stops when protein synthesis is inhibited, it is likely that both possess specific mechanisms of action.

  9. Osteogenic activity and antibacterial effect of zinc oxide/carboxylated graphene oxide nanocomposites: Preparation and in vitro evaluation.

    PubMed

    Chen, Junyu; Zhang, Xin; Cai, He; Chen, Zhiqiang; Wang, Tong; Jia, Lingling; Wang, Jian; Wan, Qianbing; Pei, Xibo

    2016-11-01

    The aim of this study was to prepare nanocomposites of carboxylated graphene oxide (GO-COOH) sheets decorated with zinc oxide (ZnO) nanoparticles (NPs) and investigate their advantages in the field of bone tissue engineering. First, ZnO/GO-COOH nanocomposites were synthesized by facile reactions, including the carboxylation of graphene oxide (GO) and the nucleation of ZnO on GO-COOH sheets. The synthesized ZnO/GO-COOH nanocomposites were then characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and transmission electron microscopy (TEM). The biocompatibility, osteogenic activity and antibacterial effect of ZnO/GO-COOH nanocomposites were further investigated. In the nanocomposites, ZnO nanoparticles with a size of approximately 12nm were uniformly decorated on GO-COOH sheets. Compared with GO-COOH and the control group, ZnO/GO-COOH nanocomposites significantly enhanced ALP activity, osteocalcin production and extracellular matrix mineralization as well as up-regulated osteogenic-related genes (ALP, OCN, and Runx2) in MG63 osteoblast-like cells. Moreover, ZnO/GO-COOH nanocomposites had an antibacterial effect against Streptococcus mutans. These results indicated that ZnO/GO-COOH nanocomposites exhibited both osteogenic activity and antibacterial effect and had great potential for designing new biomaterials in the field of bone tissue engineering.

  10. Preparation of ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Lin, Huimin; Zhang, Bin; Yu, Tian; Deng, Shanggui

    The preparation of a ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity were studied. The optimal conditions of hydrolysis by papain and ferrous chelation were obtained by single-factor experiments and orthogonal test, with the antibacterial activities as the index. In addition, the antibacterial activity of Fe(II)-HPH was evaluated using the Plackett-Burman design. The orthogonal test results showed that Fe(II)-HPH had an antibacterial activity of 98.3% under a temperature of 40 °C at pH 6.5 for an enzymolysis duration of eight hours in the presence of 20,000 U/g of enzyme. The Plackett-Burman design analysis showed that the three most significant factors (P < 0.05) influencing the antibacterial activity of Fe(II)-HPH were pH, the concentration (mg/mL), and presence of magnesium sulfate.

  11. In vitro and in vivo antibacterial activities of GV129606, a new broad-spectrum trinem.

    PubMed Central

    Di Modugno, E; Broggio, R; Erbetti, I; Lowther, J

    1997-01-01

    GV129606 is a new parenteral trinem antibiotic belonging to the beta-lactam class. It combines broad-spectrum activity (against gram-negative and -positive bacteria, aerobes and anaerobes), with high potency and resistance to beta-lactamases. Comparative in vitro and in vivo antibacterial activities were determined for GV129606 against more than 400 recent clinical isolates (aerobes, including beta-lactamase producers, and anaerobes), using representative antibacterial agents (meropenem, piperacillin, ceftazidime, cefpirome, ciprofloxacin, and gentamicin for aerobes and metronidazole, cefoxitin, piperacillin, and clindamycin for anaerobes). Against methicillin-susceptible staphylococci and streptococci, GV129606 and meropenem were the most active of the drugs tested. GV129606 showed an MIC for 90% of strains tested (MIC90) ranging from < or =0.015 to 0.06 microg/ml against methicillin-susceptible staphylococci and Streptococcus sanguis, Streptococcus pyogenes, and Streptococcus agalactiae. Against penicillin-susceptible and -resistant Streptococcus pneumoniae isolates, GV129606, meropenem, and cefpirome showed MIC90s of < or =0.015 and 1 microg/ml, respectively. Meropenem was the most active compound against members of the family Enterobacteriaceae with MIC90s of < or =0.5 microg/ml. Against these species, GV129606 possessed activity superior to those of piperacillin, ceftazidime, cefpirome, and gentamicin, with MIC90s of < or =8 microg/ml, but its activity was two- to sixfold less than that of ciprofloxacin (with the exception of Proteus rettgeri and Providencia stuartii). Haemophilus spp., Moraxella catarrhalis, Neisseria gonorrhoeae, and Pseudomonas aeruginosa were also included in the spectrum of GV129606. GV129606 showed good antianaerobe activity, similar to metronidazole. It was stable against all clinically relevant beta-lactamases (similar to meropenem). The in vitro activity was confirmed in vivo against septicemia infections induced in mice by selected

  12. Study on the antibacterial mechanism of copper ion- and neodymium ion-modified α-zirconium phosphate with better antibacterial activity and lower cytotoxicity.

    PubMed

    Cai, Xiang; Zhang, Bin; Liang, Yuanyuan; Zhang, Jinglin; Yan, Yinghui; Chen, Xiaoyin; Wu, Zhimin; Liu, Hongxi; Wen, Shuiping; Tan, Shaozao; Wu, Ting

    2015-08-01

    To improve the antibacterial activity of Cu(2+), a series of Cu(2+) and/or Nd(3+)-modified layered α-zirconium phosphate (ZrP) was prepared and characterized, and the antibacterial activities of the prepared Cu(2+) and/or Nd(3+)-modified ZrP on Gram-negative Escherichia coli were investigated. The results showed that the basal spacing of ZrP was not obviously affected by the incorporation of Cu(2+), but the basal spacing of the modified ZrP changed into an amorphous state with increasing additions of Nd(3+). An antibacterial mechanism showed that Cu(2+) and Nd(3+) could enter into E. coli cells, leading to changes in ion concentrations and leakage of DNA, RNA and protein. The Cu(2+)- and Nd(3+)-modified ZrP, combining the advantages of Cu(2+) and Nd(3+), displayed excellent additive antibacterial activity and lower cytotoxicity, suggesting the great potential application as an antibacterial powder for microbial control.

  13. Preparation and antibacterial activity of Fe3O4@Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Li, Huimin; He, Xiaoxiao; Wang, Kemin; Hu, Jianbing; Tan, Weihong; Zhang, Shouchun; Yang, Xiaohai

    2007-07-01

    Bifunctional Fe3O4@Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are present in the same particle. The superparamagnetism of Fe3O4@Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe3O4@Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe3O4@Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe3O4@Ag nanoparticles can still have antibacterial capability and can be reused.

  14. Characterization of antibacterial polyethersulfone membranes using the Respiration Activity Monitoring System (RAMOS).

    PubMed

    Kochan, Jozef; Scheidle, Marco; van Erkel, Joost; Bikel, Matías; Büchs, Jochen; Wong, John Erik; Melin, Thomas; Wessling, Matthias

    2012-10-15

    Membranes with antibacterial properties were developed using surface modification of polyethersulfone ultrafiltration membranes. Three different modification strategies using polyelectrolyte layer-by-layer (LbL) technique are described. The first strategy relying on the intrinsic antibacterial properties of poly(diallyldimethylammonium chloride) (PDADMAC) and poly(ethylenimine) (PEI) exhibits only little antibacterial effects. The other two strategies contain silver in both ionic (Ag(+)) and metallic (Ag(0)) form. Ag(+) embedded into negatively charged poly(sodium 4-styrene sulfonate) (PSS) layers totally inhibits bacterial growth. Ag(0) nanoparticles were introduced to the membrane surface by LbL deposition of chitosan- and poly(methacrylic acid) - sodium salt (PMA)-capped silver nanoparticles and subsequent UV or heat treatment. Antibacterial properties of the modified membranes were quantified by a new method based on the Respiration Activity Monitoring System (RAMOS), whereby the oxygen transfer rates (OTR) of E. coli K12 cultures on the membranes were monitored online. As opposed to colony forming counting method RAMOS yields more quantitative and reliable data on the antibacterial effect of membrane modification. Ag-imprinted polyelectrolyte film composed of chitosan (Ag(0))/PMA(Ag(0))/chitosan(Ag(0)) was found to be the most promising among the tested membranes. Further investigation revealed that the concentration and equal distribution of silver in the membrane surface plays an important role in bacterial growth inhibition. PMID:22884245

  15. Full Spectrum Visible LED Light Activated Antibacterial System Realized by Optimized Cu2O Crystals.

    PubMed

    Shi, Xiaotong; Xue, Chaowen; Fang, Fang; Song, Xiangwei; Yu, Fen; Liu, Miaoxing; Wei, Zhipeng; Fang, Xuan; Zhao, Dongxu; Xin, Hongbo; Wang, Xiaolei

    2016-04-01

    Assisted by three-dimensional printing technology, we proposed and demonstrated a full spectrum visible light activated antibacterial system by using a combination of 500 nm sized Cu2O crystals and light-emitting diode (LED) lamps. Further improved antibacterial ratios were achieved, for the first time, with pure Cu2O for both Gram-positive bacteria and Gram-negative bacteria among all of the six different color LED lamps. For practical antibacterial applications, we revealed that the nonwoven fabric could act as excellent carrier for Cu2O crystals and provide impressive antibacterial performance. Furthermore, integrated with our self-developed app, the poly(ethylene terephthalate) film loaded with Cu2O crystals also showed significant antibacterial property, thus making it possible to be applied in field of touch screen. The present research not only provided a healthier alternative to traditional ultraviolet-based sterilization but also opened an auto-response manner to decrease the rate of microbial contamination on billions of touch screen devices. PMID:26978589

  16. Full Spectrum Visible LED Light Activated Antibacterial System Realized by Optimized Cu2O Crystals.

    PubMed

    Shi, Xiaotong; Xue, Chaowen; Fang, Fang; Song, Xiangwei; Yu, Fen; Liu, Miaoxing; Wei, Zhipeng; Fang, Xuan; Zhao, Dongxu; Xin, Hongbo; Wang, Xiaolei

    2016-04-01

    Assisted by three-dimensional printing technology, we proposed and demonstrated a full spectrum visible light activated antibacterial system by using a combination of 500 nm sized Cu2O crystals and light-emitting diode (LED) lamps. Further improved antibacterial ratios were achieved, for the first time, with pure Cu2O for both Gram-positive bacteria and Gram-negative bacteria among all of the six different color LED lamps. For practical antibacterial applications, we revealed that the nonwoven fabric could act as excellent carrier for Cu2O crystals and provide impressive antibacterial performance. Furthermore, integrated with our self-developed app, the poly(ethylene terephthalate) film loaded with Cu2O crystals also showed significant antibacterial property, thus making it possible to be applied in field of touch screen. The present research not only provided a healthier alternative to traditional ultraviolet-based sterilization but also opened an auto-response manner to decrease the rate of microbial contamination on billions of touch screen devices.

  17. Easily separated silver nanoparticle-decorated magnetic graphene oxide: Synthesis and high antibacterial activity.

    PubMed

    Zhang, Huai-Zhi; Zhang, Chang; Zeng, Guang-Ming; Gong, Ji-Lai; Ou, Xiao-Ming; Huan, Shuang-Yan

    2016-06-01

    Silver nanoparticle-decorated magnetic graphene oxide (MGO-Ag) was synthesized by doping silver and Fe3O4 nanoparticles on the surface of GO, which was used as an antibacterial agent. MGO-Ag was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray (EDS), X-ray diffraction (XRD), Raman spectroscopy and magnetic property tests. It can be found that magnetic iron oxide nanoparticles and nano-Ag was well dispersed on graphene oxide; and MGO-Ag exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus. Several factors were investigated to study the antibacterial effect of MGO-Ag, such as temperature, time, pH and bacterial concentration. We also found that MGO-Ag maintained high inactivation rates after use six times and can be separated easily after antibacterial process. Moreover, the antibacterial mechanism is discussed and the synergistic effect of GO, Fe3O4 nanoparticles and nano-Ag accounted for high inactivation of MGO-Ag. PMID:26994349

  18. Easily separated silver nanoparticle-decorated magnetic graphene oxide: Synthesis and high antibacterial activity.

    PubMed

    Zhang, Huai-Zhi; Zhang, Chang; Zeng, Guang-Ming; Gong, Ji-Lai; Ou, Xiao-Ming; Huan, Shuang-Yan

    2016-06-01

    Silver nanoparticle-decorated magnetic graphene oxide (MGO-Ag) was synthesized by doping silver and Fe3O4 nanoparticles on the surface of GO, which was used as an antibacterial agent. MGO-Ag was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray (EDS), X-ray diffraction (XRD), Raman spectroscopy and magnetic property tests. It can be found that magnetic iron oxide nanoparticles and nano-Ag was well dispersed on graphene oxide; and MGO-Ag exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus. Several factors were investigated to study the antibacterial effect of MGO-Ag, such as temperature, time, pH and bacterial concentration. We also found that MGO-Ag maintained high inactivation rates after use six times and can be separated easily after antibacterial process. Moreover, the antibacterial mechanism is discussed and the synergistic effect of GO, Fe3O4 nanoparticles and nano-Ag accounted for high inactivation of MGO-Ag.

  19. Comparison of antibacterial activities of cadmium oxide nanoparticles against Pseudomonas Aeruginosa and Staphylococcus Aureus bacteria

    PubMed Central

    Salehi, Bahareh; Mortaz, Esmaeil; Tabarsi, Payam

    2015-01-01

    Background: Inorganic antibacterial factors have bacterial resistance and high thermal stability. Inorganic nanomaterials which have new structures with biological, chemical and physical properties have been made since their applications due to their nano size. In this study, the antibacterial effect of cadmium oxide nanoparticles on Staphylococcus aureus and Pseudomonas aeruginosa bacteria was investigated. Materials and Methods: The different concentrations (10 μg/ml, 15 μg/ml and 20 μg/ml) of cadmium oxide nanoparticles were prepared and their effects were studied against considered bacteria in both solid and liquid media. Results: The results showed that there is a direct relationship between inhibitory effect and amount of consumer dose of nanoparticles. Furthermore, it was observed that antibacterial properties of cadmium oxide nanoparticles on activity and growth of Staphylococcus aureus was more effective than Pseudomonas aeruginosa. Conclusion: This study showed that antibacterial effects of cadmium oxide nanoparticles on positive gram bacteria are stronger than negative gram bacteria and antibacterial effects of cdo nanoparticles against both bacteria, but Staphylococcus aureus bacteria were more sensitive to nanoparticles as compared to Pseudomonas aeruginosa. PMID:26261807

  20. In vitro and in vivo antibacterial activities of BO-1341, a new antipseudomonal cephalosporin.

    PubMed Central

    Nakagawa, S; Sanada, M; Matsuda, K; Hashizume, T; Asahi, Y; Ushijima, R; Ohtake, N; Tanaka, N

    1989-01-01

    BO-1341, a new antipseudomonal semisynthetic cephalosporin, was evaluated for in vitro and in vivo antibacterial activities in comparison with ceftazidime, cefotaxime, and cefoperazone. The in vitro activity of BO-1341 was generally superior or comparable to the activities of the reference antibiotics against clinical isolates of the family Enterobacteriaceae. BO-1341 was highly active against Pseudomonas aeruginosa (MIC for 90% of the strains tested, 1.56 micrograms/ml), Pseudomonas maltophilia (MIC for 50% of the strains tested, 1.56 micrograms/ml), and Acinetobacter calcoaceticus (MIC for 90% of the strains tested, 3.13 micrograms/ml). Furthermore, BO-1341 was highly active against P. aeruginosa isolates resistant to the other antibiotics. Of 199 P. aeruginosa isolates tested, only 2 were resistant to BO-1341. These two strains were also resistant to ceftazidime, cefotaxime, and cefoperazone. Haemophilus influenzae, Branhamella catarrhalis, and nonenteric streptococci were also susceptible to BO-1341, but Staphylococcus aureus, Streptococcus faecalis, and Bacteroides fragilis were not susceptible to the compound. The protective efficacy against experimental infections in mice caused by nine strains of gram-negative bacteria, including P. aeruginosa, reflected the potent in vitro activity. PMID:2510590

  1. Antibacterial Activity of Some Plant Extracts Against Extended- Spectrum Beta-Lactamase Producing Escherichia coli Isolates

    PubMed Central

    Saeidi, Saeide; Amini Boroujeni, Negar; Ahmadi, Hassan; Hassanshahian, Mehdi

    2015-01-01

    Background: The extended-spectrum beta-lactamase (ESBL) -producing Escherichia coli isolates make many serious infections, especially urinary tract infections. Objectives: The purpose of this study was to determine the antibacterial activities of some natural plant extracts against ESBL-producing E. coli isolates, which harbor the TEM gene in urine samples of the patients who have urinary tract infections. Materials and Methods: Evaluation has to be exactly determined for both methods of disk diffusion test and polymerase chain reaction (PCR), separately. We evaluated 120 strains of E. coli isolates from the urine culture of the patients in Boo-Ali Hospital (Zahedan, south-eastern Iran) who were suffering from urinary tract infections. The ESBL-producing E. coli isolates were evaluated by disk diffusion test and PCR through TEM gene detection. The minimal inhibitory concentration (MIC) of commonly used antibiotics including ceftazidime, ceftriaxon, amikacin, gentamicin and ciprofloxacin along with the MIC of the alcoholic extract of different natural plants including Myrtus communis L (Myrtaceae), Amaranthus retraflexus (Amaranthaceae), Cyminum cuminum L (Apiaceae), Marrubium vulgare (Laminaceae) and Peganum. harmala (Zygrophyllaceae) against the ESBL-producing E. coli isolates, which harbor the TEM genes, were determined using the microdulition method. Results: Results of this study showed that in disk diffusion method, 80 samples of E. coli produced ESBLs. In PCR method, the TEM gene distribution in the isolated ESBL-producing organisms was 50 (41.6%). Amikacin was the most effective anti-bacterial agent and ciprofloxacin was the least effective against E. coli isolates. All the natural plant extracts mentioned above, especially P. harmala, were effective against the selected isolates of ESBL-producing E. coli. The most frequent ESBL rate producing E. coli isolates (32 out of 50) had MIC of 2.5 mg/mL in ethanol extract of P. harmala. Conclusions: The alcoholic

  2. Essential Oil Composition and Antibacterial Activity of Origanum vulgare subsp. glandulosum Desf. at Different Phenological Stages

    PubMed Central

    Chaabane, Hédia; Jemli, Maroua; Boulila, Abdennacer; Boussaid, Mohamed

    2013-01-01

    Abstract Variation in the quantity and quality of the essential oil (EO) of wild population of Origanum vulgare at different phenological stages, including vegetative, late vegetative, and flowering set, is reported. The oils of air-dried samples were obtained by hydrodistillation. The yield of oils (w/w%) at different stages were in the order of late vegetative (2.0%), early vegetative (1.7%), and flowering (0.6%) set. The oils were analyzed by gas chromatography (GC) and GC–mass spectrometry (GC-MS). In total, 36, 33, and 16 components were identified and quantified in vegetative, late vegetative, and flowering set, representing 94.47%, 95.91%, and 99.62% of the oil, respectively. Carvacrol was the major compound in all samples. The ranges of major constituents were as follows: carvacrol (61.08–83.37%), p-cymene (3.02–9.87%), and γ-terpinene (4.13–6.34%). Antibacterial activity of the oils was tested against three Gram-positive and two Gram-negative bacteria by the disc diffusion method and determining their diameter of inhibition and the minimum inhibitory concentration (MIC) values. The inhibition zones and MIC values for bacterial strains, which were sensitive to the EO of O. vulgare subsp. glandulosum, were in the range of 9–36 mm and 125–600 μg/mL, respectively. The oils of various phenological stages showed high activity against all tested bacteria, of which Bacillus subtilis was the most sensitive and resistant strain, respectively. Thus, they represent an inexpensive source of natural antibacterial substances that exhibited potential for use in pathogenic systems. PMID:24320986

  3. Essential oil composition and antibacterial activity of Origanum vulgare subsp. glandulosum Desf. at different phenological stages.

    PubMed

    Béjaoui, Afef; Chaabane, Hédia; Jemli, Maroua; Boulila, Abdennacer; Boussaid, Mohamed

    2013-12-01

    Variation in the quantity and quality of the essential oil (EO) of wild population of Origanum vulgare at different phenological stages, including vegetative, late vegetative, and flowering set, is reported. The oils of air-dried samples were obtained by hydrodistillation. The yield of oils (w/w%) at different stages were in the order of late vegetative (2.0%), early vegetative (1.7%), and flowering (0.6%) set. The oils were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). In total, 36, 33, and 16 components were identified and quantified in vegetative, late vegetative, and flowering set, representing 94.47%, 95.91%, and 99.62% of the oil, respectively. Carvacrol was the major compound in all samples. The ranges of major constituents were as follows: carvacrol (61.08-83.37%), p-cymene (3.02-9.87%), and γ-terpinene (4.13-6.34%). Antibacterial activity of the oils was tested against three Gram-positive and two Gram-negative bacteria by the disc diffusion method and determining their diameter of inhibition and the minimum inhibitory concentration (MIC) values. The inhibition zones and MIC values for bacterial strains, which were sensitive to the EO of O. vulgare subsp. glandulosum, were in the range of 9-36 mm and 125-600 μg/mL, respectively. The oils of various phenological stages showed high activity against all tested bacteria, of which Bacillus subtilis was the most sensitive and resistant strain, respectively. Thus, they represent an inexpensive source of natural antibacterial substances that exhibited potential for use in pathogenic systems. PMID:24320986

  4. Antibacterial activity of graphite, graphite oxide, graphene oxide, and reduced graphene oxide: membrane and oxidative stress.

    PubMed

    Liu, Shaobin; Zeng, Tingying Helen; Hofmann, Mario; Burcombe, Ehdi; Wei, Jun; Jiang, Rongrong; Kong, Jing; Chen, Yuan

    2011-09-27

    Health and environmental impacts of graphene-based materials need to be thoroughly evaluated before their potential applications. Graphene has strong cytotoxicity toward bacteria. To better understand its antimicrobial mechanism, we compared the antibacterial activity of four types of graphene-based materials (graphite (Gt), graphite oxide (GtO), graphene oxide (GO), and reduced graphene oxide (rGO)) toward a bacterial model-Escherichia coli. Under similar concentration and incubation conditions, GO dispersion shows the highest antibacterial activity, sequentially followed by rGO, Gt, and GtO. Scanning electron microscope (SEM) and dynamic light scattering analyses show that GO aggregates have the smallest average size among the four types of materials. SEM images display that the direct contacts with graphene nanosheets disrupt cell membrane. No superoxide anion (O(2)(•-)) induced reactive oxygen species (ROS) production is detected. However, the four types of materials can oxidize glutathione, which serves as redox state mediator in bacteria. Conductive rGO and Gt have higher oxidation capacities than insulating GO and GtO. Results suggest that antimicrobial actions are contributed by both membrane and oxidation stress. We propose that a three-step antimicrobial mechanism, previously used for carbon nanotubes, is applicable to graphene-based materials. It includes initial cell deposition on graphene-based materials, membrane stress caused by direct contact with sharp nanosheets, and the ensuing superoxide anion-independent oxidation. We envision that physicochemical properties of graphene-based materials, such as density of functional groups, size, and conductivity, can be precisely tailored to either reducing their health and environmental risks or increasing their application potentials.

  5. Mechanism of Antibacterial Activity of Liposomal Linolenic Acid against Helicobacter pylori

    PubMed Central

    Jung, Sung Woo; Thamphiwatana, Soracha; Zhang, Liangfang; Obonyo, Marygorret

    2015-01-01

    Helicobacter pylori infects approximately half of the world population and is a major cause of gastritis, peptic ulcer, and gastric cancer. Moreover, this bacterium has quickly developed resistance to all major antibiotics. Recently, we developed a novel liposomal linolenic acid (LipoLLA) formulation, which showed potent bactericidal activity against several clinical isolated antibiotic-resistant strains of H. pylori including both the spiral and coccoid form. In addition, LipoLLA had superior in vivo efficacy compared to the standard triple therapy. Our data showed that LipoLLA associated with H. pylori cell membrane. Therefore, in this study, we investigated the possible antibacterial mechanism of LipoLLA against H. pylori. The antibacterial activity of LipoLLA (C18:3) was compared to that of liposomal stearic acid (LipoSA, C18:0) and oleic acid (LipoOA, C18:1). LipoLLA showed the most potent bactericidal effect and completely killed H. pylori within 5 min. The permeability of the outer membrane of H. pylori increased when treated with LipoOA and LipoLLA. Moreover, by detecting released adenosine triphosphate (ATP) from bacteria, we found that bacterial plasma membrane of H. pylori treated with LipoLLA exhibited significantly higher permeability than those treated with LipoOA, resulting in bacteria cell death. Furthermore, LipoLLA caused structural changes in the bacterial membrane within 5 min affecting membrane integrity and leading to leakage of cytoplasmic contents, observed by both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Our findings showing rapid bactericidal effect of LipoLLA suggest it is a very promising new, effective anti-H. pylori agent. PMID:25793403

  6. Phenolic content, antioxidant and antibacterial activity of selected natural sweeteners available on the Polish market.

    PubMed

    Grabek-Lejko, Dorota; Tomczyk-Ulanowska, Kinga

    2013-01-01

    Seventeen natural sweeteners available on the Polish market were screened for total phenolic content, by the Folin-Ciocalteu method, and for antioxidant activity, using the ferric reducing antioxidant power (FRAP) assay and the 2,2'-Azinobis (3-ethylbenzthiazoline-6-sulphonic acid) radical cation decolorization assay (ABTS(·+)). In addition, we analyzed antibacterial activities against Staphylococcus aureus strains: both those susceptible and those resistant to methicillin (MRSA). The results of the study showed that total phenolic content, antioxidant activity and antibacterial activity differ widely among different samples of sweeteners. Phenolic content, expressed as a gallic acid equivalent, ranged from 0 mg kg(-1) in white, refined sugar, xylitol and wheat malt syrup to 11.4 g kg(-1) in sugarcane molasses. Antioxidant activity was lowest in refined white sugar, xylitol, brown beet sugar, liquid fructose, and rape honey; it was average in spelt syrup and corn syrup, and highest in sugar cane, beet molasses, date and barley syrups. Despite the great variety of sweeteners, a strong correlation was noted between the concentration of phenolics and antioxidant properties, as determined by the ABTS(·+) method (r = 0.97) and the FRAP assay (r = 0.77). The strongest antibacterial activity was observed in sugarcane molasses, which was lethal to S. aureus strains at 2 and 4% concentrations in medium for susceptible and MRSA strains respectively. Other sweeteners kill bacteria in 6-15% solutions, whereas some did not show any antibacterial activities against S. aureus strains, even at 20% concentrations. Due to their high antioxidant and antibacterial activities, some of the tested sweeteners have potential therapeutic value as supporting agents in antibiotic therapy.

  7. Phenolic content, antioxidant and antibacterial activity of selected natural sweeteners available on the Polish market.

    PubMed

    Grabek-Lejko, Dorota; Tomczyk-Ulanowska, Kinga

    2013-01-01

    Seventeen natural sweeteners available on the Polish market were screened for total phenolic content, by the Folin-Ciocalteu method, and for antioxidant activity, using the ferric reducing antioxidant power (FRAP) assay and the 2,2'-Azinobis (3-ethylbenzthiazoline-6-sulphonic acid) radical cation decolorization assay (ABTS(·+)). In addition, we analyzed antibacterial activities against Staphylococcus aureus strains: both those susceptible and those resistant to methicillin (MRSA). The results of the study showed that total phenolic content, antioxidant activity and antibacterial activity differ widely among different samples of sweeteners. Phenolic content, expressed as a gallic acid equivalent, ranged from 0 mg kg(-1) in white, refined sugar, xylitol and wheat malt syrup to 11.4 g kg(-1) in sugarcane molasses. Antioxidant activity was lowest in refined white sugar, xylitol, brown beet sugar, liquid fructose, and rape honey; it was average in spelt syrup and corn syrup, and highest in sugar cane, beet molasses, date and barley syrups. Despite the great variety of sweeteners, a strong correlation was noted between the concentration of phenolics and antioxidant properties, as determined by the ABTS(·+) method (r = 0.97) and the FRAP assay (r = 0.77). The strongest antibacterial activity was observed in sugarcane molasses, which was lethal to S. aureus strains at 2 and 4% concentrations in medium for susceptible and MRSA strains respectively. Other sweeteners kill bacteria in 6-15% solutions, whereas some did not show any antibacterial activities against S. aureus strains, even at 20% concentrations. Due to their high antioxidant and antibacterial activities, some of the tested sweeteners have potential therapeutic value as supporting agents in antibiotic therapy. PMID:24007486

  8. Preservation of viability and antibacterial activity of Lactobacillus spp. in calcium alginate beads.

    PubMed

    Brachkova, Mariya I; Duarte, Maria A; Pinto, João F

    2010-12-23

    The objective of the study was to produce calcium alginate beads able to deliver Lactobacillus spp. (Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus bulgaricus and Lactobacillus lactis) with preserved viability and antibacterial activity. Four types of beads, containing entrapped (E), surface and entrapped (ES), surface (S) and concentrated surface and entrapped lactobacilli (C(ES)) were prepared and physically characterized. The antibacterial activity of lactobacilli cultures before and after immobilization, freeze-drying and throughout storage was studied in relationship to the viable number of lactobacilli. Multi-resistant clinical isolates (methicillin-resistant Staphylococcus aureus, vancomycine-resistant Enterococcus faecalis, VIM-2-metalo-β-lactamase producing Pseudomonas aeruginosa and CTX-M-15-β-lactamase producing strains: Escherichia coli and Klebsiella pneumoniae) were used as indicator strains. Alginate beads in which lactobacilli proliferated to the beads surface (ES and C(ES)) differed significantly from the other types of beads in their physicochemical properties, showing smoother surface morphology, more spherical shape, bigger weight, lower calcium content, density and crushing force. Lactobacilli cultures, at high cell concentrations (10(8)cfu/ml) were active against both Gram-positive and negative multi-resistant bacteria. Beads containing both entrapped and surface lactobacilli (ES) resulted in viability and antibacterial activity most similar to non-processed lactobacilli cultures. The viability and antibacterial activity of the immobilized lactobacilli remained stable after 6 months storage.

  9. Solophenols B-D and solomonin: new prenylated polyphenols isolated from propolis collected from the Solomon Islands and their antibacterial activity.

    PubMed

    Inui, Saori; Hosoya, Takahiro; Shimamura, Yuko; Masuda, Shuichi; Ogawa, Takeshi; Kobayashi, Hirokazu; Shirafuji, Kenichi; Moli, Reuben Toli; Kozone, Ikuko; Shin-ya, Kazuo; Kumazawa, Shigenori

    2012-11-28

    Three new prenylated flavonoids, namely, solophenols B (1), C (2), and D (3), as well as a new prenylated stilbene, solomonin (4), were isolated from propolis collected from the Solomon Islands. In addition, 17 known compounds were identified. The structures of the new compounds were determined by a combination of methods, including mass spectrometry and NMR. These new compounds and several known compounds were tested for antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Most of them exhibited potent antibacterial activity. These findings may indicate that propolis from the Solomon Islands has potential applications as an ingredient in food additives or pharmaceuticals. PMID:23067056

  10. Solophenols B-D and solomonin: new prenylated polyphenols isolated from propolis collected from the Solomon Islands and their antibacterial activity.

    PubMed

    Inui, Saori; Hosoya, Takahiro; Shimamura, Yuko; Masuda, Shuichi; Ogawa, Takeshi; Kobayashi, Hirokazu; Shirafuji, Kenichi; Moli, Reuben Toli; Kozone, Ikuko; Shin-ya, Kazuo; Kumazawa, Shigenori

    2012-11-28

    Three new prenylated flavonoids, namely, solophenols B (1), C (2), and D (3), as well as a new prenylated stilbene, solomonin (4), were isolated from propolis collected from the Solomon Islands. In addition, 17 known compounds were identified. The structures of the new compounds were determined by a combination of methods, including mass spectrometry and NMR. These new compounds and several known compounds were tested for antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. Most of them exhibited potent antibacterial activity. These findings may indicate that propolis from the Solomon Islands has potential applications as an ingredient in food additives or pharmaceuticals.

  11. Fabrication of silver-coated cobalt ferrite nanocomposite and the study of its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Kooti, M.; Saiahi, S.; Motamedi, H.

    2013-05-01

    A new silver coated cobalt ferrite nanocomposite, Ag@CoFe2O4, was prepared by a two-step procedure. In the first step, cobalt ferrite nanoparticles were synthesized by a combustion method using glycine as a fuel. This ferrite was then coated with nanosilver via chemical reduction of Ag+ solution. The as-synthesized Ag@CoFe2O4 was characterized by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The antibacterial activity of this composite was investigated against some Gram-positive and Gram-negative bacteria and compared with those of silver nanoparticles and some standard antibacterial drugs.

  12. Biosynthesis of silver nanoparticles using citrus sinensis peel extract and its antibacterial activity.

    PubMed

    Kaviya, S; Santhanalakshmi, J; Viswanathan, B; Muthumary, J; Srinivasan, K

    2011-08-01

    Biosynthesis of silver nanoparticles (AgNPs) was achieved by a novel, simple green chemistry procedure using citrus sinensis peel extract as a reducing and a capping agent. The effect of temperature on the synthesis of silver nanoparticles was carried out at room temperature (25°C) and 60°C. The successful formation of silver nanoparticles has been confirmed by UV-vis, FTIR, XRD, EDAX, FESEM and TEM analysis and their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa (gram-negative), and Staphylococcus aureus (gram-positive) has been studied. The results suggest that the synthesized AgNPs act as an effective antibacterial agent.

  13. Synthesis, activity and pharmacokinetics of novel antibacterial 15-membered ring macrolones.

    PubMed

    Fajdetić, Andrea; Vinter, Adrijana; Paljetak, Hana Čipčić; Padovan, Jasna; Jakopović, Ivana Palej; Kapić, Samra; Alihodžić, Sulejman; Filić, Darko; Modrić, Marina; Košutić-Hulita, Nada; Antolović, Roberto; Schoenfeld, Zrinka Ivezić; Mutak, Stjepan; Eraković Haber, Vesna; Spaventi, Radan

    2011-08-01

    Synthesis, antibacterial activity and pharmacokinetic properties of a novel class of macrolide antibiotics-macrolones-derived from azithromycin, comprising oxygen atom(s) in the linker and either free or esterified quinolone 3-carboxylic group, are reported. Selected compounds showed excellent antibacterial potency towards key erythromycin resistant respiratory pathogens. However, the majority of compounds lacked good bioavailability. The isopropyl ester, compound 35, and a macrolone derivative with an elongated linker 29 showed the best oral bioavailability in rats, both accompanied with an excellent overall microbiology profile addressing inducible and constitutive MLSb as well as efflux mediated macrolide resistance in streptococci, while compound 29 is more potent against staphylococci.

  14. Antibacterial Activity of Eravacycline (TP-434), a Novel Fluorocycline, against Hospital and Community Pathogens

    PubMed Central

    O'Brien, W.; Fyfe, C.; Grossman, T. H.

    2013-01-01

    Eravacycline (TP-434 or 7-fluoro-9-pyrrolidinoacetamido-6-demethyl-6-deoxytetracycline) is a novel fluorocycline that was evaluated for antimicrobial activity against panels of recently isolated aerobic and anaerobic Gram-negative and Gram-positive bacteria. Eravacycline showed potent broad-spectrum activity against 90% of the isolates (MIC90) in each panel at concentrations ranging from ≤0.008 to 2 μg/ml for all species panels except those of Pseudomonas aeruginosa and Burkholderia cenocepacia (MIC90 values of 32 μg/ml for both organisms). The antibacterial activity of eravacycline was minimally affected by expression of tetracycline-specific efflux and ribosomal protection mechanisms in clinical isolates. Furthermore, eravacycline was active against multidrug-resistant bacteria, including those expressing extended-spectrum β-lactamases and mechanisms conferring resistance to other classes of antibiotics, including carbapenem resistance. Eravacycline has the potential to be a promising new intravenous (i.v.)/oral antibiotic for the empirical treatment of complicated hospital/health care infections and moderate-to-severe community-acquired infections. PMID:23979750

  15. Antibacterial properties and major bioactive components of cinnamon stick (Cinnamomum burmannii): activity against foodborne pathogenic bacteria.

    PubMed

    Shan, Bin; Cai, Yi-Zhong; Brooks, John D; Corke, Harold

    2007-07-11

    Cinnamomum burmannii Blume (cinnamon stick) from Indonesia is a little-investigated spice. In this study, the antibacterial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of cinnamon stick extract were evaluated against five common foodborne pathogenic bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella anatum). Cinnamon stick extract exhibited significant antibacterial properties. Major compounds in cinnamon stick were tentatively identified by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC-MS) as a predominant volatile oil component ((E)-cinnamaldehyde) and several polyphenols (mainly proanthocyanidins and (epi)catechins). Both (E)-cinnamaldehyde and proanthocyanidins significantly contributed to the antibacterial properties. Additionally, scanning electron microscopy was used to observe morphological changes of bacteria treated with the crude extract of cinnamon stick and its major components. This study suggests that cinnamon stick and its bioactive components have potential for application as natural food preservatives.

  16. High-antibacterial activity of Urtica spp. seed extracts on food and plant pathogenic bacteria.

    PubMed

    Körpe, Didem Aksoy; İşerı, Özlem Darcansoy; Sahin, Feride Iffet; Cabi, Evren; Haberal, Mehmet

    2013-05-01

    The aim of this study was to comparatively evaluate antibacterial activities of methanol (MetOH) and aqueous (dw) leaf (L), root (R) and seed (S) extracts of Urtica dioica L. (Ud; stinging nettle) and Urtica pilulifera L. (Up; Roman nettle) on both food- and plant-borne pathogens, with total phenolic contents and DPPH radical scavenging activities (DRSA). MetOH extracts of leaves and roots of U. dioica had the highest DRSA. Extracts with high antibacterial activity were in the order Up-LMetOH (13/16) > Ud-SMetOH (11/16) > Up-SMetOH (9/16). Results obtained with Up-SMetOH against food spoiling Bacillus pumilus, Shigella spp. and Enterococcus gallinarum with minimum inhibitory concentrations (MICs) in 128-1024 μg/ml range seem to be promising. Up-SMetOH also exerted strong inhibition against Clavibacter michiganensis with a considerably low MIC (32 μg/ml). Ud-SMetOH and Up-LMetOH were also effective against C. michiganensis (MIC = 256 and 1024 μg/ml, respectively). Ud-SMetOH and Ud-RMetOH had also antimicrobial activity against Xanthomonas vesicatoria (MIC = 512 and 1024 μg/ml, respectively). Results presented here demonstrate high-antibacterial activity of U. pilulifera extracts and U. dioica seed extract against phytopathogens for the first time, and provide the most comprehensive data on the antibacterial activity screening of U. pilulifera against food-borne pathogens. Considering limitations in plant disease control, antibacterial activities of these extracts would be of agricultural importance.

  17. High-antibacterial activity of Urtica spp. seed extracts on food and plant pathogenic bacteria.

    PubMed

    Körpe, Didem Aksoy; İşerı, Özlem Darcansoy; Sahin, Feride Iffet; Cabi, Evren; Haberal, Mehmet

    2013-05-01

    The aim of this study was to comparatively evaluate antibacterial activities of methanol (MetOH) and aqueous (dw) leaf (L), root (R) and seed (S) extracts of Urtica dioica L. (Ud; stinging nettle) and Urtica pilulifera L. (Up; Roman nettle) on both food- and plant-borne pathogens, with total phenolic contents and DPPH radical scavenging activities (DRSA). MetOH extracts of leaves and roots of U. dioica had the highest DRSA. Extracts with high antibacterial activity were in the order Up-LMetOH (13/16) > Ud-SMetOH (11/16) > Up-SMetOH (9/16). Results obtained with Up-SMetOH against food spoiling Bacillus pumilus, Shigella spp. and Enterococcus gallinarum with minimum inhibitory concentrations (MICs) in 128-1024 μg/ml range seem to be promising. Up-SMetOH also exerted strong inhibition against Clavibacter michiganensis with a considerably low MIC (32 μg/ml). Ud-SMetOH and Up-LMetOH were also effective against C. michiganensis (MIC = 256 and 1024 μg/ml, respectively). Ud-SMetOH and Ud-RMetOH had also antimicrobial activity against Xanthomonas vesicatoria (MIC = 512 and 1024 μg/ml, respectively). Results presented here demonstrate high-antibacterial activity of U. pilulifera extracts and U. dioica seed extract against phytopathogens for the first time, and provide the most comprehensive data on the antibacterial activity screening of U. pilulifera against food-borne pathogens. Considering limitations in plant disease control, antibacterial activities of these extracts would be of agricultural importance. PMID:23067263

  18. Investigation on antibacterial and antioxidant activities, phenolic and flavonoid contents of some thai edible plants as an alternative for antibiotics.

    PubMed

    Lee, J H; Cho, S; Paik, H D; Choi, C W; Nam, K T; Hwang, S G; Kim, S K

    2014-10-01

    This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, 135 μg/mL. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of 306 μg/mL and 183 μg/mL, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% (EC50) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and 47.8

  19. In vitro studies on the antibacterial activity of phenoxyethanol in combination with lemon grass oil.

    PubMed

    Onawunmi, G O

    1988-01-01

    Lemon grass oil (LGO) has been reported to possess appreciable antibacterial activity especially against Grampositive bacteria. The effect of LGO on the antibacterial activity of phenoxyethanol was studied using MIC, growth inhibition, diffusion tests and bactericidal activity studies. Results showed appreciable increase in the activity of phenoxyethanol against Escherichia coli and Staphylococcus aureus when combined with 0.03% v/v LGO but not against Pseudomonas aeruginosa. The results show that the combined use of LGO and phenoxyethanol would increase the spectrum of activity of phenoxyethanol whose activity is mainly against Ps. aeruginosa. In addition, the combination reduced the effective concentration of both compounds necessary for activity. This would reduce any toxicological hazards as well as production costs.

  20. Shape control of mesoporous silica nanomaterials templated with dual cationic surfactants and their antibacterial activities.

    PubMed

    Hao, Nanjing; Chen, Xuan; Jayawardana, Kalana W; Wu, Bin; Sundhoro, Madanodaya; Yan, Mingdi

    2016-01-01

    Mesoporous silica nanomaterials of different shapes (film, platelet, sphere, rod) were synthesized simply by tuning the mole ratio of dual cationic surfactant templates, cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium iodine (TBAI). The film showed the most potent antibacterial activity against mycobacteria. PMID:26364920

  1. Shape Control of Mesoporous Silica Nanomaterials Templated with Dual Cationic Surfactants and Their Antibacterial Activities

    PubMed Central

    Hao, Nanjing; Chen, Xuan; Jayawardana, Kalana W.; Wu, Bin; Sundhoro, Madanodaya; Yan, Mingdi

    2015-01-01

    Mesoporous silica nanomaterials of different shapes (film, platelet, sphere, rod) were synthesized simply by tuning the mole ratio of dual cationic surfactant templates, cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium iodine (TBAI). The film showed the most potent antibacterial activities against mycobacteria. PMID:26364920

  2. [Preparation and characterization of activated carbon-silver composite with antibacterial behavior via vacuum impregnation method].

    PubMed

    Wang, Zi-Qiang; Liu, Shou-Xin

    2011-01-01

    Activated carbon-silver composite (Ag/AC) for antibacterial performance by controlling silver release was prepared by silver acetate vacuum impregnation method. The antibacterial activity towards E. coil and resistance of water erosion was investigated through distilled water. Surface area and porosity analyzer, Scanning electron spectroscopy (SEM) and X-ray diffraction (XRD) were used to characterize the surface morphology and pore properties. The results show that Ag0 was deposited on AC symmetrically. The content of silver supported and particle size were increased by the increasing of the concentration of CH3 COOAg, while specific surface area, total pore volume and average pore size were decreased. Ag/AC prepared with silver content of 0.97% which killed 10(7) CFU/mL concentration of E. coil in 120 min exhibited the similar antibacterial activity for E. coil with that prepared by traditional impregnation method. However, the silver loss of the Ag/AC prepared with silver content of 0.97% was 37.6%, showing much higher resistance to water erosion. High antibacterial activity and control silver release can be simultaneously realized by the silver acetate vacuum impregnation method.

  3. Isolation and activity of two antibacterial biflavonoids from leaf extracts of Garcinia livingstonei (Clusiaceae).

    PubMed

    Kaikabo, Adamu A; Samuel, Babatunde B; Eloff, Jacobus N

    2009-10-01

    The antibacterial activity of the acetone extract of Garcinia livingstonei leaves was studied using bioautography and by determining the minimum antibacterial concentration against four nosocomial pathogens. Bioautograms showed that two compounds were mainly responsible for the antibacterial activity. These were isolated by a combination of solvent-solvent fractionation and bioassay-guided chromatographic fractionation and were characterized by 1H NMR, 13C NMR and 2D NMR spectroscopy as amentoflavone and 4"-methoxy amentoflavone. The antibacterial activity of the isolated compounds was determined against Escherichia coli, Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa. Three of the tested organisms were sensitive to both compounds with MIC values ranging from 8-100 microg/mL. P. aeruginosa was resistant with MICs > 100 microg/mL. The safety of the two compounds was assessed with a tetrazolium based colorimetric assay (MTT assay) using Vero monkey kidney cells. The compounds had low toxicity against the cell line with cytotoxic concentrations to 50% of the cells (LD50) of 386 microg/mL and > 600 microg/mL for amentoflavone and 4"-methoxy amentoflavone, respectively. Berberine, the positive control had a CC50 of 170 microg/mL. 4"-Methoxy amentoflavone was more active and much less toxic than amentoflavone.

  4. Liamocin oil from Aureobasidium pullulans has antibacterial activity with specificity for species of Streptococcus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Liamocin oil from Aureobasidium pullulans NRRL 50380 was tested for antibacterial activity. Liamocins inhibited growth of Streptococcus agalactiae, S. uberis, S. mitis, S. infantarius, and S. mutans, with minimum inhibitory concentrations from 20 'g/ml to 78 'g/ml. Enterococcus faecalis was less sus...

  5. Antibacterial compounds from Rutaceae with activities against Flavobacterium columnare and Streptococcus iniae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioassay-guided fractionation of the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves yielded isomahanine (1) and mahanine (2) with antibacterial activity towards bacteria species that cause columnaris disease and streptococcosis, common diseases in pond-raised channel catfish (Ictalurus ...

  6. A new prenylated flavanoid with antibacterial activity from propolis collected in Egypt.

    PubMed

    El-Bassuony, Ashraf; AbouZid, Sameh

    2010-01-01

    A novel prenylated flavanoid, isonymphaeol-D (1), together with two known compounds, isonymphaeol-B (2) and nymphaeol-B (3), were isolated from Egyptian propolis. The structures of the isolated compounds were determined by various spectroscopic methods. 1 exhibited antibacterial activity against Gram-positive (Bacillus cereus, Staphylococcus aureus) and Gram-negative strains (Serratia sp., Pseudomonos sp., Escherichia coli).

  7. Comparison of the antibacterial activity of chelating agents using the agar diffusion method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine antibacterial activity of 2 metal chelators. Concentrations of 0 to 40 mM of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine-N,N’-disuccinic acid (EDDS) were prepared in 1.0 M potassium hydroxide (KOH). The pH of the solutions was adjusted to 1...

  8. Invitro Antibacterial Activity of the Prosopis Juliflora Seed Pods on Some Common Pathogens

    PubMed Central

    Tajbakhsh, Saeed; Barmak, Alireza; Vakhshiteh, Faezeh

    2015-01-01

    Introduction Prosopis juliflora is probably the most widespread species of genus Prosopis and it is a good source of compounds that have been shown to be pharmacologically active. This plant has been used as a traditional treatment for several diseases. Aim To investigate the in-vitro antibacterial activity of the P. juliflora seed pods from Bushehr, South West of Iran. Materials and Methods In the present study, the antibacterial activity of P. juliflora seed pods extract was tested against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) of the extract was determined for each test microorganism. Results P. juliflora seed pods extract exhibited antibacterial activity against all four test organisms. The MIC of the extract was 0.312 mg/ml and 0.078 mg/ml for S. aureus and S. epidermidis, respectively and 1.25 mg/ml for both E.coli and P.aeruginosa. Conclusion P. juliflora seed pods from Bushehr, South West of Iran could be an appropriate source of antibacterial compounds that makes it a promising candidate for further studies. PMID:26435943

  9. Effect of zinc oxide amounts on the properties and antibacterial activities of zeolite/zinc oxide nanocomposite.

    PubMed

    Alswat, Abdullah A; Ahmad, Mansor Bin; Saleh, Tawfik A; Hussein, Mohd Zobir Bin; Ibrahim, Nor Azowa

    2016-11-01

    Nanocomposites of zinc oxide loaded on a zeolite (Zeolite/ZnO NCs) were prepared using co-precipitation method. The ratio effect of ZnO wt.% to the Zeolite on the antibacterial activities was investigated. Various techniques were used for the nanocomposite characterization, including UV-vis, FTIR, XRD, EDX, FESEM and TEM. XRD patterns showed that ZnO peak intensity increased while the intensities of Zeolite peaks decreased. TEM images indicated a good distribution of ZnO-NPs onto the Zeolite framework and the cubic structure of the zeolite was maintained. The average particle size of ZnO-nanoparticles loaded on the surface of the Zeolite was in the range of 1-10nm. Moreover, Zeolite/ZnO NCs showed noticeable antibacterial activities against the tested bacteria; Gram- positive and Gram- negative bacteria, under normal light. The efficiency of the antibacterial increased with increasing the wt.% from 3 to 8 of ZnO NPs, and it reached 87% against Escherichia coli E266.

  10. Effect of zinc oxide amounts on the properties and antibacterial activities of zeolite/zinc oxide nanocomposite.

    PubMed

    Alswat, Abdullah A; Ahmad, Mansor Bin; Saleh, Tawfik A; Hussein, Mohd Zobir Bin; Ibrahim, Nor Azowa

    2016-11-01

    Nanocomposites of zinc oxide loaded on a zeolite (Zeolite/ZnO NCs) were prepared using co-precipitation method. The ratio effect of ZnO wt.% to the Zeolite on the antibacterial activities was investigated. Various techniques were used for the nanocomposite characterization, including UV-vis, FTIR, XRD, EDX, FESEM and TEM. XRD patterns showed that ZnO peak intensity increased while the intensities of Zeolite peaks decreased. TEM images indicated a good distribution of ZnO-NPs onto the Zeolite framework and the cubic structure of the zeolite was maintained. The average particle size of ZnO-nanoparticles loaded on the surface of the Zeolite was in the range of 1-10nm. Moreover, Zeolite/ZnO NCs showed noticeable antibacterial activities against the tested bacteria; Gram- positive and Gram- negative bacteria, under normal light. The efficiency of the antibacterial increased with increasing the wt.% from 3 to 8 of ZnO NPs, and it reached 87% against Escherichia coli E266. PMID:27524047

  11. Characterization of silver nanoparticles by green synthesis method using Pedalium murex leaf extract and their antibacterial activity

    NASA Astrophysics Data System (ADS)

    Anandalakshmi, K.; Venugobal, J.; Ramasamy, V.

    2016-03-01

    In this paper, an aqueous extract of fresh leaves of Pedalium murex was used for the synthesis of silver (Ag) nanoparticles. Different biological methods are gaining recognition for the production of silver nanoparticles (AgNPs) due to their multiple applications. The use of plants in the green synthesis of nanoparticles emerges as a cost-effective and eco-friendly approach. Characterization of nanoparticles was done using different methods, which include; ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDAX), fluorescence emission spectroscopy, transmission electron microscope (TEM), dynamic light scattering (DLS), zeta potential and antibacterial activity. UV-visible spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at around 430 nm. Fourier transform infrared spectra had shown that the biomolecule compounds were responsible for the reduction and capping material of silver nanoparticles. XRD study showed the particles to be crystalline in nature, with a face-centered cubic (fcc) structure. The size and stability were detected using DLS and zeta potential analysis. The antibacterial activity of AgNPs against generally found bacteria was assessed to find their potential use in silver-containing antibacterial product.

  12. Antibacterial Activities of Wasabi against Escherichia coli O157:H7 and Staphylococcus aureus

    PubMed Central

    Lu, Zhongjing; Dockery, Christopher R.; Crosby, Michael; Chavarria, Katherine; Patterson, Brett; Giedd, Matthew

    2016-01-01

    Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural “green” foods. Allyl isothiocyanate (AITC) is an antimicrobial compound naturally present in wasabi (Japanese horseradish) and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil) against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied. This study investigated the antibacterial activities of wasabi as well as AITC against E. coli O157:H7 and S. aureus. Chemical analysis showed that AITC is the major isothiocyanate in wasabi. The AITC concentration in the wasabi powder used in this study was 5.91 ± 0.59 mg/g. The minimum inhibitory concentration (MIC) of wasabi against E. coli O157:H7 or S. aureus was 1% (or 10 mg/ml). Wasabi at 4% displayed higher bactericidal activity against S. aureus than against E. coli O157:H7. The MIC of AITC against either pathogen was between 10 and 100 μg/ml. AITC at 500 μg/ml was bactericidal against both pathogens while AITC at 1000 μg/ml eliminated E. coli O157:H7 much faster than S. aureus. The results from this study showed that wasabi has strong antibacterial property and has high potential to effectively control E. coli O157:H7 and S. aureus in foods. The antibacterial property along with its natural green color, unique flavor, and advantage to safeguard foods at the point of ingestion makes wasabi a promising natural edible antibacterial plant. The results from this study may be of significant interest to the food industry as they develop new and safe foods. These results may also stimulate more research to evaluate the antibacterial effect of wasabi against other

  13. Antibacterial activity of polyacrylonitrile-chitosan electrospun nanofibers.

    PubMed

    Kim, Sam Soo; Lee, Jaewoong

    2014-02-15

    Polyacrylonitrile (PAN)-chitosan double-face films and nanofibers were manufactured. PAN and a chitosan salt were dissolved in dimethyl sulfoxide, and then thin-layered on a glass plate or electro-spun followed by coagulation in sodium hydroxide solution. The morphology of the PAN-chitosan double-face films and nanofibers was analyzed by scanning electron microscopy. The thermal behavior and the glass transition temperature of PAN-chitosan blends were assessed by differential scanning calorimetry and dynamic mechanical analysis, respectively. The antibacterial efficacy was measured by a swatch test with bacterial suspensions. The PAN-chitosan nanofibers produced a 5-log reduction against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus. PMID:24507277

  14. Study of in vitro antibacterial activity of 19 antimicrobial agents against Pseudomonas aeruginosa.

    PubMed

    Wang, R; Sun, X D; Cai, Q M

    1989-04-01

    The in vitro antibacterial activity of 19 antimicrobial agents against 40 strains of P aeruginosa was studied. The 19 antimicrobial agents included 7 semisynthetic penicillins, 6 third generation cephalosporins, 5 aminoglycosides and 1 quinolone agent. The minimal inhibition concentrations (MIGs) were measured by the serial dilution on solid agar. Ceftazidime was the most active in 19 antimicrobial agents again P aeruginosa (MIC50: 1 microgram/ml, MIC90: 2 micrograms/ml) Amikacin and ofloxaxin followed it in activity. Acylureido-penicillins, such as azlocillin, furbenicillin and piperacillin were highly active against P aeruginosa, which could inhibit, 92.5%, 90% and 85% of these strains at a concentration of 8 micrograms/ml. Cefsulodine and cefoperazone were also active against the same strains, inhibiting 92.5% and 99% of the strains at a concentration of 8 micrograms/ml. The potency of the agents mentioned above against P. aeruginosa was similar to that of aminoglycosides. The drug susceptibility of 10 strains isolated in our hospital was compared with that of 29 strains of other hospitals in Beijing. The MICS of 5 penicillins and 3 cephalosporins against the isolates of our hospital was higher than that of other hospitals, suggesting that the susceptibility of beta-lactam antibiotics against isolates of our hospital was lower. The effects of combined use of azlocillin with oxacillin and piperacillin with ofloxacin against 4 strains of carbenicillin-resistant P aeruginosa was studied using check-board testing. The synergy and partial synergy were observed in both combinations.

  15. The Antibacterial Activity of Date Syrup Polyphenols against S. aureus and E. coli

    PubMed Central

    Taleb, Hajer; Maddocks, Sarah E.; Morris, R. Keith; Kanekanian, Ara D.

    2016-01-01

    Plant-derived products such as date syrup (DS) have demonstrated antibacterial activity and can inhibit bacteria through numerous different mechanisms, which may be attributed to bioactive compounds including plant-derived phenolic molecules. DS is rich in polyphenols and this study hypothesized that DS polyphenols demonstrate inherent antimicrobial activity, which cause oxidative damage. This investigation revealed that DS has a high content of total polyphenols (605 mg/100 g), and is rich in tannins (357 mg/100 g), flavonoids (40.5 mg/100 g), and flavanols (31.7 mg/100 g) that are known potent antioxidants. Furthermore, DS, and polyphenols extracted from DS, the most abundant bioactive constituent of DS are bacteriostatic to both Gram positive and Gram negative Escherichia coli and Staphylococcus aureus, respectively. It has further been shown that the extracted polyphenols independently suppress the growth of bacteria at minimum inhibitory concentration (MIC) of 30 and 20 mg/mL for E. coli and S. aureus, and have observed that DS behaves as a prooxidant by generating hydrogen peroxide that mediates bacterial growth inhibition as a result of oxidative stress. At sub-lethal MIC concentrations DS demonstrated antioxidative activity by reducing hydrogen peroxide, and at lethal concentrations DS demonstrated prooxidant activity that inhibited the growth of E. coli and S. aureus. The high sugar content naturally present in DS did not significantly contribute to this effect. These findings highlight that DS’s antimicrobial activity is mediated through hydrogen peroxide generation in inducing oxidative stress in bacteria. PMID:26952177

  16. Erythromycin ethosomal systems: physicochemical characterization and enhanced antibacterial activity.

    PubMed

    Godin, Biana; Touitou, Elka

    2005-07-01

    The rationale behind this work was that a permeation enhancing carrier could facilitate the transport of antibacterial molecules through the two biological barriers: stratum corneum of the skin and bacterial membrane/cell wall. To this end, erythromycin ethosomes (EE) were designed and characterized, and their antibacterial efficiency was evaluated in vitro and in vivo. TEM, CLSM, DLS, DSC and ultracentrifugation tests indicate that EE are small unilamellar soft vesicles encapsulating 78.6% erythromycin. The compositions were stable for at least one year at room temperature. In live/dead viability/cytotoxicity tests, EE systems were nontoxic to cultured 3T3 dermal fibroblasts. Susceptibility studies conducted on three bacterial strains (B. subtilis ATCC 6633, S. aureus ATCC 29213 and S. aureus clinically resistant to erythromycin) showed significantly larger inhibition zones for EE as compared to erythromycin in hydroethanolic solutions. Moreover, EE reduced erythromycin MIC as compared to control solution: from 2.5 to 1.25 microg/ml for S. aureus ATCC 29213 and from 12.5 to 5.0 microg/ml for clinically isolated resistant S. aureus strain. Ethosomal erythromycin applied to the skin of ICR mice inoculated with 10(7)cfu S. aurues ATCC 29213 resulted in complete inhibition of infection. On the contrary, when hydroethanolic solution of erythromycin was applied, deep dermal and subcutaneous abscesses developed within five days after challenge. On day seven, a similar number of S. aureus colonies (1.06x10(7) vs. 0.90x10(7) cfu/g tissue) were isolated from the untreated wounds or treated with hydroethanolic erythromycin. For these animals, histopathological examination showed necrosis, destroyed skin structures and dense infiltrates of neutrophils and macrophages. These findings show that ethosomes are efficient carriers for erythromycin delivery to bacteria localized within the deep skin strata for eradication of staphylococcal infections.

  17. A Review on Antibacterial, Antiviral, and Antifungal Activity of Curcumin

    PubMed Central

    Zorofchian Moghadamtousi, Soheil; Abdul Kadir, Habsah; Hassandarvish, Pouya; Tajik, Hassan; Abubakar, Sazaly; Zandi, Keivan

    2014-01-01

    Curcuma longa L. (Zingiberaceae family) and its polyphenolic compound curcumin have been subjected to a variety of antimicrobial investigations due to extensive traditional uses and low side effects. Antimicrobial activities for curcumin and rhizome extract of C. longa against different bacteria, viruses, fungi, and parasites have been reported. The promising results for antimicrobial activity of curcumin made it a good candidate to enhance the inhibitory effect of existing antimicrobial agents through synergism. Indeed, different investigations have been done to increase the antimicrobial activity of curcumin, including synthesis of different chemical derivatives to increase its water solubility as well ass cell up take of curcumin. This review aims to summarize previous antimicrobial studies of curcumin towards its application in the future studies as a natural antimicrobial agent. PMID:24877064

  18. Antibacterial Activities and Antibacterial Mechanism of Polygonum cuspidatum Extracts against Nosocomial Drug-Resistant Pathogens.

    PubMed

    Su, Pai-Wei; Yang, Cheng-Hong; Yang, Jyh-Ferng; Su, Pei-Yu; Chuang, Li-Yeh

    2015-01-01

    Recently, drug resistance due to the extensive abuse and over-use of antibiotics has become an increasingly serious problem, making the development of alternative antibiotics a very urgent issue. In this study, the Chinese herbal medicine, Polygonum cuspidatum, was extracted with 95% ethanol and the crude extracts were further purified by partition based on solvent polarity. The antimicrobial activities of the extracts and fractions were determined by the disk diffusion and minimum inhibitory concentration (MIC) methods. The results showed that the ethyl ether fraction (EE) of the ethanol extracts possesses a broader antimicrobial spectrum and greater antimicrobial activity against all of the tested clinical drug-resistant isolates, with a range of MIC values between 0.1-3.5 mg/mL. The active extract showed complete inhibition of pathogen growth and did not induce resistance to the active components. In addition, according to scanning electron microscope observations, EE resulted in greater cell morphological changes by degrading and disrupting the cell wall and cytoplasmic membrane, whereby ultimately this cell membrane integrity damage led to cell death. In conclusion, the EE extracts from Polygonum cuspidatum may provide a promising antimicrobial agent for therapeutic applications against nosocomial drug-resistant bacteria. PMID:26087259

  19. Antibacterial activity of plant extracts on foodborne bacterial pathogens and food spoilage bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial foodborne diseases are caused by consumption of foods contaminated with bacteria and/or their toxins. In this study, we evaluated antibacterial properties of twelve different extracts including turmeric, lemon and different kinds of teas against four major pathogenic foodborne bacteria inc...

  20. Extension of the Optical Absorption Range in Zn-Doped MgO Powders and Its Effect on Antibacterial Activity

    NASA Astrophysics Data System (ADS)

    Ohira, Toshiaki; Kawamura, Mari; Fukuda, Masayuki; Alvarez, Kelly; Özkal, Burak; Yamamoto, Osamu

    2010-04-01

    In order to produce powder samples of Zn-doped MgO, the precursors, MgO and ZnO, were mixed in a molar ratio higher than 1.86 and subsequently treated at 1200 °C for 5 h in air atmosphere. With increasing Zn content in MgO, the lattice constant increased linearly, and the optical absorption intensity increased in the wavelength ranging from 200 to 400 nm. Antibacterial activity of the obtained powder samples was examined by colony count method using Escherichia coli and Staphylococcus aureus. In the antibacterial tests, it was found that the antibacterial activity enhanced with increasing Zn content in MgO. Antibacterial action toward S. aureus was greater than that toward E. coli, irrespective of the Zn content in MgO. From these results, the enhancement of the antibacterial activity could be related with the optical absorption of Zn-doped MgO.

  1. Chemical Composition and Antibacterial Activity of Essential Oil of Cosmos bipinnatus Cav. Leaves from South Africa

    PubMed Central

    Olajuyigbe, Olufunmiso; Ashafa, Anofi

    2014-01-01

    The chemical composition of essential oils isolated from the leaves of Cosmos bipinnatus and its antibacterial activity were analyzed by GC-MS and microbroth dilution assay respectively. The essential oil extracted from this plant was predominantly composed of monoterpenes (69.62%) and sesquiterpenes (22.73%). The antibacterial assay showed that the oil had significant inhibitory effects against both Gram-negative and Gram-positive bacteria isolates. The MIC of Gram-positive strains ranged between 0.16 and 0.31 mg/mL while those of Gram-negative bacteria ranged between 0.31 and 0.63 mg/mL. The Gram-positive bacteria were more susceptible to the essential oil than the Gram-negative bacteria. Most of the major components of this oil in other plants have been reported for antimicrobial activities. The antibacterial activity can be attributed to effects of the combination of several components of the oil. The results indicate that the C. bipinnatus might be exploited as natural antibacterial agent and have application in the treatment of several infectious diseases caused by these bacteria. Since this species is endemic to the eastern Free State, the plant could be collected during its bloom and used efficiently in the management of bacterial infections in South Africa. PMID:25587332

  2. Antibacterial Activity of Juglone against Staphylococcus aureus: From Apparent to Proteomic

    PubMed Central

    Wang, Jiayi; Cheng, Yuhuan; Wu, Rina; Jiang, Donghua; Bai, Bing; Tan, Dehong; Yan, Tingcai; Sun, Xiyun; Zhang, Qi; Wu, Zhaoxia

    2016-01-01

    The proportion of foodborne disease caused by pathogenic microorganisms is rising worldwide, with staphylococcal food poisoning being one of the main causes of this increase. Juglone is a plant-derived 1,4-naphthoquinone with confirmed antibacterial and antitumor activities. However, the specific mechanism underlying its antibacterial activity against Staphylococcus aureus remains unclear. To elucidate the mechanism underlying its antibacterial activity, isobaric tags for relative and absolute quantitation methods of quantitative proteomics were applied for analysis of the 53 proteins that were differentially expressed after treatment with juglone. Combined with verification experiments, such as detection of changes in DNA and RNA content and quantification of oxidative damage, our results suggested that juglone effectively increased the protein expression of oxidoreductase and created a peroxidative environment within the cell, significantly reducing cell wall formation and increasing membrane permeability. We hypothesize that juglone binds to DNA and reduces DNA transcription and replication directly. This is the first study to adopt a proteomic approach to investigate the antibacterial mechanism of juglone. PMID:27322260

  3. Study on antibacterial activity of silver nanoparticles synthesized by gamma irradiation method using different stabilizers

    NASA Astrophysics Data System (ADS)

    Van Phu, Dang; Quoc, Le Anh; Duy, Nguyen Ngoc; Lan, Nguyen Thi Kim; Du, Bui Duy; Luan, Le Quang; Hien, Nguyen Quoc

    2014-04-01

    Colloidal solutions of silver nanoparticles (AgNPs) were synthesized by gamma Co-60 irradiation using different stabilizers, namely polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), alginate, and sericin. The particle size measured from TEM images was 4.3, 6.1, 7.6, and 10.2 nm for AgNPs/PVP, AgNPs/PVA, AgNPs/alginate, and AgNPs/sericin, respectively. The influence of different stabilizers on the antibacterial activity of AgNPs was investigated. Results showed that AgNPs/alginate exhibited the highest antibacterial activity against Escherichia coli ( E. coli) among the as-synthesized AgNPs. Handwash solution has been prepared using Na lauryl sulfate as surfactant, hydroxyethyl cellulose as binder, and 15 mg/L of AgNPs/alginate as antimicrobial agent. The obtained results on the antibacterial test of handwash for the dilution to 3 mg AgNPs/L showed that the antibacterial efficiency against E. coli was of 74.6%, 89.8%, and 99.0% for the contacted time of 1, 3, and 5 min, respectively. Thus, due to the biocompatibility of alginate extracted from seaweed and highly antimicrobial activity of AgNPs synthesized by gamma Co-60 irradiation, AgNPs/alginate is promising to use as an antimicrobial agent in biomedicine, cosmetic, and in other fields.

  4. RV-23, a Melittin-Related Peptide with Cell-Selective Antibacterial Activity and High Hemocompatibility.

    PubMed

    Zhang, Shi-Kun; Ma, Qian; Li, Su-Bo; Gao, Hong-Wei; Tan, Ying-Xia; Gong, Feng; Ji, Shou-Ping

    2016-06-28

    RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV- 23's antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure. PMID:26975766

  5. Chemical Composition and Antibacterial Activity of Essential Oil of Cosmos bipinnatus Cav. Leaves from South Africa.

    PubMed

    Olajuyigbe, Olufunmiso; Ashafa, Anofi

    2014-01-01

    The chemical composition of essential oils isolated from the leaves of Cosmos bipinnatus and its antibacterial activity were analyzed by GC-MS and microbroth dilution assay respectively. The essential oil extracted from this plant was predominantly composed of monoterpenes (69.62%) and sesquiterpenes (22.73%). The antibacterial assay showed that the oil had significant inhibitory effects against both Gram-negative and Gram-positive bacteria isolates. The MIC of Gram-positive strains ranged between 0.16 and 0.31 mg/mL while those of Gram-negative bacteria ranged between 0.31 and 0.63 mg/mL. The Gram-positive bacteria were more susceptible to the essential oil than the Gram-negative bacteria. Most of the major components of this oil in other plants have been reported for antimicrobial activities. The antibacterial activity can be attributed to effects of the combination of several components of the oil. The results indicate that the C. bipinnatus might be exploited as natural antibacterial agent and have application in the treatment of several infectious diseases caused by these bacteria. Since this species is endemic to the eastern Free State, the plant could be collected during its bloom and used efficiently in the management of bacterial infections in South Africa.

  6. In vitro antibacterial activity of Hibiscus rosa-sinensis flower extract against human pathogens

    PubMed Central

    Ruban, P; Gajalakshmi, K

    2012-01-01

    Objective To access the in vitro antibacterial activity of Hibiscus rosa-sinensis (H. rosa- sinensis) flower extract against human pathogens. Methods Antibacterial activity was evaluated by using disc and agar diffusion methods. The protein was run through poly acrylmide gel electrophoresis to view their protein profile. Results The results showed that the cold extraction illustrates a maximum zone of inhibition against Bacillus subtillis (B. subtillis), Escherichia coli (E. coli) viz., (17.00 ± 2.91), (14.50 ± 1.71) mm, followed by hot extraction against, E. coli, Salmonella sp. as (11.66 ± 3.14), (10.60 ± 3.09) mm. In methanol extraction showed a highest zone of inhibition recorded against B. subtillis, E. coli as (18.86 ± 0.18), (18.00 ± 1.63) mm pursued by ethanol extraction showed utmost zone of inhibition recorded against Salmonella sp. at (20.40 ± 1.54) mm. The crude protein from flower showed a maximum inhibitory zone observed against Salmonella sp., E. coli viz., (16.55 ± 1.16), (14.30 ± 2.86) mm. The flower material can be taken as an alternative source of antibacterial agent against the human pathogens. Conclusions The extracts of the H. rosa-sinensis are proved to have potential antibacterial activity, further studies are highly need for the drug development. PMID:23569938

  7. Antibacterial free fatty acids: activities, mechanisms of action and biotechnological potential.

    PubMed

    Desbois, Andrew P; Smith, Valerie J

    2010-02-01

    Amongst the diverse and potent biological activities of free fatty acids (FFAs) is the ability to kill or inhibit the growth of bacteria. The antibacterial properties of FFAs are used by many organisms to defend against parasitic or pathogenic bacteria. Whilst their antibacterial mode of action is still poorly understood, the prime target of FFA action is the cell membrane, where FFAs disrupt the electron transport chain and oxidative phosphorylation. Besides interfering with cellular energy production, FFA action may also result from the inhibition of enzyme activity, impairment of nutrient uptake, generation of peroxidation and auto-oxidation degradation products or direct lysis of bacterial cells. Their broad spectrum of activity, non-specific mode of action and safety makes them attractive as antibacterial agents for various applications in medicine, agriculture and food preservation, especially where the use of conventional antibiotics is undesirable or prohibited. Moreover, the evolution of inducible FFA-resistant phenotypes is less problematic than with conventional antibiotics. The potential for commercial or biomedical exploitation of antibacterial FFAs, especially for those from natural sources, is discussed.

  8. Antibacterial Activity of Salvadora persica L. (Miswak) Extracts against Multidrug Resistant Bacterial Clinical Isolates

    PubMed Central

    Al-Ayed, Mohamed Saeed Zayed; Asaad, Ahmed Morad; Qureshi, Mohamed Ansar; Attia, Hany Goda; AlMarrani, Abduljabbar Hadi

    2016-01-01

    Much effort has focused on examining the inhibitory effect of Salvadora persica (miswak) on oral microorganisms, but information concerning its antibacterial activity against other human pathogens, particularly multidrug resistant (MDR) isolates, is scarce. Therefore, this study aimed to assess the in vitro antibacterial activities of Salvadora persica L. extracts against 10 MDR bacterial clinical isolates other than oral pathogens. The antibacterial activity of aqueous and methanol miswak extracts was assessed using the agar dilution and minimum inhibitory concentration (MIC) methods. Overall, the 400 mg/mL of miswak extract was the most effective on all strains. The methanol extract exhibited a stronger antibacterial activity against Gram-negative (3.3–13.6 mm) than Gram-positive (1.8–8.3 mm) bacteria. The lowest MIC value was seen for E. coli (0.39, 1.56 µg/mL), followed by Streptococcus pyogenes (1.56 µg/mL). The highest MIC value (6.25, 12.5 µg/mL) was recorded for methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, and Stenotrophomonas maltophilia. This study demonstrates, for the first time, the moderate to strong antibacterial activity of miswak extracts against all tested MDR-pathogens. Methanol extract appears to be a potent antimicrobial agent that could be considered as complementary and alternative medicine against resistant pathogens. Further studies on a large number of MDR organisms are necessary to investigate and standardize the inhibitory effect of miswak extracts against these emerging pathogens. PMID:26904146

  9. Implication of reactive oxygen species in the antibacterial activity against Salmonella typhimurium of hepatocyte cell lines.

    PubMed

    Lajarin, F; Rubio, G; Lorenzo, N; Gámiz, P; Hernandez-Caselles, T; Garcia-Peñarrubia, P

    1999-11-01

    We recently described the antibacterial activity of a murine hepatocyte cell line stimulated with interferon-gamma (IFN-gamma), interleukin-1 (IL-1), and lipopolysaccharide (LPS) against intracellular Salmonella organisms. Here we show for the first time the existence of basal antibacterial activity in cultured hepatocyte cell lines. Thus treatment of resting and stimulated hepatocytes with catalase or superoxide dismutase increased bacterial number recovered per monolayer, which suggests that the mechanism involved with antibacterial activity of hepatocytes is mediated by reactive oxygen species (ROS). Also, the capacity of these cell lines to generate intracellular peroxides under resting and stimulated conditions was investigated. This revealed that IL-1 and LPS did not induce any increase in the amount of intracellular peroxides by themselves, but they primed IFN-gamma for maximal induction of peroxides. The intracellular amount of peroxides was highly increased on stimulation with IFN-gamma, IL-1, and LPS, and it was strongly inhibited by catalase. This explains that the mechanism whereby this enzyme inhibits antibacterial activity takes place by decreasing the intracellular pool of peroxides. In turn, experiments performed in the presence of several inhibitors of metabolic pathways involved in ROS generation suggested that cyclo-oxygenase are a source of these species in hepatocyte cell lines. These results attribute a prominent role to the generation of peroxides as effector molecules of antibacterial activity in hepatocyte cell lines. Thus these cells displayed a moderate basal level, which increased on stimulation with proinflammatory cytokines such as IFN-gamma, IL-1, and bacterial products such as LPS. Finally, it has been also shown for the first time that IFN-gamma stimulation induces production of peroxides in human and murine hepatocyte cell lines.

  10. Antibacterial Activity of Salvadora persica L. (Miswak) Extracts against Multidrug Resistant Bacterial Clinical Isolates.

    PubMed

    Al-Ayed, Mohamed Saeed Zayed; Asaad, Ahmed Morad; Qureshi, Mohamed Ansar; Attia, Hany Goda; AlMarrani, Abduljabbar Hadi

    2016-01-01

    Much effort has focused on examining the inhibitory effect of Salvadora persica (miswak) on oral microorganisms, but information concerning its antibacterial activity against other human pathogens, particularly multidrug resistant (MDR) isolates, is scarce. Therefore, this study aimed to assess the in vitro antibacterial activities of Salvadora persica L. extracts against 10 MDR bacterial clinical isolates other than oral pathogens. The antibacterial activity of aqueous and methanol miswak extracts was assessed using the agar dilution and minimum inhibitory concentration (MIC) methods. Overall, the 400 mg/mL of miswak extract was the most effective on all strains. The methanol extract exhibited a stronger antibacterial activity against Gram-negative (3.3-13.6 mm) than Gram-positive (1.8-8.3 mm) bacteria. The lowest MIC value was seen for E. coli (0.39, 1.56 µg/mL), followed by Streptococcus pyogenes (1.56 µg/mL). The highest MIC value (6.25, 12.5 µg/mL) was recorded for methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, and Stenotrophomonas maltophilia. This study demonstrates, for the first time, the moderate to strong antibacterial activity of miswak extracts against all tested MDR-pathogens. Methanol extract appears to be a potent antimicrobial agent that could be considered as complementary and alternative medicine against resistant pathogens. Further studies on a large number of MDR organisms are necessary to investigate and standardize the inhibitory effect of miswak extracts against these emerging pathogens. PMID:26904146

  11. Antibacterial activity of Lactobacillus spp. isolated from the feces of healthy infants against enteropathogenic bacteria.

    PubMed

    Davoodabadi, Abolfazl; Soltan Dallal, Mohammad Mehdi; Rahimi Foroushani, Abbas; Douraghi, Masoumeh; Sharifi Yazdi, Mohammad Kazem; Amin Harati, Farzaneh

    2015-08-01

    Lactobacilli are normal microflora of the gastrointestinal (GI) tract and are a heterogeneous group of lactic acid bacteria (LAB). Lactobacillus strains with Probiotic activity may have health Benefits for human. This study investigates the probiotic potential of Lactobacillus strains obtained from the feces of healthy infants and also explores antibacterial activity of Lactobacillus strains with probiotic potential against enteropathogenic bacteria. Fecal samples were collected from 95 healthy infants younger than 18 months. Two hundred and ninety Lactobacillus strains were isolated and assessed for probiotic potential properties including ability to survive in gastrointestinal conditions (pH 2.0, 0.3% oxgall), adherence to HT-29 cells and antibiotic resistance. Six strains including Lactobacillus fermentum (4 strains), Lactobacillus paracasei and Lactobacillus plantarum showed good probiotic potential and inhibited the growth of enteropathogenic bacteria including ETEC H10407, Shigella flexneri ATCC 12022, Shigella sonnei ATCC 9290, Salmonella enteritidis H7 and Yersinia enterocolitica ATCC 23715. These Lactobacillus strains with probiotic potential may be useful for prevention or treatment of diarrhea, but further in vitro and in vivo studies on these strains are still required.

  12. Modulation of haemocyte phagocytic and antibacterial activity by alpha-adrenergic receptor in scallop Chlamys farreri.

    PubMed

    Zhou, Zhi; Jiang, Qiufeng; Wang, Mengqiang; Yue, Feng; Wang, Lingling; Wang, Leilei; Li, Fengmei; Liu, Rui; Song, Linsheng

    2013-09-01

    The adrenergic receptors are a class of G protein-coupled receptors, through which norepinephrine and epinephrine trigger the second messenger to modulate the immune response in immunocytes of vertebrate. In the present study, a gene coding the homologue of α-adrenergic receptor was identified from scallop Chlamys farreri (designated CfαAR). Its deduced protein comprised 318 amino acids, and contained a conserved 7tm_1 domain. After CfαAR protein was expressed in the HEK293 cells, the stimulation of octopamine, tyramine, epinephrine and isoprenaline (β-adrenergic receptor agonist) did not change significantly the intracellular cAMP concentration, whereas the stimulation of norepinephrine and phenylephrine (α-adrenergic receptor agonist) lowered significantly the cAMP level to 0.52 and 0.84 pmol μl(-1) (P < 0.05), respectively. The CfαAR transcripts were ubiquitously detected in the tested tissues including haemocytes, adductor muscle, kidney, hepatopancreas, gill, gonad and mantle, with the highest expression in the gill. The expression level of CfαAR mRNA decreased significantly (0.21-fold, P < 0.05) at 3 h after the challenge of bacteria Vibrio anguillarum. Then, it began to increase (4.74-fold, P < 0.05) at 12 h, and reached the highest level (4.92-fold, P < 0.05) at 24 h after bacteria challenge. The addition of α-adrenergic receptor agonist to the primary scallop haemocytes repressed significantly the increase of phagocytic and antibacterial activity induced by LPS stimulation, while the induction was reverted by the addition of α-adrenergic receptor antagonist. These results collectively suggested that α-adrenergic receptor could be regulated dynamically in the transcriptional level during the immune response, and it could modulate the haemocyte phagocytic and antibacterial function through the second messenger cAMP, which might be requisite for pathogen elimination and the homeostasis maintenance in scallop.

  13. A preliminary study on the antibacterial mechanism of Tegillarca granosa hemoglobin by derived peptides and peroxidase activity.

    PubMed

    Bao, Yongbo; Wang, Juanjuan; Li, Chenghua; Li, Peifen; Wang, Sufang; Lin, Zhihua

    2016-04-01

    The blood clam, Tegillarca granosa, is one of the few bivalve molluscs containing hemoglobin (Hb). In the present study, we purified two types of T. granosa hemoglobin, Tg-HbI and Tg-HbII, using size exclusion chromatography and measured their antibacterial and peroxidase activities. We also tested antibacterial activities of peptides prepared by trypsin digestion of purified Tg-Hb and reversed-phase high-performance liquid chromatography purification. Purified Tg-HbI and Tg-HbII showed antibacterial activity against Escherichia coli, Pseudomonas putida, Bacillus subtilis, and Bacillus firmus, with differences in minimal inhibitory concentrations (MICs), but lacked antibacterial activity against Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi and Staphylococcus aureus. In contrast, 7 Tg-Hb derived peptides exhibited varying degrees of antibacterial activity against V. alginolyticus (MICs: 12-200 μg/ml), V. parahaemolyticus (11-100 μg/ml) and V. harveyi (1-200 μg/ml). The antibacterial activity of Hb derived peptides was confirmed by fluorescence microscopy. In addition, peroxidase activity was detected in Tg-HbI and Tg-HbII. The results indicated that in addition to functioning as a respiratory protein T. granosa hemoglobins likely play a role in host antibacterial defense probably via a peroxidase activity of native molecules and some internal peptides released from the proteins. PMID:26876330

  14. Antibacterial activity and synergy, in vitro and in vivo, of a combination of amoxycillin and flucloxacillin.

    PubMed

    Comber, K R; Merrikin, D J; Sutherland, R

    1979-01-01

    The antibacterial activity of a combination of equal parts of amoxycillin and flucloxacillin was compared in vitro and in vivo with that of amoxycillin and flucloxacillin against a range of gram-positive and gram-negative bacteria. The combination generally showed additive effects against bacteria sensitive to the individual penicillins and there was no evidence of antagonism, but synergistic effects were observed between amoxycillin and flucloxacillin against certain amoxycillin-resistant gram-negative bacilli. The extent of synergism varied according to the particular bacterial species under test and synergy was observed only against bacteria with chromosomally-mediated beta-lactamases and not against bacteria with R-factor-mediated beta-lactamases. In general, amoxycillin + flucloxacillin demonstrated activity against experimental mouse infections in good agreement with demonstrated activity against experimental mouse infections in good agreement with its in vitro activity, and synergy was produced against a range of gram-negative bacilli in vivo. The data suggest that clinical trial with amoxycillin + flucloxacillin in the treatment of selected infections including those due to some amoxycillin-resistant bacteria may well be justified.

  15. Diversity and antibacterial activities of culturable fungi associated with coral Porites pukoensis.

    PubMed

    Li, Jun; Zhong, Min; Lei, Xiaoling; Xiao, Shenglan; Li, Zhiyong

    2014-10-01

    The diversity of coral associated fungi is not enough understood, especially for scleractinian corals. Members of Porites are common and dominant species of scleractinian corals. To date, the fungal communities associated with coral Porites pukoensis have been not reported. In this paper, the diversity and activity of coral associated fungi in P. pukoensis were explored, 23 fungal strains were isolated, belonging to 10 genera and Aspergillus sp. (30.4 %) was predominant fungal genera. The sequence of isolate C1-23 in GenBank was only 90 % similarity to the most closely related sequences. It is concluded that rich fungal symbionts are attached to P. pukoensis, the rate of isolates with antibacterial activity was up to 30 %, particularly some isolates showed stronger bioactivities to gram-negative bacteria. It is included that the diversity of coral associated fungi in P. pukoensis is abundant and its activity is obviously. So the activities of fungi in P. pukoensis were deserved for further study.

  16. In vitro Antioxidant and Antibacterial Activities of Methanol Extract of Kyllinga nemoralis

    PubMed Central

    Sindhu, T.; Rajamanikandan, S.; Srinivasan, P.

    2014-01-01

    The present study was designed to evaluate the antioxidant and antibacterial activity of methanol extract of Kyllinga nemoralis. Six different in vitro antioxidant assays including 2,2-diphenyl-1-picrylhydrazyl, hydroxyl radical, superoxide anion radical, hydrogen peroxide radical, ferric reducing antioxidant power assay and reducing power were carried out to ensure the scavenging effect of the plant on free radicals. In addition, total antioxidant capacity assay, total phenolic contents, tannins, flavonoids and flavonol contents of the plant were also analysed by the standard protocols. Kyllinga nemoralis exhibited high antioxidant activity on 2,2-diphenyl-1-picrylhydrazyl assay (IC50= 90 μg/ml), superoxide radical scavenging assay (IC50= 180 μg/ml) and hydrogen peroxide radical scavenging assay (IC50= 200 μg/ml), compared with standards. These observations provide comprehensible supporting evidence for the antioxidant potential of the plant extract. Reducing power (IC50= 213.16 μg/ml) and hydroxyl radical scavenging activity (IC50= 223 μg/ml) of the plant extract was remarkable. The methanol extract of K. nemoralis exhibited significant antimicrobial activity against Gram-positive human pathogenic bacteria. Standard in vitro antioxidant assays assessed the electron donating ability of the plant extract in scavenging free radicals. The inhibitory effect of the plant extract against bacterial pathogens may be due to the presence of phytochemicals. Thus, the results suggest that Kyllinga nemoralis is a potential source of antioxidants and could serve as the base for drug development. PMID:24843192

  17. Evaluation of antioxidant and antibacterial activity of methanolic extracts of Gentiana kurroo royle

    PubMed Central

    Baba, Shoib A.; Malik, Shahid A.

    2014-01-01

    In this study our objective was to evaluate the antioxidant and antimicrobial activity of methanolic extracts of leaves and roots of Gentiana kurroo. The antioxidant activities of the extracts were examined using different biochemical assays namely diphenylpicrylhydrazyl (DPPH), nitroblue tetrazolium (NBT) and ferric reducing power (FRAP). In all the assays, root extract exhibited stronger antioxidant activity than that of leaves. The antibacterial activity of the extracts was also evaluated and MIC values were calculated by broth dilution method. Although, the extracts prevented the growth of both Gram positive and Gram negative bacteria, the MIC values of methanolic extract of the leaves were higher than those of the root extract. The antibacterial and antioxidant activity of the extracts was found to be positively associated with the total phenolic and flavonoid content of the extracts. PMID:25313286

  18. Study on the sorption process of triclosan on cationic microfibrillated cellulose and its antibacterial activity.

    PubMed

    Zhang, Hongjie; Zeng, Xu; Xie, Jinglei; Li, Zhiqiang; Li, Hailong

    2016-01-20

    Cationic microfibrillated cellulose (CMFC), as one kind of cellulose-based materials, is widely used in many fields. In this work, it was functionalized with a traditional antibacterial agent (triclosan, TCS). The sorption process of TCS onto CMFC was expressed by kinetic and isotherm models. The results showed that there was a high correlation coefficient (R(2)>0.9) in the pseudo-second-order model and the isotherm models, indicating that CMFC had a good sorption capacity for TCS. The sorption type was chemisorption, and the reaction power was electrostatic interactions. The antibacterial activity of the assembled TCS/CMFC compound was tested by disk diffusion method, and it was found a higher antibacterial activity than CMFC alone (bigger inhibition zone diameters). Further, the functionalized TCS/CMFC compound was used in the fiber network during handsheets making, and it had a higher antibacterial rate than TCS alone (increase by 45.1% against Escherichia coli and by 54.8% against Staphylococcus aureus, respectively).

  19. Antibacterial activities of Ligaria cuneifolia and Jodina rhombifolia leaf extracts against phytopathogenic and clinical bacteria.

    PubMed

    Soberón, José R; Sgariglia, Melina A; Dip Maderuelo, María R; Andina, María L; Sampietro, Diego A; Vattuone, Marta A

    2014-11-01

    Six plant extracts prepared from Ligaria cuneifolia and Jodina rhombifolia were screened for their potential antimicrobial activities against phytopathogens and clinically standard reference bacterial strains. Bioautography and broth microdilution methods were used to study samples antibacterial activities against 7 bacterial strains. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of samples were attained. An antibacterial activity guided isolation and identification of active compounds was carried out for L. cuneifolia methanolic extract (LCME). Both methanolic and aqueous extracts from L. cuneifolia showed inhibitory activities against phytopathogenic bacteria, with MICs ranging from 2.5 to 156 μg mL(-1) for LCME and 5 mg mL(-1) for the aqueous extract. None of the three J. rhombifolia extracts showed significant antibacterial activities against phytopathogenic strains (MIC > 5 mg mL(-1)), except for the aqueous extracts against Pseudomonas syringae (MIC = 312 μg mL(-1)). Only LCME showed bactericidal activities against phytopathogenic strains (MBCs = 78 μg mL(-1)). The LCME exhibited significant inhibitory activity against reference clinical strains: Escherichia coli (MIC = 156 μg mL(-1)) and Staphylococcus aureus (MIC = 78 μg mL(-1), MBC = 312 μg mL(-1)). LCME active compounds were identified as flavonol mono and diglycosides, and gallic acid. The antibacterial activity of purified compounds was also evaluated. A synergistic effect against S. aureus was found between gallic acid and a quercetin glycoside. Hence, anti-phytopathogenic bacteria potential compounds isolated from L. cuneifolia could be used as an effective source against bacterial diseases in plants. PMID:24894684

  20. In Vitro and In Vivo Antibacterial Activities of OPC-20011, a Novel Parenteral Broad-Spectrum 2-Oxaisocephem Antibiotic

    PubMed Central

    Matsumoto, Makoto; Tamaoka, Hisashi; Ishikawa, Hiroshi; Kikuchi, Mikio

    1998-01-01

    OPC-20011, a new parenteral 2-oxaisocephem antibiotic, has an oxygen atom at the 2- position of the cephalosporin frame. OPC-20011 had the best antibacterial activities against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, and penicillin-resistant Streptococcus pneumoniae: MICs at which 90% of the isolates were inhibited were 6.25, 6.25, and 0.05 μg/ml, respectively. Its activity is due to a high affinity of the penicillin-binding protein 2′ in MRSA, an affinity which was approximately 1,050 times as high as that for flomoxef. Against gram-negative bacteria, OPC-20011 also showed antibacterial activities similar to those of ceftazidime. The in vivo activities of OPC-20011 were comparable to or greater than those of reference compounds in murine models of systemic infection caused by gram-positive and -negative pathogens. OPC-20011 was up to 10 times as effective as vancomycin against MRSA infections in mice. This better in vivo efficacy is probably due to the bactericidal activity of OPC-20011, while vancomycin showed bacteriostatic activity against MRSA. OPC-20011 produced a significant decrease of viable counts in lung tissue at a dose of 2.5 mg/kg of body weight, an efficacy similar to that of ampicillin at a dose of 10 to 20 mg/kg on an experimental murine model of respiratory tract infection caused by non-ampicillin-susceptible S. pneumoniae T-0005. The better therapeutic efficacy of OPC-20011 was considered to be due to its potent antibacterial activity and low affinity for serum proteins of experimental animals (29% in mice and 6.4% in rats). PMID:9797230

  1. Domino Synthesis of Embelin Derivatives with Antibacterial Activity.

    PubMed

    Peña, Rosalyn; Martín, Pedro; Feresin, Gabriela E; Tapia, Alejandro; Machín, Félix; Estévez-Braun, Ana

    2016-04-22

    A series of dihydropyran embelin derivatives was synthesized through a direct and highly efficient approach based on a domino Knoevenagel intramolecular hetero-Diels-Alder reaction from natural embelin (1), using unsaturated aldehydes in the presence of organocatalysts such as ethylendiamine diacetate or l-proline. The aliphatic aldehydes yielded exclusively trans adducts, while mixtures of trans and cis isomers were found in reactions with aromatic aldehydes, with the cis form always predominating. Some of the compounds obtained were active and selective against Gram-positive bacteria, including multiresistant Staphylococcus aureus clinical isolates. PMID:26924672

  2. Modeling and optimization of antibacterial activity of the chitosan-based hydrogel films using central composite design.

    PubMed

    Lahooti, Behnaz; Khorram, Mohammad; Karimi, Gholamreza; Mohammadi, Aliakbar; Emami, Amir

    2016-10-01

    In the present study, hydrogel films composed of chitosan-poly(vinyl alcohol)-gelatin-thyme honey were successfully prepared by casting method, and their anti-bacterial properties were modeled and optimized. Antibacterial properties of the prepared films were analyzed by applying agar diffusion method. Staphylococcus aureus and Pseudomonas aeruginosa were tested as Gram-positive and Gram-negative bacteria, respectively. In order to obtain the composition of the film with maximum inhibition zone against both above-mentioned bacterial strains, the experiments were designed using response surface methodology based on five-level central composite design with four parameters, including concentrations of chitosan, poly(vinyl alcohol), gelatin, and honey. The results indicated that the prepared samples had good antibacterial activities against these two studied bacteria strains. Response surface method is conducted to develop mathematical models for process responses. Variance analysis on the experimental data shows that inhibition zone can be predicted effectively with quadratic models. In addition, swelling properties and rate of water vapor transmission of the prepared hydrogel films were studied. Due to the successful results, this hydrogel film has an excellent potential to be explored further as a wound healing material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2544-2553, 2016. PMID:27241899

  3. Total Phenolic Content and Antibacterial Activity of Five Plants of Labiatae against Four Foodborne and Some Other Bacteria

    PubMed Central

    Mahboubi, Arash; Kamalinejad, Mohammad; Ayatollahi, Abdul Majid; Babaeian, Mohammad

    2014-01-01

    The aim of this study was to evaluate the antibacterial effects of Thymus vulgaris, Thymus caramanicus, Zataria multiflora, Ziziphora clinopodioides and Ziziphora tenuior against four foodborne and four other bacteria including Staphylococcus aureus, Shigella dysenteriae, Salmonella typhimurium, Escherichia coli, Staphylococcus epidermidis, Bacillus subtilis, MRSA and Pseudomona aeruginosa and measuring the amount of total phenolics of the plants. The extracts were prepared by maceration method. Pre-evaluation of the antimicrobial effect was utilized by cup-plate technique and then Minimum Inhibitory Concentration was determined by agar dilution method according to NCCLS. The total phenolics as a possible cause of antibacterial effect, was measured by Folin-Ciocalteucolorimetry. The results showed that T. caramanicus and Z. multiflora were the most effective ones with MIC values between 0.78-3.125 mg/mL against all of the Bactria and Z. tenuior and Z. clinopodioides had the minimum antimicrobial activity. Total phenolic contents of these five plants were different and followed the general pattern of the antimicrobial effect. The antibacterial effects and the total phenolic content of T. caramanicus and Z. multiflora were remarkable and should be investigated more in future studies. PMID:25237351

  4. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants.

    PubMed

    Manitchotpisit, Pennapa; Bischoff, Kenneth M; Price, Neil P J; Leathers, Timothy D

    2013-05-01

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Four bacterial strains, designated as ALT3A, ALT3B, ALT17, and MR1, produced inhibitory effects on growth of LAB. Sequencing of rRNA identified these strains as species of Bacillus subtilis (ALT3A and ALT3B) and B. cereus (ALT17 and MR1). Cell mass from colonies and agar samples from inhibition zones were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The spectra of ALT3A and ALT3B showed a strong signal at m/z 1,060, similar in mass to the surfactin family of antimicrobial lipopeptides. ALT3A and ALT3B were analyzed by zymogram analysis using SDS-PAGE gels placed on agar plates inoculated with LAB. Cell lysates possessed an inhibitory protein of less than 10 kDa, consistent with the production of an antibacterial lipopeptide. Mass spectra of ALT17 and MR1 had notable signals at m/z 908 and 930 in the whole cell extracts and at m/z 687 in agar, but these masses do not correlate with those of previously reported antibacterial lipopeptides, and no antibacterial activity was detected by zymogram. The antibacterial activities produced by these strains may have application in the fuel ethanol industry as an alternative to antibiotics for prevention and control of bacterial contamination.

  5. Superior Antibacterial Activity of Fe3O4-TiO2 Nanosheets under Solar Light.

    PubMed

    Ma, Shuanglong; Zhan, Sihui; Jia, Yanan; Zhou, Qixing

    2015-10-01

    Fe3O4-TiO2 nanosheets (Fe3O4-TNS) were synthesized by means of lamellar reverse micelles and solvothermal method, which were characterized by TEM, XRD, XPS, BET, and magnetic property analysis. It can be found that Fe3O4-TNS nanosheets exhibited better photocatalytic antibacterial activity toward Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus than pure Fe3O4 and TNS, and the antibacterial efficiency could reach 87.2% and 93.7% toward E. coli and S. aureus with 100 μg/mL Fe3O4-TNS after 2 h of simulated solar light illumination, respectively. The photocatalytic destruction of bacteria was further confirmed by fluorescent-based cell live/dead test and SEM images. It was uncovered that Fe3O4-TNS inactivated G- E. coli and G+ S. aureus by different mechanisms: the destruction of outer membranes and ruptured cell bodies were responsible for the bactericidal effect against E. coli, while the antibacterial effect toward S. aureus were due to the fact that the cells were adsorbed in form of clusters by massive Fe3O4-TNS, which could restrict their activities and cause malfunction of the selective permeable barriers. Furthermore, the antibacterial mechanism was studied by employing scavengers to understand exact roles of different reactive species, indicating the key roles of h(+) and H2O2. The recovery and reusability experiments indicated that Fe3O4-TNS still retained more than 90% bacteria removal efficiency even after five cycles. Considering the easy magnetic separation, bulk availability, and high antibacterial activity of Fe3O4-TNS, it is a promising candidate for cleaning the microbial contaminated water environment.

  6. Superior Antibacterial Activity of Fe3O4-TiO2 Nanosheets under Solar Light.

    PubMed

    Ma, Shuanglong; Zhan, Sihui; Jia, Yanan; Zhou, Qixing

    2015-10-01

    Fe3O4-TiO2 nanosheets (Fe3O4-TNS) were synthesized by means of lamellar reverse micelles and solvothermal method, which were characterized by TEM, XRD, XPS, BET, and magnetic property analysis. It can be found that Fe3O4-TNS nanosheets exhibited better photocatalytic antibacterial activity toward Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus than pure Fe3O4 and TNS, and the antibacterial efficiency could reach 87.2% and 93.7% toward E. coli and S. aureus with 100 μg/mL Fe3O4-TNS after 2 h of simulated solar light illumination, respectively. The photocatalytic destruction of bacteria was further confirmed by fluorescent-based cell live/dead test and SEM images. It was uncovered that Fe3O4-TNS inactivated G- E. coli and G+ S. aureus by different mechanisms: the destruction of outer membranes and ruptured cell bodies were responsible for the bactericidal effect against E. coli, while the antibacterial effect toward S. aureus were due to the fact that the cells were adsorbed in form of clusters by massive Fe3O4-TNS, which could restrict their activities and cause malfunction of the selective permeable barriers. Furthermore, the antibacterial mechanism was studied by employing scavengers to understand exact roles of different reactive species, indicating the key roles of h(+) and H2O2. The recovery and reusability experiments indicated that Fe3O4-TNS still retained more than 90% bacteria removal efficiency even after five cycles. Considering the easy magnetic separation, bulk availability, and high antibacterial activity of Fe3O4-TNS, it is a promising candidate for cleaning the microbial contaminated water environment. PMID:26372171

  7. Purity of graphene oxide determines its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Barbolina, I.; Woods, C. R.; Lozano, N.; Kostarelos, K.; Novoselov, K. S.; Roberts, I. S.

    2016-06-01

    Nanomaterials based on two-dimensional (2D) atomic crystals are considered to be very promising for various life-science and medical applications, from drug delivery to tissue modification. One of the most suitable materials for these purposes is graphene oxide (GO), thanks to a well-developed methods of production and water solubility. At the same time, its biological effect is still debated. Here we demonstrate that highly purified and thoroughly washed GO neither inhibited nor stimulated the growth of E.coli, ATCC25922; E.coli NCIMB11943 and S.aureus ATCC25923 at concentrations of up to 1 mg ml-1. Moreover, transmission electron microscopy (TEM) of GO exposed bacteria did not reveal any differences between GO exposed and not exposed populations. In contrast, a suspension of insufficiently purified GO behaved as an antibacterial material due to the presence of soluble acidic impurities, that could be removed by extended purification or neutralisation by alkaline substrates. A standardised protocol is proposed for the generation of clean GO, so it becomes suitable for biological experiments. Our findings emphasise the importance of GO purification status when dealing with biological systems as the true effect of material can be masked by the impact of impurities.

  8. Purity of graphene oxide determines its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Barbolina, I.; Woods, C. R.; Lozano, N.; Kostarelos, K.; Novoselov, K. S.; Roberts, I. S.

    2016-06-01

    Nanomaterials based on two-dimensional (2D) atomic crystals are considered to be very promising for various life-science and medical applications, from drug delivery to tissue modification. One of the most suitable materials for these purposes is graphene oxide (GO), thanks to a well-developed methods of production and water solubility. At the same time, its biological effect is still debated. Here we demonstrate that highly purified and thoroughly washed GO neither inhibited nor stimulated the growth of E.coli, ATCC25922; E.coli NCIMB11943 and S.aureus ATCC25923 at concentrations of up to 1 mg ml‑1. Moreover, transmission electron microscopy (TEM) of GO exposed bacteria did not reveal any differences between GO exposed and not exposed populations. In contrast, a suspension of insufficiently purified GO behaved as an antibacterial material due to the presence of soluble acidic impurities, that could be removed by extended purification or neutralisation by alkaline substrates. A standardised protocol is proposed for the generation of clean GO, so it becomes suitable for biological experiments. Our findings emphasise the importance of GO purification status when dealing with biological systems as the true effect of material can be masked by the impact of impurities.

  9. Antifungal and antibacterial activities of Taxus wallichiana Zucc.

    PubMed

    Nisar, Muhammad; Khan, Inamullah; Ahmad, Bashir; Ali, Ihsan; Ahmad, Waqar; Choudhary, Muhammad Iqbal

    2008-04-01

    Current study was undertaken to evaluate the in vitro antifungal and antibacterial potential of methanol extract and subsequent fractions obtained after partitioning in organic solvents with variable polarity of the aerial parts of the tree Taxus wallichiana Zucc. Traditionally, this plant is often used in folk medicines in Pakistan for treating microbial infections. In order to rationalize the traditional use, methanol extracts of leaf, bark, and heartwood of Taxus wallichiana Zucc. were tested against six bacteria and six fungal strains using the Hole diffusion and macro-dilution methods. All extracts and fractions displayed significant antimicrobial effect. Only three fungal strains, Trichophyton longifusus, Microspoum canis, and Fusarium solani were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. Comparison results were carried out using imipinem, miconazole and amphotericin B as standard antibiotics. PMID:18343912

  10. Antibacterial and antifungal activity of Iranian propolis against Staphylococcus aureus and Candida albicans.

    PubMed

    Ghasem, Yousef-Beigi; Ownagh, Abdolghaffar; Hasanloei, M

    2007-04-15

    Propolis samples from West North region of Iran were studied for their antibacterial (against Staphylococcus aureus) and antifungal (against Candida albicans) activities. In this article, yield of extracts and their pH values were measured. Antibacterial and antifungal activities of Ethanol-Extracted Propolis (EEP) were investigated by Petri dish bioassay method. Dilutions of EPP in agar with serial concentrations ranging from 0/04 to 10% (W/V) were prepared and antimicrobial activities were determined as Minimal Inhibitory Concentrations (MIC). All samples were active against the fungal and bacterial test strains. MIC values for different propolis samples against Staphylococcus aureus were, respectively 4, 3 and 1.5% (W/V) and against Candida albicans were, respectively 2, 4 and 3% (W/V).

  11. Production of polypeptide antibiotic from Streptomyces parvulus and its antibacterial activity.

    PubMed

    Shetty, Prakasham Reddy; Buddana, Sudheer Kumar; Tatipamula, Vinay Bharadwaj; Naga, Yaswanth Varanasi Venkata; Ahmad, Jamal

    2014-01-01

    A highly potent secondary metabolite producing actinomycetes strain is isolated from marine soil sediments of Visakhapatnam sea coast, Bay of Bengal. Over all ten strains are isolated from the collected soil sediments. Among the ten actinomycetes strains the broad spectrum strain RSPSN2 was selected for molecular characterization, antibiotic production and its purification. The nucleotide sequence of the 1 rRNA gene (1261 base pairs) of the most potent strain evidenced a 96% similarity with Streptomyces parvulus 1044 strain, Streptomyces parvulus NBRC 13193 and Streptomyces parvulus BY-F. From the taxonomic features, the actinomycetes isolate RSPSN2 matches with Streptomyces parvulus in the morphological, physiological and biochemical characters. Thus, it was given the suggested name Streptomyces parvulus RSPSN2. The active metabolite was extracted using ethyl acetate (1:3, v/v) at pH 7.0. The separation of active ingredient and its purification was performed by using both thin layer chromatography (TLC) and column chromatography (CC) techniques. Spectrometric studies such as UV-visible, FTIR, and NMR and mass were performed. The antibacterial activity of pure compound was performed by cup plate method against some pathogenic bacteria including of streptomycin resistant bacteria like (Pseudomonas mirabilis, Pseudomonas putida and Bacillus cereus). In conclusion, the collected data emphasized the fact that a polypeptide antibiotic (Actinomycin D) was produced by Streptomyces parvulus RSPSN2.

  12. Production of polypeptide antibiotic from Streptomyces parvulus and its antibacterial activity

    PubMed Central

    Shetty, Prakasham Reddy; Buddana, Sudheer Kumar; Tatipamula, Vinay Bharadwaj; Naga, Yaswanth Varanasi Venkata; Ahmad, Jamal

    2014-01-01

    A highly potent secondary metabolite producing actinomycetes strain is isolated from marine soil sediments of Visakhapatnam sea coast, Bay of Bengal. Over all ten strains are isolated from the collected soil sediments. Among the ten actinomycetes strains the broad spectrum strain RSPSN2 was selected for molecular characterization, antibiotic production and its purification. The nucleotide sequence of the 1 rRNA gene (1261 base pairs) of the most potent strain evidenced a 96% similarity with Streptomyces parvulus 1044 strain, Streptomyces parvulus NBRC 13193 and Streptomyces parvulus BY-F. From the taxonomic features, the actinomycetes isolate RSPSN2 matches with Streptomyces parvulus in the morphological, physiological and biochemical characters. Thus, it was given the suggested name Streptomyces parvulus RSPSN2. The active metabolite was extracted using ethyl acetate (1:3, v/v) at pH 7.0. The separation of active ingredient and its purification was performed by using both thin layer chromatography (TLC) and column chromatography (CC) techniques. Spectrometric studies such as UV-visible, FTIR, and NMR and mass were performed. The antibacterial activity of pure compound was performed by cup plate method against some pathogenic bacteria including of streptomycin resistant bacteria like (Pseudomonas mirabilis, Pseudomonas putida and Bacillus cereus). In conclusion, the collected data emphasized the fact that a polypeptide antibiotic (Actinomycin D) was produced by Streptomyces parvulus RSPSN2. PMID:24948949

  13. Isolation and Molecular Identification of Streptomyces spp. with Antibacterial Activity from Northwest of Iran

    PubMed Central

    Maleki, Hadi; Dehnad, Alireza; Hanifian, Shahram; Khani, Sajjad

    2013-01-01

    Introduction: Streptomyces are a group of prokaryotes that are usually found in all types of ecosystems including water and soil. This group of bacteria is noteworthy as antibiotic producers; so the isolation and characterization of new species seemed to be crucial in introduction of markedly favorable antibiotics. Therefore, in this study we aim to isolate and characterize novel strains of Streptomyces with high antibiotic production capability. Methods: To achieve this goal, from 140 isolates collected throughout northwest of Iran, 12 selected Streptomyces isolates which exhibited high antibacterial activity against pathogenic bacteria were subjected to PCR reaction for identification via 16S rDNA gene and random amplified polymorphic DNA (RAPD) pattern analysis. Results: Analysis of morphological and biochemical characteristics and the 16S rDNA gene sequence indicated that all 12 selected isolates belonged to the genus Streptomyces. Moreover, screening of the isolates with regard to their antimicrobial activity against indicator bacteria as well as their classification using RAPD analysis revealed that G614C1 and K36C5 isolates have considerable antimicrobial activity and high similarity to Streptomyces coelicolor and Sreptomyces albogriseolus, respectively. Conclusion: Since many isolates in this study showed inhibitory effects against pathogenic bacteria, soil of northwest of Iran could be used as a rich source to be explored for novel Streptomyces strains with high potency of antibiotic production. PMID:24163805

  14. Helical 1:1 α/Sulfono-γ-AA Heterogeneous Peptides with Antibacterial Activity.

    PubMed

    She, Fengyu; Nimmagadda, Alekhya; Teng, Peng; Su, Ma; Zuo, Xiaobing; Cai, Jianfeng

    2016-05-01

    As one of the greatest threats facing the 21st century, antibiotic resistance is now a major public health concern. Host-defense peptides (HDPs) offer an alternative approach to combat emerging multi-drug-resistant bacteria. It is known that helical HDPs such as magainin 2 and its analogs adopt cationic amphipathic conformations upon interaction with bacterial membranes, leading to membrane disruption and subsequent bacterial cell death. We have previously shown that amphipathic sulfono-γ-AApeptides could mimic magainin 2 and exhibit bactericidal activity. In this article, we demonstrate for the first time that amphipathic helical 1:1 α/sulfono-γ-AA heterogeneous peptides, in which regular amino acids and sulfono-γ-AApeptide building blocks are alternatively present in a 1:1 pattern, display potent antibacterial activity against both Gram-positive and Gram-negative bacterial pathogens. Small angle X-ray scattering (SAXS) suggests that the lead sequences adopt defined helical structures. The subsequent studies including fluorescence microscopy and time-kill experiments indicate that these hybrid peptides exert antimicrobial activity by mimicking the mechanism of HDPs. Our findings may lead to the development of HDP-mimicking antimicrobial peptidomimetics that combat drug-resistant bacterial pathogens. In addition, our results also demonstrate the effective design of a new class of helical foldamer, which could be employed to interrogate other important biological targets such as protein-protein interactions in the future. PMID:27030636

  15. Analysis and antibacterial activity of Nigella sativa essential oil formulated in microemulsion system.

    PubMed

    Shaaban, Hamdy A; Sadek, Zainab; Edris, Amr E; Saad-Hussein, Amal

    2015-01-01

    The Essential oil (EO) of Nigella sativa (black cumin) was extracted from the crude oil and the volatile constituents were characterized using gas chromatographic analysis. The EO was formulated in water-based microemulsion system and its antibacterial activity against six pathogenic bacteria was evaluated using the agar well diffusion method. This activity was compared with two other well known biologically active natural and synthetic antimicrobials namely eugenol and Ceftriaxone(®). Results showed that N. sativa EO microemulsion was highly effective against S. aureus, B. cereus and S. typhimurium even at the lowest tested concentration of that EO in the microemulsion (100.0 μg/well). Interestingly, the EO microemulsion showed higher antibacterial activity than Ceftriaxone solution against S. typhimurium at 400.0 μg/well and almost comparable activity against E. coli at 500.0 μg/well. No activity was detected for the EO microemulsion against L. monocytogenes and P. aeruginosa. Eugenol which was also formulated in microemulsion was less effective than N. sativa EO microemulsion except against P. aeruginosa. The synthetic antibiotic (Ceftriaxone) was effective against most of the six tested bacterial strains. This work is the first report revealing the formulation of N. sativa EO in microemulsion system and investigating its antibacterial activity. The results may offer potential application of that water-based microemulsion in controlling the prevalence of some pathogenic bacteria.

  16. Comparative study of the antibacterial activity of propolis from different geographical and climatic zones.

    PubMed

    Seidel, Véronique; Peyfoon, Elham; Watson, David G; Fearnley, James

    2008-09-01

    Propolis is a natural substance produced by honeybees upon collection and transformation of resins and exudates from plants. Comparative studies on propolis collected from a wide range of countries are crucial for linking its provenance to antibacterial activity and thus ensuring that the beneficial properties of propolis are used more efficiently by the general public. This study reports the in vitro screening of ethanol extracts of propolis (n = 40), collected from a wide range of countries within the tropical, subtropical and temperate zones, and on the comparison of their activity against a range of Gram-positive and Gram-negative bacteria using a broth microdilution assay. The results obtained revealed that propolis extracts were mostly active against Gram-positive bacteria. The samples were subjected to principal component analysis (PCA) in order to model their activity against Gram-positive microorganisms. Three distinct clusters were distinguished in the PCA mapping based on MIC values, categorizing samples with strong (MIC range 3.9-31.25 mg/L), moderate (MIC range 31.25-> or =500 mg/L) and weak antibacterial activity or inactivity (MIC > or = 500 mg/L only). It is hypothesized that for samples of tropical provenance differences in the activity profiles may depend on the climatic characteristics of the collection sites. High antibacterial activity was observed for samples from locations characterized by a wet-tropical rainforest-type climate.

  17. Analysis and antibacterial activity of Nigella sativa essential oil formulated in microemulsion system.

    PubMed

    Shaaban, Hamdy A; Sadek, Zainab; Edris, Amr E; Saad-Hussein, Amal

    2015-01-01

    The Essential oil (EO) of Nigella sativa (black cumin) was extracted from the crude oil and the volatile constituents were characterized using gas chromatographic analysis. The EO was formulated in water-based microemulsion system and its antibacterial activity against six pathogenic bacteria was evaluated using the agar well diffusion method. This activity was compared with two other well known biologically active natural and synthetic antimicrobials namely eugenol and Ceftriaxone(®). Results showed that N. sativa EO microemulsion was highly effective against S. aureus, B. cereus and S. typhimurium even at the lowest tested concentration of that EO in the microemulsion (100.0 μg/well). Interestingly, the EO microemulsion showed higher antibacterial activity than Ceftriaxone solution against S. typhimurium at 400.0 μg/well and almost comparable activity against E. coli at 500.0 μg/well. No activity was detected for the EO microemulsion against L. monocytogenes and P. aeruginosa. Eugenol which was also formulated in microemulsion was less effective than N. sativa EO microemulsion except against P. aeruginosa. The synthetic antibiotic (Ceftriaxone) was effective against most of the six tested bacterial strains. This work is the first report revealing the formulation of N. sativa EO in microemulsion system and investigating its antibacterial activity. The results may offer potential application of that water-based microemulsion in controlling the prevalence of some pathogenic bacteria. PMID:25748382

  18. Green synthesis of silver nanoparticles in aloe vera plant extract prepared by a hydrothermal method and their synergistic antibacterial activity

    PubMed Central

    Phromviyo, Nutthakritta; Boueroy, Parichart; Chompoosor, Apiwat

    2016-01-01

    Background There is worldwide interest in silver nanoparticles (AgNPs) synthesized by various chemical reactions for use in applications exploiting their antibacterial activity, even though these processes exhibit a broad range of toxicity in vertebrates and invertebrates alike. To avoid the chemical toxicity, biosynthesis (green synthesis) of metal nanoparticles is proposed as a cost-effective and environmental friendly alternative. Aloe vera leaf extract is a medicinal agent with multiple properties including an antibacterial effect. Moreover the constituents of aloe vera leaves include lignin, hemicellulose, and pectins which can be used in the reduction of silver ions to produce as AgNPs@aloe vera (AgNPs@AV) with antibacterial activity. Methods AgNPs were prepared by an eco-friendly hydrothermal method using an aloe vera plant extract solution as both a reducing and stabilizing agent. AgNPs@AV were characterized using XRD and SEM. Additionally, an agar well diffusion method was used to screen for antimicrobial activity. MIC and MBC were used to correlate the concentration of AgNPs@AV its bactericidal effect. SEM was used to investigate bacterial inactivation. Then the toxicity with human cells was investigated using an MTT assay. Results The synthesized AgNPs were crystalline with sizes of 70.70 ± 22-192.02 ± 53 nm as revealed using XRD and SEM. The sizes of AgNPs can be varied through alteration of times and temperatures used in their synthesis. These AgNPs were investigated for potential use as an antibacterial agent to inhibit pathogenic bacteria. Their antibacterial activity was tested on S. epidermidis and P. aeruginosa. The results showed that AgNPs had a high antibacterial which depended on their synthesis conditions, particularly when processed at 100 oC for 6 h and 200 oC for 12 h. The cytotoxicity of AgNPs was determined using human PBMCs revealing no obvious cytotoxicity. These results indicated that AgNPs@AV can be effectively utilized in

  19. In vitro and in vivo antibacterial activities of BO-2727, a new carbapenem.

    PubMed Central

    Asahi, Y; Miyazaki, S; Yamaguchi, K

    1995-01-01

    BO-2727, a new injectable carbapenem, was evaluated for its in vitro and in vivo antibacterial activities in comparison with those of biapenem, meropenem, imipenem, cefpirome, and ceftazidime. BO-2727 had activity comparable to that of imipenem against methicillin-susceptible staphylococci and streptococci, with MICs at which 90% of strains tested (MIC90s) are inhibited being equal to 0.5 microgram/ml or less. Against methicillin-resistant staphylococci, BO-2727 was the most active among the antibiotics tested, with MIC90s ranging from 4 to 8 micrograms/ml. BO-2727 was highly active against members of the family Enterobacteriaceae, Haemophilus influenzae, and Moraxella catarrhalis, with MIC90s ranging from 0.006 to 2 micrograms/ml. BO-2727 was also highly active against Pseudomonas aeruginosa (imipenem-susceptible strains), for which the MIC90 was 2 micrograms/ml, which was lower than those of imipenem, cefpirome, and ceftazidime and comparable to those of biapenem and meropenem. Differences in activity between BO-2727 and the other carbapenems against imipenem-resistant P. aeruginosa were particularly striking (MIC90, 8 micrograms/ml). Furthermore, BO-2727 displayed a high degree of activity against many of the ceftazidime-, ciprofloxacin-, and/or gentamicin-resistant isolates of P. aeruginosa. The in vivo efficacy of BO-2727 against experimental septicemia caused by gram-positive and gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and imipenem-resistant P. aeruginosa, reflected its potent in vitro activity and high levels in plasma. PMID:7625784

  20. Copper and Graphene activated ZnO nanopowders for enhanced photocatalytic and antibacterial activities

    NASA Astrophysics Data System (ADS)

    Ravichandran, K.; Chidhambaram, N.; Gobalakrishnan, S.

    2016-06-01

    ZnO, ZnO:Cu and ZnO:Cu:Graphene nanopowders were synthesized via a facile wet chemical method. The XRD studies show that the synthesized samples have hexagonal wurtzite structure. It is found that graphene addition induces a decrease in crystallite size. UV-vis absorption spectra of the samples show sharp absorption edges around 380 nm. Photoluminescence studies reveal that the incorporation of copper and graphene in ZnO facilitates the efficient photo generated electron-hole pair separation. It is found that the ZnO:Cu and ZnO:Cu:Graphene nanopowder exhibit improved photocatalytic efficiency for the photodegradation of Methylene Blue (MB) under visible light irradiation. Moreover, improved antibacterial activity of ZnO:Cu:Graphene nanopowder against Escherichia coli and Staphylococcus aureus bacteria is observed.

  1. In vitro antibacterial activity in seed extracts of Manilkara zapota, Anona squamosa, and Tamarindus indica.

    PubMed

    Kothari, Vijay; Seshadri, Sriram

    2010-01-01

    Extracts prepared from seeds of Manilkara zapota, Anona squamosa, and Tamarindus indica were screened for their antibacterial activity by disc diffusion and broth dilution methods. Acetone and methanol extracts of T. indica seeds were found active against both gram-positive and gram-negative organisms. MIC values of potent extracts against susceptible organisms ranged from 53-380 μg/mL. Methanol extract of T. indica and acetone extract of M. zapota seeds were found to be bactericidal.

  2. Influence of alkyl chain length on the surface activity of antibacterial polymers derived from ROMP.

    PubMed

    Altay, Esra; Yapaöz, Melda Altıkatoğlu; Keskin, Bahadır; Yucesan, Gundoğ; Eren, Tarik

    2015-03-01

    The purpose of this study is to understand the antibacterial properties of cationic polymers on solid surfaces by investigating the structure-activity relationships. The polymer synthesis was carried via ring opening metathesis polymerization (ROMP) of oxanorbornene derivatives. Modulation of molecular weights and alkyl chain lengths of the polymers were studied to investigate the antibacterial properties on the glass surface. Fluorescein (Na salt) staining contact angle measurements were used to characterize the positive charge density and hydrophobicity on the polymer coated surfaces. Positive charge density for the surface coated polymers with molecular weights of 3000 and 10,000 g mol(-1) is observed to be in the range of 2.3-28.5 nmol cm(-2). The ROMP based cationic pyridinium polymer with hexyl unit exhibited the highest bactericidal efficiency against Escherichia coli on solid surface killing 99% of the bacteria in 5 min. However, phenyl and octyl functionalized quaternary pyridinium groups exhibited lower biocidal properties on the solid surfaces compared to their solution phase biocidal properties. Studying the effect of threshold polymer concentrations on the antibacterial properties indicated that changing the concentrations of polymer coatings on the solid surface dramatically influences antibacterial efficiency.

  3. A High-Throughput Screen Identifies a New Natural Product with Broad-Spectrum Antibacterial Activity

    PubMed Central

    Ymele-Leki, Patrick; Cao, Shugeng; Sharp, Jared; Lambert, Kathleen G.; McAdam, Alexander J.; Husson, Robert N.; Tamayo, Giselle; Clardy, Jon; Watnick, Paula I.

    2012-01-01

    Due to the inexorable invasion of our hospitals and communities by drug-resistant bacteria, there is a pressing need for novel antibacterial agents. Here we report the development of a sensitive and robust but low-tech and inexpensive high-throughput metabolic screen for novel antibiotics. This screen is based on a colorimetric assay of pH that identifies inhibitors of bacterial sugar fermentation. After validation of the method, we screened over 39,000 crude extracts derived from organisms that grow in the diverse ecosystems of Costa Rica and identified 49 with reproducible antibacterial effects. An extract from an endophytic fungus was further characterized, and this led to the discovery of three novel natural products. One of these, which we named mirandamycin, has broad-spectrum antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Vibrio cholerae, methicillin-resistant Staphylococcus aureus, and Mycobacterium tuberculosis. This demonstrates the power of simple high throughput screens for rapid identification of new antibacterial agents from environmental samples. PMID:22359585

  4. Interdigitated silver-polymer-based antibacterial surface system activated by oligodynamic iontophoresis - an empirical characterization study.

    PubMed

    Shirwaiker, Rohan A; Wysk, Richard A; Kariyawasam, Subhashinie; Voigt, Robert C; Carrion, Hector; Nembhard, Harriet Black

    2014-02-01

    There is a pressing need to control the occurrences of nosocomial infections due to their detrimental effects on patient well-being and the rising treatment costs. To prevent the contact transmission of such infections via health-critical surfaces, a prophylactic surface system that consists of an interdigitated array of oppositely charged silver electrodes with polymer separations and utilizes oligodynamic iontophoresis has been recently developed. This paper presents a systematic study that empirically characterizes the effects of the surface system parameters on its antibacterial efficacy, and validates the system's effectiveness. In the first part of the study, a fractional factorial design of experiments (DOE) was conducted to identify the statistically significant system parameters. The data were used to develop a first-order response surface model to predict the system's antibacterial efficacy based on the input parameters. In the second part of the study, the effectiveness of the surface system was validated by evaluating it against four bacterial species responsible for several nosocomial infections - Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis - alongside non-antibacterial polymer (acrylic) control surfaces. The system demonstrated statistically significant efficacy against all four bacteria. The results indicate that given a constant total effective surface area, the system designed with micro-scale features (minimum feature width: 20 μm) and activated by 15 μA direct current will provide the most effective antibacterial prophylaxis.

  5. Detection and qualification of optimum antibacterial and cytotoxic activities of silver-doped bioactive glasses.

    PubMed

    Gholipourmalekabadi, Mazaher; Nezafati, Nader; Hajibaki, Leila; Mozafari, Masoud; Moztarzadeh, F; Hesaraki, Saeed; Samadikuchaksaraei, Ali

    2015-08-01

    This study aims to detect the optimum antibacterial activity of silver-doped bioactive glasses (Ag-BGs) for prevention of post-transplant infections in tissue engineering. The results have shown that the Ag-BG samples had broad-spectrum antibacterial efficacy in an Ag concentration-dependent manner. The 2% Ag-BG had the highest effect during the first 10 min to 72 h. The minimum inhibitory concentration of 2% Ag-BG was estimated to be 2 mg/ml for Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and 2.66 mg/ml for Staphylococcus aureus (S. aureus). A concentration of 0.5% Ag-BG repressed growth of E. coli after 1 h, but did not have any detectable antibacterial effect for longer periods. Evaluation of the effects of prepared Ag-BG on human osteoblast cells viability showed that 1 and 2% samples changed the cell proliferation rate in masses of more than 3.33 and 2 mg/ml, respectively. Moreover, in a typical manner, the release of Ag ions from the glass structure started immediately, continued steadily and affected bacterial growth when it reached its critical concentration in the medium. This systematic study can illustrate the optimum antibacterial property of the Ag-BG samples in masses of 3.33 and 2 mg/ml for 1 and 2% Ag, respectively, for prevention of post-transplant infections. PMID:26224350

  6. Antibacterial activity of extracts from plants of central Argentina--isolation of an active principle from Achyrocline satureioides.

    PubMed

    Joray, Mariana B; del Rollán, María R; Ruiz, Gustavo M; Palacios, Sara M; Carpinella, María C

    2011-01-01

    The great increase in bacterial infections is fueling interest in the search for antibacterial products of plant origin. Extracts obtained from 51 native and naturalized plants from central Argentina were therefore evaluated for their IN VITRO inhibitory activity on pathogenic bacteria with the aim of selecting the most active ones as new sources of effective antibiotics. The susceptibility of reference and clinical strains of Enterococcus faecalis, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus was determined. Extracts from Achyrocline satureioides, Flourensia oolepis, Lepechinia floribunda, and Lithrea molleoides were the most potent, with MIC and MBC values ranging from 0.006 to 2 and 0.012 to 10 mg/mL, respectively, on both gram-positive and negative bacteria. The antibacterial activity-guided isolation of A. satureioides ethanol extract showed 23-methyl-6-O-desmethylauricepyrone (1) to be the most active compound. This compound showed inhibitory effects against gram-positive bacteria with MIC and MBC values of 0.002 and 0.008 mg/mL, respectively, while on gram-negative strains, the MIC and MBC were 0.062-0.250 and 0.062-0.500 mg/mL, respectively. The strong antibacterial activity shown by the four plant extracts or the compound isolated from A. satureioides suggests that they could become part of the arsenal of antibacterial drugs currently used.

  7. Chemical composition and antibacterial activities of the essential oils isolated from Juniperus thurifera L. var. Africana.

    PubMed

    Bahri, F; Harrak, R; Achak, N; Romane, A

    2013-01-01

    This study describes the chemical composition and antibacterial activities of essential oils of Moroccan Juniperus thurifera L. var. Africana (Cupressaceae). The essential oil of dried leaves was isolated by hydrodistillation, vapohydrodistillation and microwaves. Sixty-four compounds in J. thurifera L. var. Africana oils were identified (79.9%, 92.4% and 98.4% of the oil, respectively). The most abundant compound in J. thurifera L. var. Africana oils is sabinene (38%, 36.2% and 39.4%). Antibacterial activities of J. thurifera essential oils was tested against bacteria Gram ( - ) and Gram (+). The oil is very active against all bacteria tested except Pseudomonas, which turned out to be very resistant.

  8. Facile Preparation of Ag/NiO Composite Nanosheets and Their Antibacterial Activity

    NASA Astrophysics Data System (ADS)

    Shi, Cui-E.; Pan, Lu; Wang, Cheng-Run; He, Yi; Wu, Yong-Feng; Xue, Sai-Sai

    2016-01-01

    Sheet-like precursors of NiO and Ag/NiO with different Ag contents were synthesized by a facile and easily controlled hydrothermal method. The NiO and Ag/NiO composite nanosheets were prepared by calcination of the corresponding precursors at 400°C for 3 h. The as-synthesized samples were characterized by thermogravimetric analysis, x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The antibacterial activity of NiO and Ag/NiO composites to several gram-positive and gram-negative bacteria was examined. Results showed that NiO nanosheets hardly exhibited antibacterial activity; however, Ag/NiO composites displayed higher activity even with low Ag content.

  9. Phenolic constituents from the aerial parts of Glycyrrhiza inflata and their antibacterial activities.

    PubMed

    Zhou, Biao; Wan, Chuan-Xing

    2015-01-01

    Chemical investigation on 90% ethanol extracts of the aerial parts of Glycyrrhiza inflata afforded two new phenolic constituents, 2-(3-methyl-2-butenyl)-3,5,4'-trihydroxy-bibenzyl (1) and (2S)-6-[(E)-3-hydroxymethyl-2-butenyl]-3',4',5,7-tetrahydroxy-dihydroflavanone (2) along with seven known dihydroflavanones (3-9). Compounds 1-9 were tested for their minimum inhibitory concentration (MIC) values of inhibiting Staphylococcus aureus and Staphylococcus epidermidis. Compound 1 showed moderate antibacterial activities against both S. aureus (MIC of 50.00 μg/ml) and S. epidermidis (MIC of 12.50 μg/ml). The analysis of structure-activity relationships revealed that the antibacterial activity of dihydroflavanones (2-9) was significantly affected by the position of prenyl group.

  10. Synthesis, antibacterial, antifungal and antitubercular activities of N-pyrazolylbenzamide derivatives.

    PubMed

    Kulkarni, Ravindra; Kumar, Vijay; Babu, Harish; Kumar, Krishna; Gaddam, Naveen; Fatima, Aneesa; Muvvala, Sudhakar; Bhikshapathi, D V R N; Sriram, D; Garlapati, Achaiah; Vishnav, Jagrut; Gurav, Prashant

    2014-03-01

    A series of new N-pyrazolylbenzamides (5a-x) were synthesized by aroylation of 5-amino-1-phenyl-3-tbutylpyrazole. The structures of synthesized compounds were established based on spectral (FTIR, (1)H NMR, ESI Mass) analysis and purity was ascertained by HPLC. The antibacterial screening revealed that seven molecules exhibited an excellent antibacterial activity and eight compounds demonstrated considerable antifungal activity. Three molecules of the series 5e, 5s and 5w were found to be highly effective against Klebsilla pneumoneia with MIC of 3.12 µg/ml. Compounds 5b, 5f, 5g and 5o exhibited significant antitubercular activity with MIC of 12.5 µg/ml.

  11. Phenolic constituents from the aerial parts of Glycyrrhiza inflata and their antibacterial activities.

    PubMed

    Zhou, Biao; Wan, Chuan-Xing

    2015-01-01

    Chemical investigation on 90% ethanol extracts of the aerial parts of Glycyrrhiza inflata afforded two new phenolic constituents, 2-(3-methyl-2-butenyl)-3,5,4'-trihydroxy-bibenzyl (1) and (2S)-6-[(E)-3-hydroxymethyl-2-butenyl]-3',4',5,7-tetrahydroxy-dihydroflavanone (2) along with seven known dihydroflavanones (3-9). Compounds 1-9 were tested for their minimum inhibitory concentration (MIC) values of inhibiting Staphylococcus aureus and Staphylococcus epidermidis. Compound 1 showed moderate antibacterial activities against both S. aureus (MIC of 50.00 μg/ml) and S. epidermidis (MIC of 12.50 μg/ml). The analysis of structure-activity relationships revealed that the antibacterial activity of dihydroflavanones (2-9) was significantly affected by the position of prenyl group. PMID:25315253

  12. Novel zinc alginate hydrogels prepared by internal setting method with intrinsic antibacterial activity.

    PubMed

    Straccia, Maria Cristina; d'Ayala, Giovanna Gomez; Romano, Ida; Laurienzo, Paola

    2015-07-10

    In this paper, a controlled gelation of alginate was performed for the first time using ZnCO3 and GDL. Uniform and transparent gels were obtained and investigated as potential wound dressings. Homogeneity, water content, swelling capability, water evaporation rate, stability in normal saline solution, mechanical properties and antibacterial activity were assessed as a function of zinc concentration. Gelation rate increased at increasing zinc content, while a decrease in water uptake and an improvement of stability were found. Release of zinc in physiological environments showed that concentration of zinc released in solution lies below the cytotoxicity level. Hydrogels showed antimicrobial activity against Escherichia coli. The hydrogel with highest zinc content was stabilized with calcium by immersion in a calcium chloride solution. The resulting hydrogel preserved homogeneity and antibacterial activity. Furthermore, it showed even an improvement of stability and mechanical properties, which makes it suitable as long-lasting wound dressing.

  13. Chemical composition and antibacterial activity of Opuntia ficus-indica f. inermis (cactus pear) flowers.

    PubMed

    Ennouri, Monia; Ammar, Imene; Khemakhem, Bassem; Attia, Hamadi

    2014-08-01

    Opuntia ficus-indica f. inermis (cactus pear) flowers have wide application in folk medicine. However, there are few reports focusing on their biological activity and were no reports on their chemical composition. The nutrient composition and hexane extracts of Opuntia flowers at 4 flowering stages and their antibacterial and antifungal activities were investigated. The chemical composition showed considerable amounts of fiber, protein, and minerals. Potassium (K) was the predominant mineral followed by calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), and zinc (Zn). The main compounds in the various hexane extracts were 9.12-octadecadienoic acid (29-44%) and hexadecanoic acid (8.6-32%). The antibacterial activity tests showed that O. inermis hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, making this botanical source a potential contender as a food preservative or food control additive.

  14. Isothiazolopyridones: synthesis, structure, and biological activity of a new class of antibacterial agents.

    PubMed

    Wiles, Jason A; Hashimoto, Akihiro; Thanassi, Jane A; Cheng, Jijun; Incarvito, Christopher D; Deshpande, Milind; Pucci, Michael J; Bradbury, Barton J

    2006-01-12

    We report the syntheses of first-generation derivatives of isothiazolopyridones and their in vitro evaluation as antibacterial agents. These compounds, containing a novel heterocyclic nucleus composed of an isothiazolone fused to a quinolizin-4-one (at C-2 and C-3 of the quinolizin-4-one), were prepared using a sequence of seven synthetic transformations. The solid-state structure of 7-chloro-9-ethyl-1-thia-2,4a-diazacyclopenta[b]naphthalene-3,4-dione was determined by X-ray diffraction. The prepared derivatives of desfluoroisothiazolopyridones exhibited (a) antibacterial activity against Gram-negative and Gram-positive organisms, (b) inhibitory activities against DNA gyrase and topoisomerase IV, and (c) no inhibitory activity against human topoisomerase II.

  15. Antibacterial activity and composition of the essential oil of Nepeta menthoides from Iran.

    PubMed

    Sonboli, Ali; Gholipour, Abbas; Yousefzadi, Morteza; Mojarrad, Mehran

    2009-02-01

    The antibacterial activity and chemical composition of the essential oil obtained from the aerial flowering parts of Nepeta menthoides were analyzed by GC and GC-MS. Twenty-nine compounds representing 97.6% of the total oil were identified. Oxygenated monoterpenes (71.9%) were the principal fraction of the oil with 1,8-cineole (33.8%) and 4aa-7alpha-7aalpha-nepetalactone (23.2%) as the main constituents. The antibacterial activity of the oil and its two main constituents were tested against seven bacteria. High activity of the oil and its two main constituents was demonstrated against all the tested bacteria with MIC values in the range of 1.8 - 7.2, 0.9 - 7.2 and 1.8 - 15 mg/mL, respectively.

  16. Antibacterials. Synthesis and structure-activity studies of 3-aryl-2-oxooxazolidines. 1. The "B" group.

    PubMed

    Gregory, W A; Brittelli, D R; Wang, C L; Wuonola, M A; McRipley, R J; Eustice, D C; Eberly, V S; Bartholomew, P T; Slee, A M; Forbes, M

    1989-08-01

    The synthesis and structure/activity studies of the effect of varying the "B" group in a series of oxazolidinone antibacterials (I) are described. Two synthetic routes were used: (1) alkylation of aniline with glycidol followed by dialkyl carbonate heterocyclization to afford I (A = H, B = OH), whose arene ring was further elaborated by using electrophilic aromatic substitution methodology; (2) cycloaddition of substituted aryl isocyanates with epoxides to give A and B with a variety of values. I with B = OH or Br were converted to other "B" functionalities by using SN2 methodology. Antibacterial evaluation of compounds I with A = acetyl, isopropyl, methylthio, methylsulfinyl, methylsulfonyl, and sulfonamido and a variety of different "B" groups against Staphylococcus aureus and Enterococcus faecalis concluded that the compounds with B = aminoacyl, and particularly acetamido, were the most active of those examined in each A series, possessing MICs in the range of 0.5-4 micrograms/mL for the most active compounds described.

  17. Antibacterial Activity of Extracts of Acacia Aroma Against Methicillin-Resistant And Methicillin-Sensitive Staphylococcus

    PubMed Central

    Mattana, C.M.; Satorres, S.E.; Sosa, A.; Fusco, M.; Alcará, L.E.

    2010-01-01

    Antibacterial activity of organic and aqueous extracts of Acacia aroma was evaluated against methicillin-resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus epidermidis. Inhibition of bacterial growth was determined using agar diffusion and bioautographic methods. Among all assayed organic extracts only ethanolic and ethyl acetate extracts presented highest activities against all tested Staphylococcus strains with minimal inhibitory concentration (MIC) values ranging from 2.5 to 10 mg/ml and from 2.5 to 5 mg/ml respectively. The aqueous extracts show little antibacterial activity against Staphylococcus strains. The bioautography assay demonstrated well-defined growth inhibition zones against S. aureus in correspondence with flavonoids and saponins. A. aroma would be an interesting topic for further study and possibly for an alternative treatment for skin infections. PMID:24031532

  18. Activity of antibacterial protein from maggots against Staphylococcus aureus in vitro and in vivo.

    PubMed

    Zhang, Zhen; Wang, Jiangning; Zhang, Bo; Liu, Huanran; Song, Wei; He, Jiao; Lv, Decheng; Wang, Shouyu; Xu, Xiaoguang

    2013-05-01

    Maggots (larvae of Lucilia sericata) have shown therapeutic effects on refractory wounds infected with bacteria, yet the bacterial killing mechanisms are unclear. Herein, we report the isolation and purification of an antibacterial protein from maggots (MAMP). MAMP demonstrated inhibitory activity against both standard strains and clinically isolated antibiotic-resistant strains of Staphylococcus aureus in vitro. The topical use of MAMP effectively decreased the viability of S. aureus and promoted wound healing in an S. aureus mouse skin infection model. MAMP exerted its antibacterial activity via a bactericidal mechanism based on observations using scanning electron and transmission electron microscopy. MAMP interacted with the bacterial cell membrane and disrupted the cell surface structure. In addition, MAMP had weak hemolytic activity at a high concentration. Taken together, MAMP exhibits potential use as a topical agent for treating bacterial infections.

  19. Antibacterial and antifouling activities of chitosan/TiO2/Ag NPs nanocomposite films against packaged drinking water bacterial isolates.

    PubMed

    Natarajan, Saravanan; Bhuvaneshwari, M; Lakshmi, D Shanthana; Mrudula, P; Chandrasekaran, N; Mukherjee, Amitava

    2016-10-01

    TiO2 and Ag NPs are widely used as antibacterial agents against many bacterial pathogens. Chitosan (polymer) itself acts as a strong antibacterial agent. Hence, chitosan/TiO2/Ag NPs incorporated nanocomposite film was prepared against packed drinking water bacterial strains. A concentration-dependent increase in the reduction of cell viability was observed in all the isolates under UV-C and dark exposure conditions. The bacteria consortium showed greater resistance against antibacterial effects of chitosan/TiO2/Ag nanocomposite as compared to single isolates. Glycocalyx test and mass assessment conclude the effective antibacterial activity by inhibiting bacterial adhesion on the film surface. The release of LDH and generation of ROS act as the predominant antibacterial mechanism induced by TiO2/Ag NPs. Surface characterization of chitosan/TiO2/Ag nanocomposite was studied by FTIR and XRD analyses and SEM analysis after interaction with the bacteria.

  20. Antibacterial and antifouling activities of chitosan/TiO2/Ag NPs nanocomposite films against packaged drinking water bacterial isolates.

    PubMed

    Natarajan, Saravanan; Bhuvaneshwari, M; Lakshmi, D Shanthana; Mrudula, P; Chandrasekaran, N; Mukherjee, Amitava

    2016-10-01

    TiO2 and Ag NPs are widely used as antibacterial agents against many bacterial pathogens. Chitosan (polymer) itself acts as a strong antibacterial agent. Hence, chitosan/TiO2/Ag NPs incorporated nanocomposite film was prepared against packed drinking water bacterial strains. A concentration-dependent increase in the reduction of cell viability was observed in all the isolates under UV-C and dark exposure conditions. The bacteria consortium showed greater resistance against antibacterial effects of chitosan/TiO2/Ag nanocomposite as compared to single isolates. Glycocalyx test and mass assessment conclude the effective antibacterial activity by inhibiting bacterial adhesion on the film surface. The release of LDH and generation of ROS act as the predominant antibacterial mechanism induced by TiO2/Ag NPs. Surface characterization of chitosan/TiO2/Ag nanocomposite was studied by FTIR and XRD analyses and SEM analysis after interaction with the bacteria. PMID:27388596

  1. Effects of quaternization on the morphological stability and antibacterial activity of electrospun poly(DMAEMA-co-AMA) nanofibers.

    PubMed

    Xu, Jing-Wei; Wang, Yao; Yang, Yun-Feng; Ye, Xiang-Yu; Yao, Ke; Ji, Jian; Xu, Zhi-Kang

    2015-09-01

    Electrospun nanofibers with antibacterial activity are greatly promising for medical treatment and water purification. Herein we report antibacterial nanofibers electrospun from a series of poly(dimethylamino ethyl methacrylate-co-alkyl methacrylates) (poly(DMAEMA-co-AMA)) and to distinguish the effects of free and cross-linked cations derived from quanternization on the antibacterial activity. Poly(DMAEMA-co-AMA)s are simply synthesized by free radical polymerization from commercial monomers. DSC analysis indicates that they have Tg lower than room temperature and thus the electrospun nanofibers adhere to each other and evenly tend to form films, instead of keeping cylinderic shape. Benzyl chloride (BC) and p-xylylene dichloride (XDC) can quaternize DMAEMA units and to generate cations on the nanofiber surface. XPS analysis and colorimetric assay determine the quaternization degree and the surface accessible quaternary amines (N(+)), respectively. It is very promising that this quaternization endows the electrospun nanofibers with both stable morphology and antibacterial activity. The BC-quaternized fibers show better antibacterial behavior against Escherichia coli and Staphylococcus aureus than those of the XDC-quaternized/cross-linked ones, because cross-linking suppresses the chain mobility of cations. Our results confirm that antibacterial nanofibers can be facilely prepared and chain mobility of the formed cations is the necessary prerequisite for their antibacterial activity.

  2. Discovery of an ultra-short linear antibacterial tetrapeptide with anti-MRSA activity from a structure-activity relationship study.

    PubMed

    Lau, Qiu Ying; Ng, Fui Mee; Cheong, Jin Wei Darryl; Yap, Yi Yong Alvin; Tan, Yoke Yan Fion; Jureen, Roland; Hill, Jeffrey; Chia, Cheng San Brian

    2015-11-13

    The overuse and misuse of antibiotics has resulted in the emergence of drug-resistant pathogenic bacteria, including meticillin-resistant Staphylococcus aureus (MRSA), the primary pathogen responsible for human skin and soft-tissue infections. Antibacterial peptides are known to kill bacteria by rapidly disrupting their membranes and are deemed plausible alternatives to conventional antibiotics. One advantage of their membrane-targeting mode of action is that bacteria are unlikely to develop resistance as changing their cell membrane structure and morphology would likely involve extensive genetic mutations. However, major concerns in using peptides as antibacterial drugs include their instability towards plasma proteases, toxicity towards human cells due to their membrane-targeting mode of action and high manufacturing cost. These concerns can be mitigated by developing peptides as topical agents, by the judicial selection of amino acids and developing very short peptides respectively. In this preliminary report, we reveal a linear, non-hemolytic tetrapeptide with rapid bactericidal activity against MRSA developed from a structure-activity relationship study based on the antimicrobial hexapeptide WRWRWR-NH2. Our finding opens promising avenues for the development of ultra-short antibacterials to treat multidrug-resistant MRSA skin and soft tissue infections. PMID:26489599

  3. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity

    NASA Astrophysics Data System (ADS)

    Ashraf, Sumaira; Chatha, Mariyam Asghar; Ejaz, Wardah; Janjua, Hussnain Ahmed; Hussain, Irshad

    2014-10-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests.

  4. Essential Oil Yield Pattern and Antibacterial and Insecticidal Activities of Trachyspermum ammi and Myristica fragrans.

    PubMed

    Soni, Rajgovind; Sharma, Gaurav; Jasuja, Nakuleshwar Dut

    2016-01-01

    Two Indian spices, Trachyspermum ammi and Myristica fragrans, were studied for their essential oil (EO) yielding pattern, insecticidal activity, antibacterial activity, and composition. The essential oils (EOs) of T. ammi (1.94 ± 30 mL/100 gm) and M. fragrans (5.93 ± 90 mL/100 gm) were extracted using hydrodistillation method. In Gas Chromatography analysis, the beta-pinene, alpha-pinene, alpha-p-menth-1-en-4-ol, Limonene, and elemicin were found as major constituents of T. ammi essential oil whereas M. fragrans essential oil mostly contains Gamma-Terpinolene, p-Cymene, Thymol, and beta-pinene. The insecticidal activities of EO were demonstrated using LC50 values against Plodia interpunctella and EO of T. ammi was found comparatively more effective than EO of M. fragrans. Further, individual EO and combination of essential oil were examined for antibacterial activity against three Gram (-) bacterial strains (E. coli-MTCC 443, P. vulgaris-MTCC 1771, and K. pneumoniae-MTCC number 7028) and three Gram (+) bacterial strains (S. aureus-MTCC 3381, B. subtilis-MTCC 10619, and B. megaterium-MTCC 2412) by well agar diffusion method. The essential oil in combination (CEO) exhibited higher antibacterial activity as compared with individual essential oils.

  5. Essential Oil Yield Pattern and Antibacterial and Insecticidal Activities of Trachyspermum ammi and Myristica fragrans

    PubMed Central

    Sharma, Gaurav

    2016-01-01

    Two Indian spices, Trachyspermum ammi and Myristica fragrans, were studied for their essential oil (EO) yielding pattern, insecticidal activity, antibacterial activity, and composition. The essential oils (EOs) of T. ammi (1.94 ± 30 mL/100 gm) and M. fragrans (5.93 ± 90 mL/100 gm) were extracted using hydrodistillation method. In Gas Chromatography analysis, the beta-pinene, alpha-pinene, alpha-p-menth-1-en-4-ol, Limonene, and elemicin were found as major constituents of T. ammi essential oil whereas M. fragrans essential oil mostly contains Gamma-Terpinolene, p-Cymene, Thymol, and beta-pinene. The insecticidal activities of EO were demonstrated using LC50 values against Plodia interpunctella and EO of T. ammi was found comparatively more effective than EO of M. fragrans. Further, individual EO and combination of essential oil were examined for antibacterial activity against three Gram (−) bacterial strains (E. coli-MTCC 443, P. vulgaris-MTCC 1771, and K. pneumoniae-MTCC number 7028) and three Gram (+) bacterial strains (S. aureus-MTCC 3381, B. subtilis-MTCC 10619, and B. megaterium-MTCC 2412) by well agar diffusion method. The essential oil in combination (CEO) exhibited higher antibacterial activity as compared with individual essential oils. PMID:27190677

  6. Tuning the biological activity profile of antibacterial polymers via subunit substitution pattern.

    PubMed

    Liu, Runhui; Chen, Xinyu; Chakraborty, Saswata; Lemke, Justin J; Hayouka, Zvi; Chow, Clara; Welch, Rodney A; Weisblum, Bernard; Masters, Kristyn S; Gellman, Samuel H

    2014-03-19

    Binary nylon-3 copolymers containing cationic and hydrophobic subunits can mimic the biological properties of host-defense peptides, but relationships between composition and activity are not yet well understood for these materials. Hydrophobic subunits in previously studied examples have been limited mostly to cycloalkane-derived structures, with cyclohexyl proving to be particularly promising. The present study evaluates alternative hydrophobic subunits that are isomeric or nearly isomeric with the cyclohexyl example; each has four sp(3) carbons in the side chains. The results show that varying the substitution pattern of the hydrophobic subunit leads to relatively small changes in antibacterial activity but causes significant changes in hemolytic activity. We hypothesize that these differences in biological activity profile arise, at least in part, from variations among the conformational propensities of the hydrophobic subunits. The α,α,β,β-tetramethyl unit is optimal among the subunits we have examined, providing copolymers with potent antibacterial activity and excellent prokaryote vs eukaryote selectivity. Bacteria do not readily develop resistance to the new antibacterial nylon-3 copolymers. These findings suggest that variation in subunit conformational properties could be generally valuable in the development of synthetic polymers for biological applications. PMID:24601599

  7. Ultrathin hexagonal MgO nanoflakes coated medical textiles and their enhanced antibacterial activity

    NASA Astrophysics Data System (ADS)

    Veeran Ponnuvelu, Dinesh; Selvaraj, Aravind; Prema Suriyaraj, Shanmugam; Selvakumar, Rajendran; Pulithadathail, Biji

    2016-10-01

    A facile hydrothermal method for development of ultrathin MgO nanoplates from different precursors and their enhanced antibacterial activity after coating onto medical textiles is reported. Ultrathin MgO nanoplates having hexagonal structure were characterized using UV–visible spectroscopy, atomic force microscopy, field emission scanning electron microscopy, x-ray diffraction and high resolution transmission electron microscopy. The formation of MgO nanoplates was found to exhibit profound anionic effect leading to ultrathin, planar structures with exposed MgO [111] facets, which may be responsible for enhanced antimicrobial activity. Medical fabrics (bleached 100% cotton) were coated with MgO nanoplates using pad-dry-cure method. The antibacterial activity of these fabrics was tested against Bacillus subtilis and Escherichia coli. The MgO nanoplates coated onto the fabric were found to have good adherence properties owing to their two-dimensional structure and were durable even after repeated washings without substantial reduction in the antimicrobial activity. The enhanced antibacterial activity may be attributed to the presence of oxygen vacancies, surface oxygen anions and hydroxyl groups on the surface of MgO nanoplates. This cost-effective functional finish (anti-microbial) to cotton fabric using MgO nanoplates may be suitable for many prospective medical applications and can serve as an alternative to the costlier silver based antimicrobial textiles.

  8. Phenolic compounds in drumstick peel for the evaluation of antibacterial, hemolytic and photocatalytic activities.

    PubMed

    Surendra, T V; Roopan, Selvaraj Mohana; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Sridharan, Makuteswaran

    2016-08-01

    Most of the wastes emitted from the food processing industries are not utilized for any further purpose. The economic value of the food waste is very less when compared to the collection or reuse or discard. To increase the economic value we have to design the food waste as useful product or applicable in most of the current field. Nothing is waste in this world with this concept we have investigated the phytochemical analysis of drumstick peel (Moringa oleifera). The result supports the presence of phenols, alkaloids, flavanoids, glycosides and tannins. Since various functional groups containing molecules are present in the extract; it has been further subjected to antibacterial and hemolytic activities. To analysis the antibacterial studies we have employed human pathogenic Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacterium. The result of antibacterial activity clearly shows that it possesses significant activity on both bacterial cultures. The hemolytic activity was performed on red blood cells (RBCs). From this result we observed that drumstick peel extract has been considered as non-toxic on RBCs. Malachite green was selected to perform photocatalytic activity. The results stated that the drumstick peel extract possessed good behaviour towards photocatalytic investigation. The malachite green was degraded upto 99.7% using drumstick peel extract. PMID:27318603

  9. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity

    PubMed Central

    2014-01-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests. PMID:25435831

  10. Essential Oil Yield Pattern and Antibacterial and Insecticidal Activities of Trachyspermum ammi and Myristica fragrans.

    PubMed

    Soni, Rajgovind; Sharma, Gaurav; Jasuja, Nakuleshwar Dut

    2016-01-01

    Two Indian spices, Trachyspermum ammi and Myristica fragrans, were studied for their essential oil (EO) yielding pattern, insecticidal activity, antibacterial activity, and composition. The essential oils (EOs) of T. ammi (1.94 ± 30 mL/100 gm) and M. fragrans (5.93 ± 90 mL/100 gm) were extracted using hydrodistillation method. In Gas Chromatography analysis, the beta-pinene, alpha-pinene, alpha-p-menth-1-en-4-ol, Limonene, and elemicin were found as major constituents of T. ammi essential oil whereas M. fragrans essential oil mostly contains Gamma-Terpinolene, p-Cymene, Thymol, and beta-pinene. The insecticidal activities of EO were demonstrated using LC50 values against Plodia interpunctella and EO of T. ammi was found comparatively more effective than EO of M. fragrans. Further, individual EO and combination of essential oil were examined for antibacterial activity against three Gram (-) bacterial strains (E. coli-MTCC 443, P. vulgaris-MTCC 1771, and K. pneumoniae-MTCC number 7028) and three Gram (+) bacterial strains (S. aureus-MTCC 3381, B. subtilis-MTCC 10619, and B. megaterium-MTCC 2412) by well agar diffusion method. The essential oil in combination (CEO) exhibited higher antibacterial activity as compared with individual essential oils. PMID:27190677

  11. Lysozyme-coated silver nanoparticles for differentiating bacterial strains on the basis of antibacterial activity.

    PubMed

    Ashraf, Sumaira; Chatha, Mariyam Asghar; Ejaz, Wardah; Janjua, Hussnain Ahmed; Hussain, Irshad

    2014-01-01

    Lysozyme, an antibacterial enzyme, was used as a stabilizing ligand for the synthesis of fairly uniform silver nanoparticles adopting various strategies. The synthesized particles were characterized using UV-visible spectroscopy, FTIR, dynamic light scattering (DLS), and TEM to observe their morphology and surface chemistry. The silver nanoparticles were evaluated for their antimicrobial activity against several bacterial species and various bacterial strains within the same species. The cationic silver nanoparticles were found to be more effective against Pseudomonas aeruginosa 3 compared to other bacterial species/strains investigated. Some of the bacterial strains of the same species showed variable antibacterial activity. The difference in antimicrobial activity of these particles has led to the conclusion that antimicrobial products formed from silver nanoparticles may not be equally effective against all the bacteria. This difference in the antibacterial activity of silver nanoparticles for different bacterial strains from the same species may be due to the genome islands that are acquired through horizontal gene transfer (HGT). These genome islands are expected to possess some genes that may encode enzymes to resist the antimicrobial activity of silver nanoparticles. These silver nanoparticles may thus also be used to differentiate some bacterial strains within the same species due to variable silver resistance of these variants, which may not possible by simple biochemical tests. PMID:25435831

  12. The Wound Healing and Antibacterial Activity of Five Ethnomedical Calophyllum inophyllum Oils: An Alternative Therapeutic Strategy to Treat Infected Wounds

    PubMed Central

    Léguillier, Teddy; Lecsö-Bornet, Marylin; Lémus, Christelle; Rousseau-Ralliard, Delphine; Lebouvier, Nicolas; Hnawia, Edouard; Nour, Mohammed; Aalbersberg, William; Ghazi, Kamelia; Raharivelomanana, Phila; Rat, Patrice

    2015-01-01

    Background Calophyllum inophyllum L. (Calophyllaceae) is an evergreen tree ethno-medically used along the seashores and islands of the Indian and Pacific Oceans, especially in Polynesia. Oil extracted from the seeds is traditionally used topically to treat a wide range of skin injuries from burn, scar and infected wounds to skin diseases such as dermatosis, urticaria and eczema. However, very few scientific studies reported and quantified the therapeutic properties of Calophyllum inophyllum oil (CIO). In this work, five CIO from Indonesia (CIO1), Tahiti (CIO2, 3), Fiji islands (CIO4) and New Caledonia (CIO5) were studied and their cytotoxic, wound healing, and antibacterial properties were presented in order to provide a scientific support to their traditional use and verify their safety. Methods The safety of the five CIO was ascertained using the Alamar blue assay on human keratinocyte cells. CIO wound healing properties were determined using the scratch test assay on human keratinocyte cells. CIO-stimulated antibacterial innate immune response was evaluated using ELISA by measuring β defensin-2 release in human derivative macrophage cells. CIO antibacterial activity was tested using oilogramme against twenty aerobic Gram- bacteria species, twenty aerobic Gram+ bacteria species, including a multi-drug resistant Staphylococcus aureus strain and two anaerobic Gram+ bacteria species e.g. Propionibacterium acnes and Propionibacterium granulosum. To detect polarity profile of the components responsible of the antibacterial activity, we performed bioautography against a Staphylococcus aureus strain. Results Based on Alamar Blue assay, we showed that CIO can be safely used on keratinocyte cells between 2.7% and 11.2% depending on CIO origin. Concerning the healing activity, all the CIO tested accelerated in vitro wound closure, the healing factor being 1.3 to 2.1 higher compared to control when keratinocytes were incubated after scratch with CIO at 0.1%. Furthermore

  13. Anti-adhesion and antibacterial activity of silver nanoparticles supported on graphene oxide sheets.

    PubMed

    de Faria, Andreia Fonseca; Martinez, Diego Stéfani Teodoro; Meira, Stela Maris Meister; de Moraes, Ana Carolina Mazarin; Brandelli, Adriano; Filho, Antonio Gomes Souza; Alves, Oswaldo Luiz

    2014-01-01

    This work reports on the preparation, characterization and antibacterial activity of a nanocomposite formed from graphene oxide (GO) sheets decorated with silver nanoparticles (GO-Ag). The GO-Ag nanocomposite was prepared in the presence of AgNO3 and sodium citrate. The physicochemical characterization was performed by UV-vis spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy and transmission electron microscopy (TEM). The average size of the silver nanoparticles anchored on the GO surface was 7.5 nm. Oxidation debris fragments (a byproduct adsorbed on the GO surface) were found to be crucial for the nucleation and growth of the silver nanoparticles. The antibacterial activity of the GO and GO-Ag nanocomposite against the microorganism Pseudomonas aeruginosa was investigated using the standard counting plate methodology. The GO dispersion showed no antibacterial activity against P. aeruginosa over the concentration range investigated. On the other hand, the GO-Ag nanocomposite displayed high biocidal activity with a minimum inhibitory concentration ranging from 2.5 to 5.0 μg/mL. The anti-biofilm activity toward P. aeruginosa adhered on stainless steel surfaces was also investigated. The results showed a 100% inhibition rate of the adhered cells after exposure to the GO-Ag nanocomposite for one hour. To the best of our knowledge, this work provides the first direct evidence that GO-Ag nanocomposites can inhibit the growth of microbial adhered cells, thus preventing the process of biofilm formation. These promising results support the idea that GO-Ag nanocomposites may be applied as antibacterial coatings material to prevent the development of biofilms in food packaging and medical devices. PMID:24060936

  14. Antibacterial activity and genotypic-phenotypic characteristics of bacteriocin-producing Bacillus subtilis KKU213: potential as a probiotic strain.

    PubMed

    Khochamit, Nalisa; Siripornadulsil, Surasak; Sukon, Peerapol; Siripornadulsil, Wilailak

    2015-01-01

    The antimicrobial activity and probiotic properties of Bacillus subtilis strain KKU213, isolated from local soil, were investigated. The cell-free supernatant (CFS) of a KKU213 culture containing crude bacteriocins exhibited inhibitory effects on Gram-positive bacteria, including Bacillus cereus, Listeria monocytogenes, Micrococcus luteus, and Staphylococcus aureus. The antibacterial activity of the CFS precipitated with 40% ammonium sulfate (AS) remained even after treatment at 60 and 100 °C, at pH 4 and 10 and with proteolytic enzymes, detergents and heavy metals. When analyzed by SDS-PAGE and overlaid with the indicator strains B. cereus and S. aureus, the 40% AS precipitate exhibited inhibitory activity on proteins smaller than 10 kDa. However, proteins larger than 25 kDa and smaller than 10 kDa were still observed on a native protein gel. Purified subtilosin A was prepared by Amberlite XAD-16 bead extraction and HPLC and analyzed by Nano-LC-QTOF-MS. Its molecular mass was found to be 3.4 kDa, and it retained its antibacterial activity. These results are consistent with the detection of the anti-listerial subtilosin A gene of the sbo/alb cluster in the KKU213 strain, which is 100% identical to that of B. subtilis subsp. subtilis 168. In addition to stable and cyclic subtilosin A, a mixture of many extracellular antibacterial peptides was also detected in the KKU213 culture. The KKU213 strain produced extracellular amylase, cellulase, lipase and protease, is highly acid-resistant (pH 2) when cultured in inulin and promotes health and reduces infection of intestinally colonized broiler chickens. Therefore, we propose that bacteriocin-producing B. subtilis KKU213 could be used as a potential probiotic strain or protective culture. PMID:25440998

  15. Antibacterial activities of selected Cameroonian spices and their synergistic effects with antibiotics against multidrug-resistant phenotypes

    PubMed Central

    2011-01-01

    Background The emergence of multi-drug resistant (MDR) phenotypes is a major public health problem today in the treatment of bacterial infections. The present study was designed to evaluate the antibacterial activities of the methanol extracts of eleven Cameroonian spices on a panel of twenty nine Gram negative bacteria including MDR strains. Methods The phytochemical analysis of the extracts was carried out by standard tests meanwhile the liquid micro-broth dilution was used for all antimicrobial assays. Results Phytochemical analysis showed the presence of alkaloids, phenols and tannins in all plants extracts. The results of the antibacterial assays indicated that all tested extracts exert antibacterial activities, with the minimum inhibitory concentration (MIC) values varying from 32 to 1024 μg/ml. The extracts from Dichrostachys glomerata, Beilschmiedia cinnamomea, Aframomum citratum, Piper capense, Echinops giganteus, Fagara xanthoxyloïdes and Olax subscorpioïdea were the most active. In the presence of efflux pump inhibitor, PAßN, the activity of the extract from D. glomerata significantly increased on 69.2% of the tested MDR bacteria. At MIC/5, synergistic effects were noted with the extract of D. glomerata on 75% of the tested bacteria for chloramphenicol (CHL), tetracycline (TET) and norfloxacin (NOR). With B. cinnamomea synergy were observed on 62.5% of the studied MDR bacteria with CHL, cefepime (FEP), NOR and ciprofloxacin (CIP) and 75% with erythromycin (ERY). Conclusion The overall results provide information for the possible use of the studied extracts of the spices in the control of bacterial infections involving MDR phenotypes. PMID:22044718

  16. A study of in vitro antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand

    PubMed Central

    Al Momani, Waleed Mahmoud; Taha, Ziyad Ahmed; Ajlouni, Abdulaziz Mahmoud; Shaqra, Qasem Mohammad Abu; Al Zouby, Muaz

    2013-01-01

    Objective To establish the antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand L. Methods (N, N′-bis (1-naphthaldimine)-o-phenylenediamine) was prepared from the condensation of 2-hydroxy-1-naphthaldehyde with o-phenylenediamine in a molar ratio of 2:1. The antimicrobial activity of the resultant Ln (III) complexes was investigated using agar well diffusion and micro-broth dilution techniques; the latter was used to establish the minimum inhibitory concentrations for each compound investigated. Results Most of Ln (III) complexes were found to exhibit antibacterial activities against a number of pathogenic bacteria with MICs ranging between 1.95-250.00 µg/mL. Staphylococcus aureus was the most susceptible bacterial species to [LaL(NO3)2(H2O)](NO3) complex while Shigella dysenteriae and Escherichia coli required a relatively higher MIC (250 µg/mL). The complexes La (III) and Pr (III) were effective inhibitors against Staphylococcus aureus, whereas Sm (III) complex was effective against Serratia marcescens. On the other hand, Gd (III), La (III) and Nd (III) were found to be more potent inhibitors against Pseudomonas aeruginosa than two of commonly used antibiotics. The remaining Ln (III) complexes showed no remarkable activity as compared to the two standard drugs used. Conclusions Tetradentate Schiff base ligand L and its complexes could be a potential antibacterial compounds after further investigation. PMID:23646299

  17. Both Enhanced Biocompatibility and Antibacterial Activity in Ag-Decorated TiO2 Nanotubes

    PubMed Central

    Lan, Ming-Ying; Liu, Chia-Pei; Huang, Her-Hsiung; Lee, Sheng-Wei

    2013-01-01

    In this study, Ag is electron-beam evaporated to modify the topography of anodic TiO2 nanotubes of different diameters to obtain an implant with enhanced antibacterial activity and biocompatibility. We found that highly hydrophilic as-grown TiO2 nanotubes became poorly hydrophilic with Ag incorporation; however they could effectively recover their wettability to some extent under ultraviolet light irradiation. The results obtained from antibacterial tests suggested that the Ag-decorated TiO2 nanotubes could greatly inhibit the growth of Staphylococcus aureus. In vitro biocompatibility evaluation indicated that fibroblast cells exhibited an obvious diameter-dependent behavior on both as-grown and Ag-decorated TiO2 nanotubes. Most importantly, of all samples, the smallest diameter (25-nm-diameter) Ag-decorated nanotubes exhibited the most obvious biological activity in promoting adhesion and proliferation of human fibroblasts, and this activity could be attributed to the highly irregular topography on a nanometric scale of the Ag-decorated nanotube surface. These experimental results demonstrate that by properly controlling the structural parameters of Ag-decorated TiO2 nanotubes, an implant surface can be produced that enhances biocompatibility and simultaneously boosts antibacterial activity. PMID:24124484

  18. Both enhanced biocompatibility and antibacterial activity in Ag-decorated TiO2 nanotubes.

    PubMed

    Lan, Ming-Ying; Liu, Chia-Pei; Huang, Her-Hsiung; Lee, Sheng-Wei

    2013-01-01

    In this study, Ag is electron-beam evaporated to modify the topography of anodic TiO2 nanotubes of different diameters to obtain an implant with enhanced antibacterial activity and biocompatibility. We found that highly hydrophilic as-grown TiO2 nanotubes became poorly hydrophilic with Ag incorporation; however they could effectively recover their wettability to some extent under ultraviolet light irradiation. The results obtained from antibacterial tests suggested that the Ag-decorated TiO2 nanotubes could greatly inhibit the growth of Staphylococcus aureus. In vitro biocompatibility evaluation indicated that fibroblast cells exhibited an obvious diameter-dependent behavior on both as-grown and Ag-decorated TiO2 nanotubes. Most importantly, of all samples, the smallest diameter (25-nm-diameter) Ag-decorated nanotubes exhibited the most obvious biological activity in promoting adhesion and proliferation of human fibroblasts, and this activity could be attributed to the highly irregular topography on a nanometric scale of the Ag-decorated nanotube surface. These experimental results demonstrate that by properly controlling the structural parameters of Ag-decorated TiO2 nanotubes, an implant surface can be produced that enhances biocompatibility and simultaneously boosts antibacterial activity.

  19. Identification of the phenolic compounds contributing to antibacterial activity in ethanol extracts of Brazilian red propolis.

    PubMed

    Inui, Saori; Hatano, Ai; Yoshino, Megumi; Hosoya, Takahiro; Shimamura, Yuko; Masuda, Shuichi; Ahn, Mok-Ryeon; Tazawa, Shigemi; Araki, Yoko; Kumazawa, Shigenori

    2014-01-01

    The purpose of this study is to identify the quantity and antibacterial activity of the individual phenolic compounds in Brazilian red propolis. Quantitative analysis of the 12 phenolic compounds in Brazilian red propolis was carried out using reversed-phase high-performance liquid chromatography. The main phenolic compounds in Brazilian red propolis were found to be (3S)-vestitol (1), (3S)-neovestitol (2) and (6aS,11aS)-medicarpin (4) with quantities of 72.9, 66.9 and 30.8 mg g of ethanol extracts(- 1), respectively. Moreover, the antibacterial activities of each compound against Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa were evaluated by measuring the minimum inhibitory concentrations. In particular, compound 4 exhibited the most potent antibacterial activity among all the assayed compounds against selected bacteria, indicating that 4 is the most active compound in Brazilian red propolis extracts. Thus, Brazilian red propolis may be used as food additives and pharmaceuticals to protect against bacteria.

  20. Photocatalytic and antibacterial activity of cadmium sulphide/zinc oxide nanocomposite with varied morphology.

    PubMed

    Jana, T K; Maji, S K; Pal, A; Maiti, R P; Dolai, T K; Chatterjee, K

    2016-10-15

    Nanocomposites with multifunctional application prospects have already dragged accelerating interests of materials scientists. Here we present CdS/ZnO nanocomposites with different morphology engineering the precursor molar ratio in a facile wet chemical synthesis route. The materials were structurally and morphologically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX) and high-resolution transmission electron microscopy (HRTEM). The growth mechanism of the composite structure with varying molar ratio is delineated with oriented attachment self assemble techniques. Photocatalytic activity of CdS/ZnO nanocomposites with varying morphology were explored for the degradation of rhodamine B (RhB) dye in presence of visible light irradiation and the results reveal that the best catalytic performance arises in CdS/ZnO composite with 1: 1 ratio. The antibacterial efficiency of all nanocomposites were investigated on Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia without light irradiation. Antibacterial activity of CdS/ZnO nanocomposites were studied using the bacteriological test-well diffusion agar method and results showed significant antibacterial activity in CdS/ZnO composite with 1:3 ratio. Overall, CdS/ZnO nanocomposites excel in different potential applications, such as visible light photocatalysis and antimicrobial activity with their tuneable structure.

  1. Antibacterial activities of selected edible plants extracts against multidrug-resistant Gram-negative bacteria

    PubMed Central

    2013-01-01

    Background In response to the propagation of bacteria resistant to many antibiotics also called multi-drug resistant (MDR) bacteria, the discovery of new and more efficient antibacterial agents is primordial. The present study was aimed at evaluating the antibacterial activities of seven Cameroonian dietary plants (Adansonia digitata, Aframomum alboviolaceum, Aframomum polyanthum, Anonidium. mannii, Hibiscus sabdarifa, Ocimum gratissimum and Tamarindus indica). Methods The phytochemical screening of the studied extracts was performed using described methods whilst the liquid broth micro dilution was used for all antimicrobial assays against 27 Gram-negative bacteria. Results The results of the phytochemical tests indicate that all tested extracts contained phenols and triterpenes, other classes of chemicals being selectively present. The studied extracts displayed various degrees of antibacterial activities. The extracts of A. digitata, H. sabdarifa, A. polyanthum, A. alboviolaceum and O. gratissimum showed the best spectra of activity, their inhibitory effects being recorded against 81.48%, 66.66%, 62.96%, 55.55%, and 55.55% of the 27 tested bacteria respectively. The extract of A. polyanthum was very active against E. aerogenes EA294 with the lowest recorded minimal inhibitory concentration (MIC) of 32 μg/ml. Conclusion The results of the present work provide useful baseline information for the potential use of the studied edible plants in the fight against both sensitive and MDR phenotypes. PMID:23837916

  2. Antioxidant and Antibacterial Activities of Crude Extracts and Essential Oils of Syzygium cumini Leaves

    PubMed Central

    Mohamed, Amal A.; Ali, Sami I.; El-Baz, Farouk K.

    2013-01-01

    This research highlights the chemical composition, antioxidant and antibacterial activities of essential oils and various crude extracts (using methanol and methylene chloride) from Syzygium cumini leaves. Essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS).The abundant constituents of the oils were: α-pinene (32.32%), β-pinene (12.44%), trans-caryophyllene (11.19%), 1, 3, 6-octatriene (8.41%), delta-3-carene (5.55%), α-caryophyllene (4.36%), and α-limonene (3.42%).The antioxidant activities of all extracts were examined using two complementary methods, namely diphenylpicrylhydrazyl (DPPH) and ferric reducing power (FRAP). In both methods, the methanol extract exhibited a higher activity than methylene chloride and essential oil extracts. A higher content of both total phenolics and flavonoids were found in the methanolic extract compared with other extracts. Furthermore, the methanol extract had higher antibacterial activity compared to methylene chloride and the essential oil extracts. Due to their antioxidant and antibacterial properties, the leaf extracts from S. cumini may be used as natural preservative ingredients in food and/or pharmaceutical industries. PMID:23593183

  3. Antioxidant and antibacterial activities of crude extracts and essential oils of Syzygium cumini leaves.

    PubMed

    Mohamed, Amal A; Ali, Sami I; El-Baz, Farouk K

    2013-01-01

    This research highlights the chemical composition, antioxidant and antibacterial activities of essential oils and various crude extracts (using methanol and methylene chloride) from Syzygium cumini leaves. Essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS).The abundant constituents of the oils were: α-pinene (32.32%), β-pinene (12.44%), trans-caryophyllene (11.19%), 1, 3, 6-octatriene (8.41%), delta-3-carene (5.55%), α-caryophyllene (4.36%), and α-limonene (3.42%).The antioxidant activities of all extracts were examined using two complementary methods, namely diphenylpicrylhydrazyl (DPPH) and ferric reducing power (FRAP). In both methods, the methanol extract exhibited a higher activity than methylene chloride and essential oil extracts. A higher content of both total phenolics and flavonoids were found in the methanolic extract compared with other extracts. Furthermore, the methanol extract had higher antibacterial activity compared to methylene chloride and the essential oil extracts. Due to their antioxidant and antibacterial properties, the leaf extracts from S. cumini may be used as natural preservative ingredients in food and/or pharmaceutical industries. PMID:23593183

  4. Antioxidant and antibacterial activities of crude extracts and essential oils of Syzygium cumini leaves.

    PubMed

    Mohamed, Amal A; Ali, Sami I; El-Baz, Farouk K

    2013-01-01

    This research highlights the chemical composition, antioxidant and antibacterial activities of essential oils and various crude extracts (using methanol and methylene chloride) from Syzygium cumini leaves. Essential oils were analyzed by gas chromatography-mass spectrometry (GC-MS).The abundant constituents of the oils were: α-pinene (32.32%), β-pinene (12.44%), trans-caryophyllene (11.19%), 1, 3, 6-octatriene (8.41%), delta-3-carene (5.55%), α-caryophyllene (4.36%), and α-limonene (3.42%).The antioxidant activities of all extracts were examined using two complementary methods, namely diphenylpicrylhydrazyl (DPPH) and ferric reducing power (FRAP). In both methods, the methanol extract exhibited a higher activity than methylene chloride and essential oil extracts. A higher content of both total phenolics and flavonoids were found in the methanolic extract compared with other extracts. Furthermore, the methanol extract had higher antibacterial activity compared to methylene chloride and the essential oil extracts. Due to their antioxidant and antibacterial properties, the leaf extracts from S. cumini may be used as natural preservative ingredients in food and/or pharmaceutical industries.

  5. Structure elucidation of β-sitosterol with antibacterial activity from the root bark of Malva parviflora.

    PubMed

    Ododo, Mesfin Medihin; Choudhury, Manash Kumar; Dekebo, Ahmed Hussen

    2016-01-01

    The powder of root bark of Malva parviflora (Malvaceae) was successively extracted with petroleum ether (b.p. 60-80 °C), chloroform and ethanol. The chloroform extract showed antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the ethanolic extract showed antibacterial activity against only S. aureus. The chloroform extract, after column chromatographic separation on silica gel using petroleum ether:chloroform (3:1) as eluent, furnished 98 mg of white crystalline compound. The yield of the compound is 0.316 % (w/w). The compound has a melting point of 134-136 °C and the Rf value 0.56 in benzene:chloroform:acetone (1:15:1) on silica gel TLC. The compound was characterized as β-sitosterol by physical properties, chemical test, spectral analysis (FTIR, NMR and MS) and comparing the data obtained from the literature.

  6. Structure elucidation of β-sitosterol with antibacterial activity from the root bark of Malva parviflora.

    PubMed

    Ododo, Mesfin Medihin; Choudhury, Manash Kumar; Dekebo, Ahmed Hussen

    2016-01-01

    The powder of root bark of Malva parviflora (Malvaceae) was successively extracted with petroleum ether (b.p. 60-80 °C), chloroform and ethanol. The chloroform extract showed antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the ethanolic extract showed antibacterial activity against only S. aureus. The chloroform extract, after column chromatographic separation on silica gel using petroleum ether:chloroform (3:1) as eluent, furnished 98 mg of white crystalline compound. The yield of the compound is 0.316 % (w/w). The compound has a melting point of 134-136 °C and the Rf value 0.56 in benzene:chloroform:acetone (1:15:1) on silica gel TLC. The compound was characterized as β-sitosterol by physical properties, chemical test, spectral analysis (FTIR, NMR and MS) and comparing the data obtained from the literature. PMID:27516948

  7. Decoction, infusion and hydroalcoholic extract of cultivated thyme: antioxidant and antibacterial activities, and phenolic characterisation.

    PubMed

    Martins, Natália; Barros, Lillian; Santos-Buelga, Celestino; Silva, Sónia; Henriques, Mariana; Ferreira, Isabel C F R

    2015-01-15

    Bioactivity of thyme has been described, but mostly related to its essential oils, while studies with aqueous extracts are scarce. Herein, the antioxidant and antibacterial properties of decoction, infusion and hydroalcoholic extract, as also their phenolic compounds, were evaluated and compared. Decoction showed the highest concentration of phenolic compounds (either phenolic acids or flavonoids), followed by infusion and hydroalcoholic extract. In general, the samples were effective against gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and gram-negative (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Enterococcus aerogenes, Proteus vulgaris and Enterobacter sakazakii) bacteria, with decoction presenting the most pronounced effect. This sample also displayed the highest radical scavenging activity and reducing power. Data obtained support the idea that compounds with strong antioxidant and antibacterial activities are also water-soluble. Furthermore, the use of thyme infusion and decoction, by both internal and external use, at recommended doses, is safe and no adverse reactions have been described.

  8. Decoction, infusion and hydroalcoholic extract of cultivated thyme: antioxidant and antibacterial activities, and phenolic characterisation.

    PubMed

    Martins, Natália; Barros, Lillian; Santos-Buelga, Celestino; Silva, Sónia; Henriques, Mariana; Ferreira, Isabel C F R

    2015-01-15

    Bioactivity of thyme has been described, but mostly related to its essential oils, while studies with aqueous extracts are scarce. Herein, the antioxidant and antibacterial properties of decoction, infusion and hydroalcoholic extract, as also their phenolic compounds, were evaluated and compared. Decoction showed the highest concentration of phenolic compounds (either phenolic acids or flavonoids), followed by infusion and hydroalcoholic extract. In general, the samples were effective against gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and gram-negative (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Enterococcus aerogenes, Proteus vulgaris and Enterobacter sakazakii) bacteria, with decoction presenting the most pronounced effect. This sample also displayed the highest radical scavenging activity and reducing power. Data obtained support the idea that compounds with strong antioxidant and antibacterial activities are also water-soluble. Furthermore, the use of thyme infusion and decoction, by both internal and external use, at recommended doses, is safe and no adverse reactions have been described. PMID:25148969

  9. Synthesis of biscoumarin and dihydropyran derivatives with promising antitumor and antibacterial activities.

    PubMed

    Li, Jing; Sui, Yun-Peng; Xin, Jia-Jia; Du, Xin-Liang; Li, Jiang-Tao; Huo, Hai-Ru; Ma, Hai; Wang, Wei-Hao; Zhou, Hai-Yu; Zhan, Hong-Dan; Wang, Zhu-Ju; Li, Chun; Sui, Feng; Li, Xia

    2015-12-01

    Two series of biscoumarin (1-3) and dihydropyran (4-12) derivatives were successfully synthesized as new antitumor and antibacterial agents. The molecular structures of four representative compounds 2, 4, 7 and 10 were confirmed by single crystal X-ray diffraction study. The synthesized compounds (1-12) were evaluated for their antitumor activities against human intestinal epithelial adenocarcinoma cell line (HuTu80), mammary adenocarcinoma cell line (4T1) and pancreatic cancer cell line (PANC1) and antibacterial activities against one drug-sensitive Staphylococcus aureus (S. aureus ATCC 29213) strain and three MRSA strains (MRSA XJ 75302, Mu50, USA 300 LAC). The further mechanism study demonstrated that the most potent compound 1 could obviously inhibit the proliferation of cancer cells via the mechanism to induce apoptosis.

  10. Cellulase-assisted extraction of polysaccharides from Cucurbita moschata and their antibacterial activity.

    PubMed

    Qian, Zhi-Gang

    2014-01-30

    In this study, cellulase-assisted extraction of water soluble polysaccharides from pumpkin (Cucurbita moschata) and their antibacterial activity were investigated. The polysaccharides yield was monitored during the extraction process. The optimum extraction conditions were determined as follows: time, 40 min; temperature, 55°C; pH, 4.5; and cellulase amount, 4,000 U/g. The extracts were centrifuged, filtered, proteins removed by Sevag method, concentrated to approximately 15% (w/v), precipitated with 5 volumes of absolute ethanol, freeze-dried, and pulverized to yield a water soluble powder of pumpkin polysaccharides (PP). The sugar content of the product was 68.3%, and the yield was 17.34% (w/w), respectively. The PP had high antibacterial activity against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli at the concentration of 100 mg/mL.

  11. Design, recombinant expression, and antibacterial activity of the cecropins-melittin hybrid antimicrobial peptides.

    PubMed

    Cao, Yu; Yu, Rong Qing; Liu, Yi; Zhou, Huo Xiang; Song, Ling Ling; Cao, Yi; Qiao, Dai Rong

    2010-09-01

    In order to evaluate their antibacterial activities and toxicities, the cecropins-melittin hybrid antimicrobial peptide, CA(1-7)-M(4-11) (CAM) and CB(1-7)-M(4-11) (CBM), were designed by APD2 database. The recombinant hybrid antimicrobial peptides were successfully expressed and purified in Pichia pastoris. Antimicrobial activity assay showed that both of the two hybrid antimicrobial peptides had strong antibacterial abilities against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus subtilis, Bacillus thuringiensis, and Salmonella derby. The potency of CAM and CBM to E. coli 25922 were 0.862 and 0.849, respectively, slightly lower than Amp's 0.957. The hemolytic assays indicated CAM and CBM had no hemolytic in vivo and in vitro, and so they had a good application prospect. PMID:20111863

  12. Cellulase-assisted extraction and antibacterial activity of polysaccharides from the dandelion Taraxacum officinale.

    PubMed

    Wang, Hong-Bin

    2014-03-15

    In the present study, we investigated the cellulase-assisted extraction and antibacterial activity of water-soluble polysaccharides from the dandelion Taraxacum officinale. The extraction conditions, optimized for improving yield, were as follows: time, 46.11 min; temperature, 54.87 °C; pH, 4.51 and cellulase enzyme, 4000 U/g. Under these conditions, the yield of polysaccharides from dandelion (PD) reached 20.67% (w/w). The sugar content of PD was 95.6% (w/w), and it displayed high antibacterial activity at a concentration of 100mg/mL against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. These results indicate that PD may be a viable option for use as a food preservative.

  13. Synthesis, photoluminescent, antibacterial activities and theoretical studies of 4-hydroxycoumarin derivatives

    NASA Astrophysics Data System (ADS)

    Li, Jing; Hou, Zheng; Li, Fen; Zhang, Zi-dan; Zhou, Ying; Luo, Xiao-xing; Li, Ming-kai

    2014-10-01

    Two new biscoumarin and epoxydicoumarin derivatives, namely, 3,3‧-(4-di-p-tolyl-amino-benzylidene)-bis-(4-hydroxycoumarin) (DBH) and 9-(4-di-p-tolyl-amino-phenyl)-1,8-dioxo-9H-dibenzo[c,h]-2,7,10-trioxanthene (DDT), were synthesized and characterized via IR, 1H NMR, HRMS, single crystal X-ray crystallography and UV-vis absorption spectra. The fluorescence behaviors of DBH and DDT in dichloromethane solutions were observed. The in vitro antibacterial activity of DBH and DDT against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) was evaluated by observing the minimum inhibitory concentration. The results showed that compared with compound DDT, DBH exhibited better potent antibacterial activity.

  14. Constructing MnO2/single crystalline ZnO nanorod hybrids with enhanced photocatalytic and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Yu, Weiwei; Liu, Tiangui; Cao, Shiyi; Wang, Chen; Chen, Chuansheng

    2016-07-01

    In order to improve the photocatalytic and antibacterial activity of ZnO nanorods, ZnO nanorods decorated with MnO2 nanoparticles (MnO2/ZnO nanorod hybrids) were prepared by using microwave assisted coprecipitation method under the influence of hydrogen peroxide, and the structure, photocatalytic activity and antibacterial property of the products were studied. Experimental results indicated that MnO2 nanoparticles are decorated on the surface of single crystalline ZnO nanorods. Moreover, the resultant MnO2/ZnO nanorod hybrids have been proven to possess good photocatalytic and antibacterial activity, which their degradated efficiency for Rhodamin B (RhB) is twice as the pure ZnO nanorods. Enhancement for photocatalytic and antibacterial activity is mainly attributed to the low band gap energy and excellent electrochemical properties of MnO2 nanoparticles.

  15. Diversity and antibacterial activities of fungi derived from the Gorgonian Echinogorgia rebekka from the South China Sea.

    PubMed

    Wang, Ya-Nan; Shao, Chang-Lun; Zheng, Cai-Juan; Chen, Yi-Yan; Wang, Chang-Yun

    2011-01-01

    The diversity of symbiotic fungi associated with the gorgonian coral Echinogorgia rebekka from the Weizhou coral reef in the South China Sea was investigated. Combined with morphologic traits, ITS-rDNA sequences revealed 18 fungal strains from this gorgonian. All of the 18 fungi belonged to the phylum Ascomycota and were distributed among seven genera in five orders: Eurotiales (Aspergillus and Penicillium), Pleosporales (Alternaria), Capnodiales (Cladosporium), Trichosphaeriales (Nigrospora) and Hypocreales (Hypocrea and Nectria). Antibacterial activities of these fungal strains were investigated with five pathogenic bacteria. All of the 18 fungal strains displayed different levels of antibacterial activities, most of which exhibited moderate to high antibacterial activities to the Gram-positive pathogens Staphylococcus aureus and Micrococcus tetragenus, and showed relatively low bioactivities to other three pathogenic bacteria. Several fungal strains in the genera Penicillium and Cladosporium with strong antibacterial activities provide potential for further research on isolation of bioactive secondary metabolites.

  16. Antibacterial activity against Clostridium genus and antiradical activity of the essential oils from different origin.

    PubMed

    Kačániová, Miroslava; Vukovič, Nenad; Horská, Elena; Salamon, Ivan; Bobková, Alica; Hleba, Lukáš; Fiskelová, Martina; Vatľák, Alexander; Petrová, Jana; Bobko, Marek

    2014-01-01

    In the present study, the antimicrobial and antiradical activities of 15 essential oils were investigated. The antimicrobial activities were determined by using agar disc diffusion and broth microdilution methods against Clostridium genus and antioxidant properties of essential oils by testing their scavenging effect on DPPH radicals activities. We determined the antibacterial activity of Clostridium butyricum, Clostridium hystoliticum, Clostridium intestinale, Clostridium perfringens and Clostridium ramosum. We obtained the original commercial essential oils samples of Lavandula angustifolia, Carum carvi, Pinus montana, Mentha piperita, Foeniculum vulgare Mill., Pinus sylvestris, Satureia montana, Origanum vulgare L. (2 samples), Pimpinella anisum, Rosmarinus officinalis L., Salvia officinalis L., Abies alba Mill., Chamomilla recutita L. Rausch and Thymus vulgaris L. produced in Slovakia (Calendula a.s., Nova Lubovna, Slovakia). The results of the disk diffusion method showed very high essential oils activity against all tested strains of microorganisms. The best antimicrobial activity against C. butyricum was found at Pimpinella anisum, against C. hystoliticum was found at Pinus sylvestris, against C. intestinale was found at Satureia hortensis L., against C. perfringens was found at Origanum vulgare L. and against C. ramosum was found at Pinus sylvestris. The results of broth microdilution assay showed that none of the essential oils was active against C. hystoliticum. The best antimicrobial activity against C. butyricum was found at Abies alba Mill., against C. intestinale was found at Abies alba Mill., against C. perfringens was found at Satureia montana and against C. ramosum was found at Abius alba and Carum carvi. Antioxidant DPPH radical scavenging activity was determined at several solutions of oil samples (50 μL.mL(-1)-0.39 μL.mL(-1)) and the best scavenging effect for the highest concentration (50 μL.mL(-1)) was observed. The antioxidant properties

  17. Antibacterial activity against Clostridium genus and antiradical activity of the essential oils from different origin.

    PubMed

    Kačániová, Miroslava; Vukovič, Nenad; Horská, Elena; Salamon, Ivan; Bobková, Alica; Hleba, Lukáš; Fiskelová, Martina; Vatľák, Alexander; Petrová, Jana; Bobko, Marek

    2014-01-01

    In the present study, the antimicrobial and antiradical activities of 15 essential oils were investigated. The antimicrobial activities were determined by using agar disc diffusion and broth microdilution methods against Clostridium genus and antioxidant properties of essential oils by testing their scavenging effect on DPPH radicals activities. We determined the antibacterial activity of Clostridium butyricum, Clostridium hystoliticum, Clostridium intestinale, Clostridium perfringens and Clostridium ramosum. We obtained the original commercial essential oils samples of Lavandula angustifolia, Carum carvi, Pinus montana, Mentha piperita, Foeniculum vulgare Mill., Pinus sylvestris, Satureia montana, Origanum vulgare L. (2 samples), Pimpinella anisum, Rosmarinus officinalis L., Salvia officinalis L., Abies alba Mill., Chamomilla recutita L. Rausch and Thymus vulgaris L. produced in Slovakia (Calendula a.s., Nova Lubovna, Slovakia). The results of the disk diffusion method showed very high essential oils activity against all tested strains of microorganisms. The best antimicrobial activity against C. butyricum was found at Pimpinella anisum, against C. hystoliticum was found at Pinus sylvestris, against C. intestinale was found at Satureia hortensis L., against C. perfringens was found at Origanum vulgare L. and against C. ramosum was found at Pinus sylvestris. The results of broth microdilution assay showed that none of the essential oils was active against C. hystoliticum. The best antimicrobial activity against C. butyricum was found at Abies alba Mill., against C. intestinale was found at Abies alba Mill., against C. perfringens was found at Satureia montana and against C. ramosum was found at Abius alba and Carum carvi. Antioxidant DPPH radical scavenging activity was determined at several solutions of oil samples (50 μL.mL(-1)-0.39 μL.mL(-1)) and the best scavenging effect for the highest concentration (50 μL.mL(-1)) was observed. The antioxidant properties

  18. Electrochemical oxidation of fluoroquinolone antibiotics: Mechanism, residual antibacterial activity and toxicity change.

    PubMed

    Zhu, Linyan; Santiago-Schübel, Beatrix; Xiao, Hongxia; Hollert, Henner; Kueppers, Stephan

    2016-10-01

    In this paper, we studied the electrochemical oxidation mechanisms of three typical fluoroquinolone antibiotics (FQs), and investigated residual antibacterial activity and toxicity changes after oxidation processes. Electrochemistry coupled to mass spectrometry (EC-MS) was used to study the oxidation processes of ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL). Eight oxidation products for each parent compound were identified and their chemical structures were elucidated. The transformation trend of each product, with the continuous increase of voltage from 0 to 3000 mV, was recorded by online EC-MS. The oxidation pathways were proposed based on the structural information and transformation trends of oxidation products. We found the oxidation mechanisms of FQs consisted of the hydroxylation and cleavage of piperazinyl ring via reactions with hydroxyl radicals, while the fluoroquinolone core remained intact. The antibacterial activity of the parent compounds and their oxidation mixtures was estimated using zone inhibition tests for gram-negative bacteria Salmonella typhimurium. It was found that the oxidation mixtures of CIP and NOR retained the antibacterial properties with lower activity compared to their parent compounds, while the antibacterial activity of OFL was almost eliminated after oxidation. Furthermore, the toxicity of the three FQs and their oxidation mixtures were evaluated using algal growth inhibition test (Desmodesmus subspicatus). The median effective concentration (EC50) values for the algal inhibition tests were calculated for the end point of growth rate. The toxicity of CIP and NOR to green algae after electrochemical oxidation, remained unchanged, while that of OFL significantly increased. The results presented in this paper contribute to an understanding of the electrochemical oxidation mechanisms of FQs, and highlight the potential environmental risks of FQs after electrochemical oxidation processes.

  19. Electrochemical oxidation of fluoroquinolone antibiotics: Mechanism, residual antibacterial activity and toxicity change.

    PubMed

    Zhu, Linyan; Santiago-Schübel, Beatrix; Xiao, Hongxia; Hollert, Henner; Kueppers, Stephan

    2016-10-01

    In this paper, we studied the electrochemical oxidation mechanisms of three typical fluoroquinolone antibiotics (FQs), and investigated residual antibacterial activity and toxicity changes after oxidation processes. Electrochemistry coupled to mass spectrometry (EC-MS) was used to study the oxidation processes of ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL). Eight oxidation products for each parent compound were identified and their chemical structures were elucidated. The transformation trend of each product, with the continuous increase of voltage from 0 to 3000 mV, was recorded by online EC-MS. The oxidation pathways were proposed based on the structural information and transformation trends of oxidation products. We found the oxidation mechanisms of FQs consisted of the hydroxylation and cleavage of piperazinyl ring via reactions with hydroxyl radicals, while the fluoroquinolone core remained intact. The antibacterial activity of the parent compounds and their oxidation mixtures was estimated using zone inhibition tests for gram-negative bacteria Salmonella typhimurium. It was found that the oxidation mixtures of CIP and NOR retained the antibacterial properties with lower activity compared to their parent compounds, while the antibacterial activity of OFL was almost eliminated after oxidation. Furthermore, the toxicity of the three FQs and their oxidation mixtures were evaluated using algal growth inhibition test (Desmodesmus subspicatus). The median effective concentration (EC50) values for the algal inhibition tests were calculated for the end point of growth rate. The toxicity of CIP and NOR to green algae after electrochemical oxidation, remained unchanged, while that of OFL significantly increased. The results presented in this paper contribute to an understanding of the electrochemical oxidation mechanisms of FQs, and highlight the potential environmental risks of FQs after electrochemical oxidation processes. PMID:27318447

  20. Synthesis and activities of naphthalimide azoles as a new type of antibacterial and antifungal agents.

    PubMed

    Zhang, Yi-Yi; Zhou, Cheng-He

    2011-07-15

    Naphthalimide-derived azoles as a new type of antimicrobial agents were synthesized and evaluated for their efficiency in vitro against eight bacteria and two fungi by two fold serial dilution technique. Most title compounds exhibited good antimicrobial potency with low MIC values ranging from 1 to 16μg/mL. Notably, some synthesized compounds displayed comparable or even better antibacterial and antifungal activities against some tested strains than the reference drugs Orbifloxacin, Chloromycin and Fluconazole, respectively.

  1. Complex secondary metabolites from Ludwigia leptocarpa with potent antibacterial and antioxidant activities.

    PubMed

    Mabou, Florence Déclaire; Tamokou, Jean-de-Dieu; Ngnokam, David; Voutquenne-Nazabadioko, Laurence; Kuiate, Jules-Roger; Bag, Prasanta Kumar

    2016-01-01

    Diarrhea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. The aim of the present study was to evaluate the antibacterial and antioxidant activities of extracts and compounds from Ludwigia leptocarpa, a plant traditionally used for its vermifugal, anti-dysenteric, and antimicrobial properties. A methanol extract was prepared by maceration of the dried plant and this was successively extracted with ethyl acetate to obtain an EtOAc extract and with n-butanol to obtain an n-BuOH extract. Column chromatography of the EtOAc and n-BuOH extracts was followed by purification of different fractions, leading to the isolation of 10 known compounds. Structures of isolated compounds were assigned on the basis of spectral analysis and by comparison to structures of compounds described in the literature. Antioxidant activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and gallic acid equivalent antioxidant capacity (GAEAC) assays. Antibacterial activity was assessed with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) with respect to strains of a Gram-positive bacterium, Staphylococcus aureus (a major cause of community and hospital-associated infection), and Gram-negative multi-drug-resistant bacteria, Vibrio cholerae (a cause of cholera) and Shigella flexneri (a cause of shigellosis). All of the extracts showed different degrees of antioxidant and antibacterial activities. 2β-hydroxyoleanolic acid, (2R,3S,2''S)-3''',4',4''',5,5'',7,7''-heptahydroxy-3,8"-biflavanone, and luteolin-8-C-glucoside displayed the most potent antibacterial and antioxidant properties, and these properties were in some cases equal to or more potent than those of reference drugs. Overall, the present results show that L. leptocarpa has the potential to be a natural source of anti-diarrheal and antioxidant products, so further investigation is warranted. PMID:27431270

  2. Chemical composition and antibacterial activity of essential oil of Pulicaria odora L.

    PubMed

    Hanbali, Fadwa E L; Akssira, Mohamed; Ezoubeiri, Aicha; Gadhi, Chems Eddoha A; Mellouki, Fouad; Benherraf, Ahmed; Blazquez, Amparo M; Boira, Herminio

    2005-07-14

    The chemical composition of the volatile oil constituent from Pulicaria odora L. roots has been analyzed by GC/MS. Twenty-seven components were identified, being thymol (47.83%) and its derivative isobutyrate (30.05%) the main constituents in the oil. Furthermore, the oil was tested against seven bacteria at different concentrations. Results showed that the oil exhibited a significant antibacterial activity.

  3. Identification of novel aminopiperidine derivatives for antibacterial activity against Gram-positive bacteria.

    PubMed

    Lee, Hee-Yeol; An, Kyung-Mi; Jung, Juyoung; Koo, Je-Min; Kim, Jeong-Geun; Yoon, Jong-Min; Lee, Myong-Jae; Jang, HyeonSoo; Lee, Hong-Sub; Park, Soobong; Kang, Jae-Hoon

    2016-07-01

    We have previously reported amidopiperidine derivatives as a novel peptide deformylase (PDF) inhibitor and evaluated its antibacterial activity against Gram-positive bacteria, but poor pharmacokinetic profiles have resulted in low efficacy in in vivo mouse models. In order to overcome these weaknesses, we newly synthesized aminopiperidine derivatives with remarkable antimicrobial properties and oral bioavailability, and also identified their in vivo efficacy against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP). PMID:27173797

  4. Synthesis, antibacterial and cytotoxic activities of new biflorin-based hydrazones and oximes.

    PubMed

    Souza, Luciana G da S; Almeida, Macia C S; Lemos, Telma L G; Ribeiro, Paulo R V; de Brito, Edy S; Silva, Vera L M; Silva, Artur M S; Braz-Filho, Raimundo; Costa, José G M; Rodrigues, Fábio F G; Barreto, Francisco S; de Moraes, Manoel O

    2016-01-15

    Biflorin 1 is a biologically active quinone, isolated from Capraria biflora. Five new biflorin-based nitrogen derivatives were synthesized, of which two were mixtures of (E)- and (Z)- isomers: (Z)-2a, (Z)-2b, (Z)-3a, (Z)- and (E)-3b, (Z)- and (E)-3c. The antibacterial activity was investigated using the microdilution method for determining the minimum inhibitory concentration (MIC) against six bacterial strains. Tests have shown that these derivatives have potential against all bacterial strains. The cytotoxic activity was also evaluated against three strains of cancer cells, but none of the derivatives showed activity.

  5. Antibacterial Activity of Netilmicin, a New Aminoglycoside Antibiotic, Compared with That of Gentamicin

    PubMed Central

    Phillips, Ian; Smith, Anne; Shannon, Kevin

    1977-01-01

    The antibacterial activity of netilmicin (Sch 20569), a new semisynthetic aminoglycoside, was compared with that of gentamicin against a variety of gram-negative bacteria, staphylococci, and streptococci. Both antibiotics had similar activity against most organisms, but netilmicin had appreciably greater activity against gram-negative organisms that were resistant to gentamicin because these species synthesized aminoglycoside 3-N-acetyltransferase I or aminoglycoside 2″-O-nucleotidyltransferase. Netilmicin was also more active than gentamicin against gentamicin-resistant strains of Staphylococcus aureus that produced two enzymes–aminoglycoside-2″-O-phosphotransferase and aminoglycoside-6′-N-acetyltransferase. PMID:301004

  6. Antibacterial and antifungal activity of sulfur-containing compounds from Petiveria alliacea L.

    PubMed

    Kim, Seokwon; Kubec, Roman; Musah, Rabi A

    2006-03-01

    A total of 18 organosulfur compounds originating from Petiveria alliacea L. roots have been tested fo