TiO2 antifouling coating based on epoxy-modified tung oil waterborne resin

2021 ◽  
pp. 096739112110111
Author(s):  
Hailiang Hu ◽  
Minmin Chen ◽  
Mengye Cao

The eco-friendly functionalized TiO2/polymer antifouling (AF) coating was successfully synthesized by dispersing TiO2 nanoparticles in waterborne epoxy-modified tung oil resin. The AF effectiveness of coating was evaluated toward Staphylococcus aureus ( S. aureus, ATCC6538), Escherichia coli ( E. coli, ATCC8739) and diatom ( Cyclotella sp., FACHB-1635). The nanoTiO2/polymer AF coating showed good antimicrobial activity both under the light and dark conditions by comparison with the pristine TiO2 nanoparticles and bulk polymer. Under light irradiation for 50 min, the AF coating showed only 8.4% and 8% survival rate for S. aureus and E. coli. In addition, The AF coatings exhibited favorable inhibition efficacy toward the growth and adhesion of Cyclotella sp., and the efficacy was enhanced with the increase of TiO2 content. It can be concluded that TiO2 nanoparticles endow the AF coatings with promoted fouling resistance properties.

2011 ◽  
Vol 63 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Gordana Zavisic ◽  
Zeljka Radulovic ◽  
Valentina Vranic ◽  
Jelena Begovic ◽  
L. Topisirovic ◽  
...  

The aim of this study was to investigate the probiotic potential of bacteriocin-producing lactobacilli strain Lactobacillus plantarum G2 isolated from the vaginal mucus of healthy women. The antimicrobial effect of G2 was confirmed in the mixed culture with pathogenic Escherichia coli, Staphylococcus aureus, Salmonella abony and Pseudomonas aeruginosa, while bacteriocine activity was detected against S. aureus and S. abony only. The strain showed an excellent survival rate in low pH and in the presence of bile salts. The percentage of adhered cells of L. plantarum G2 to hexadecane was 63.85?2.0 indicating the intermediate hydrophobicity.


2020 ◽  
Vol 151 ◽  
pp. 15550-15558
Author(s):  
Amégninou Agban ◽  
Yao Hoekou ◽  
Passimna Pissang ◽  
Tchadjobo Tchacondo ◽  
Komlan Batawila

Objectif : L’objectif de ce travail était d’évaluer in vitro l’activité antimicrobienne des extraits de feuilles et tige de Jatropha multifida sur la croissance de Candida albicans, Escherichia coli et Staphylococcus aureus, puis d’évaluer in vivo la toxicité de cette plante. Méthodologie et résultats : Les méthodes de diffusion en milieu gélosé et de microdilution en milieu liquide ont été utilisées pour évaluer l’effet antimicrobien. Une étude en subaigüe était réalisée afin d’explorer les effets toxiques de l’extrait aqueux des feuilles. Les résultats des tests antimicrobiens montrent une activité des extraits de feuilles et tige de J. multifida sur la croissance des souches utilisées avec des diamètres de zones d’inhibition allant de 8 à 25 mm et des concentrations minimales inhibitrices (CMI) variant de 0,039 mg/mL à 1,25 mg/mL à l’exception des souches de E. coli qui sont résistantes aux extraits de la tige. L’administration en subaigüe de l’extrait aqueux des feuilles de J. multifida à la dose de 600 mg/kg entraîne une perte significative de poids chez les souris. Conclusion et applications des résultats : Les extraits aqueux, éthanolique et hydroéthanolique des feuilles et tige de J. multifida possèdent d’activité antimicrobienne et pourraient être utilisés dans le traitement des Candidoses à C. albicans et des infections à S. aureus. Mais l’essai de toxicité subaigüe montre que l’extrait aqueux de la plante serait toxique. Des études toxicologiques approfondies restent donc nécessaires sur ces extraits afin de mieux élucider leur inocuité. Mots-clés : Jatropha multifida, extraits de feuilles et de tige, activités antifongique et antibactérienne, toxicité. Agban et al., J. Appl. Biosci. 2020 Evaluation du potentiel antimicrobien et de la toxicité des extraits de Jatropha multifida Linn, (Euphorbiaceae) 15551 Evaluation of antimicrobial potential and toxicity of Jatropha multifida Linn, (Euphorbiaceae) extracts ABSTRACT Objective: The objective of this study was to evaluate in vitro the antimicrobial activity of leaves and stem of Jatropha multifida extracts against Candida albicans, Escherichia coli and Staphylococcus aureus, and then to evaluate in vivo the toxicity of this plant. Methodology and Results: The agar well-diffusion and the NCCLS broth microdilution methods were used to assess the antimicrobial effect. A subacute study was carried out to explore the toxic effects of the aqueous extract of the leaves. The results of the antimicrobial tests show an activity of the extracts of leaves and stems of J. multifida on the growth of the strains used with diameters of inhibitory zones ranging from 8 to 25 mm and minimum inhibitory concentrations (MIC) varying from 0.039 mg/mL to 1.25 mg/mL exception E. coli strains which are resistant to extracts from the stem. Subacute administration of the aqueous extract of the leaves of J. multifida at a dose of 600 mg/kg leads to a significant loss of weight in the mice. Conclusion and application of findings : The aqueous, ethanolic and hydroethanolic extracts of the leaves and stem of J. multifida have antimicrobial activity and could be used in the treatment of Candidiasis and bacterial infections due respectively to C. albicans and S. aureus. But the subacute toxicity test shows that the aqueous extract of the plant would be toxic. Extensive toxicological studies therefore remain necessary on these extracts in order to better elucidate their safety. Keywords: Jatropha multifida extracts of leaves and stem, antifungal and antibacterial activities, toxicity


2020 ◽  
Vol 4 (1) ◽  
pp. 49
Author(s):  
Gracielle Oliveira Sabbag Cunha ◽  
Ana Paula Terezan ◽  
Andreia Pereira Matos ◽  
Marcela Carmen De Melo Burger ◽  
Paulo Cezar Vieira ◽  
...  

This study evaluated the antimicrobial activity of isolated compounds and semisynthetic derivatives from Miconia ferruginata (Melastomataceae) against five microorganisms: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623), Pseudomonas aeruginosa (ATCC 15442), and Candida albicans (ATCC 10231). The isomeric mixture of ursolic and oleanolic acids was active against S. aureus (MIC = 250 μg mL-1) and against E. coli, B. subtilis, and P. aeruginosa (MIC = 500 μg mL-1). The flavone 5,6,7-trihydroxy-4’-methoxyflavone and the methyl esters, semisynthetic derivatives of a mixture of ursolic and oleanolic acids, showed no activity against the tested microorganisms. These results suggest that the carboxyl group present in the triterpenes may contribute to antimicrobial activity.


2021 ◽  
Author(s):  
Mbarga Manga Joseph Arsene ◽  
Podoprigora Irina Viktorovna ◽  
Anytoulou Kitio Linda Davares ◽  
Mouafo Hippolyte Tene ◽  
Irma Aurelia Monique Manga ◽  
...  

Background and aim: The Cameroonian flora abounds in plants with multidimensional therapeutic virtues which can play an important role in the fight against resistance to antibiotics and the search for new antimicrobials. This study aimed to screen the antimicrobial potential of aqueous and ethanolic extracts of thirteen (13) samples (Bark, leaf, seed) of eight (8) plants from Cameroon against 3 reference pathogens and to evaluate their synergy with conventional antibiotics against eleven (11) multiresistant uropathogenic (MRU) bacteria. Method: Bioactive compounds were extracted from leaves of Leucanthemum vulgare, Cymbopogon citratus (DC.) Stapf, Moringa oleifera Lam and Vernonia amygdalina Delile; barks of Cinchona officinalis and Enantia chlorantha Oliv; barks and seeds of Garcinia lucida Vesque and leaves and seeds of Azadirachta indica (Neem) using distilled water and ethanol as solvents. The extracts were tested against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538 and Candida albicans 10231 using the well diffusion method and the microdilution method. The synergistic effect was assessed (using disc diffusion method and the checkerboard method) against MRU bacteria namely Achromobacter xylosoxidans 4892, Citrobacter freundii 426, Enterococcus avium 1669, Escherichia coli 1449, Klebsiella oxytoca 3003, Kocuria rizophilia. 1542, Moraxella catarrhalis 4222, Morganella morganii 1543, Pseudomonas aeruginosa 3057, Staphylococcus aureus 1449 and Streptococcus agalactiae 3984. Results: We found that distilled water extracted a more important mass of phytochemical compounds (7.9-21.2%) compared to ethanol (5.8-12.4%). Except C. officinalis and G. lucida leaves, the rest of extracts were active with inhibition diameters (ID) ranging from 5 to 36 mm. Both ethanolic (EE) and aqueous extract (AE) of E. chloranta bark (ECB) were the most active against all pathogens with the mean ID of 17 and 36 mm vs S. aureus ATCC 6538, 23 and 14 mm vs E. coli ATCC 25922 and 36 and 19 mm vs C. albicans ATCC 10231. Only the EE of E. chloranta bark (ECB) had a strong activity against all the microorganisms tested (MIC <2 mg / ml); L. vulgare leaves (LVL) and G. lucida seed (GLS) had moderate (average MIC of 8 mg/ml) while all other extracts showed very weak antimicrobial activity. In addition, the fractional inhibitory concentration (FIC) ranged from 0.125 to 0.750. No antagonism (FIC> 4) or indifference (1≤ FIC≤4) was noted between the extracts and the antibiotics, but the best synergies were found with ECB which well-modulated Kanamycin (FIC = 0.125 against S. aureus and 0.250 against E. coli), nitrofurantoin (FIC = 0.250 against S. aureus and 0.188 against E. coli) and ampicillin (FIC = 0.125 against E. coli). Similarly, compared to other extracts, ECB, LVL and GLS also well-modulated ampicillin, ceftazidime, tetracycline, nitrofurantoin, and trimethoprim against all the above-mentioned resistant uropathogenic bacteria with important increase in fold area (IFA). Conclusion: This study show that E. chlorantha bark, L. vulgare leaves G. lucida seed, have good antimicrobial activity against both bacteria (Gram positive and Gram negative) and fungi (C. albicans); and should be more investigated for their possible use to the fight against MDR and MRU microorganisms.


2021 ◽  
Vol 10 (13) ◽  
pp. e329101320579
Author(s):  
Alexandre Horácio Couto Bittencourt ◽  
Jaqueline Souza Machado ◽  
Mariana Garcia da Silva ◽  
Braz Antônio Pereira Cosenza

Devido ao aumento da resistência de patógenos humanos e animais aos medicamentos atuais, pesquisas por novos antimicrobianos têm sido incentivadas, principalmente por meio de plantas medicinais. Eugenia uniflora L., conhecida como pitangueira, é popularmente utilizada com diversas funções terapêuticas, justificando estudos nesta espécie. Assim, os objetivos deste estudo foram avaliar a atividade antibacteriana “in vitro” de extratos de folhas e cascas de Eugenia uniflora L. sobre Escherichia coli e Staphylococcus aureus. Para as etapas de triagem fitoquímica e microbiologia, foram utilizadas as metodologias usuais nessas áreas para obtenção dos extratos e avaliação da atividade antibacteriana com uso de controle positivo e negativo. Os resultados obtidos mostraram que no extrato das folhas foi verificada a presença de saponinas, flavonóides, alcalóides e taninos, enquanto na casca foram obtidos apenas saponinas e alcalóides. Os extratos da folha e da casca foram capazes de inibir o crescimento de Stapylococcus aureus apenas, promovendo halos de inibição de meio de 19,4 mm e 14,4 mm, respectivamente. As análises permitiram concluir que os extratos apresentam metabólitos secundários interessantes e de grande potencial antimicrobiano e que esses extratos foram capazes de inibir apenas as cepas de S. aureus, sendo resistentes às cepas de E. Coli.


2019 ◽  
Vol 40 (11) ◽  
pp. 1284-1286 ◽  
Author(s):  
William A. Rutala ◽  
Maria F. Gergen ◽  
Emily E. Sickbert-Bennett ◽  
Deverick J. Anderson ◽  
David J. Weber ◽  
...  

AbstractA novel disinfectant studied using an EPA protocol demonstrated sustained antimicrobial activity (ie, 3–5 log10 reduction) in 5 minutes after 24 hours for Staphylococcus aureus, vancomycin-resistant Enterococcus, Candida auris, carbapenem-resistant Escherichia coli and antibiotic-susceptible E. coli, and Enterobacter spp. Only ∼2 log10 reduction occurred with carbapenem-resistant Enterobacter spp and K. pneumoniae, and antibiotic-susceptible K. pneumoniae.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina L. Páez ◽  
Claudia M. Bazán ◽  
María E. Bongiovanni ◽  
Judith Toneatto ◽  
Inés Albesa ◽  
...  

The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. The main aim of this work was to establish the potential of the syntheticα-diimine chromium(III) and ruthenium(II) complexes (where theα-diimine ligands are bpy = 2,2-bipyridine, phen = 1,10-phenanthroline, and dppz = dipyrido[3,2-a:2′,3′-c]-phenazine) like [Cr(phen)3]3+, [Cr(phen)2(dppz)]3+, [Ru(phen)3]2+, and [Ru(bpy)3]2+as antibacterial agents by generating oxidative stress. The [Cr(phen)3]3+and [Cr(phen)2(dppz)]3+complexes showed activity against Gram positive and Gram negative bacteria with minimum inhibitory concentrations (MICs) ranging from 0.125 μg/mL to 1 μg/mL, while [Ru(phen)3]2+and [Ru(bpy)3]2+do not exhibit antimicrobial activity against the two bacterial genera studied at the concentration range used. When ciprofloxacin was combined with [Cr(phen)3]3+for the inhibition ofStaphylococcus aureusandEscherichia coli, an important synergistic effect was observed, FIC 0.066 forS. aureusand FIC 0.064 forE. coli. The work described here shows that chromium(III) complexes are bactericidal forS. aureusandE. coli. Our results indicate thatα-diimine chromium(III) complexes may be interesting to open new paths for metallodrug chemotherapy against different bacterial genera since some of these complexes have been found to exhibit remarkable antibacterial activities.


2012 ◽  
Vol 65 (4) ◽  
pp. 343 ◽  
Author(s):  
Mei Zhang ◽  
Dong-Mei Xian ◽  
Hai-Hua Li ◽  
Ji-Cai Zhang ◽  
Zhong-Lu You

A series of new halo-substituted aroylhydrazones have been prepared and structurally characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectra, and single crystal X-ray diffraction. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Among the tested compounds, N′-(2-chloro-5-nitrobenzylidene)-2-fluorobenzohydrazide showed the most effective antimicrobial activity with minimum inhibitory concentration values of 0.82, 2.5, 1.7, 15.2, and 37.5 μg mL–1 against B. subtilis, S. aureus, E. coli, P. fluorescence, and C. albicans, respectively. The biological assay indicated that the presence of the electron-withdrawing groups in the aroylhydrazones improved their antimicrobial activities.


Author(s):  
ROSALINA YULIANA AYEN ◽  
ENDANG KUSDIYANTINI ◽  
SRI PUJIYANTO

Objective: This research aimed to isolate, determine the characteristics of lactic acid bacteria (LAB) of Sui Wu’u from Bajawa, Nusa Tenggara Timur and identify LAB using 16S rRNA potential as antimicrobial activity against pathogenic bacteria. Methods: Sui Wu’u which has been stored for 6 months was obtained from Bajawa district, inoculated on de Man Rogosa-Sharpe Agar (Merck) + 0.5% CaCO3, purification of LAB, characterization of selected isolates, biochemical test, tolerance test for pH, viability to test temperature, and content NaCl, determination of antimicrobial action by the agar well disk diffusion method using antibiotic (Amoxicillin) as a control and as indicator bacteria (Staphylococcus aureus and Escherichia coli) and isolation of genomic 16S rRNA; molecular identification. Results: Based on research results obtained five isolates of LAB, Gram staining the LAB isolated from Sui Wu’u showed that the isolated bacteria (bacilli and coccus) are Gram-positive, catalase-negative and the isolates have tolerance of viability at temperatures of 10°C, 45°C, and 50°C and to salinitas of 4% and 6.5%. The inhibitory zone LAB isolates (2PKT) against E. coli bacteria (20 mm) and S. aureus (12 mm), and (2PKB) against E. coli bacteria (17 mm) and S. aureus (10 mm). The two selected isolates were identified as Lactobacillus fermentum strain HB bacteria with 100% identification value and 98.93% query cover and L. fermentum strain HT with 100% identification value and 99.23% query cover. Conclusion: L. fermentum from Sui Wu’u has antibacterial activity against Staphylococcus aureus and Escherichia coli.


1977 ◽  
Vol 40 (8) ◽  
pp. 520-522 ◽  
Author(s):  
AN LING SHIH ◽  
NATHOLYN D. HARRIS

Tripticase soy broth containing 100, 150, 200 and 400 ppm of butylated hydroxyanisole (BHA), propyl gallate, nordihydroguaiaretic acid (NDGA), or combined BHA and propyl gallate was inoculated with Escherichia coli or Staphylococcus aureus to determine the antimicrobial effect of these antioxidants. Both propyl gallate and NDGA at 400 ppm had a strong lethal effect against E. coli. BHA and the BHA-propyl gallate combination were more effective against S. aureus than against E. coli. NDGA had the strongest antimicrobial activity. Only 50 ppm of NDGA were highly inhibitory to S. aureus.


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