Antimicrobial Activity Of Different Concentrations Research Articles

The effectiveness of local action of nano oxides on wound infection

The treatment of wound-related combat injuries and antibiotic resistance require the search for new approaches to reduce the risk of infectious complications, this will increase the effectiveness of therapy and even save lives. The aim of our study was to establish the mechanism of action and effectiveness of nano oxides applied to wound infection. The antimicrobial activity of different concentrations of solutions of zinc (nZnO), magnesium (nMgO) and silicon (nSiO2) nano oxides was studied by agar diffusion against clinical antibiotic-sensitive strains of opportunistic Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), isolated from patients with purulent-septic diseases. It was found that nZnO exhibits extremely high antibacterial activity against S. aureus, E. сoli. The ultra-low content of nZnO (1.56 mg/ml) completely destroys S. aureus, unlike nMgO, the effective concentration of which exceeds the minimum by 16 times. It is known that nZnO has the highest antimicrobial properties against S. aureus and E. coli, this effectiveness is achieved due to the features of the structure and the possibility of the formation of oxygen and a number of other radicals. These qualities of nZnO make it possible to integrate it into dressings for wound treatment.

Phytochemical characterization and biological activities of Inula viscosa L. Aiton: a promising plant from Turkey

ABSTRACT The methanol extract of Inula viscosa (IVM) was investigated for its antioxidant potential using the DPPH and ABTS radical scavenging as well as iron chelating assays (ICA). The total phenol (TPC) and flavonoid contents (TFC) of IVM were determined using the Folin-Ciocalteu and aluminum trichloride methods, respectively. Antimicrobial activity of different concentrations of I. viscosa methanol extract was investigated by disc diffusion and broth microdilution method. The IVM extract was found to be containing TPC (236.78 ± 7.63 mg GAE/g) and TFC (94.36 ± 1.86 mg QE/g). Antioxidant activity IC50 values for the DPPH, ABTS and ICA assays were found to be 277.7 ± 3.68, 2.44 ± 0.02, and 222.1 ± 0.71 µg/mL, respectively. The MIC values of the IVM on the tested microorganisms ranged from 0.48 to 7.81 mg/mL. Furthermore, IVM extract was demonstrated 18.32 ± 1.37%, 23.06 ± 1.05%, 4.72 ± 0.13%, 15.13 ± 0.37% and 37.64 ± 4.02% inhibition against tyrosinase, α-amylase, α-glucosidase, AChE and BChE, respectively. In the results of LC-MS/MS analysis, acacetin, quercetin, chlorogenic acid and protocatechuic acid were determined as most dominant compounds. These findings suggested that this plant may be a natural resource for creating novel medicinal compounds.

Phytochemical Analysis and Antibacterial Studies of Some Yemeni Medicinal Plants against Selected Common Human Pathogenic Bacteria

In traditional medicine, medicinal plants are often used to treat a wide range of infectious diseases in humans. Objective: The aim of this study was to identify the phytochemicals contained in thirteen parts of six Yemeni medicinal plants: Artemisia Judaica, Ficus carica L., Nerium oleander L., Olea europaea, Santolina chamaecyparissus L. and Withania somnifera and to investigate the antimicrobial activity of different concentrations of methanol extracts from the aerial part of the selected plants against S. saprophyticus, Salmonella and E. coli in vitro. Methods: Phytochemical screening was carried out using standard procedures and the antibacterial activity of different extracts of each plant was studied by agar well diffusion method. Results: Phytochemical analysis of the plant extracts revealed the presence of phenols, saponins, essential oils, flavonoids, steroids, tannins, cardiac glycosides and alkaloids. The occurrence of phytochemicals varied from plant to plant. Tannins and phenols were found in all samples, while all other test samples contained at least five of the phytochemicals tested. Almost all extracts were able to inhibit the growth of the bacterial strains, with the exception of the species S. saprophyticus, which was resistant to the methanolic extracts of A. judaica and F. carica L. However, the methanol extract (0.1 g/ml) of S. chamaecyparissus L. and O. europaea showed the largest zone of inhibition (35 mm and 20 mm, respectively) against S. saprophyticus. This is the first report on the antibacterial activity of S. chamaecyparissus L. species against S. saprophyticus. Conclusions: The present screening result shows that the methanol extract of the tested traditional Yemeni medicinal plants exhibits potent antibacterial activity, and the studied plants may represent a new source for the discovery of novel antibacterial compounds for the treatment of drug-resistant human pathogens.

Green Synthesis and Characterization of Copper Nanoparticles Using Urginea wightii and its Biological Activities

Objectives: To investigate the potential of copper and copper oxide nanoparticles synthesized from the bulb extract of Urginea wightii (U. wightii). Methods: Copper and copper oxide nanoparticles (Cu-Cu2O NPs) were synthesized by the reduction method and were characterized by using UV-vis spectroscopy, FTIR, XRD, SEM, and EDX. Antioxidant activity was calculated by DPPH and ABTS method. In vitro antimicrobial activity by agar well diffusion method and cytotoxic activities by MTT assay. Findings: The presence of Cu-Cu2O NPs was confirmed by visible colour change, XRD pattern showed distinctive peaks corresponding to 110, 111, 200, 220, and 222 planes revealing the crystalline nature; FTIR spectra showed the presence of different functional groups such as alcohol (OH-stretch), alkene (C=C stretching) and amines (NH bending), etc. SEM studies revealed the morphological and structural characteristics of biosynthesized NPs and the percentage of inhibition was 92% and 90% at 100 mg/mL respectively. Further studies of in vitro antimicrobial activity of different concentrations of Cu-Cu2O NPs of U. wightii, showed the highest inhibition zone against Pseudomonas aeruginosa (22 mm). The NPs exhibited cytotoxic activity against the A549 lung cancer cell line in a dose-dependent manner with IC50 of 83.629 mg/mL. Novelty: This study showed that Cu-Cu2O NPs synthesized from U. wightii are a good antioxidant agent, potent antimicrobial, and cytotoxicity, hence can be used in clinical therapeutic applications. Keywords: Urginea wightii; green synthesis; antioxidant; antimicrobial; cytotoxicity

Synthesis and Characterization of Copper Oxide Nanoparticles from Aqueous Extract of Cyanotis tuberosa (Roxb.) Schult. & Schult. F. and Analysis of Antioxidant, Antimicrobial and Anticancer Activity

Cyanotis tuberosa (Roxb.) Schult. & Schult.f family Commelinaceae is traditionally used as ethnomedicine for curing several health problems in India. In this study copper oxide CuONPs were synthesized using C. tuberosa tubers aqueous extract. The biosynthesized CuONPs were characterized using an Ultra violet–visible spectroscopy, Fourier-Transform Infra Red spectroscopy, X-RAY Diffraction Analysis, Scanning electron microscopy. The results obtained from SEM showed that the copper oxide nanoparticles were a face-centered cubic crystal structure. The characterization of the biosynthesized CuONPs through EDS also indicated that the reaction product was composed of highly pure CuO NPs. The invitro antimicrobial activity of different concentrations of green synthesized copper oxide nanoparticles of C. tuberosa showed that the highest inhibition zone was observed on Klebsiella pneumonia (15.25 mm). Furthermore, the antioxidant activity of green synthesized CuONPs of C. tuberosa tubers aqueous extract was also tested the highest percentage activity was exhibited at 100 μg/ml CuONPs (56.32). The human cancer cell line was used for cytotoxicity analysis at 48 hrs of incubation period, a significant abatement in cell viability was observed against the treated cell lines. The study concludes that the C. tuberosa tubers aqueous extract can be successfully used for the synthesis of CuONPs that exhibit effective in vitro anti-bacterial, antioxidant and anticancer activity.

Synergetic Effect of Green Tea Aqueous and Alcoholic Extracts with Ciprofloxacin Against some Standard bacterial Strains: In vitro study

Resistance to commonly-prescribed antibiotics is a global public health problem. Unfortunately resistance has been reported even to newer, potent and expensive antimicrobial agents thus, it necessary to find alternative treatment, such as medicinal plants either alone or in combination with antibiotics due to their fewer reported side effects moreover, their possible affordability and availability. Green Tea (GT) has potential benefits in many aspects most notably in cardiovascular diseases, cancer and obesity. The present study designed to investigate the antimicrobial activity of different concentrations of GT aqueous and alcoholic extracts against standard strains of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Moreover, this study provides novel findings about the synergetic activity of GT alcoholic extract and Ciprofloxacin against Staphylococcus aureus ATCC 25923. Two standard antimicrobial susceptibility procedures were used, well diffusion method and broth dilution technique. The clear inhibition zone diameter (IZD) of each extract was measured. The results obtained showed that the GT alcoholic extract had promising antibacterial activity against S. aureus ATCC 25923 only whereas, the two tested strains were resistant to all concentrations of GT aqueous extract. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of the GT alcoholic extract against S. aureus ATCC 25923 were 225 mg/ml and 250 mg/ml respectively. Moreover, sub-MIC (200mg/ml) of GT alcoholic extract increased the IZD of Ciprofloxacin against S. aureus ATCC 25923 by 62.5 % which confirmed the synergistic effect. Finally, further studies in the GT with other organic solvents are of paramount importance and highly recommended.

Evaluation of the Effectiveness of Nine Brands of Toothpaste on Streptococcus mutans Isolated from the Mouth of Students in Veritas University, Abuja

Dental caries is an infectious microbiological disease of the teeth that end up in the destruction of dental hard tissues. The use of toothpaste has been used to reduce the bacterial load in the mouth because they contain antimicrobial properties such as triclosan, fluoride, and so on. The study aimed to determine the effect of nine brands of toothpaste on Streptococcus mutans isolated from the mouth of students in veritas university. Following the isolation of Streptococcus mutans from samples collected from the mouths of Veritas students’, the antimicrobial activity of different concentrations of the dentifrices was determined by modified agar well diffusion method. In this method, Muller Hinton agar plates were seeded with a loop full of 24-hour cultures of the bacterial isolate. A sterile 8 mm cork-borer was used to cut one central and five wells at equidistance in each of the plates. 0.3 ml of the dentifrice dilutions was introduced into each of the five wells while the same amount of sterile distilled water was introduced into the first well as control. The plates were incubated at 37°C for 24 hours. The antimicrobial activity was evaluated by measuring the diameter of zones of inhibition (in mm). The diameter in which the bacteria were inhibited was indicative of the toothpaste’s antibacterial potential. The zones of inhibition on the growth of the test strain were defined by the location where visible growth had been inhibited. All the plates were made in triplicates and the experiments repeated twice. The result showed that Mentadent-P was the most effective dentifrice with an inhibition zone of 2.8 mm, Pepsodent had inhibition zone of 2.6 mm, Oral B with 2.3 mm, Close up with 2.2 mm, followed by Colgate with a diameter of 1.9 mm, Special Lucky with a diameter of 1.6 mm, Darbur Promise with a diameter of 1.6 mm, Maclean’s with a zone of inhibition of 1.5 mm, and MY- MY with the least effective toothpaste with a zone of inhibition of 1.0 mm in diameter. The results also showed that toothpaste containing fluoride as their main antimicrobial agent proved more effective against streptococcusmutans than other toothpaste not containing fluoride as their main antimicrobial agent.

Photo-Activated Carbon Dots for Combating Drug Resistant Bacteria

Bacterial infections are the major cause of infectious diseases and mortality. Antibiotics have been used as an effective treatment method because of the cost and their powerful effects. However, the widespread and the abuse of antibiotics have led to the emergence of many drug resistant bacterial strains. The crisis of bacterial resistance has promoted the global search for novel and effective alternative therapies to complement or replace existing antibiotics/antimicrobial treatments. This research focused on the assessment of the newly explored carbon dots (CDots) as a class of visible light activated antimicrobial agents against multidrug-resistant (MDR) bacteria, using different strains of MDR Enterococci (BM 46, BM 29, and 9756) and non drug-resistant strain (9144) as models, the antimicrobial activity of different concentrations of CDots were evaluated using the log reduction in viable cell number compared to the untreated controls. Several factors including treatment time, buffer, and light intensity were also investigated to examine their effects on the antimicrobial effectiveness of CDots. The study also explored the mechanism of action of CDots’ antimicrobial activity. The results indicated the intracellular reactive oxygen species (ROS) levels in bacteria increased dramatically upon CDots treatment, with ~290% to ~400% increases in tested Enterococcus strains. The addition of radical scavengers, L-Histidine, significantly protected cells from the antimicrobial activity of CDots, while tert-Butanol did not perceivably protect cells from inactivation by CDots, indicating that singlet oxygen is the primary ROS species generated by CDots treatment. The generation of ROS also caused lipid peroxidation in bacteria cells. Live and Dead staining assay and TEM imaging indicated increased cell membrane permeability and cytoplasmic disruption upon CDots treatment. Acknowledgement: The research was supported by NSF grants DMR# 1701399 and the NIH grant R15GM114752.

Synergistic effects of LFchimera and antibiotic against planktonic and biofilm form of Aggregatibacter actinomycetemcomitans.

Adjunctive use of antibiotics in periodontal treatment have limitations and disadvantages including bacterial resistance. Antimicrobial peptides (AMPs) are potential new agents that can combat bacterial infection. In this study, antimicrobial activity of different concentrations of conventional antibiotics minocycline (MH), doxycycline (DOX), and antimicrobial peptides LL-37, LL-31, Lactoferrin chimera (LFchimera) and Innate Defense Regulator Peptide 1018 (IDR-1018) against Aggregatibacter actinomycetemcomitans ATCC 43718 were determined using colony culturing assay. Subsequently, in vitro activity of the most effective drug and peptide combination was evaluated by checkerboard technique. Impact of the drug and peptide co-administration on biofilm at different stages, i.e., during adhesion and 1-day old biofilm was compared to each of the agents used alone. Results revealed that the killing effects of all AMPs range from 13–100%. In contrast, MH and DOX at 1 and 5 μM showed no killing activity and instead stimulated growth of bacteria. DOX has better killing activity than MH. LFchimera displayed the strongest killing amongst the peptides. Checkerboard technique revealed that combining DOX and LFchimera yielded synergism. Confocal laser scanning microscopy further showed that the combination of DOX and LFchimera caused significant reduction of bacterial adhesion and reduction of biomass, average biofilm thickness and substratum biofilm coverage of 1-day old biofilm compared to DOX and LFchimera alone. In conclusion, LFchimera alone and in combination with DOX exhibited strong antibacterial and anti-biofilm property against A. actinomycetemcomitans. The findings suggest that LFchimera should be considered for development as a new potential therapeutic agent that may be used as an adjunctive treatment for periodontitis.

Antimicrobial activity of the hydroalcoholic extract of Piper angustifolium (Piperaceae) on Proteus mirabilis

The aim of the present investigation was to determine the antimicrobial activity of different concentrations of hydroalcoholic extract of Piper angustifolium “matico” leaves on the growth of Proteus mirabilis under laboratory conditions. To obtain the hydroalcoholic extract of P. angustifolium leaves, Soxhlet equipment with 95% ethyl alcohol was used; dilutions were made with Tween 80 (10, 15, 20, 25 and 30 mg / ml). To evaluate the microbial activity of the extract, the Kirby-Bauer method with 0.7 mm Watman No. 4 paper discs was used, using five discs for each of the concentration, using ciprofloxacin as a positive control and a negative control (Tween 80), the plates were incubated at 37 ° C for 24 hours, after which time the diameters (mm) of the inhibition zones were measured. The highest inhibition halo (18.7 mm) was obtained at the highest concentration, finding a directly proportional effect between the concentration of the extract and the antimicrobial activity. The results showed significant differences between the different concentrations used.

Antimicrobial activity of the ethanolic extract of propolis against bacteria that cause mastitis in cattle

A própolis é uma substância coletada por abelhas, especialmente pela Apis mellifera, a partir de resinas de brotos de plantas que possuem numerosas propriedades biológicas, como antimicrobiana e antiinflamatória. Atividades como a pecuária leiteira orgânica apresentam alta demanda por produtos naturais com propriedades como as presentes na própolis, uma vez que a contaminação do leite e a mastite são grandes problemas da indústria de laticínios. O objetivo deste trabalho foi avaliar a atividade antimicrobiana in vitro do extrato etanólico de própolis (EEP) em diferentes concentrações. Ação do EEP extraído de colmeias no sul do Brasil foi testada contra 13 diferentes gêneros de agentes bacterianos causadores de mastite em bovinos leiteiros. O experimento foi conduzido no laboratório de Parasitologia e Microbiologia da Universidade Federal do Pampa, Campus Dom Pedrito – RS, durante os meses de maio e junho de 2016. Seguiram-se as técnicas de difusão em ágar e microdiluição em placas. Através dos resultados do teste de concentração inibitória mínima (CIM), pode-se afirmar que o EEP possui atividade inibitória em 100% das bactérias testadas em concentrações acima de 10% (p/v). Tais resultados mostram que a própolis apresenta potencial antimicrobiano frente as principais bactérias envolvidas nos processos de mastite.

Assessment of antimicrobial activity of different concentrations of Tinospora cordifolia against Streptococcus mutans: An in vitro study

The antimicrobial property of Tinospora cordifolia has been tested against a variety of microorganisms in the literature. The present study aimed to assess the antimicrobial activity of different concentrations of commercially available T. cordifolia powder against Streptococcus mutans. An in vitro study was undertaken in which extract of T. cordifolia was obtained using 100% ethanol by maceration. Seven different concentrations were prepared and tested against S. mutans in brain-heart infusion agar medium. Plates were incubated aerobically at 37°C for 48 h, and zone of inhibition was measured using Vernier caliper. 0.2% chlorhexidine and dimethylformamide were used as positive and negative controls respectively. The data were analysed by descriptive analytic tests. The maximum antibacterial activity of T. cordifolia was observed with a volume of 40 μl at 2% concentration with a zone of inhibition of 19 mm. A 30 μl volume of 0.2% chlorhexidine showed a zone of inhibition of 28 mm, and no zone of inhibition was observed with dimethylformamide. Tinospora exhibited antimicrobial activity against S. mutans. However, it needs to be confirmed further with in vivo studies.

Phytochemical analysis and antioxidant potential of the crude extract of Allium oschaninii scape

The present study focuses on the antioxidant potential of aqueous and ethanolic extracts of the scape of Allium oschaninii. Phytochemical analysis and total phenolic content for both the extracts and Total flavonoid content for ethanolic extract were determined. Anti-microbial activity of different concentrations of both the extracts against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Bacillus cereus was investigated. The total antioxidant power (TAP), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric reducing ability of plasma (FRAP) assays were carried out. IC50 values of aqueous and ethanolic extract to scavenge ABTS and DPPH free radical were determined as 0.2524, 0.5467 and 0.6155, 0.9591 (mg/mL) respectively. FRAP and TAP results of both aqueous and ethanolic extracts were determined to be 2530.972 and 1199.86 (µmol of Fe2+ per 1000 µg of extract) and 84.13 ± 5.51 and 141.88 ± 40.49 (equivalent mg of ferulic acid per 150 mg dried sample) respectively. These results signify the antioxidant power potential of the scape of A.oschaninii.

Synthesis and characterization of ZrO2 nanoparticles-antimicrobial activity and their prospective role in dental care

Nanomaterials are exerting a pull on deal with biological and pharmaceutical applications. Biomedical grade of zirconia reveals potential mechanical features of oxide ceramics. In this study, antimicrobial activity and anti-tooth decay applications of the synthesized NPs of ZrO2 were determined. The as-prepared ZrO2 NPs were characterized by UV–vis spectroscopy, FTIR and XRD, which determined the formation of ZrO2NPs and their crystalline nature. SEM analysis further revealed spherical shaped NPs and TEM analysis determined the size of the particles in the range of 15–21 nm, respectively. The antimicrobial activity of different concentrations of the synthesized ZrO2NPs was examined against gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa), respectively. The synthesized ZrO2NPs displayed a better inhibitory action against Pseudomonas aeruginosa (inhibition zone size of 20 mm) at the concentration of 100 μg/ml compared to other bacteria due to the negatively charged P. aeruginosa cell wall readily attracting positively charged ZrO2NPs and thereby inhibiting microbial actions. Moreover, the concentration of ZrO2NPs was directly proportional to their inhibitory actions against the tested microorganisms. Finally, the preventive role of ZrO2NPs in a tooth decay pathway has been elucidated. Hence, it could be concluded that the as-prepared ZrO2NPs possess viable biomedical applications.

Alexidine: a Safer and an Effective Root Canal Irrigant than Chlorhexidine.

Chlorhexidine (CHX) is generally used as the final irrigating solution in root canal therapy. Recent studies have reported that, toxic precipitates containing parachloroaniline (PCA) are formed when CHX reacts with sodium hypochlorite (NaOCl). Whereas, Alexidine (ALX), a bisbiguanide disinfectant similar to CHX, has proven to form no precipitates with NaOCl. To compare antimicrobial activity of different concentrations of ALX with CHX individually and when combined with NaOCl against E. faecalis strains. Different concentrations of ALX and CHX (0.5%, 1%, and 2%) were tested individually and when mixed with 2.5% NaOCl (1:1 ratio) using disc diffusion method against E. faecalis. After 24 hours incubation at 37°C, zones of inhibition were measured for each solution. The results obtained were statistically analysed using one way ANOVA and Scheffe's post-hoc tests. The p-value <0.001 was considered as highly significant. Regardless of the concentrations, ALX obtained the best results in comparison to CHX. There was no statistically significant difference between ALX + NaOCl and CHX + NaOCl mixtures. The present study showed that, the antimicrobial property of ALX against E. faecalis was found to be superior to CHX at same concentrations.

Phytochemical and Antibacterial Properties of Echinophora Orientalis Essential Oil against Staphylococcus aureus in Soup

Using of chemical preservatives in food may have harmful effects on human health and reduce food safety; Natural preservatives can be used to improve food safety. Echinophora Orientalis is one of the medicinal herbs that traditionally has been used as natural preservative. The objective of the present investigation was to determine the chemical composition and antimicrobial effect of E. orientalis essential oil (EO) against Staphylococcus aureus in a food model. In order to preparing E. orientalis EO, the aerial parts of the plant were collected from Binalud mountain in Nishapur, East of Iran. The EO was extracted using Clevenger and its chemical composition was determined by Gas chromatography–mass spectrometry. Assessment of antibacterial activity of the EO was performed by inoculating the amount of 103 cfu/ml S. aureus into a certain amount of soup samples. Different concentrations of the EO (6.25, 12.5, 25 μg ml-1) added into the soup samples. The antimicrobial activity of different concentrations of the EO on S. aureus was examined in the commercial barley soup kept under fridge condition in 1, 2, 3, 4, 5 days after S. aureus inoculation. In total 43 components were identified in E. orientalis EO by GC-MS analysis, comprising 99.05% of the volatile oil, of which γ-decalactone (21.15%), β- cis-Ocimene (15.27%), Linalool L (8.82%), Spathulenol (7.74 %), Eugenol methyl ether (6.61%) were the major components. The EO showed strong antimicrobial activity against tested bacteria, so that no bacterial growth was observed in concentrations of 12.5 μg ml-1 and 25 μg ml-1 five days after bacterial inoculation, but bacterial growth was observed at concentrations of 6.25 μg ml-1. Average growth of bacteria in concentrations of 6.25, within five days counting were respectively 34 and 35 respectively 62.33±4.07, 42.66±3.02, 16±0.81, 1.33±0.65, 0 Cfu/ml (p<0.05). Evaluation of the sensory properties showed that concentration of 6.25 μg ml-1 of the EO was the most acceptable concentration. It was concluded that E. orientalis EO is a strong preservative and a flavoring agent in foods.

Improvement of corrosion resistance, antimicrobial activity, mechanical and chemical properties of epoxy coating by loading chitosan as a natural renewable resource

Chitosan is the most plentiful, renewable marine polymer; it is also one of the most potential eco-friendly candidates for surface coating purposes with excellent film forming ability, corrosion protection ability due to its barrier property and affinity towards metals. In this study, extraction and characterization of chitosan were investigated via several analyses such as elemental analysis, FTIR, 1HNMR and degree of deacetylation. The extracted chitosan was mixed as natural organic filler with epoxy coating in varying loading levels from 2% to 20% to form chitosan − epoxy coating composite. This work represents the corrosion resistance and the antimicrobial activity of a composite formed by chitosan and epoxy coating. The corrosion resistance was evaluated via salt spray test; Gram-negative bacteria, Gram-positive bacteria and fungi were used to study the antimicrobial activity of different concentrations of chitosan − epoxy coating composite. The dynamic mechanical analysis (DMA) of the coating composite was also studied, to characterize the viscoelastic properties of the extracted chitosan. Mechanical and chemical resistance was also investigated. The obtained results showed that, the chitosan − epoxy coating composite showed uniform and lower corrosion rates than that of blank epoxy coating. The antimicrobial effect of chitosan in different loading showed that, the antimicrobial effect strengthened as the loading of chitosan increased. The antimicrobial activity of chitosan for Gram- positive bacteria were higher than to Gram- negative bacteria and fungi. The DMA reported in this work showed that, chitosan may be useful to improve the viscoelstic characteristics of epoxy coating. The mechanical and chemical resistance was also improved and this improvement increases with increase chitosan loading up to, and including, a 15% chitosan.

Synthesis and Characterization of the Antibacterial Activity of Zinc Oxide Nanoparticles against Salmonella typhi

Metal oxides can be used as a series of new and effective anti-bacterial agents. In this study, four concentrations of ZnO nanoparticles (0.2, 0.5, 0.7 and 1.0 mol/L) were synthesized using a low-temperature sol–gel method annealed at 400 and 550 °C. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). XRD results show the hexagonal wurtzite structure of the nanoparticles with the grain size in the range of 38–43 nm. TEM micrographs exhibit a polyhedral form of the synthesized nanoparticles. The antimicrobial activity of different concentrations of nanoparticles against Salmonella typhi PTCC 1609 was determined by disk diffusion and agar dilution method at five concentrations of 10, 5, 2.5, 1.25 and 0.625 mg/mL. Analysis shows that the prepared ZnO nanoparticles have a very effective antimicrobial activity against Salmonella typhi. This activity increases by reducing the size of nanoparticles and increasing their content in the bacterial growth medium.

Microbiologic Evaluation of Matricaria and Chlorhexidine against E. faecalis and C. albicans.

Objective:To evaluate the antimicrobial activity of different concentrations of Matricaria chamomilla and Chlorhexidine gel against Candida albicans and Enterococcus faecalis.Materials and Methods:The agar diffusion test was used to evaluate the antimicrobial activity of 15%, 25% Matricaria chamomilla in aq. base and 2% chlorhexidine gel against C. albicans (ATCC 24433) and E. faecalis (ATCC 24212) strains. Vancomycin was used as the positive control for E. faecalis and fluconazole for C. albicans . The agar plates were incubated at 37°C for 48 h after which the zone of inhibition were measured separately for each material. Data thus obtained were statistically analyzed using the Wilcoxon rank–order test.Results:2% chlorhexidine showed maximum inhibitory zone for C. albicans (33.26 mm) and E. faecalis (24.54 mm). 25% Matricaria showed zones of 24.16 mm and 20.62 mm for C. albicans and E. faecalis, respectively. 15% Matricaria did not show any antimicrobial activity (0 mm).Conclusion:The results of the current in vitro study suggest that 25% Matricaria can be used as an antimicrobial agent, but it is less effective than 2% chlorhexidine gluconate gel against C. albicans and E. faecalis. Matricaria at a lesser concentration of 15% aq. base is ineffective against both the microorganisms.

The use of chitosan, lysozyme, and the nano-silver as antimicrobial ingredients of edible protective hydrosols applied into the surface of meat.

The aim of this study was to design and produce biologically active edible hydrosols, which, when applied to the surface of food products, will protect them from oxidative changes, spoilage and growth of microorganisms. Verification of testing hypothesis and the degree of aim realization were performed by assessing a DPPH radical scavenging activity and microbial reduction of experimental hydrosols on the basis of hydroxypropylmethylcellulose (HPMC), chitosan (CH), lysozyme (L) and nanocolloidal silver (NAg). Antimicrobial activity of different concentrations of CH, L and NAg hydrosols against Gram (+) bacteria: Bacilllus cereus and Micrococcus flavus and Gram (-) bacteria: Escherichia coli and Pseudomonas fluorescens, which exist more often in food, were analyzed using serial dilution test. Total number of microorganisms was determined on meat sample covered by tested sols. Hydrosols containing chitosan and other bioactive substances caused death of each tested microorganism. Lack of chitosan in hydrosols is reflected in a slight inhibition of M. flavus, E. coli and P. fluorescens. Simultaneous influence of CH, L and NAg addition and storage time on total number of bacteria in meat samples with hydrosols was showed. The addition of lysozyme to sols composition significantly increases antioxidant activity.