Maximum Inhibition Zone Diameter Research Articles

Preparation of modified silica gel supported silver nanoparticles and its evaluation using zone of inhibition for water disinfection

In this work, preparation of modified silica gel supported silver nanoparticles and its evaluation using zone of inhibition for water disinfection were investigated. The silica contents of the teff straw [TS] and teff straw ash [TSA] are 5.92 and 92.21 %, respectively. The calcinated TS ash at 700 °C was mixed with NaOH solution. The solution is then neutralized with HCl solution and then gel formation using the sol gel method. The silica gel yield was recorded and characterized. The SG with major silica functional group, amorphous structure, high porosity from the morphology, high surface area of 807.163 m2/g, pore volume of 0.34 cm3/g, pore diameter of 1.70 nm and silica gel purity of 99.39 % were achieved at a calcination temperature of 700 °C. It is then; further modified using trimethylchlorosilane (TMCS)/ethanol/hexane at different volumetric ratio and the resulting product is modified silica gel (MSG). MSG has excellent hydrophobic properties that have been required during water treatment. In this method, MSG with a major silica functional group, well ordered structure due to the TMCS modifier, maximum surface area of 510.40 m2/g was achieved at volumetric ratio of 0.25:0.25:1 of TMCS/ethanol/hexane, respectively. Then, MSG supported AgNPs (MSG-AgNPs) was prepared by mixing different concentrations of AgNPs-MSG and characterized. The MSG-AgNPs have shown AgNPs on the surface of MSG from the EDX result, different absorbance, pore from the morphology, with a maximum surface area of 475.0 m2/g was obtained at 1.5 mM of AgNPs concentrations. The performance of MSG-AgNPs was evaluated using zone of inhibition measurement and batch disinfection studies against E. coli and S. aureus. At 1.5 x 108 CFU/mL initial bacterial concentrations, the maximum inhibition zone diameter was 12.80 and 14.30 mm for E. coli and S. aureus, respectively.

Antibacterial Activity of Zinc Oxide Nanoparticles Synthesized by Green Eichhornia Crassipes Extract Method

Purpose: Zinc Oxide Nanoparticle (ZnO NPs) production has become more common because of the benefits of the green strategy, which include its ease of use, environmental friendliness, and cheap operating costs. In order to accomplish the goal of green chemistry, the green synthesis process also uses safe solvents like water and ethanol. ZnO NPs are among the metal oxide-NPs used in antibacterial and bioremediation applications. Materials and Methods: Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), and Field Emission Scanning Electron Microscopy (FESEM) were used to analyze the green-produced ZnO NPs. Results: ZnO nanoparticles have an average size of 22.89 nm, which is corroborated by FESEM pictures, indicating that the particles are tiny. The excellent purity of ZnO NPs has been confirmed by EDX data. The antibacterial activity of ZnO NPs was assessed against a few dangerous pathogens. Zinc oxide nanoparticles were shown to have an interesting antibacterial action against both gram-positive and gram-negative bacteria at micromolar concentrations because they exhibit the maximum diameter of inhibition zone at concentrations 100 mg/ml of S. aureus, E. coli, K. pneumonia, Acintobacret spp, S. fecalis reaching (27,19,18,17, and 14) mm, respectively while S. pneumonia were resistant.The ZnO NPs recorded at a concentration of 12.5 mg/ml lowest areas of the inhibition zone against the same isolates reaching (16, 11, 11, 12, and 10) mm while S. pneumonia were resistant, respectively, as well. Conclusion: ZnO NPs, since they have excellent antibacterial properties, and are biocompatible, they will open up a new line of inquiry for antibacterial agent research because they are stable, nontoxic, and harmless.

Blend Electrospinning of Nigella sativa-Incorporating PCL/PLA/HA Fibers and Its Investigation for Bone Healing Applications.

One of the well-known postoperative complications that requires a number of prophylactic and curative treatments is infection. The implications of postsurgical infections are further exacerbated by the emergence of antibiotic-resistant strains. Reduced effectiveness of synthetic antibiotics has led to an interest in plant-based substances. Extracts obtained from Nigella sativa have been shown to possess effective anti-infectious agents against bacteria frequently seen in bone infections. In this study, a fiber-based bone scaffold containing polycaprolactone, poly(lactic acid), and hydroxyapatite with N. sativa oil at varying concentrations was developed. Solvent electrospinning was used to fabricate the fibers with the specified composition. According to FE-SEM analysis, fibers with average diameters of 751 ± 82, 1000 ± 100, 1020 ± 90, and 1223 ± 112 nm were formed and successful integration of N. sativa oil into the fiber's structure was confirmed via FTIR. Staphylococcus aureus showed moderate susceptibility against the fibers with a maximum inhibition zone diameter of 11.5 ± 1.6 mm. MTT assay analysis exhibited concentration-dependent cell toxicity against fibroblast cells. In short, the antibacterial fibers synthesized in this study possessed antibacterial properties while also allowing moderate accommodation of CDD fibroblast cells at low oil concentrations, which can be a potential application for bone healing and mitigating postsurgical infections.

Antibacterial, Antibiofilm, and Tooth Color Preservation Capacity of Magnesium Oxide Nanoparticles Varnish (in vitro Study).

Antibacterial and antibiofilm properties of magnesium oxide nanoparticles (MgONPs) mixture assessed against Streptococcus mutans (S. mutans), in addition to examining MgONPs varnish impact on the preservation of the tooth color and inhibition of methylene blue diffusion to the enamel. MgONPs mixture was prepared in deionized water (DW), absolute ethanol (E), and rosin with ethanol (RE), named varnish. The antibacterial and antibiofilm capacities of MgONPs mixtures were tested by agar well diffusion, colony-forming unit (CFU), and biofilm inhibition microtiter methods in triplicate and compared to sodium fluoride varnish (NaF) and chlorhexidine mouthwash (ChX). A spectrophotometer was used to record basic tooth color. The artificial demineralization was initiated for 96 h. Then, experimental materials were applied to the corresponding group, and 10-day pH cycles proceeded. Then, the color was recorded in the same ambient environment. The methylene blue diffusion was evaluated by staining the samples for 24 h. After that, the diffusion test was calculated by a digital camera attached to the stereomicroscope. The agar well diffusion test expressed a significant inhibition zone with all MgONPs mixtures (p = 0.000), and maximum inhibition zone diameter associated with MgONPs-RE. The same finding was observed in the CFU test. Additionally, 2.5%, 5%, and 10% MgONPs-RE varnish showed strong biofilm inhibition capacity (p = 0.039) compared to NaF and ChX groups that inhibit biofilm formation moderately (p = 0.003). The study shows that the 5% MgONPs-RE varnish maintains basic tooth color with minimal methylene blue diffusion compared to NaF varnish (p = 0.00). Evaluating MgONPs as a mixture revealed antibacterial and antibiofilm capacity against S. mutans with a higher effect of MgONPs-RE varnish. Also, examining the topical effect of MgONPs-RE varnish on the preservation of the tooth color after pH cycle challenges and methylene blue diffusion to enamel confirmed the high performance of MgONPs-RE varnish at 5%.

Evaluation of Antioxidant and Antimicrobial Activity of Ethanolic Extract of Medicinal Plants Baccaurea Ramiflora and Microcos Paniculata.

The present study was undertaken to investigate the antioxidant and antimicrobial effect of ethanolic leaf extract of Baccaurea ramiflora and Microcos paniculata. DPPH radical scavenging activity, Nitric oxide scavenging activity, Super oxide anion radical scavenging activity, Reducing power assay were used to assess antioxidant efficacy. Zone of Inhibition determination by Agar well diffusion assay was used to assess antimicrobial activity. The Baccaurea ramiflora and Microcos paniculata leaves extracted with different solvents such as petroleum ether, chloroform, ethanol and water among that in leaves ethanolic extract produce 10.78, 10.38 percentage yield respectively. Both the extracts subjected for phytochemical investigation revealed the presence of alkaloids, glycosides, tannins, saponins, proteins and flavonoids. Ethanolic extract of Baccaurea ramiflora showed maximum inhibition zone diameter was obtained in Salmonella typhi (Gram-negative bacteria) with diameter 29 mm and 25 mm respectively at 200mg/ml and 100mg/ml. Similarly, Ethanolic extract of Microcos paniculata showed minimum inhibition zone diameter compare to Baccaurea ramiflora was obtained in Salmonella typhi (Gram-negative bacteria) with diameter 23 mm and 19 mm respectively at 200mg/ml and 100mg/ml. Ethanolic extract of Baccaurea ramiflora showed maximum inhibition zone diameter was obtained in Aspergillus fumigates with diameter 25 mm and 22 mm respectively at 200mg/ml and 100mg/ml. Similarly, Ethanolic extract of Microcos paniculata showed minimum inhibition zone diameter compare to Baccaurea ramiflora was obtained in Aspergillus fumigates with diameter 21 mm and 19 mm respectively at 200mg/ml and 100mg/ml. The current findings point to Baccaurea ramiflora and Microcos paniculata antioxidant and antimicrobial properties. However future studies should be designed to isolate the active constituents responsible for the specified effect.

Investigation on phytochemical constituents of Achillea aucheri Boiss. Endemic to Iranian flora accompanied by antioxidant and antimicrobial evaluations

In traditional medicine, the genus Achillea is utilized for its anti-inflammatory, antispasmodic, and diuretic properties. Achillea aucheri Boiss., species native to Iranian flora was studied due to the Achillea genus's rich supply of phytochemical substances and the absence of essential phytochemical investigations.The methanolic extract (ME) from aerial parts of A. aucheri was fractionated using a C-18 pre-packed cartridge and vacuum liquid chromatography, followed by chromatographic separation using a reversed-phase preparative HPLC. The isolated components were structurally elucidated using 1D and 2D-NMR spectroscopy. Furthermore, essential oil from A. aucheri was isolated through hydrodistillation. Analysis of the essential oil was done through gas chromatography–mass spectrometry (GC-MS) and GC-FID. Free-radical scavenging activity, total flavonoid and phenolic content of the ME were determined using the DPPH assay, AlCl3, and Folin-Ciocalteu reagents, respectively. Anti-microbial activity of the A. aucheri essential oil was investigated against different bacteria and fungus via disk diffusion and micro-dilution methods.Structure elucidation of the purified compounds revealed presence of one major flavonoid (1) and a sesquiterpene (2) in ME. From the A. aucheri essential oil, α-thujone (45.6%), artemisia alcohol (26.5%), and yomogi alcohol (8.8%) were the major constituents. The total flavonoid, phenolic content of the ME were 39.70 ± 0.05 mgQE/gE and 66.70 ± 0.08 mgGAE/gE, respectively, while IC50 value in DPPH assay was 86.28 ± 0.01 μg/mL. Concerning the achieved antimicrobial activity, maximum diameter of inhibition zone of the essential oil was obtained against S. aureus (31.5 ± 0.5 mm) followed by S. epidermidis (13.5 ± 0.7 mm) and M. luteus (11.5 ± 0.5 mm). Additionally, the minimum inhibitory concentration (MIC) values for S. aureus, S. epidermidis, and M. luteus were recorded as 2.5, 2.5 and 1.25% (v/v), respectively. Exhibited activity could be explained to the presence of α-thujone, artemisia alcohol and yomogi alcohol, the most abundant phytochemicals of A. aucheri essential oil.

Antibacterial activity and mechanism of flavonoids from Chimonanthus salicifolius S. Y. Hu. and its transcriptome analysis against Staphylococcus aureus.

Chimonanthus salicifolius S. Y. Hu. (FCS) possess many biological activities, but the antibacterial activity and underlying mechanisms of flavonoids from Chimonanthus salicifolius S. Y. Hu. (FCS) is still unknown. Maximum diameter of inhibition zone (DIZ), maximum diameter of inhibition zone (DIZ), the lowest minimum inhibition concentration (MIC), and the lowest minimum bactericide concentration (MBC) were used to detect the antibacterial activity. Meanwhile, related enzyme activities, the transcriptome analysis and quantitative RT-PCR were used to investigate the antibacterial activity mechanisms. The results showed that FCS (with a purity of 84.2 ± 2.0%) has potential effects on tested strains with the maximum diameter of inhibition zone (DIZ) was 15.93 ± 2.63 mm, the lowest minimum inhibition concentration (MIC) was 1.56 mg/ml and the lowest minimum bactericide concentration (MBC) was 6.25 mg/ml. In addition, the bacterial growth curve test, release of extracellular alkaline phosphatase (AKP), loss of intracellular components, DNA damage and transmission electron microscope (TEM) suggested that FCS could destroy the cell wall and membrane, cause the loss of intracellular substance, cause DNA damage and even lead to cell death. Moreover, the antibacterial mechanism of FCS against Staphylococcus aureus (S. aureus, Gram-positive bacteria) was further confirmed by the transcriptome analysis and quantitative RT-PCR at the molecular level for the first time. A total of 671 differentially expressed genes (DEGs) were identified after treated with FCS (1/2 MIC), with 338 and 333 genes showing up-regulation and down-regulation, respectively. The highlighted changes were those related to the biosynthesis of bacteria wall and membrane, DNA replication and repair, and energy metabolism. Overall, our research provides theoretical guidance for the application of FCS, which is expected to be potentially used as a natural antimicrobial agent in food safety.

Preparation, characterization, and biological activity of Cinnamomum cassia essential oil nano-emulsion

To solve the problems of low bioavailability and unstable properties of Cinnamomum cassia Essential oil (CCEO), encapsulation technology was introduced as an effective means to improve its shortcomings. In this study, Cinnamomum cassia Essential oil nano-emulsion (CCEO-NE) was successfully synthesized by the oil-in-water method and characterized by standard analytical methods, including dynamic light scattering (DLS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The results show that the synthesized CCEO is spherical, smooth in surface, and uniform in shape, with an average particle size of 221.8 ± 1.95 nm, which is amorphous. In this experiment, by simulating the digestion of CCEO-NE in the gastrointestinal tract, it was found that CCEO-NE was undigested in the oral cavity, mainly in the stomach, followed by the small intestine. By understanding the digestion of CCEO-NE, we can improve the potential of CCEO bioavailability in food and drug applications. In addition, through the study of ABTS and DPPH free radicals by CCEO and CCEO-NE, it was found that the antioxidant activity of CCEO-NE was more potent than that of CCEO. When the concentration of CCEO-NE and CCEO is 400 μg/mL, the DPPH free radical scavenging rate is 92.03 ± 0.548% and 80.46 ± 5.811%, respectively. In comparison, ABTS free radical scavenging rate is 90.35 ± 0.480% and 98.44 ± 0.170% when the concentration of CCEO- NE, and CCEO is 75 μg/mL, respectively. The antibacterial test shows that CCEO-NE can inhibit both Gram-positive and Gram-negative bacteria. Among them, CCEO-NE has a stronger antibacterial ability than CCEO, and the maximum inhibition zone diameter of CCEO can reach 15 mm, while that of CCEO-NE can reach 18 mm. Meanwhile, SEM and TEM showed that CCEO-NE treatment destroyed the ultrastructure of bacteria. Generally speaking, we know the situation of CCEO in the gastrointestinal tract. CCEO-NE has more potent antioxidant and antibacterial ability than CCEO. Our research results show that whey protein is an effective packaging strategy that can improve the effectiveness, stability, and even bioavailability of CCEO in various applications, including food and health care industries.

Facile synthesis of rare earth metal dual-doped Pr2O3 nanostructures: Enhanced electrochemical water-splitting and antimicrobial properties

Dual metal doping is a state-of-the-art technique for improving the electrocatalytic characteristics for oxygen evolution reaction (OER) and enhancement of the antibacterial activity of the material. Series of rare earth dual metal-doped Pr2O3 electrocatalysts (Pr2CeMO3, M = Sm, Yb, Er) were successfully fabricated by employing sol-gel treatment. The antimicrobial and electrochemical applications of grown products were studied along with physical properties using advanced techniques such as FESEM, EDX, XRD, FTIR, IV, CV, LSV, EIS, and ECSA. The prepared products retain the monoclinic Pr2O3 structure with the successful doping of rare-earth elements. From the FESEM analysis, grown products have the grainy conglomerate shape, icy monoclinic boxes, irregular lamellar shaped, and well-crystallized grains with the plate-like morphology. EDX has confirmed the presence of metal elements Pr, Ce, Sm, Yb, and Er in grown samples. The electrochemical measurements exhibited the enhancement by dual-doping, and Pr2CeSmO3 has an extraordinarily low overpotential of 189 mV to reach 10 mAcm−2 density and lower Tafel slope (75 mV/dec) for oxygen evolution reaction (OER) in 1.0 M KOH electrolyte. Furthermore, the electrocatalytic efficiency of Pr2CeSmO3 electrocatalyst for OER is extremely long-lasting for (>16 h). The antibacterial test showed that all grown single and dual-doped nanostructures have good antibacterial performance, but Pr2CeSmO3 exhibits strong inhibition activity towards E. coli, K. pneumoniae, S. aureus, and P. vulgaris bacterial strains with maximum inhibition zone diameter 30, 32, 35, and 31 mm, respectively. This low-cost method for the production of rare earth dual metal-doped materials holds a lot of potential for making efficient catalysts, electrochemical energy-conversion devices, and economical antibacterial agents.

Phytochemical and Antimicrobial Activity of Ocimum suave Against Selected Human Pathogenic Bacteria

Worldwide, the use of antibiotics is losing effectiveness due to the substantial resistance to the antimicrobial developed by many pathogenic bacteria. African populations including Rwanda, use frequently traditional medicine for primary care. This study aimed to determine the phytochemicals and the antimicrobial activity of Ocimum. suave (O. suave) against selected human pathogenic bacteria (two strains of S. aureus, P. aeruginosa, two strains of E. coli, S. pneumonia, S. pyogene, K. oxytoca, H. influenza, S. sonei). The leaf and stem extracts were prepared using maceration technique. The antimicrobial activities of extracts were evaluated using the impregnated disc and agar well diffusion methods. The tests revealed the presence of phytochemical substances such as tannins, flavonoids, saponins, steroids alkaloids and phenolics in leaves and only saponins in stem. S. aureus ATCC 43300 was the most sensitive while H. influenza was the most resistant among the microorganisms tested. Aqueous and methanolic crude extract of O. suave displayed maximum diameter of inhibition zone against bacteria (9-26.5 mm and 9-23.5 respectively) and Two-way ANOVA showed statistical significance difference between their means. T-test was used in comparison with standards antibiotics and showed that the distilled water extracts exhibited much higher activity against all tested organisms than activity of streptomycin. Combination of distilled water and methanol extracts with streptomycin revealed synergistic activity against E. coli ATCC 25922 and S. pneumonia ATCC 49618. The leaves of O. suave have a great potential antibacterial activity and should be fully explored for future treatment.
 Keywords: phytochemical; antimicrobial activity; Ocimum suave, Rwanda

One-pot biosynthesis of silver nanoparticles using green tea plant extract/rosemary oil and investigation of their antibacterial activity

Silver nanoparticles is successfully biosynthesized in a one-pot procedure by using a mixture of green tea extract (GTE) and Rosemary oil (RO). Different relative ratios of GTE, RO and AgNO3 in reaction mixture has affected the sizes and concentration of produced nanoparticles. Increasing the relative concentrations of GTE/RO resulted to the increase in size of obtained SNPs, and optimal conditions is observed with relative ratio of RO(1 mL), GTE(0.135 mg) and AgNO3(15.3 mg) producing 9 nm nanoparticles. By varying ratio of GTE(g)/AgNO3(mol) from 0.4 to 2.8, the optimum results and smallest nanoparticles has observed at ratio of 1.5. Antibacterial activity of the products is evaluated against various bacteria strains. The maximum inhibition zone diameter is observed for optimal sample against S. dysenteriae, S. epidermidis and S. pyogenes strains. The optimal sample capped with PVA nanofibers (94 nm) has exhibited a sensibly better antibacterial performance as compared to bare nanoparticles, with almost 15% larger exhibition zones than other samples.

Optimization of glycerol-based medium composition for antifungal metabolites production by Bacillus subtilis

Bacillus species are promising producers of various compounds that have pronounced antimicrobial, antiviral and antitumor activities. Due to its GRAS status, Bacillus subtilis represents an excellent candidate for the usage in plant pathogens biocontrol. In this research, evaluation of antifungal metabolites biosynthesis by Bacillus subtilis ATCC 6633 and optimization of glycerol-based medium composition, using response surface methodology, for the production of compounds effective against Neurospora crassa were investigated. The results of disc-diffusion method indicate that applied Bacillus strain produces compounds with antifungal activity against tested fungus. In order to find optimal cultivation medium composition, the experiments were carried out in accordance with Box-Behnken design, and optimization was performed using the concept of desirability function combined with previously defined mathematical equation, which describes examined bioprocess. The optimization model predicts that maximum inhibition zone diameter against Neurospora crassa of 32.24 mm is achieved when initial content of glycerol, NaNO2 and K2HPO4 were 49.68 g/L, 2.90 g/L and 6.49 g/L, respectively. Additionally, the second optimization set was made to minimize the consumption of medium components and costs of medium preparation. The obtained results are the basis for further research aimed to develop medium appropriate for economically justified production of bioactive compounds at industrial scale.

Fabrication of dual Z-scheme TiO2-WO3-CeO2 heterostructured nanocomposite with enhanced photocatalysis, antibacterial, and electrochemical performance

Direct dual Z-scheme heterostructured nanocomposite TiO2-WO3-CeO2 (NC) and pristine metal oxides nanostructures (NSs) were fabricated using a facile co-precipitation route. XRD, FTIR, and Raman data have confirmed the formation of NSs and NC. FESEM images showed quasi-mesoporous morphology of as-grown nanocomposite. EDX analysis confirmed the existence of titanium (Ti), cerium (Ce), and tungsten (W) in grown NC. The energy bandgap of NC was narrow 2.45 eV as compared to NSs. The higher electrical conductivity and lower recombination rate of NC were observed in IV and PL analysis. The photodegradation efficiency of NC was recorded 99.8% after 60 min under sunlight radiation against methylene blue (MB), which was significantly higher than NSs. NC catalyst has shown excellent photodegradation against other organic pollutants and has superior recyclability up to 7th cycle toward MB dye with a ~ 6% deficit in photodegradation efficiency. The antimicrobial activity results indicated the higher inhibition ability of NC against E. coli, K. pneumoniae, S. aureus, P. Vulgaris, and P. aeruginosa with maximum inhibition zone diameter 25, 29, 26, 28, and 27 mm, respectively. The electrochemical tests including CV, EIS, and GCD exhibited the superior capacitive behaviour of NC. These results demonstrate that grown NC is an efficient material for electrochemical devices, water purification, and biomedical applications.

Saccharomyces Cerevisiae as an Untapped Source of Fungal Chitosan for Antimicrobial Action.

Despite being widely available, Saccharomyces cerevisiae has not been widely explored for direct extraction of chitosan biopolymer for antimicrobial applications. In our study, S. cerevisiae from Baker's yeast and Aspergillus niger from moldy onion extracts are studied as alternative sources of chitosan; and S cerevisiae chitosan tested for antimicrobial efficacy. The properties of S. cerevisiae chitosan are compared with moldy onion chitosan and shrimp chitosan extracted from shrimp shells. Chitosan extracted from S. cerevisiae is tested for antimicrobial efficacy against Staphylococcus Aureus. The maximum yields of fungal chitosan are 20.85 ± 0.35mg/g dry S. cerevisiae biomass at 4th day using a culture broth containing sodium acetate, and 16.15 ± 0.95mg/g dry A. niger biomass at 12th day. The degree of deacetylation (DD%) of the extracted fungal chitosan samples from S. cerevisiae and A. niger is found to be 63.4%, and 61.2% respectively, using Fourier Transform Infrared Spectroscopy. At a concentration of 2g/L, S. cerevisiae chitosan shows the maximum inhibition zone diameter of 15.48 ± 0.07mm. Baker's yeast S cerevisiae biomass and A. niger from moldy onions has not been previously explored as a source of extractible fungal chitosan. This study gives insight that S. cerevisiae and A. niger from agricultural or industrial wastes could be a potential biomass source for production of the chitosan biopolymer. The S. cerevisiae chitosan displayed effective antimicrobial properties against S aureus, indicating the viablitiy of S cerevisae as a resource for extraction of high-quality chitosan.

Antibacterial activity of Alternanthera philoxeroides (Mart.) Griseb. against bacterial phytopathogens: Erwinia carotovora, Ralstonia solanacearum and Xanthomonas axonopodis

We investigated the antibacterial activity of alligator weed (Alternanthera philoxeroides) organic extracts against three bacterial phytopathogens (Erwinia carotovora, Ralstonia solanacearum and Xanthomonas axonopodis). The extracts were prepared by soaking the dry powder of leaf, stem and root of A. philoxeroides into methanol, n-hexane, chloroform and ethyl acetate. The disk diffusion method was used to determine the antibacterial activity at 100 mg/mL extract concentration. The n-hexane extract of A. philoxeroides leaves showed the maximum inhibition zone diameter (IZD)= 28.1 mm against R. solanacearum, while, the corresponding value for the positive control (Penicillin) was 48 mm IZD. There was no antibacterial activity of negative control, dimethyl sulfoxide (DMSO). Gas Chromatography Mass-Spectrometry (GC-MS) analysis revealed the presence of acetic acid, 2-(2-methoxycarbonylamino-5-nitrophenylthio)-, methyl ester, at the highest concentration (31.9 %), followed by 1, 4-benzenediol, 2, 5-bis (1,1-dimethylethyl)- (15.06 %),. It was concluded that the observed biological activity in this study may be due to the presence of these compounds.

Silver nanospheres: Biosynthesis using resurrection plant extract, characterization and in vitro antibacterial activity

This work aims to synthesis silver nanoparticles using the extract of resurrection plant as a reducing agent. The resulting product of silver nanoparticles was characterized using XRD and TEM and the results show that there is a pure silver nanoparticles was produced with sphere-like nano silver of 30–50 nm. Furthermore, the as-prepared nanosilver was used as potential anti-bacterial against two Gram positive bacteria; s. aureus and s. epidermidis. The results prove that the as-prepared silver nanosphere is able to inhibit the bacteria growth with maximum inhibition zone diameter of 15 mm (s. aureus) and 20 mm (s. epidermidis) using 160 µg/ml concentration from Ag nanospheres.

Investigation of the Biochemical and Ultrastructural Mechanisms Underlying the Antimicrobial Activity of Mimusops spp. Extracts

Antibiotic resistance is the major growing threat facing the pharmacological treatment of bacterial infections. Therefore, bioprospecting the medicinal plants could provide potential sources for antimicrobial agents. Mimusops, the biggest and widely distributed plant genus of family Sapotaceae, is used in traditional medicines due to its promising pharmacological activities. This study was conducted to elucidate the antimicrobial effect of three unexplored Mimusops spp. (M. kummel, M. laurifolia and M. zeyheri). Furthermore, the mechanisms underlying such antibacterial activity were studied. The Mimusops leaf extracts revealed significant antibacterial activities against the five tested bacterial strains with a maximum inhibition zone diameter of 22.0 mm against B. subtilis compared with standard antibiotic ciprofloxacin. The minimal inhibitory and bactericidal concentration values against tested Gram-positive and Gram-negative bacterial strains ranged from 3.15-12.5 µg/ml. However, weak antifungal effect was recorded against Candida albicans with MIC value ˃25 µg/ml. The 1, 1-diphenyl-2-picrylhydrazyl (DPPH) assay showed that M. caffra was the best antioxidant (IC50=14.75±0.028 µg/ml), while M. laurifolia was the least one (IC50=34.22±0.014 µg/ml). The phenolics in plant leaves extracts were identified and quantified by high performance liquid chromatography (HPLC) which revealed the presence of seven phenolic acids and four flavonoids. The abundant phenolic compounds were rutin (5.216±0.067 mg/g dried wt.) and gallic acid (0.296±0.068 mg/g) followed by myricetin (0.317±0.091 mg/g) then kaempferol (0.113±0.049 mg/g) as flavonoids. The antibacterial mechanism of M. laurifolia extract, as a representative species, induces ultrastructural changes in the model bacterium Staphylococcus aureus with cell wall and plasma membrane lysis as revealed by transmission electron microscopy. Overall, Mimusops species (M. laurifolia, M. kummel and M. zeyheri) are promising natural alternative sources for antimicrobial agents.

Chemical Analysis, Antimicrobial and Antioxidant Activities of Harsingar (Nyctanthes arbortristis) essential oil

The present investigation deal with study of chemical composition of Harsingar (Nyctanthes arbortristis) essential oil from leaves antimicrobial and antioxidant potential of essential oil, major compound eugenol and its derivatives. The essential oil was extracted through hydro-distillation using Clevenger apparatus. Gas chromatography-Mass spectrometry analysis of essential oil revealed the presence of eugenol (88.20 %) as major compound which was isolated from essential oil by column chromatography. It was chemically transformed into two derivatives i.e. eugenol -5- aldehyde (2) and 5-allyl-2-hydroxy-3-methoxybenzenesulfonic acid (3). The essential oil, eugenol and its derivatives were evaluated for their antimicrobial activity against Klebsiella pneumoniae and Pseudomonas aeruginosa by disc plate method and against Fusarium oxysporum using agar well diffusion method. They were also evaluated for their antioxidant potential by 2, 2-diphenyl-1- picrylhydrazyl (DPPH) and NO free radical scavenging activities. The essential oil showed maximum antibacterial potential with diameter of inhibition zone of 23.8 and 26.3 mm at 1000 μg/ml against K. pneumoniae and P. aeruginosa respectively. 5-allyl-2-hydroxy-3-methoxybenzenesulfonic acid (3) was most effective against F. oxysporum with maximum diameter of inhibition zone of 29.5 mm at 2500 μg/ml. Eugenol (1) showed maximum antioxidant potential with 90.77 and 88.99 % radical scavenging in DPPH and NO radical scavenging assays having IC50 values of 18.07 and 26.50 μg/ml respectively. Harsingar essential oil, eugenol and its derivatives may be used as promising antimicrobial and antioxidising agents and will help in the development of natural antimicrobials and antioxidants as substitute for their synthetic analogues.

Evaluation of antimicrobial effect of Malaysian geopropolis with Aloe vera against Enterococcus faecalis to be used as an intracanal medicament in endodontics.

Introduction:Enterococcus faecalis can be found in failed endodontic treatment (FET) even after performing primary endodontic treatment (PET). Calcium hydroxide (Ca(OH)2) cannot fully eliminate this microorganism during PET. Brazilian green propolis (bee glue) was found to be more effective against E. faecalis when compared to Ca(OH)2. A much less studied Malaysian geopropolis (MP) as well as Aloe vera (AV) is antibacterial but is unknown against E. faecalis.Objective:The objective of this study is to determine the antimicrobial effects of MP, AV, and MP + AV in comparison with Ca(OH)2 against E. faecalis, as an intracanal medicament.Materials and Methods:Antimicrobial activity of MP, AV, MP + AV, Ca(OH)2, and dimethyl sulfoxide was tested against E. faecalis using antimicrobial sensitivity testing, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results were analyzed by Kruskal–Wallis test with Mann–Whitney post hoc test and repeated measures analysis of variance with Bonferroni post hoc test (P < 0.05).Results:For agar well-diffusion method, MP + AV gave maximum inhibition zone diameter (mean: 8.11 ± 0.015 mm), MP (mean: 6.21 ± 0.046 mm, Ca(OH)2 (mean: 5.5 ± 0.006), and AV (mean: 5.05 ± 0.012) with P < 0.05. MIC for MP + AV was 2 mg/ml, MP at 8 mg/ml, Ca(OH)2 at 8 mg/ml, and AV at 16 mg/ml. The MBC for MP + AV is at 4 mg/ml, MP at 16 mg/ml, Ca(OH)2 at 16 mg/ml, and AV at 32 mg/ml.Conclusion:The combination of MP and AV consistently showed better antimicrobial activity compared to MP and AV alone against E. faecalis. The findings suggest that MP and AV used in combination may be an ideal intracanal medicament in FET and PET.

Phytochemical, Antibacterial, and Antioxidant Activities of Anthurium Hookerii leaves Extracts

Many plants of the family of Araceae possess significant benefit as medicinal plants. Anthurium hookerii is herbaceous genus of the family of Araceae. A. hookerii leaves were extracted with five dissimilarity solvents (methanolic, water, ethyl acetate, n-hexane, and dichloromethane). The extracts were evaluated for their phytochemical, total phenolic contents, and antibacterial potential. The presences of tannins and saponins were found in all crude extracts. The steroid was only found in dichloromethane extract, whereas flavonoid was obtained in methanol and water extracts. Besides; methanol, ethyl acetate, water, and n-hexane extracts showed triterpenoid contents. Alkaloid presences in ethyl acetate, methanolic, dichloromethane, and water extracts. The total phenol content was examined by Follin-Ciocalteu assay, which varied from 9.52-76.56 mg/g GAE. The highest total phenolic was found in methanol extract. Antioxidant activity was calculated based on diphenyl picryl hydrazyl radical scavenging ability that showed the scavenging activity with range 7.24-66.11%, which the methanoilic extract have the excellent antioxidant potential (IC50 232.90 µg/ml). Antibacterial activity of leaves extracts of A. hookerii was screened based on disc diffusion method. Water extract showed the wide spectrum antibacterial potential. Klebsiella sp., Bacillus subtilis, Pripioni agnes, and Strepticoccus mutans with maximum diameter of inhibition zone 10.30, 14.20, 9.60, and 15.10 mm, respectively.