Diameter Of Growth Inhibition Research Articles

Antimicrobial screening of pecan shell extract and efficacy of pecan shell extract-pullulan coating against Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus on blueberries

Pecan shell is considered an agricultural waste; however, it contains various bioactive compounds with potential inhibitory effect against microorganisms. This study evaluated the antimicrobial efficacy of pecan shell extract (PSE) in vitro using disc-diffusion method and in vivo on blueberries as an antimicrobial coating using pullulan. For in vitro study, 5 and 10 % of aqueous (A-PSE) or ethanol pecan shell extract (E-PSE) incorporated into pullulan film were tested against different bacterial and fungal strains. Pullulan film disc was used as control. The diameter of growth inhibition (mm) around discs was measured. For in vivo study, PSE-P (5 % w/v aqueous pecan shell extract+5 % w/v pullulan), P (5 % w/v pullulan) or control (water) were spray coated on blueberries inoculated (∼5 log CFU/g) with Listeria monocytogenes, Salmonella enterica or Staphylococcus aureus; and stored at 4 °C, 50 ± 10 % RH for 15 days. The effect of antimicrobial coating against pathogens and its impact on quality during storage were determined. A-PSE and E-PSE films were more effective against Gram-positive bacteria and showed no antifungal effect at tested concentrations when evaluated in vitro. Immediately after coating on blueberries, PSE-P significantly reduced Listeria monocytogenes by 2 log CFU/g and lowered survival until day 5 than control or P. Native aerobic microbial population was reduced (P < 0.05) by 0.7 log CFU/g immediately after coating. PSE-P coating or storage time had no significant effect (P > 0.05) on the survival of S. enterica, S. aureus and native fungal population. PSE-P maintained the firmness of blueberry with no significant effect on its color, TSS, and pH during 15 days storage. PSE-P significantly reduced (P < 0.05) the spoilage rate by 21 % than control (28.5 %) and P (37 %); and minimized (P < 0.05) weight loss during storage. Pecan shell extracts show promise as a potential antimicrobial compound whose application on various food products or packaging material could be further explored.

Green synthesis and characterization of silver nanoparticles from Ducrosia flabellifolia Boiss. aqueous extract: Anti-quorum sensing screening and antimicrobial activities against ESKAPE pathogens.

Biosynthesis of silver nanoparticles using natural compounds derived from plant kingdom is currently used as safe and low-cost technique for nanoparticles synthesis with important abilities to inhibit multidrug resistant microorganisms (MDR). ESKAPE pathogens, especially MDR ones, are widely spread in hospital and intensive care units. In the present study, AgNPs using Ducrosia flabellifolia aqueous extract were synthesized using a reduction method. The green synthesized D. flabellifolia-AgNPs were characterized by UV-Vis spectrophotometer, Scanning electron microscopy (SEM), and X-ray diffraction assays. The tested D. flabellifolia aqueous extract was tested for its chemical composition using Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (LC-ESI-MS). Anti-quorum sensing and anti-ESKAPE potential of D. flabellifolia-AgNPs was also performed. Results from LC-ESI-MS technique revealed the identification of chlorogenic acid, protocatechuic acid, ferulic acid, caffeic acid, 2,5-dihydroxybenzoic acid, and gallic acid as main phytoconstituents. Indeed, the characterization of newly synthetized D. flabellifolia-AgNPs revealed spherical shape with mean particle size about 16.961±2.914 nm. Bio-reduction of silver was confirmed by the maximum surface plasmon resonance of D. flabellifolia-AgNPs at 430 nm. Newly synthetized D. flabellifolia-AgNPs were found to possess important anti-ESKAPE activity with low minimal inhibitory concentrations (MICs) ranging from 0.078 to 0.312 mg/mL, and low minimal bactericidal concentrations (MBCs) varying from 0.312 to 0.625 mg/mL. Moreover, D. flabellifolia-AgNPs were active against Candida utilis ATCC 9255, C. tropicalis ATCC 1362, and C. albicans ATCC 20402 with high mean diameter of growth inhibition at 5 mg/mL, low MICs, and minimal fungicidal concentrations values (MFCs). The newly synthetized D. flabellifolia-AgNPs were able to inhibit violacein production in Chromobacterium violaceum, pyocyanin in Pseudomonas aeruginosa starter strains. Hence, the newly synthesized silver nanoparticles using D. flabellifolia aqueous extract can be used as an effective alternative to combat ESKAPE microorganisms. These silver nanoparticles can attenuate virulence of Gram-negative bacteria by interfering with the quorum sensing system and inhibiting cell-to-cell communication.

Alkaline Methanolysis and Octylamine Addition Products of Dehydrocostus Lactone Isolated from Echinops kebericho Root

Abstract: Dehydrocostus lactone is biosynthesized in Saussurea lappa (commonly known as costus), Echinops kebericho, and E. amplexicaulis. Since reports described the compound as a bioactive metabolite, many analogues were synthesized to evaluate the structure-activity relationship. In this study, two new analogues of the active principle were synthesized to compare their mycelial growth inhibition potential against two plant pathogens, namely, Fusarium species causing root rot/wilt of faba bean and Phytophthora infestans triggering potato late blight in Ethiopia. Structural changes at the lactone ring of the synthesized compounds led to a decrease in growth inhibition diameter, which describes the role of the α-methylene-γ-lactone moiety in determining the observed bioactivity. The chemical structures of the two new compounds are elucidated using spectroscopic analysis and reported for the first time.

Antibacterial Efficacy of Polymer-Coated Ceramic Microparticles Loaded with a Modified Combination of Antibiotics on the Enterococcus faecalis Biofilm.

Nano-technology applied for the local delivery of different agents and/or drugs has made its path to endodontics. In the current study, the antibacterial efficacy of biopolymer-coated ceramic microparticles loaded with a modified combination of triple antibiotics, i.e. Penicillin G, Metronidazole and Ciprofloxacin (PMC), was evaluated against two strains of Enterococcus faecalis (E.faecalis); a standard clinical strain obtained from previously root-filled teeth with persistent periapical lesions, and compared to the most common antimicrobials used in endodontics. After synthesis of the polymer-coated microparticles loaded with antibiotics, the 21-day release of antibiotics were evaluated and a stock solution was produced using the maximum released amount of drugs and distilled water. The antibacterial activity of PMC, triple antibiotic paste (TAP), calcium hydroxide (CH), chlorhexidine (CHX) and sodium hypochlorite (NaOCl) against two bacterial strains was determined using "Minimum Inhibitory Concentration" and "Agar Diffusion Test". Additionally, "Microtiter Plate Assay" was performed to assess anti-biofilm properties. Minimum inhibitory concentration values reported for TAP and PMC were 1/256. PMC showed the maximum diameter of growth inhibition in both strains (33 mm and 35 mm), while CH had the minimum diameters (13 mm and13 mm). Based on microtiter plate assay, TAP showed higher biofilm formation than PMC. Biofilm formation was higher in the standard strain for PMC; however, NaOCl, CHX and CH completely inhibited biofilm formation. Based on the findings of the present study, it could be concluded that PMC and TAP were the most effective medicaments against E.faecalis in its planktonic form; however, none could inhibit its biofilm formation. Further studies using larger sample size and "Confocal Scanning Laser Microscopy" are recommended.

Chemical Composition of Ducrosia flabellifolia L. Methanolic Extract and Volatile Oil: ADME Properties, In Vitro and In Silico Screening of Antimicrobial, Antioxidant and Anticancer Activities.

In the present study, the chemical composition of the volatile oil and methanolic extract from Ducrosia flabellifolia Boiss. was investigated. The antimicrobial, antioxidant, and anticancer activities of the methanolic extract from D. flabellifolia aerial parts were screened using experimental and computational approaches. Results have reported the identification of decanal (28.31%) and dodecanal (16.93%) as major compounds in the essential oil obtained through hydrodistillation. Farnesyl pyrophosphate, Methyl 7-desoxypurpurogallin-7-carboxylate trimethyl ether, Dihydro-Obliquin, Gummiferol, 2-Phenylaminoadenosine, and 2,4,6,8,10-dodecapentaenal, on the other hand, were the dominant compounds in the methanolic extract. Moreover, the tested extract was active against a large collection of bacteria and yeast strains with diameter of growth inhibition ranging from 6.67 ± 0.57 mm to 17.00 ± 1.73 mm, with bacteriostatic and fungicidal activities against almost all tested microorganisms. In addition, D. flabellifolia methanolic extract was dominated by phenolic compounds (33.85 ± 1.63 mg of gallic acid equivalent per gram of extract) and was able to trap DPPH• and ABTS•+ radicals with IC50 about 0.05 ± 0 mg/mL and 0.105 ± 0 mg/mL, respectively. The highest percentages of anticancer activity were recorded at 500 µg/mL for all cancer cell lines with IC50 about 240. 56 µg/mL (A-549), 202.94 µg/mL (HCT-116), and 154.44 µg/mL (MCF-7). The in-silico approach showed that D. flabellifolia identified compounds bound 1HD2, 2XCT, 2QZW, and 3LN1 with high affinities, which together with molecular interactions and the bond network satisfactorily explain the experimental results using antimicrobial, antioxidant, and anticancer assays. The obtained results highlighted the ethnopharmacological properties of the rare desertic D. flabellifolia plant species growing wild in Hail region (Saudi Arabia).

A GC-MC analysis of chemical compounds and identification of the antibacterial characteristics of the essential oil of two species exclusive to Iranian habitats: New chemotypes.

BackgroundThe diversity found in the chemical compounds of a single species in different regions results in different biologic characteristics which can be considered as a strong source for identifying new chemotypes. Hymenocrater incanus Bunge and Dracocephalum kotschyi Boiss. are exclusive species of the Lamiaceae family which grow in the western and central habitats of Iran. This study was designed and carried out to determine the yield, identify the chemical compounds, and evaluate the antimicrobial characteristics of the essential oil (EO) of these two species in Iran for the first time.MethodsThe flowering twigs of the species D. kotschyi and H. incanus were collected from the villages of Totmach and Kamu in Isfahan province respectively, in May 2019. The EO of these plants was extracted and separated using the water distillation method, utilizing the Clevenger device. The EO compounds were analyzed using a gas chromatograph coupled with a mass spectrometer (GC-MS). The evaluation of antimicrobial characteristics was carried out by determining the growth inhibition zone implementing the Agar method, the minimum inhibition concentration (MIC), and the minimum bactericidal/fungicidal concentration (MFC/MBC) utilizing liquid dilution culture.ResultsThe results indicated that the highest yield belonged to the EO of D. kotschyi at %2.6 (w/w). In this EO there were citral (%25.44), neral (%20.87), α-pinene (%14.48), trans-geranic acid methyl ester (%9.74), and D-limonene (%6.87). Moreover, H. incanus had the dominant compounds (-)-Spathulenol (%12.61), caryophyllene (%10.00), linolenic acid (%8.54), 1,8-cineole (%5.95), palmitic acid (%5.35), and α-cadinol (%5.17). The largest diameter of growth inhibition zone belonged to the H. incanus EO against the Gram-positive bacteria S. pyogenes (~17.67mm). The strongest inhibition activities in the form of growth inhibition diameter exhibited by the D. kotschyi EO were against the Gram-negative bacteria S. paratyphi-A serotype (~ 12 mm), K. pneumoniae, and Sh. dysenteriae (~ 11 mm) which was significant compared to the Gram-positive rifampin (~ 8 mm).ConclusionsIt can be seen that these species are new chemotypes with special and novel chemical compounds which can potentially be used to manufacture natural antibiotics against some bacterial strains.

Antibacterial and anti-trichomunas characteristics of local landraces of Lawsonia inermis L.

BackgroundHenna (Lawsonia inermis) with anti-bacterial properties has been widely used in traditional medicine especially Persian medicine. Henna oil is suggested for diseases of infectious origin, such as cervical ulcers. Group B Streptococcus agalactiae, Pseudomonas aeruginosa and, Trichomonas vaginalis are involved in the infection of women especially cervicitis. Henna grows in dry and tropical regions. The main important landraces of henna landraces are cultivated in Kerman, Sistan and Baluchestan, Hormozgan, and Bushehr provinces in Iran.Proper use of antimicrobial agents, use of new antimicrobial strategies, and alternative methods, such as herbal methods may help reduce drug resistance in the future. This study’s objective was to investigate the anti-Trichomonas vaginalis activity of three different henna landraces and antimicrobial effects against group B Streptococcus agalactiae and, Pseudomonas aeruginosa.MethodsTotal phenol content was measured by Folin ciocaltu method. Antibacterial effect of landraces of Henna against P. aeruginosa and S. agalactiae were assayed by well diffusion method and minimal inhibitory concentration assessments were done using the broth micro-dilution technique. Anti-Trichomonas effect of Henna landraces were assayed by Hemocytometery method.ResultsTotal phenol content of Shahdad, Rudbar-e-Jonub, and Qaleh Ganj was 206.51, 201.96, and 254.85 μg/ml, respectively. Shahdad, Rudbar-e-Jonub, and Qaleh Ganj had MIC against GBS at 15, 15 and, 4 μg/ml. The growth inhibition diameter of the most effective henna (Shahdad landrace) at a concentration of 20 μg/ml on P. aeruginosa was 2.46 ± 0.15 cm and in the MIC method at a concentration of 5 μg/ml of Shahdad landrace, P. aeruginosa did not grow. IC50 of shahdad Henna after 24 h, 48 h, and 72 h was 7.54, 4.83 and 20.54 μg/ml, respectively. IC50 of Rudbar-e-Jonub extract was 5.76, 3.79 and 5.77 μg/ml in different days. IC50 of Qaleh Ganj extract was 6.09, 4.08 and 5.74 μg/ml in different days.ConclusionsThe amount of total phenol in Qaleh Ganj was higher than the other varieties. In the well diffusion method, Qaleh Ganj was more effective against group B Streptococcus (Gram-positive bacterium) than the other two landraces, and Shahdad landrace was more effective against P. aeruginosa (Gram-negative bacterium) than other. In the MIC method, the same result was obtained as in the well diffusion method, but at a lower concentration.

Plant Alkylbenzenes and Terpenoids in the Form of Cyclodextrin Inclusion Complexes as Antibacterial Agents and Levofloxacin Synergists.

Allylpolyalkoxybenzenes (APABs) and terpenoids from plant essential oils exhibit a range of remarkable biological effects, including analgesic, antibacterial, anti-inflammatory, antioxidant, and others. Synergistic activity with antibiotics of different classes has been reported, with inhibition of P-glycoprotein and impairment of bacterial cell membrane claimed as probable mechanisms. Clearly, a more detailed understanding of APABs’ biological activity could help in the development of improved therapeutic options for a range of diseases. However, APABs’ poor solubility in water solutions has been a limiting factor for such research. Here, we found that complex formation with β-cyclodextrins (CD) is an efficient way to transform the APABs into a water-soluble form. Using a combination of spectroscopic (FTIR, NMR, UV) methods, we have estimated the binding constants, loading capacity, and the functional groups of both APABs and monoterpenes involved in complex formation with CD: ethylene, aromatic, methoxy and hydroxy groups. In the presence of a molar excess of CD (up to 5 fold) it was possible to achieve the complete dissolution of APABs and terpenoids in an aqueous medium (at 90–98% encapsulation) higher by 10–1000 times. Further, we have demonstrated that CD-APABs, if used in combination with levofloxacin (Lev), can be antagonistic, indifferent, additive, or synergistic, mostly depending on the concentration ratio: at high Lev concentration with the addition of APAB is typically neutral or even antagonistic; while at a Lev concentration below MIC, the addition of CD-APAB is either additive or synergistic (according to FICI criteria). An over three-fold increase in Lev antibacterial activity was observed in combination with eugenol (EG), as per the growth inhibition diameter measurement in agar. Interestingly, a synergistic effect could be observed with both Gram-positive and Gram-negative bacteria. So, obviously, the APAB-CD and terpenoid-CD mechanism of action is not limited to their interaction with the bacterial membrane, which has been shown earlier for CDs. Further research may open new prospects for the development of adjuvants to improve the therapeutic regimens with existing, as well as with new anti-infective drugs.

In-Vitro antibacterial activity of glass ionomer cements containing silver nanoparticles synthesized from leaf extract of Mentha piperita

Purpose: The aim of this study was to evaluate the antibacterial activity of glass ionomer cement incorporated with silver nanoparticles (AgNPs) synthetized using mint leaf extract (Mentha piperita, M. piperita) on some oral cavity bacteria.Materials and methods: In the present study, M. piperita leaf extract was used for the synthesis of AgNPs. A total of 60 glass ionomer cement (GIC) disk-shaped specimens were prepared and divided into two groups: conventional GIC (C-GIC), and glass ionomer cement with 2 wt% AgNPs (GIC-AGNPs). The antibacterial activity of the GIC specimens in comparison with Ampicillin disk (10 µg/ml) was investigated against Streptococcus mutans, Enterococcus faecalis, Lactobacillus acidophilus, Lactobacillus casei, and Streptococcus aureus by measuring the diameter of growth inhibition zones.Results: C-GIC specimens failed to show any antibacterial effect against the studied bacteria. However, the GIC-AgNPs had relatively significant antibacterial effects on S. mutans, L. acidophilus, L. casei and S. aureus. The highest antibacterial effect of GIC-AgNPs specimens was reported against L. acidophilus (P &lt;0.001). GIC-AgNPs had no antibacterial effect on E. faecalis.Conclusion: Glass ionomer cement incorporated with AgNPs synthetized using M. piperita showed a promising antibacterial effect against oral cariogenic pathogens.

Anticancer, antioxidant, antiviral and antimicrobial activities of Kei Apple (Dovyalis caffra) fruit

Secondary plant metabolites remain one of the key sources of therapeutic agents despite the development of new approaches for the discovery of medicinal drugs. In the current study, chemical analysis, and biological activities of Kei apple (Dovyalis caffra) methanolic extract were evaluated. Chemical analysis was performed using HPLC and GC–MS. Antiviral and anticancer effect were assessed using the crystal violet technique and activity against human liver cells (HepG2), respectively. Antibacterial activity was tested with the disc diffusion method. The obtained results showed that chlorogenic acid (2107.96 ± 0.07 µg/g), catechin (168 ± 0.58 µg/g), and gallic acid (15.66 ± 0.02 µg/g) were the main bioactive compounds identified by HPLC techniques. While, compounds containing furan moieties, as well as levoglucosenone, isochiapin B, dotriacontane, 7-nonynoic acid and tert-hexadecanethiol, with different biological activities were identified by GC–MS. Additionally, inhibition of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) scavenging was 79.25% at 2000 µg/mL, indicating its antioxidant activity with IC50 of 728.20 ± 1.04 µg/mL. The tested extract exhibited potential anticancer activity (58.90% toxicity) against HepG2 cells at 1000 µg/mL. Potential bacterial inhibition was observed mainly against Escherichia coli and Proteus vulgaris, followed by Staphylococcus aureus and Bacillus subtilis with a diameter of growth inhibition ranging from 13 to 24 mm. While weak activities were recorded for fungi Candida albicans (10 mm). The extract showed mild antiviral activity against human coronavirus 229E with a selective index (SI) of 10.4, but not against human H3N2 (SI of 0.67). The molecular docking study's energy ratings were in good promise with the experiment documents of antibacterial and antiviral activities. The findings suggest that D. caffra juice extract is a potential candidate for further experiments to assess its use as potential alternative therapeutic agent.

Comparative Analysis of the Antimicrobial Activity of Essential Oils and Their Formulated Microemulsions against Foodborne Pathogens and Spoilage Bacteria.

The antimicrobial activity of several essential oils (EOs) and their related microemulsions (MEs) was investigated. EOs were obtained from Cannabis sativa L. cv CS (C. sativa), Carum carvi L. (C. carvi), Crithmum maritimum L. (C. maritimum), Cuminum cyminum L. (C. cyminum), x Cupressocyparis leylandii A.B. Jacks & Dallim. (C. leylandii), Cupressus arizonica Greene (C. arizonica), Ferula assa-foetida L. (F. assa-foetida)., Ferula gummosa Boiss. (F. gummosa), Juniperus communis L. (J. communis), Juniperus x pfitzeriana (Spath) P.A. Schmidt (J. pfitzeriana), Pimpinella anisum L (P. anisum). Preliminary screening revealed that Cuminum cyminum, Crithmum maritimum, and Pimpinella anisum (10% v/v) were effective against all tested microorganisms (Escherichia coli ATCC 35218, Listeria monocytogenes ATCC 7644, Staphylococcus aureus ATCC 29213, Pseudomonas fluorescens DSM 4358, and Candida albicans ATCC 10231), with growth inhibition diameter from 10 to 25 mm. These EOs were used to formulate the MEs with an average size < 50 nm and a good stability over 30 days. EOs’ antimicrobial activity was further enhanced in the MEs, with a generalized lowering of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. C. cyminum-ME reached, in most cases, MIC two times lower (0.312%) than the corresponding EO (0.625%) and even eight times lower against S. aureus (0.156 vs. 1.25%). A more remarkable microbicide effect was noted for C. cyminum-ME, with MBC values eight times lower (from 0.312 to 0.625%) than the corresponding EO (from 2.5 to 5%). Overall, MEs resulted in an efficient system for EOs encapsulation, enhancing solubility and lowering concentration to exert antimicrobial efficacy.

Brocchia cinerea (Delile) Vis. Essential Oil Antimicrobial Activity and Crop Protection against Cowpea Weevil Callosobruchus maculatus (Fab.)

Antibiotics and synthetic pesticides are now playing a role in the spread of resistant pathogens. They continue to have negative consequences for animal and plant health. The goal of this work is to identify the chemical composition of Brocchia cinerea (Delile) Vis. essential oil (EO) using GC-MS(Gas Chromatography-Mass Spectrometer), evaluate its antimicrobial properties, and investigate its insecticidal and repellent effectiveness against Callosobruchus maculatus (C. maculatus). The GC-MS indicated the presence of 21 chemicals, with thujone (24.9%), lyratyl acetate (24.32%), camphor (13.55%), and 1,8-cineole (10.81%) being the most prominent. For the antimicrobial assay, the yeast Candida albicans was very sensitive to the EO with a growth inhibition diameter of (42.33 mm), followed by Staphylococcus aureus (31.33 mm). Fusarium oxysporum is the mycelia strain that appeared to be extremely sensitive to the utilized EO (88.44%) compared to the two species of Aspergillus (A. flavus (48.44%); A. niger (36.55%)). The results obtained in the microdilution method show that Pseudomonas aeruginosa was very sensitive to the EO, inhibited by a very low dose (0.0018 mg/mL). The minimum inhibitory concentration (MIC) results were between 0.0149 and 0.06 mg/mL. B. cinerea EO also demonstrated a potent insecticidal effect and a medium repulsive effect against C. maculatus. Thus, the LC50 value in the contact test was 0.61 μL/L of air, lower than that observed in the inhalation test (0.72 μL/L of air). The present study reveals that B. cinerea EO has the potential to be an antimicrobial and insecticidal agent with a better performance against several pathogenic microorganisms.

Composition phytochimique et activités antioxydante et antimicrobienne des huiles essentielles de Thymus capitatus et de Rosmarinus officinalis de Tunisie

Introduction. Essential oils and their components are currently of great interest as a potential source of highly bioactive natural molecules. They are being studied for their possible use as safe alternative for food protection against oxidation and microbial spoilage. Objective. This study aimed on the phytochemical prospection of Thymus capitatus and Rosmainus officinalis essential oils and their oral toxicity evaluation. Material and methods. Chemical analysis of tested essential oils was carried out using gas chromatography combined to mass spectroscopic (GC-MS). Their safety limit was evaluated by acute toxicity. The antioxidant activity was estimated using in vitro methods. The antimicrobial activity was evaluated against twelve pathogenic germs. Results. Results showed that carvacrol and 1,8-cineol were the major compounds of Thymus capitatus and Rosmarinus officinalis essential oils. Acute toxicity results exhibited that both tested essential oils were inoffensive at 2000 mg/kg. Additionally, Thymus capitatus essential oil presented higher antioxidant activity than Rosmarinus officinalis: 2,2-diphényl-1-picrylhydrazyl (DPPH) assay results showed lower IC50 for Thymus capitatus essential oil than Rosmarinus officinalis. Concerning the antimicrobial results, Thymus capitatus essential oil presented greater efficacy than R. officinalis. Indeed, the minimal growth inhibition diameter generated by thyme essential oil exceeded 38 mm (except for Salmonella typhirium) and reached 60 mm (against C. tropicalis and C. albicans). However, the maximal growth inhibition diameter generated by R. officinalis essential oil was limited to 36 mm (against Shigella sonnei). Conclusion. Overall, Thymus capitatus and Rosmarinus officinalis essential oils have strong potential applicability for pharmaceutical industries.

The Pharmacophore Model for the Antistaphylococcal Activity Screening Among Thiazolidinone-Related Structures

Aim. To develop a pharmacophore model suitable for the antistaphylococcal activity screening among thiazolidinone, thiopyrano[2,3-d]thiazole and thiazolo[4,5-b]pyridine derivatives.Results and discussion. The best pharmacophore model in the series of models developed has a planar structure and consists of an aromatic ring (or cycle with π-bonds), a hydrophobic region, a projection of a hydrogen bond donor and two projections of a hydrogen bond acceptor. Its classification accuracy is 72.4 %. The diameter line of the model is formed by the projection of the hydrogen bond donor and the projection of the hydrogen bond acceptor, and its length is 8.05 Å. The analysis of conformations of active compounds consistent with the pharmacophore mode revealed two different ways of spatial arrangement of active molecules, in which the conditions of the pharmacophore model are fully met.Experimental part. The antistaphylococcal activity was determined by the agar diffusion method against methicillin-resistant strain of Staphylococcus aureus (MRSA) and evaluated by measuring the diameter of the microbial growth inhibition zone. The plates were incubated for 24 h at 37 °C. Compounds with the growth inhibition diameter of more than 7.5 mm were considered to be active. Computer processing of the results of the microbiological experiment and modeling of the probable pharmacophore were performed in the MOE software environment version 2007.09. The geometry of the compounds was optimized by molecular mechanics using the MMFF94x force field. Accuracy of classification was used as the main quality criterion of the pharmacophore model.Conclusions. The pharmacophore model developed can be used for virtual screening of the antistaphylococcal activity for the compounds similar to the training sample. When applying it to the in-home database of compounds the enrichment factor is EF = 2.05.Received: 27.09.2020 Revised: 23.10.2020 Accepted: 03.11.2020

Agreement of Quantitative and Qualitative Antimicrobial Susceptibility Testing Methodologies: The Case of Enrofloxacin and Avian Pathogenic Escherichia coli.

Avian pathogenic Escherichia coli (APEC) is the causal agent of colibacillosis, one of the most common bacterial infections in the poultry sector. Antimicrobial susceptibility testing (AST) is essential for rational and prudent antimicrobial therapy. Subsequently, uniformity in test results from the various testing methodologies used in diagnostic laboratories is pivotal. The aim of this study was therefore to evaluate the agreement between different AST methods in determining fluoroquinolone resistance in APEC. Twenty APEC isolates were selected and subjected to four different susceptibility tests: the quantitative microbroth dilution, agar dilution and gradient strip tests, and the qualitative disk diffusion method. The experiments were performed in triplicate. Categorical agreement, essential agreement and different errors were assessed. Moreover, agreement was also evaluated by calculating intraclass correlation coefficients (ICCs) for the quantitative tests and determining the Pearson correlation coefficients for the agreement between the disk diffusion method and the quantitative tests. Categorical agreement and essential agreement when compared with the microbroth technique ranged from 85–95% and 85–100%, respectively. No very major errors (false susceptible) and only one major error (false resistant) and minor errors (results involving an intermediary category) were detected. The calculated ICC values of the three quantitative tests fluctuated around 0.970 (range 0.940–0.988). There was a high negative correlation between the disk diffusion method and the other tests (correlation coefficients ranging from −0.979 to −0.940), indicating a clear inverse relationship between the minimum inhibitory concentration value and the zone diameter of growth inhibition. In conclusion, the overall agreement between the four different testing methodologies was very high. These results confirm the reliability of the disk diffusion and gradient strip test methods as substantiated alternatives, next to the gold standard agar and microbroth dilution, for fluoroquinolone susceptibility testing of APEC isolates.

Screening research of 90% aqueous ethanolic plant extracts antimicrobial activity against Propionobacterium acnes — an etiological factor of acne occurrence

Annotation. Prolonged antibacterial therapy of acne, mainly by antibiotics of MLS-group (macrolides, lincosamides and streptogramin B), has a number of side effects, the main of which is the emergence of resistant strains. Considering the risks and side effects of traditional etiotropic acne therapy, the use of herbal medicines may be an alternative of this disease treatment. The purpose of this study was to perform a screening study of 90% aqueous-ethanolic medicinal plant extracts antimicrobial activity against P acnes test strains. Antimicrobial activity of 242 aqueous-ethanolic extracts of 183 medicinal and aromatic plants of various organs against two P. acnes strains: sensitive and MLS resistant by HB (Heart Brain) agar diffusion method was studied. Statistical processing of results has been caried by UTHSCSA ImageTool 2.0, Microsoft Office Excel 2011. Eupatorium cannabinum L. and Grindelia squarrosa (Pursh) Dun. aerial parts, Populus nigra L. fruits and needles, Helichrysum arenarium L., Evernia prunastri (L.) Ach. herbs, Calendula officinalis L. flowers, Geranium pratense L. rhizomes and Larix decidua Mill. needles exhibited strong antimicrobial activity (diameter of growth inhibition≥ 15 mm) against test strains. Representatives with antimicrobial properties against acne agents have been found among medicinal plants of Ukraine's flora. The detection of pronounced antimicrobial properties in various pharmacopoeial and non-pharmacopoeial plants necessitates the need for phytochemical study of the raw material to isolate and identify its active components.

Comparison of antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times.

ABSTRACT Introduction: Plaque accumulation can cause white spot lesions. Adding nanoparticles to composites can be effective in reducing the number and function of microorganisms. Objective: The aim of this study was to evaluate the antibacterial effects of orthodontic composites containing different nanoparticles on Streptococcus mutans at different times. Methods: Hydroxyapatite, titanium oxides, zinc oxide, copper oxide and silver oxide nanoparticles were prepared at 0.5% and 1% weight concentrations. Accordingly, ten study groups and one control group were obtained. Then, 26 composite discs were prepared from each group. Strain of Streptococcus mutans was cultured, and colonies of Streptococcus mutans were counted. Further bacterial culture was swapped onto enriched Mueller-Hinton agar. The composites were placed on the culture medium, and after incubation the diameter of growth inhibition was measured. To investigate the long-term effect of nanoparticles, the colonies were counted at days 3, 15 and 30. Results: The results showed that 1% copper oxide and 1% silver oxide significantly reduced the number of bacteria (p< 0.05), but there was no significant difference between the other groups and control group (p> 0.05). At day three, there was a significant difference between control group and 0.5% silver oxide, 1% silver oxide and 1% copper oxide groups (p< 0.05). However, colonies had grown in all groups at day 30 but showed no significant difference with control group (p> 0.05).Conclusion: Addition of 1% copper oxide and 1% silver oxide has short-term antibacterial effects, so the clinical use of these nanoparticles cannot be justified.

Antifungals from forest trees: Usefulness in the control of etiological agents of late season soybean diseases

Septoria brown spot and Cercospora leaf blight are late season diseases caused by Septoria glycines and Cercospora kikuchii, respectively. New antifungals are required against these diseases because the chemical controls currently used have detrimental impacts on wildlife and human health. In this work, 48 extracts originated from the leaves, bark, sapwood or heartwood of four forestry species were assayed by the disc diffusion method against S. glycines and C. kikuchii. Although 18 extracts showed antifungal activity, only 5 were active on both fungal species. The leaf methanolic extract of Blepharocalyx salicifolius showed the lowest minimum inhibitory dose (MID) and the highest diameter of growth inhibition (DI) on both fungal species (MID = 200 μg, DI = 14.2 mm, C. kikuchii; MID = 400 μg, DI = 12.2 mm, S. glycines). Pinocembrin was identified as the main antifungal constituent of the methanolic extract. Both the methanolic leaf extract of B. salicifolius and pinocembrin synergized in vitro the effect of the fungicide difenoconazole. Preventive applications of the extract and the mixture extract + difenoconazole (2.4 mg/mL + 0.006 mg/mL) strongly reduced disease severity generated by S. glycines and C. kikuchii 21 days after inoculation of the soybean plants. This effect was significantly stronger than that generated by difenoconazole. Our results suggest that the application of the methanolic extract of B. salicifolius, alone or in mixture with difenoconazole is a promising strategy to be incorporated in the chemical control of S. glycines and C. kikuchii.

An in vitro determination of antibacterial effect of silver nanoparticles gel as an intracanal medicament in combination with other medicaments against Enterococcus fecalis.

Aim:The main aim of the study is to compare the antibacterial effect of Silver nanoparticle gel alone and combination of silver nanoparticle gel with various medicaments.Materials and Methods:Intracanal dressings: Group 1 –Silver Nanocure gel, Group 2 - Silver Nanocure gel+ Cavisept gel(1:1),Group 3- Silver Nanocure gel+ Aveu-Cal gel(1:1) ,Group 4 – Silver Nanocure gel +Cavisept gel +Aveu-Cal gel(1:1:1) were taken on a culture plate inoculated with E.faecalis. Antibacterial activity was assessed using Agar diffusion test and results were noted as diameter of growth inhibition zone.Statistical Analysis:Student t –test was used to analyse results.Results:The diameter of combination of Silver nanocure gel+Cavisept +Aveu-Cal gel(1:1:1) was highest in comparison to other medicaments tested.Conclusion:Intracanal dressing with a combination of all the three {Silver nanocure gel+Cavisept +Aveu-Cal gel(1:1:1) } is the best treatment for elimination of highly resistant Enterococcus faecalis in root canals.

Carboxymethyl chitosan as an antifungal agent on gauze

Chitosan is a biopolymer that has antifungal activity against C. albicans. Chemical modification of chitosan can provide it with new functional properties for a wide range of biological and biomedical applications. Carboxymethyl chitosan is a derivative of chitosan obtained by etherification of alkaline chitosan with monochloroacetic acid. Carboxymethyl chitosan has a higher solubility than chitosan; therefore it is more readily applicable for use in various fields. Chitosan also has antifungal activity against C. albicans. This study evaluated carboxymethyl chitosan as a gauze-coating material to be used for its antifungal properties. This study also optimized the coating process. Gauze was coated with carboxymethyl chitosan then characterized by Fourier Transform Infra-Red Spectrophotometer (FTIR), X-ray diffraction and scanning electron microscopy (SEM). The antifungal activities of gauze-coated samples were then tested by the diffusion method. The results show that the optimum conditions for the process of coating gauze with carboxymethyl chitosan are dipping ten times at a concentration of 1% for 50 s. Antifungal activities of carboxymethyl chitosan-coated gauze as measured by the diameter of the growth inhibition area are 0.30 cm higher than chitosan-coated gauze, which has a growth-inhibition diameter of 0.12 cm.