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EN
Polyurethane (PU) is a polymer widely used in the biomedical field with excellent mechanical properties and good biocompatibility. However, it usually exhibits poor antibacterial properties for practical applications. Efforts are needed to improve the antibacterial activities of PU films for broader application prospect and added application values. In the present work, two PU films, TDI-P(E-co-T) and TDI-N-100-P(E-co-T), were prepared. Silver nanoparticles (AgNPs) were composited into the TDI-N-100-P(E-co-T) film for better mechanical properties and antibacterial activities, and resultant PU/AgNPs composite film was systematically characterized and studied. The as-prepared PU/AgNPs composite film exhibits much better antibacterial properties than the traditional PU membrane, exhibiting broader application prospect.
EN
1-Acetyl-3-{4'-[(4'''-chlorophenyl) (phenyl) methyl amino] phenyl}-5-aryl-pyrazolines (3a-3l) and 1-Phenyl-3-{4'-[(4'''-chlorophenyl) (phenyl) methyl amino] phenyl}-5-aryl-pyrazolines (4a-4l) have been synthesized. The products have been assayed for their biological activity against Gram +ve, Gram -ve bacteria and fungi. Some of the compounds showed moderate activity in concentration 50 μg/ml. The structure of the products have been elucidated by IR, 1H-NMR, mass spectral data elemental analysis and Thin layer chromatography.
EN
5-(4-Aminophenyl)-2-thiol-1,3,4-oxadiazole (3) was synthesized via the reaction of carbon disulfide with 4-aminobenzoyl hydrazide in presence of potassium hydroxide in absolute ethanol. Compound 3 was converted to the corresponding diazonium salt which was introduced in coupling reaction with alkaline solution of 2-hydroxybenzaldehyde as coupling reagent to give azooxadiazole derivative (4) containing aldehyde group. The resulting aldehyde (4) was then introduced in condensation reactions with the aromatic Thiophenol derivatives including using microwave irradiation technique in absolute ethanol to produce ten 2-amino-4-(2-hydroxy-5-((4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenyl)diazenyl)phenyl)-6-(phenylthio)pyridine-3,5-dicarbonitrile derivatives (5a-j), respectively in vitro Antibacterial activity of the target compounds were investigated using two types of bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The results indicated that the newly synthesized 2-amino-4-(2-hydroxy-5-((4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenyl) diazenyl)phenyl)-6-(phenylthio)pyridine-3,5-dicarbonitrile derivatives (compounds 5d and 5f) showed enhanced activity against Gram-negative bacteria when compared with that of the control drug (gentamycin).
EN
Sol-gel method was successfully used for synthesis of ZnO nanoparticles doped with 10 % Mg or Cu. The structure, morphology and optical properties of the prepared nanoparticles were studied as a function of doping content. The synthesized ZnO:(Mg/Cu) samples were characterized using XRD, TEM, FTIR and UV-Vis spectroscopy techniques. The samples show hexagonal wurtzite structure, and the phase segregation takes place for Cu doping. Optical studies revealed that Mg doping increases the energy band gap while Cu incorporation results in decrease of the band gap. The antibacterial activities of the nanoparticles were tested against Escherichia coli (Gram negative bacteria) cultures. It was found that both pure and doped ZnO nanosuspensions show good antibacterial activity which increases with copper doping, and slightly decreases with adding Mg.
EN
A library of novel 3-(5-bromothiophen-2-yl)-6-phenyl-1,7a-dihydro-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole were synthesized in excellent yields via domino one-pot two component reactions of 4-amino-3-(5-bromothiophen-2-yl)-4,5-dihydro-1H-1,2,4-triazole-5-thiol and benzoic acid derivatives respectively. A triazolo-thiadiazole system may be viewed as a cyclic analogue of two very important components - thiosemicarbazide and biguanide which often display diverse biological activities. The significant advantages of this reaction include one-pot process, simple work-up procedure, excellent yields and no column chromatographic purification. All intermediates and final compounds were confirmed by 1H NMR, 13C NMR, Mass Spectroscopy methods and IR analysis.
EN
In this study, we report the synthesis of 2,5-substituted 1,3,4-oxadiazole derivatives using condensation of cyclohexanecarbohydrazide derivatives and carbon disulfide. In present study, we have prepared total seven derivatives based on 1,3,4-oxadiazole core further functionalized with thiol moieties. The structures of synthesized compounds (C1-C9) were confirmed by the 1H NMR, and Mass spectrometry. These synthesized molecules were subjected to antibacterial and fungal activity against selected microbial and fungal strains. Some of derivatives showed good biological behaviour against gram positive and gram negative bacteria.
7
Content available remote Silver nanoparticles as an alternative strategy against bacterial biofilms
100%
EN
Biofilms are complex bacterial communities that resist the action of antibiotics and the human immune system. Bacteria within biofilms are the cause of numerous, almost impossible to eradicate, persistent infections. Biofilms can form on many medical devices and implants, and so have an enormous impact on medicine. Due to the lack of effective anti-biofilm antibiotics, novel alternative compounds or strategies are urgently required. This review describes some of the latest approaches in the field of biofilm treatment. New anti-biofilm technologies target different stages in the biofilm formation process. Some act to modify the colonized biomaterials to make them resistant to biofilm formation. One potentially important candidate treatment uses silver nanoparticles that show anti-bacterial and anti-biofilm activity. The biological action of nano-silver is complex and seems to involve a number of pathways. However, there have been few reports on the anti-biofilm activity of silver nanoparticles and the precise mechanism underlying their action remains unresolved. Here, we describe some anti-biofilm approaches employing AgNPs and consider the challenges and problems that need to be addressed in order to make silver nanoparticles a part of an effective anti-biofilm strategy.
EN
Some lanthanum(III) complexes have been synthesized by reacting lanthanum(III) metal salt with Schiff bases derived from 3-substituted-4-amino-5-mercapto-1,2,4-triazole and glyoxal/ biacetyl/ benzyl. All these complexes are not soluble in common organic solvents. However sparingly soluble in DMF and DMSO. The chemical analysis of the complexes confirmed to the stoichiometry of the type La(III)LNO3•H2O. La(III)LCl•H2O and La(III)LNCS•H2O respectively. The chelation of the complexes has been proposed in the light of analytical, spectral studies. The measured molar conductance values indicate that, the complexes are non-electrolytes. The Schiff bases and their complexes have been screened for their antibacterial and antifungal activities. The results of these studies show the metal complexes to be more antibacterial and antifungal as compared to the uncomplexed coumarins. lanthanum(III) complexes.
EN
Schinus areira L. is a native plant from South America used for centuries in traditional medicine. Here, we investigate the antimicrobial activity of four essential oils extracted from leaves and fruits of S. areira exhibiting different chemical profiles. The antibacterial activity against the human pathogenic bacteria Staphylococcus aureus susceptible as well as methicillin resistant strain was assessed by the broth microdilution assay. The results showed that the limonene-rich oil extracted from the leaves and fruits have potent antibacterial effect on S. aureus ATCC 25923, while the α-phellandrene-rich fruit oil having a lower content of limonene showed the lowest antibacterial efficacy. In this work, for the first time, we demonstrated the bactericidal activity of essential oils isolated from fruits and leaves of S. areira against susceptible and methicillin resistant S. aureus strains. All results point out the potential use of the S. areira oils as antimicrobial agents to be used, at least against Staphylococcal infections.
10
Content available remote Plasma-chemical modifications of cellulose for biomedical applications
88%
EN
A 6-carboxycellulose (in medicine known as “oxidized cellulose” or “oxycellulose”) is one of the cellulose derivatives popular in the field of surgery. Health products based on oxidized cellulose are great local hemostatics with unique bactericidal and fully bioabsorbable effects. Traditional process of native cellulose oxidation is described as a complex radical reaction in strong acidic liquid medium doped by toxic nitrous radicals (NO*). Our plasma-chemical reaction demonstrates a new synthesis method of oxidized cellulose with unique bactericidal effect. This plasma-chemical treatment is based on atmospheric plasma discharge in liquid medium leading to the oxidation of polysaccharide molecules resulting in oxycellulose. Final oxycellulose properties were evaluated by infrared spectroscopy and carboxyl content determination. The biological impact showed a strong germicidal effect.
EN
In this work, synthesis of three pyrazoline derivatives (6-8) is described. (E)-1,3-(phenylsubstituted)-prop-2-en-1-one (3-5) is prepared by the reaction of substituted benzaldehyde with 4-methylacetophenone, whereas condensation cyclization of the same chalcones (3-5) with phenylhydrazine hydrate in ethanol yielded 6-8. The structures of the title compounds (6-8) were characterized by chemical reactions, elemental analysis, and spectral methods such as IR spectra. The synthesized chalcone and pyrazolines were evaluated for in-vitro antibacterial and antioxidant activities against standard. The zone of inhibition for some of the newly synthesized compounds showed notable antibacterial activity against selected bacterial strains when compared with ampicillin. Significant antioxidant activities were also shown by chalcone and pyrazolines.
EN
2-(chloromethyl)-5-(4-nitrophenyl)-1,3,4-oxadiazole was synthesized via reaction of chloroacetic acid with 4-nitrobenzohydrazide in phosphonyl chloride(4). Compound 4 was treated with 4-aminophenol to form 4-((5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl)methoxy)aniline(5) having free -NH2 group,which is reacted with chloroacetyl chloride to give 2-chloro-N-(4-((5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl)methoxy)phenyl)acetamide(6). Compound 6 was cyclized by ammonium thiocyanate to form 2-((4-((5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl)methoxy)phenyl)amino)thiazol-4(5H)-one(7) with thiazolone ring. Compound was reacted different aldehydes to form (E)-5-benzylidene -2-((4-((5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl) methoxy)phenyl) amino)thiazol-4(5H)-one derivatives(8a-j). In vitro antibacterial activity of the target compounds were investigated using two types of bacteria, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). The results indicated that the newly synthesized (E)-5-benzylidene-2-((4-((5-(4-nitrophenyl)-1,3,4-oxadiazol-2-yl)methoxy) phenyl)amino)thiazol-4(5H)-one derivatives (compounds 8d and 8f) showed enhanced activity against Gram-negative bacteria when compared with that of the control drug (gentamycin).
EN
A series of novel triazolo[1,5-a]pyrimidine derivatives was synthesized from 5-amino-1,2,4-triazole and biologically active morpholinone amine in excellent yield as promising class of antimicrobial agents. The antimicrobial activities were investigated against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus pyogen, Candida albicans, Aspergillusniger, Aspergillusclavatus and compared with standard drugs Ampicillin, Chloramphenicol, Norfloxacin and Griseofulvin. All the synthesized compounds were characterized by IR, 1H NMR, 13C and mass spectroscopy. The result of antimicrobial activity data revealed that compound 4f,4g and 4i were found more active against bacterial species and compound 4c, 4d, 4g, 4i and 4jwere found more active against fungal strain, while other compounds shows moderate to law activity against microbes.
EN
A library of quinoline analog two novel series of azetidin (SH1-5) and thiazolidin (SHa-e) derivatives were designed and synthesized with simple and eco-friendly methodologies. The structures of the compounds were elucidated with the aid of elemental analysis, IR, 1H-NMR and mass spectral data. These novel synthesized compounds were evaluated for antibacterial activity against two gram-positive bacteria (Staphylococcus aureus, Staphylococcus pyogenus) and two gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli). The title compounds were also studied for their antifungal activity with Candida albicans, Aspergillus niger, Aspergillus clavatus using the broth dilution technique. Most of the compounds were the best bio-active desired antibacterial analog with less MIC value against different tested strains.
EN
Hydrogel mineralization with calcium phosphate (CaP) and antibacterial activity are desirable for applications in bone regeneration. Mineralization with CaP can be induced using the enzyme alkaline phosphatase (ALP), responsible for CaP formation in bone tissue. Incorporation of polyphenols, plant-derived bactericidal molecules, was hypothesized to provide antibacterial activity and enhance ALP-induced mineralization. Three phenolic rich plant extracts from: (i) green tea, rich in epigallocatechin gallate (EGCG) (herafter referred to as EGCG-rich extract); (ii) pine bark and (iii) rosemary were added to gellan gum (GG) hydrogels and subsequently mineralized using ALP. The phenolic composition of the three extracts used were analyzed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MSn). EGCG-rich extract showed the highest content of phenolic compounds and promoted the highest CaP formation as corroborated by dry mass percentage meassurements and ICP-OES de-termination of mass of elemental Ca and P. All three extracts alone exhibited antibacterial activity in the following order EGCG-rich > PI > RO, respectively. However, extract-loaded and mineralized GG hydro-gels did not exhibit appreciable antibacterial activity by diffusion test. In conclusion, only the EGCG-rich extract promotes ALP-mediated mineralization.
EN
The tremendous rise in development of resistance to antimicrobials has created an alarming situation for researchers and clinicians. In this regard, an attempt has been made to develop a series of azole-based derivatives. The presented study consists of the design and synthesis of some newer derivatives by incorporating the isoxazole nucleus in the pharmacophore. These are also characterized physicochemically and by spectral means (IR and microanalysis). Moreover, the antioxidant activity of these derivatives was assessed using DPPH radical scavenging methods Finally, all of the newly isolated compounds were tested for their antimicrobial activities. Herein, antimicrobial screening using the agar disc diffusion method revealed that the majority of the derivatives are most active.
EN
A series of novel 1,3,5-trisubstituted pyrazoline derivatives (P1-P10) have been synthesized by the reaction of substituted chalcones (C1-C10) with 4-hydroxybenzhydrazide. The starting material, chalcones were prepared by claisen Schmidt condensation of 4-methylacetophenone with substituted aldehydes in the presence of sodium hydroxide in ethanol. 4-hydroxybenzhydrazide was synthesized by condensing methyl 4-hydroxybenzoate with hydrazine hydrate. The cycloaddition of chalcones with 4-hydroxybenzhydrazide gives 1, 3, 5-trisubstituted pyrazoline derivatives. The structures of synthesized derivatives were confirmed by IR, 1HNMR and 13C NMR spectrum. The synthesized compounds were screened for their antibacterial and antifungal activity.
EN
As heterocyclic compounds show good biological activity, we have synthesized nitrogen containing compounds among them 6b, 6d, 8a and 8b have shown very good antimicrobial activity with remarkable inhibition zones N'-(anthracen-9-ylmethylene)-5-methyl-1-phenyl-1H-1,2,3-triazole-4 carbohydrazide and N'-(3-(benzyloxy)benzylidene)-5-methyl-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide (6a-d, 8a-d) was synthesized from various aldehyde and 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carbohydrazide by condensation in acidic media. All intermediates and final compounds were confirmed by 1H-NMR, 13C-NMR, Mass Spectroscopy methods and IR analysis.
EN
The aim of present study was isolation and characteriation of raw and purified melanin from Armillaria mellea rhizomorphs. Native melanin was isolated from the rhizomorphs of A. mellea by alkaline extraction. Obtained pigment was purifed by acid hydrolysis and washed by organic solvents. Chemical tests, FT-IR and Raman spectroscopy analysis were conducted to determine the melanin nature of the isolated pigment. UV-Vis, transmittance and colour properties were evaluated. Antioxidant activity was determined using ABTS and antibacterial activity by a well diffusion method. The results of the study demonstrated that melanins isolated from A. mellea rhizomorphs had antioxidant, light barrier and antibacterial properties. A purified form of melanin offered better light properties and higher antioxidant activity than the raw form. Both melanins showed antimicrobial activity, raw melanin form had broader activity compared to the pure form. This study revealed that A. mellea rhizomorphs may be considered as a promising source of natural melanin. Isolated pigments presented all the physical and chemical properties common to natural and synthetic melanins. Raw and purified melanins showed differences in chemical composition, antioxidant activity and light barrier properties. Results of this study suggest that, melanins from A. mellea could be applied in the food, cosmetics and pharmaceutical industries.
EN
The aim of this study was to isolate and evaluate biological properties of raw and purified melanins isolated from Scleroderma citrinum. Native melanin was isolated from the gleba of fresh S. citrinum fruiting bodies by alkaline extraction. Obtained pigment was purifed by acid hydrolysis and washed by organic solvents. Chemical tests, FT-IR and Raman spectroscopy analysis were conducted to determine the melanin nature of the isolated pigments. UV-Vis, transmittance, total polyphenolic content and colour properties were evaluated. Antioxidant activity was determined using ABTS and antibacterial activity by a well diffusion method. The results of the study demonstrated that melanins isolated from S. citrinum had antioxidant, light barrier and antibacterial properties. A purified form of melanin offered better light properties and higher antioxidant activity than the raw form. Both melanins inhibited the growth of E. facealis and P. aeruginosa. This study revealed that S. citrinum may be considered as a promising source of natural melanin. Isolated pigments presented all the physical and chemical properties common to natural and synthetic melanins. Raw and purified melanins showed differences in chemical composition, antioxidant activity and light barrier properties. Results suggest that, melanins from S. citrinum possess remarkable therapeutic action and could be applied in the food, cosmetics and pharmaceutical industries.
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