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1.
Int J Biol Macromol ; 190: 837-844, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517032

RESUMO

The applications of edible coatings stemmed exclusively from alginate in food packaging are restricted due to their inherent deficient antimicrobial, barrier, and UV-barrier properties. In this work, we aimed to design smart alginate-based coatings for active food packaging through the addition of both aloe vera (AV) and garlic oil (GO). The interactions between the film components were verified by FTIR and XRD. Thermal and mechanical properties were improved by the presence of AV and GO. The presence of AV and GO did not significantly influence the transparency of alginate films. The films exhibited a significant UV-shielding to all UV regions. Water vapor permeability was significantly (p < 0.05) reduced either through the incorporation of AV or GO. The antimicrobial properties of the prepared films were considerably improved by the presence of AV and GO. The shelf-life of tomatoes (Solanum lycopersicum L.) was extended when coated with the alginate film incorporated with AV and GO. Owing to the outstanding UV-shielding, mechanical, thermal, and antimicrobial properties, the alginate/AV/GO active coatings could potentially be implemented in the food packaging industry.

2.
Molecules ; 26(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34299385

RESUMO

An efficient and simple protocol for the synthesis of a new class of diverse bis(indolyl)pyridines analogues of the marine alkaloid nortopsentin has been reported. A one-pot four-component condensation of 3-cyanocarbomethylindole, various aldehyde, 3-acetylindole, and ammonium acetate in glacial acetic acid led to the formation of 2,6-bis(1H-indol-3-yl)-4-(substituted-phenyl)pyridine-5-carbonitriles. Additionally, 2,6-bis(1H-indol-3-yl)-4-(benzofuran) pyridine-5-carbonitriles were prepared via a one-pot four-component condensation of 3-cyanocarbomethylindole, various N-substituted-indole-3-aldehydes, 2-acetylbenzofuran, and ammonium acetate. The synthesized compounds were evaluated for their ability to inhibit biofilm formation against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 6538 and the Gram-negative strain Escherichia coli ATCC 25922. Some of the new compounds showed a marked selectivity against the Gram-positive and Gram-negative strains. Remarkably, five compounds 4b, 7a, 7c, 7d and 8e demonstrated good antibiofilm formation against S. aureus and E. coli. On the other hand, the release of reducing sugars and proteins from the treated bacterial strains over the untreated strains was considered to explain the disruption effect of the selected compound on the contact cells of S. aureus and E. coli. Out of all studied compounds, the binding energies and binding mode of bis-indole derivatives 7c and 7d were theoretically the best thymidylate kinase, DNA gyrase B and DNA topoisomerase IV subunit B inhibitors.


Assuntos
Alcaloides/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Inibidores Enzimáticos/farmacologia , Indóis/química , Biofilmes/efeitos dos fármacos , DNA Girase/química , DNA Topoisomerase IV/antagonistas & inibidores , Inibidores Enzimáticos/química , Simulação de Acoplamento Molecular , Núcleosídeo-Fosfato Quinase/antagonistas & inibidores , Piridinas/química
3.
World Neurosurg ; 152: e235-e240, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34058357

RESUMO

BACKGROUND: One of the most preventable errors of a surgeon's career is operating on the incorrect surgical site (ICSS). No study in any specialty has ever investigated the incidence of ICSS events in lower-income countries. This study focuses on identifying the occurrence of these events along with an analysis of potential causes leading to these unfortunate events. METHODS: The authors distributed a survey to neurosurgical colleagues from around the world. These surgeons were first asked to identify details about their practice and incidence and personal experience with ICSS in their own careers. At the end of the survey, they responded to questions about their knowledge of safety checklists. RESULTS: In this study there was a 63.4% response rate. When combined with those who participated through various social media platforms, there were 178 responses. The incidence rate for every 10,000 cases performed was found to be 22.8 in the cranial group, 88.6 in the cervical group, and 158.8 in the lumbar procedural group. This study identified that 40% of participants had never learned or experienced the ABCD time-out strategy and that 60% of surgeons did not use intraoperative navigation or imaging in their practices. The error has never been disclosed to the patient in 48% of the ICSS cases. CONCLUSIONS: Due to a lack of application of safety checklist protocol, there is an increased occurrence of ICSS events in lower-income countries. The results of this study demonstrate the necessity of investing time and resources dedicated to avoiding preventable errors.

4.
Int J Biol Macromol ; 165(Pt A): 1187-1197, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33035528

RESUMO

Edible films based on chitosan biguanidine hydrochloride and CMC were optimized for the minimum water vapor permeability (WVP) using the 3-level factorial design. Titanium oxide nanoparticles (nTiO2) were incorporated in different contents into the optimized film (Owvp). FTIR and 1H NMR confirmed the successful preparation of films. FE-SEM showed that nTiO2 was homogeneously distributed, with a size of about 25.78 nm for the film containing 5 wt% of nTiO2. XRD was used to study the film's crystallinity, and calculate the crystallite size of nTiO2 using Debye-Scherrer Equation. Thermal stability, by TGA, was improved while the water vapor permeability was reduced upon increasing the nTiO2 content. Color measurements showed that the nTiO2 incorporation didn't significantly affect the transparency. Elongation at break was decreased upon nTiO2 incorporation while tensile strength and Young's modulus were increased with increasing nTiO2 up to 3 wt% then begin to decrease. The nanocomposites exhibited significant UV-barrier properties and enhanced antimicrobial activity especially at high contents of nTiO2. Shelf-life studies on green bell pepper coated with the nanocomposite films showed excellent resistance to mass loss and spoilage during storage. The obtained data confirm the efficiency of the prepared nTiO2 nanocomposite films to extend the shelf-life of food.


Assuntos
Carboximetilcelulose Sódica/química , Quitosana/química , Embalagem de Alimentos , Nanopartículas/química , Capsicum/efeitos dos fármacos , Capsicum/efeitos da radiação , Guanidina/química , Humanos , Titânio/química , Raios Ultravioleta/efeitos adversos
5.
Microorganisms ; 8(10)2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096635

RESUMO

Marine endophytic fungi from under-explored locations are a promising source for the discovery of new bioactivities. Different endophytic fungi were isolated from plants and marine organisms collected from Wadi El-Natrun saline lakes and the Red Sea near Hurghada, Egypt. The isolated strains were grown on three different media, and their ethyl acetate crude extracts were evaluated for their antimicrobial activity against a panel of pathogenic bacteria and fungi as well as their antioxidant properties. Results showed that most of the 32 fungal isolates initially obtained possessed antimicrobial and antioxidant activities. The most potent antimicrobial extracts were applied to three different cellulose containing fabrics to add new multifunctional properties such as ultraviolet protection and antimicrobial functionality. For textile safety, the toxicity profile of the selected fungal extract was evaluated on human fibroblasts. The 21 strains displaying bioactivity were identified on molecular basis and selected for chemical screening and dereplication, which was carried out by analysis of the MS/MS data using the Global Natural Products Social Molecular Networking (GNPS) platform. The obtained molecular network revealed molecular families of compounds commonly produced by fungal strains, and in combination with manual dereplication, further previously reported metabolites were identified as well as potentially new derivatives.

6.
Int J Biol Macromol ; 165(Pt B): 2693-2701, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33098892

RESUMO

This work aims to prepare multifunctional edible coating based on alginate and Aloe vera (AV) optimized to minimum water vapor permeability (WVP) using Box-Behnken design. Titanium oxide nanoparticles (nTiO2) were incorporated into the optimized film at different contents. FTIR confirmed the structures, while XRD confirmed nTiO2 incorporation with a size ranging from 20.38 to 28.81 nm. The UV-shielding was enhanced either in the presence of AV or nTiO2. Thermal stability by TGA was improved upon increasing the nTiO2 content. WVP was significantly decreased from 21.53 g mm/m2 day kPa for calcium alginate to 7.18 g mm/m2 day kPa in the presence of AV and nTiO2 (5 wt%). Color measurements showed non-significant changes in the film's transparency after AV and nTiO2 incorporation. Mechanical and antimicrobial properties were improved in the presence of nTiO2. Shelf-life studies on tomatoes showed significant resistance to mass loss and spoilage when coated with (alginate/AV) film containing 5 wt% of nTiO2.


Assuntos
Alginatos/química , Quitosana/farmacologia , Nanopartículas/química , Preparações de Plantas/farmacologia , Alginatos/farmacologia , Aloe/química , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Filmes Comestíveis , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/microbiologia , Preparações de Plantas/química , Resistência à Tração , Titânio/química
7.
Toxicon ; 181: 57-68, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32353570

RESUMO

This study aimed to identify the bioactive compounds of the ethyl acetate extract of Aspergillus niger SH2-EGY using GC-MS and to evaluate their protective role against aflatoxin B1 (AFB1)-induced oxidative stress, genotoxicity and cytotoxicity in rats. Six groups of male Sprague-Dawley rats were treated orally for 4 weeks included the control group, AFB1-treated group (80 µg/kg b.w); fungal extract (FE)-treated groups at low (140) or high dose (280) mg/kg b.w and the groups treated with AFB1 plus FE at the two tested doses. The GC-MS analysis identified 26 compounds. The major compounds found were 1,2,3,4,6-Penta-trimethylsilyl Glucopyranose, Fmoc-L-3-(2-Naphthyl)-alanine, D-(-)-Fructopyranose, pentakis (trimethylsilyl) ether, bis (2-ethylhexyl) phthalate, trimethylsilyl ether-glucitol, and octadecanamide, N-(2- methylpropyl)-N-nitroso. The in vivo results showed that AFB1 significantly increased serum ALT, AST, creatinine, uric acid, urea, cholesterol, triglycerides, LDL, carcinoembryonic antigen, alpha-fetoprotein, interleukin-6, Malondialdehyde, nitric oxide, Bax, caspase-3 and P53 mRNA expression, chromosomal aberrations and DNA fragmentation. It decreased serum TP, albumin, HDL, Bcl-2 mRNA expression, hepatic and renal TAC, SOD and GPx content and induced histological changes in the liver and kidney. FE prevented these disturbances in a dosage-dependent manner. It could be concluded that A. niger SH2-EGY extract is safe a promising agent for pharmaceutical and food industries.


Assuntos
Aflatoxina B1/toxicidade , Antioxidantes/uso terapêutico , Aspergillus niger , Animais , Fragmentação do DNA/efeitos dos fármacos , Inativação Metabólica/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley
8.
Food Chem Toxicol ; 141: 111399, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32418920

RESUMO

This study aimed to determine the bioactive compounds of Bacillus sp. MERNA97 extract and to evaluate their efficacy against the oxidative damage, genotoxicity, chromosomal aberration and DNA fragmentation in rats treated with AFB1. Sixty male Sprague-Dawley rats were divided into 6 groups and treated for 6 weeks and included the control group, AFB1-treated group (80 µg/kg b. w), the groups treated with Bacillus extract (BE) at low (2 mg/kg b.w) or high (4 mg/kg b.w) dose and the groups treated with AFB1 plus BE at the two doses. Blood and tissues samples were collected for different assays. The GC-MS results revealed the isolation of 44 compounds belong to different classes. The in vivo results showed that AFB1 disturbs all the biochemical parameters, oxidative stress markers, cytokines gene expression chromosomal aberration and DNA fragmentation along with the histological changes in the liver tissue. BE at the two tested doses induced a significant improvement in all parameters tested and the histological picture in a dose dependent manner. It could be concluded that the extract of Bacillus sp. MERNA97 isolated from the marine environment in the Red Sea is a promise as a source of novel compounds with therapeutically benefits.


Assuntos
Aflatoxina B1/toxicidade , Bacillus/metabolismo , Carcinógenos/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Mutagênicos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Venenos/toxicidade , Animais , Biomarcadores/metabolismo , Aberrações Cromossômicas , Citocinas/genética , Relação Dose-Resposta a Droga , Masculino , Ratos , Ratos Sprague-Dawley
9.
Int J Biol Macromol ; 139: 614-620, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31381919

RESUMO

Chitosan biguanidine hydrochloride (CBg) was prepared as a novel multifunctional biodegradable polymer with antimicrobial and excellent water-solubility properties, and used as a crosslinker to prepare carboxymethyl cellulose (CMC)/alginate (A)/CBg edible coating. FTIR confirmed the successful preparation of CBg and CMC/A/CBg films. Wide-angle X-ray diffraction showed that the amorphous structure of CMC/A had some degree of order after CBg addition. The film thickness and solubility were decreased after CBg addition due to the formation of a dense crosslinked structure. CBg addition significantly improved the thermal properties of the films as detected from the calculated IPDT values from TGA curves. Water vapor permeability was reduced to 54% of the value of CMC/A when CBg was added by15 wt%. The addition of CBg didn't change the transparency of CMC/A films. The mechanical properties and antibacterial properties were significantly enhanced after the addition of CBg. CMC/A/CBg were coated on tomato fruits, and the shelf-life studies showed that the storage weight loss was significantly reduced, and the spoilage was inhibited after coating. These results suggest that CMC/A/CBg edible coating might be a promising candidate in food preservation industries.


Assuntos
Alginatos/química , Carboximetilcelulose Sódica/química , Filmes Comestíveis , Conservação de Alimentos , Guanidina/química , Antibacterianos/química , Anti-Infecciosos/farmacologia , Bacillus subtilis , Quitosana/química , Reagentes para Ligações Cruzadas , Escherichia coli , Embalagem de Alimentos , Lycopersicon esculentum , Teste de Materiais , Permeabilidade , Polímeros/química , Solubilidade , Vapor , Streptococcus pneumoniae , Resistência à Tração , Termogravimetria , Água/química , Difração de Raios X
10.
Int J Biol Macromol ; 139: 1162-1167, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31415850

RESUMO

This study aims to prepare binary edible films made from carboxymethyl cellulose (CMC) and chitosan biguanidine hydrochloride (CBg) activated with frankincense oil (FO). The interactions between CMC, CBg and FO were confirmed by FTIR. XRD showed that the addition of FO led to decreasing the crystallinity of CMC/CBg films. The water vapour permeability was reduced upon increasing the FO content. The presence of FO made the films brighter and didn't change their transparency as detected from the color measurements. The films exhibited better mechanical properties in the presence of FO as detected from the improved values of both tensile strength and elongation at break. The prepared films exhibited excellent antibacterial activity especially at high content of FO (5%). CMC/CBg/FO films might be used potentially in the production of edible films due to their excellent physical and antibacterial properties.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Carboximetilcelulose Sódica/química , Quitosana/química , Franquincenso/química , Óleos Voláteis/química , Bacillus subtilis/efeitos dos fármacos , Teste de Materiais , Permeabilidade , Vapor , Streptococcus pneumoniae/efeitos dos fármacos , Resistência à Tração
11.
Int J Biol Macromol ; 134: 912-920, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31100402

RESUMO

Novel antimicrobial copolymers resulted from free radical copolymerization of gelatinized corn starch in aqueous solution with different amounts of 4-acrylamidobenzoic acid monomer using ammonium persulfate (APS)/sodium bisulfite (NaHSO3) as a redox initiator. The grafting copolymerization was evidenced by FTIR, 1HNMR, scanning electron microscopy (SEM) and X-ray diffraction. The thermal stability was improved after the grafting reaction as detected from IPDT values calculated from the thermogravimetric analysis. The effect of changing grafting parameters (initiator concentration, monomer concentration, reaction time and temperature) on graft copolymerization were studied by measuring the grafting percentage (%G), grafting efficiency (%GE) and homopolymer percentage (%H). The optimum grafting conditions were determined as follows: Initiator concentration [I] = 3 × 10-2 mol/L, monomer concentration [M] = 0.25 mol/L, reaction temperature = 65 °C and reaction time = 2 h. The prepared copolymers exhibited swelling ability in both water and 0.9% saline solution. The antimicrobial study revealed a high degree of inhibition against different strains of Gram-positive bacteria, Gram-negative bacteria and fungi when compared with neat starch.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Ácido Benzoico/química , Polímeros/química , Amido/química , Antibacterianos/química , Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Fenômenos Químicos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Análise Espectral , Temperatura , Termogravimetria
12.
Int J Biol Macromol ; 116: 443-450, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29727654

RESUMO

Novel bioactive edible films based on sodium alginate (A) and chitosan biguanidine hydrochloride (CG) with different weight percents were successfully prepared. 13C NMR and 1H NMR confirmed the successful guanidylation of chitosan. Fourier transform infrared confirmed the successful reaction between CG and A. The interaction between CG and A was confirmed through the reduction of the crystalline peaks of both CG and A as detected from their wide-angle X-ray diffraction. Thermogravimetric analysis confirmed that CG enhanced the thermal stability of films as detected from the calculated integral procedure decomposition temperature (IPDT) values. CG incorporation improved the mechanical properties of dry and wet samples. A/CG films exhibited a reduced water vapor permeability and good color properties. The antibacterial study proved that the prepared films showed a remarkable antibacterial killing ability. These results revealed that A/CG films could be an alternative candidate to be used as antibacterial edible films in food industries.


Assuntos
Alginatos/química , Antibacterianos/química , Quitosana/química , Guanidina/química , Cor , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Espectroscopia de Ressonância Magnética/métodos , Permeabilidade/efeitos dos fármacos , Vapor , Temperatura , Termogravimetria/métodos , Água/química , Difração de Raios X/métodos
13.
Int J Biol Macromol ; 117: 179-188, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29807082

RESUMO

The cellulose-based antimicrobial hydrogel was prepared from seed and husk cellulosic fibers of olive industry residues by load silver nanoparticles (AgNPs) onto grafted acrylamide monomer (Am) cellulosic fibers. The grafting approach was the free radical mechanism by utilizing ceric ammonium nitrate (CAN) as initiator in aqueous medium and N,N methylene bisacrylamide (MBAm) as a cross linker. The effect of different grafting conditions on the properties of produced hydrogels has been studied by determining the grafting parameters, i.e. concentration of Am, MBAm, grafting time and temperature to optimize grafting yield (G %), grafting efficiency (GE %), and swelling %. Characterizations of the obtained hydrogels were performed through monitoring swelling behavior, FTIR spectroscopy, SEM, and EDX. AgNPs were grown into the prepared hydrogel. Hydrogel/AgNPs were characterized by FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The hydrogel loaded AgNPs exhibit high efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Celulose/química , Celulose/farmacologia , Hidrogéis/química , Resíduos Industriais , Azeite de Oliva/química , Candida albicans/efeitos dos fármacos , Cinética , Nanopartículas Metálicas/química , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Temperatura
14.
Int J Biol Macromol ; 116: 840-848, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29777814

RESUMO

This work aims to study the effect of a vinyl-modified montmorillonite (VMT) on the physical and antimicrobial properties of chitosan-graft-polyacrylic acid superabsorbent (Ch-g-PA). Ch-g-PA was first optimized using Box-Behnken design to obtain the maximum equilibrium swelling, and the model was efficient to express the experimental swelling data (R2 = 0.999). VMT was further added to the optimized Ch-g-PA in different contents 0, 4, 7 and 10 wt%. FTIR confirmed the successful synthesis of the copolymers and their nanocomposites. Morphology and the average pores size were studied using SEM. Wide angle X-ray diffraction showed the formation of exfoliated nanocomposites after VMT addition. Thermal stability studied by TGA was greatly enhanced in the presence of VMT. The swelling kinetics by Voigt-based viscoelastic model showed that the equilibrium swelling was increased by increasing the VMT up to 7 wt% then decreased after further incorporation. The superabsorbents exhibited salt and pH-responsive properties and showed a pH-reversibility at two buffer solutions (pH = 2 and pH = 9). Moreover, the prepared superabsorbents exhibited a strong bacterial and fungal killing ability which becomes more pronounced upon increasing the VMT content. The obtained results encourage the usage of the prepared copolymer nanocomposites in many fields as antimicrobial superabsorbents of improved physical properties.


Assuntos
Resinas Acrílicas , Anti-Infecciosos , Bactérias/crescimento & desenvolvimento , Bentonita , Quitosana , Resinas Acrílicas/química , Resinas Acrílicas/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bentonita/química , Bentonita/farmacologia , Quitosana/química , Quitosana/farmacologia
15.
Glob Chall ; 2(10): 1800048, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31565310

RESUMO

Silver nanoparticles (AgNPs) have become known as a broad-spectrum antimicrobial agent. The antimicrobial activity of AgNPs is dependent on the particle size and the dispersion status. In this study, a simple and effective approach is developed for sequestering the biosynthesized AgNPs in silica composites during the gel formation of MCM-41. Composites with different Ag concentrations of 0.034% (Ag1@MCM-41), 0.151% (Ag2@MCM-41), and 0.369% (Ag3@MCM-41) are synthesized and then heated at 400 °C to produce Ag1@MCM-41H, Ag2@MCM-41H, and Ag3@MCM-41H, respectively. The samples are characterized by flame atomic absorption spectrometry, Fourier-transform infrared spectroscopy, X-ray diffraction, N2 physisorption, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The AgNPs are confirmed to be highly dispersed in the amorphous silica framework. The antimicrobial activity of the AgNP-silica samples is investigated against Staphylococcus aureus, Escherichia coli, and Candida albicans using the cup-plate and the plate-count techniques. The results show an excellent antimicrobial effect of these samples against the studied microorganisms. Importantly, the AgNP-silica samples are found to be stable up to 58 months under ambient conditions. These stable and powerful antimicrobial composites provide a more practical and effective strategy for combating biomedical pathogens and public health threats.

16.
Curr Microbiol ; 74(11): 1294-1300, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28752341

RESUMO

Cancer is a leading cause of death in several countries. In the search for new anticancer drugs, marine organisms have played an important role in the discovery of lead compounds and the development of new pharmaceuticals for their wide diversity of chemical structures and biological activities. In the present study, the cytotoxicity on colorectal cancer cells HCT116 exerted by marine fungus Aspergillus sp. 2C1-EGY extracts associated with the soft coral Sinularia sp. was investigated; the sub-fractions Fr 2c and Fr 2d had significantly high cytotoxic activity (88 and 85%, respectively). Moreover, the major hexadecanoic, octadecanoic, and octadecenoic acids as well as their methyl esters were isolated. GC/MS analysis revealed the identification of 46 major and minor compounds, from which 19 saturated and unsaturated fatty acids and eight fatty acid esters were identified.


Assuntos
Antozoários/microbiologia , Antineoplásicos/farmacologia , Aspergillus/química , Produtos Biológicos/farmacologia , Animais , Antineoplásicos/química , Aspergillus/classificação , Aspergillus/genética , Produtos Biológicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Espectroscopia de Ressonância Magnética , Filogenia , RNA Ribossômico 18S/genética
17.
ACS Appl Mater Interfaces ; 9(23): 20132-20141, 2017 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-28548818

RESUMO

The use of biodegradable polymers is of great importance nowadays in many applications. Some of the most commonly used biopolymers are polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) due to their superior properties and availability. In this manuscript, we use a facile and green modification method of organoclay (OC) by antimicrobial natural rosin which is considered as a toxicity-free reinforcing material, thus keeping the green character of the material. It increases the interlayer spacing between the clay platelets. This was proven by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and found to impart antimicrobial properties to PLA/PBAT blends. The morphology of the resulting blends was conducted using scanning and transmission electron microscopies (SEM and TEM), and evidence of exfoliation and intercalation was observed. The thermal properties of the blends were studied using differential scanning calorimetry (DSC), and a detailed study of the crystallization of both PLA and PBAT was reported showing cold crystallization behavior of PLA. The final effect on mechanical and antimicrobial properties was also investigated. The obtained results reveal excellent possibility of using expanded OC modified PLA/PBAT polymer blends by adding a green material, antimicrobial natural rosin, for food packaging and biomembranes applications.


Assuntos
Resinas Vegetais/química , Antibacterianos , Anti-Infecciosos , Varredura Diferencial de Calorimetria , Poliésteres
18.
Curr Microbiol ; 74(1): 6-13, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27743105

RESUMO

Marine organisms have been considered as the richest sources of novel bioactive metabolites, which can be used for pharmaceutical purposes. In the last years, the interest for marine microorganisms has grown for their enormous biodiversity and for the evidence that many novel compounds isolated from marine invertebrates are really synthesized by their associated bacteria. Nevertheless, the discovery of a chemical communication Quorum sensing (QS) between bacterial cells and between bacteria and host has gained the researchers to expand the aim of their study toward the role of bacteria associated with marine invertebrates, such as marine sponge. In the present paper, we report the evaluation of biological activities of different extracts of bacteria Vibrio sp. and Bacillus sp. associated with marine sponges Dysidea avara and Ircinia variabilis, respectively. Moreover, we evaluated the biological activities of some diketopiperazines (DKPs), previously isolated, and able to activate QS mechanism. The results showed that all extracts, fractions, and DKPs showed low scavenging activity against DPPH and superoxide anion, low cytotoxic and anti-tyrosinase activities, but no antimicrobial and acetylcholinesterase inhibitory activities. One DKP [cyclo-(trans-4-hydroxy-L-prolyl-L-leucine)] has the highest α-glucosidase inhibitory activity even than the standard acarbose.


Assuntos
Bactérias/química , Dicetopiperazinas/farmacologia , Poríferos/microbiologia , Animais , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicetopiperazinas/análise , Dicetopiperazinas/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Glucosidases/análise , Glucosidases/antagonistas & inibidores , Humanos
19.
Appl Biochem Biotechnol ; 176(8): 2225-41, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26100387

RESUMO

Macrococcus bovicus was locally isolated from soil and used in the green synthesis of nano-scaling silver (NSAg). It was immobilized on a sodic-montmorillonite clay (MMT1) and cetyltrimethylammonium bromide-modified montmorillonite (MMT2) which was also calcined at 300 °C (MMT3). The NSAg clays were characterized by X-ray fluorescence, Fourier transform infrared spectra, X-ray diffractometry, surface area measurement, UV-Vis spectrometry, scanning electron microscope, transmission electron microscope and thermogravimetric analysis. NSAg was confirmed to be included in the interparticular cavities of the clay sheets and its mechanical stability was evidenced. The antimicrobial activity of the NSAg-modified clays was investigated against Staphylococcus aureus, Escherichia coli and Candida albicans using the cup plate and the plate count techniques. The antimicrobial activity of the NSAg clays was confirmed and attributed to the caging of NSAg in MMT cavities. MMT3 was found to inhibit the microbial growth to as high as 65 % as observed from the plate count method. Graphical Abstract Scheme of the biosynthesis of nano-scaling Ag and its immobilization and antimicrobial application.


Assuntos
Silicatos de Alumínio/química , Anti-Infecciosos/farmacologia , Bentonita/farmacologia , Química Verde/métodos , Nanopartículas Metálicas/química , Prata/química , Staphylococcaceae/metabolismo , Argila , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcaceae/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Termogravimetria , Difração de Raios X
20.
J Nat Prod ; 77(7): 1734-8, 2014 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-25010124

RESUMO

The first naturally occurring trimeric anthracene derivatives, stemphylanthranols A and B (1 and 2), were obtained from the endophytic fungus Stemphylium globuliferum that had been isolated from Juncus actus growing in Egypt. The structures of the new compounds were unambiguously determined by 1D and 2D NMR, and by HRMS. A hypothetical biosynthetic pathway for the new trimers is proposed.


Assuntos
Antracenos/isolamento & purificação , Ascomicetos/química , Antracenos/química , Egito , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular
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