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New effective assay to detect antimicrobial activity of filamentous fungi

Pereira, Eric Carvalho; Santos, A.; Reis, Francisca; Tavares, Rui Manuel; Baptista, Paula; Lino-Neto, Teresa; Almeida-Aguiar, Cristina
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
45.95%
The search for new antimicrobial compounds and the optimization of production methods turn the use of antimicrobial susceptibility tests a routine. The most frequently used methods are based on agar diffusion assays or on dilution in agar or broth. For filamentous fungi, the most common antimicrobial activity detection methods comprise the co-culture of two filamentous fungal strains or the use of fungal extracts to test against single-cell microorganisms. Here we report a rapid, effective and reproducible assay to detect fungal antimicrobial activity against single-cell microorganisms. This method allows an easy way of performing a fast antimicrobial screening of actively growing fungi directly against yeast. Because it makes use of an actively growing mycelium, this bioassay also provides a way for studying the production dynamics of antimicrobial compounds by filamentous fungi. The proposed assay is less time consuming and introduces the innovation of allowing the direct detection of fungal antimicrobial properties against single cell microorganisms without the prior isolation of the active substance(s). This is particularly useful when performing large screenings for fungal antimicrobial activity. With this bioassay...

Synthesis, characterization and antifungal activity of quaternary derivatives of chitosan on Aspergillus flavus

de Oliveira Pedro, Rafael; Takaki, Mirelle; Gorayeb, Teresa Cristina Castilho; Bianchi, Vanildo Luiz Del; Thomeo, João Cláudio; Tiera, Marcio José; de Oliveira Tiera, Vera Aparecida
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 50-55
ENG
Relevância na Pesquisa
55.73%
Two series of new chitosan derivatives were synthesized by reaction of deacetylated chitosan (CH) with propyl (CH-Propyl) and pentyl (CH-Pentyl) trimethylammonium bromides to obtain derivatives with increasing degrees of substitution (DS). The derivatives were characterized by 1H NMR and potentiometric titration techniques and their antifungal activities on the mycelial growth of Aspergillus flavus were investigated in vitro. The antifungal activities increase with DS and the more substituted derivatives of both series, CH-Propyl and CH-Pentyl, exhibited antifungal activities respectively three and six times higher than those obtained with commercial and deacetylated chitosan. The minimum inhibitory concentrations (MIC) were evaluated at 24, 48 and 72h by varying the polymer concentration from 0.5 to 16g/L and the results showed that the quaternary derivatives inhibited the fungus growth at polymer concentrations four times lower than that obtained with deacetylated chitosan (CH). The chitosans modified with pentyltrimethylammonium bromide exhibited higher activity and results are discussed taking into account the degree of substitution (DS). © 2012 Elsevier GmbH.

Experimental and theoretical approach of nanocrystalline TiO2 with antifungal activity

Longo, Valeria M.; Picon, Francini C.; Zamperini, Camila; Albuquerque, Anderson R.; Sambrano, Julio R.; Vergani, Carlos Eduardo; Machado, Ana L.; Andrés, Juan; Hernandes, Antônio C.; Varela, José Arana; Longo, Elson
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 114-120
ENG
Relevância na Pesquisa
55.69%
Using a solvothermal method for this research we synthesized nanocrystalline titanium dioxide (nc-TiO2) anatase particles with a mean diameter of 5.4 nm and evaluated their potential antifungal effect against planktonic cells of Candida albicans without UV radiation. To complement experimental data, we analyzed structural and electronic properties of both the bulk and the (1 0 1) surface of anatase by first-principles calculations. Based on experimental and theoretical results, a reactive O2H- and OH- species formation mechanism was proposed to explain the key factor which facilitates the antifungal activity. © 2013 Published by Elsevier B.V.

Gallic acid and cyclodextrins : inclusion complexes and antimicrobial activity

Pinho, Eva Patrícia Paiva Santos; Soares, Graça M. B.; Henriques, Mariana
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
55.85%
Gallic acid (GA), or 3,4,5-trihydroxybenzoic acid, is the commonest and simplest phenolic acid, with just one aromatic ring. This phenolic molecule has been described as antioxidant, anti-inflammatory and anti-tumour, also, antimicrobial and anti-fungal activity has been attributed to it. Besides all the GA biological activities, this compound is cheap, due to the easy plant extraction, and non-toxic. Thus, this phenolic acid has been widely used in food, drugs and cosmetic industry. GA, as other phenolic compounds, is susceptible to environmental factors which may lead to the losing their structural integrity and bioactivity. This can be overcome by the encapsulation with cyclodextrins (CD). They are cyclic oligosaccharides arising from the degradation of starch; inexpensive and friendly to humans. CD are able to form an inclusion complex with a wide range of bioactive molecules, including hydrophobic ones, protect and modulate their release. In the present work, the formation of an inclusion complex (IC) between βCD, HPβCD (2-Hydroxypropyl-β-cyclodextrin) or MβCD (methyl-β-cyclodextrin) and GA was analysed by UV spectrophotometry. The antimicrobial activity of the complexes was also assessed, by qualitative and quantitative methods. The influence of the buffer and pH on the formation of the IC and on the GA antimicrobial activity was also tested. The IC formation was analysed in 2 buffer solutions (K2HPO4/ KH2PO4 and H3PO4/NaOH). The GA and IC absorbance spectrum showed different appearances depending on the buffer used. When K2HPO4/ KH2PO4 was used...

Anti-fungal activity of SiO(2)/Ag(2)S nanocomposites against Aspergillus niger

Fateixa, Sara; Neves, Márcia C.; Almeida, Adelaide; Oliveira, João; Trindade, Tito
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
96.06%
Submicron particles of amorphous SiO2 have been used to grow Ag2S nanophases at their surfaces. SEM and TEM analysis showed morphological well-defined nanocomposite particles consisting of Ag2S nanocrystals dispersed over the silica surfaces. These SiO2/Ag2S nanocomposites were investigated as anti-fungal agents against Aspergillus niger in different experimental conditions, including as nanofillers in cellulosic fibres. The anti-fungal activity in these composite systems is suggested to result from a synergistic effect due to Ag2S anti-fungal centres and the SiO2 surfaces in promoting the adsorption of the fungus.

An artificial intelligence approach to Bacillus amyloliquefaciens CCMI 1051 cultures: Application to the production of anti-fungal compounds

Caldeira, A. Teresa; Arteiro, José; Roseiro, José; Neves, José; Vicente, Henrique
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
85.94%
The combined effect of incubation time (IT) and aspartic acid concentration (AA) on the predicted biomass concentration (BC), Bacillus sporulation (BS) and anti-fungal activity of compounds (AFA) produced by Bacillus amyloliquefaciens CCMI 1051, was studied using Artificial Neural Networks (ANNs). The values predicted by ANN were in good agreement with experimental results, and were better than those obtained when using Response Surface Methodology. The database used to train and validate ANNs contains experimental data of B. amyloliquefaciens cultures (AFA, BS and BC) with different incubation times (1–9 days) using aspartic acid (3–42 mM) as nitrogen source. After the training and validation stages, the 2–7-6–3 neural network results showed that maximum AFA can be achieved with 19.5 mM AA on day 9; however, maximum AFA can also be obtained with an incubation time as short as 6 days with 36.6 mM AA. Furthermore, the model results showed two distinct behaviors for AFA, depending on IT.

Development of novel active pharmaceutical ionic liquids and salts based on antibiotics and anti-fungal drugs

Ferraz, Ricardo João Vieira
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Tese de Doutorado
Publicado em /09/2013 ENG
Relevância na Pesquisa
65.9%
Ionic Liquids (ILs) are class of compounds, which have become popular since the mid-1990s. Despite the fact that ILs are defined by one physical property (melting point), many of the potential applications are now related to their biological properties. The use of a drug as a liquid can avoid some problems related to polymorphism which can influence a drug´s solubility and thus its dosages. Also, the arrangement of the anion or cation with a specific drug might be relevant in order to: a) change the correspondent biopharmaceutical drug classification system; b) for the drug formulation process and c) the change the Active Pharmaceutical Ingredients’ (APIs). The main goal of this Thesis is the synthesis and study of physicochemical and biological properties of ILs as APIs from beta-lactam antibiotics (ampicillin, penicillin G and amoxicillin) and from the anti-fungal Amphotericin B. All the APIs used here were neutralized in a buffer appropriate hydroxide cations. The cation hydroxide was obtained on Amberlite resin (in the OH form) in order to exchange halides. The biological studies of these new compounds were made using techniques like the micro dilution and colorimetric methods. Overall a total of 19 new ILs were synthesised (6 ILs based on ampicillin...

Composition and antimicrobial activities of the leaf essential oil of Machilus zuihoensis from Taiwan

Ho,Chen-Lung; Liao,Pei-Chun; Su,Yu-Chang
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2012 EN
Relevância na Pesquisa
46.05%
This study investigated the chemical composition, and antimicrobial and anti-wood-decay fungal activities of the essential oil isolated from the leaf of endemic Machilus zuihoensis Hayata, Lauraceae, of Taiwan. The essential oil from the fresh leaves of M. zuihoensis was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 104 compounds were identified, representing 100% of the oil. The main components identified were n-dodecanal (23.8%) and (E)-nerolidol (10.5%). The antimicrobial activity of the oil was tested by the disc diffusion method and micro-broth dilution method against ten microbial species (Bacillus cereus, Staphylococcus aureus, S. epidermidis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Aspergillus niger, and Candida albicans), respectively. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 35~43 mm to MIC values of 125 µg mL-1, respectively. The anti-wood-decay fungal activity of the oil was also evaluated. Results showed that the oil demonstrated excellent activity against four wood-decay-fungi species (Trametes versicolor, Phaneochaete chrysosporium...

Anti-Candida activity and chemical composition of Cinnamomum zeylanicum blume essential oil

Castro,Ricardo Dias de; Lima,Edeltrudes Oliveira
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 EN
Relevância na Pesquisa
45.98%
The purpose of this study was to identify the anti-Candida activity and chemical composition of the essential oil (EO) of Cinnamomum zeylanicum (cinnamon). For this, tests were conducted to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) and the action of C. zeylanicum EO on fungal cell wall of Candida albicans, C. tropicalis and C. krusei strains. The composition of the was analysed by gas chromatography with mass spectrometry. Significant antifungal activity of the EO was observed on the strains tested, with 87.5% and 62.5% of them sensitive, respectively at a MIC of 312.5 µg/mL and MFC of 2500 µg/mL. In the presence of sorbitol, the MIC was 625 µg/mL against all the strains, showing a possible action of the EO on fungal cell wall. Eugenol (73.27%) and trans-β-caryophyllene (5.38%) were found in higher concentrations. The results indicated anti-Candida activity of the EO analyzed and suggested that it occurred due to the action on fungal cell wall.

Anti-adherent activity of Rosmarinus officinalis essential oil on Candida albicans: an SEM analysis

Cavalcanti,Yuri Wanderley; Almeida,Leopoldina de Fátima D. de; Padilha,Wilton Wilney Nascimento
Fonte: Pontifícia Universidade Católica do Rio Grande do Sul Publicador: Pontifícia Universidade Católica do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
Relevância na Pesquisa
55.91%
PURPOSE: To evaluate the anti-adherent activity of Rosmarinus officinalis (Rosemary) essential oil on Candida albicans (ATCC289065). METHODS: The effect of the essential oil of R. officinalis at concentrations of 0.56 mg/mL,1.12 mg/mL and 2.25 mg/mL on C. albicans adherence was examined using Scanning Electron Microscopy (SEM) analysis. A test piece of acrylic resin, 2 mL of Sabouraud Dextrose broth,0.2 mL of fungal inoculum and 2 mL of R. officinalis essential oil in the various test concentrations were combined in sterile glass tubes. Sterile distilled water and nystatin (100.000 IU/mL) were used as controls. The essential oil test products were combined with the fungal samples under two different conditions: at the same time as the other components of the adhesion device(t=0 h) or 24 h after the combination of the other components (t=24 h). The tubes were incubated at 37 °C for 48 h. The specimens were fixed and prepared for SEM analysis. RESULTS: At 0.56 mg/mL, the effect of R. officinalis essential oil was similar to that of nystatin (t=0h and t=24 h). At 2.25 mg/mL, the essential oil caused significant cell disruption and inhibition of adhesion. An intermediate effect was observed at 1.12 mg/mL. Greater inhibition of adhesion was observed at t = 24 h. CONCLUSION: The essential oil of R. officinalis had an anti-adherent effect on C. albicans. Greater inhibition of adhesion was observed in cultures undergoing cellular aggregation (t=24 h) and at higher concentrations of the natural product.

Potential Role for a Carbohydrate Moiety in Anti-Candida Activity of Human Oral Epithelial Cells

Steele, Chad; Leigh, Janet; Swoboda, Rolf; Ozenci, Hatice; Fidel, Paul L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2001 EN
Relevância na Pesquisa
55.89%
Candida albicans is both a commensal and a pathogen at the oral mucosa. Although an intricate network of host defense mechanisms are expected for protection against oropharyngeal candidiasis, anti-Candida host defense mechanisms at the oral mucosa are poorly understood. Our laboratory recently showed that primary epithelial cells from human oral mucosa, as well as an oral epithelial cell line, inhibit the growth of blastoconidia and/or hyphal phases of several Candida species in vitro with a requirement for cell contact and with no demonstrable role for soluble factors. In the present study, we show that oral epithelial cell-mediated anti-Candida activity is resistant to gamma-irradiation and is not mediated by phagocytosis, nitric oxide, hydrogen peroxide, and superoxide oxidative inhibitory pathways or by nonoxidative components such as soluble defensin and calprotectin peptides. In contrast, epithelial cell-mediated anti-Candida activity was sensitive to heat, paraformaldehyde fixation, and detergents, but these treatments were accompanied by a significant loss in epithelial cell viability. Treatments that removed existing membrane protein or lipid moieties in the presence or absence of protein synthesis inhibitors had no effect on epithelial cell inhibitory activity. In contrast...

Vaginal and Oral Epithelial Cell Anti-Candida Activity

Nomanbhoy, Fatema; Steele, Chad; Yano, Junko; Fidel, Jr., Paul L.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2002 EN
Relevância na Pesquisa
55.8%
Candida albicans is the causative agent of acute and recurrent vulvovaginal candidiasis (VVC), a common mucosal infection affecting significant numbers of women in their reproductive years. While any murine host protective role for cell-mediated immunity (CMI), humoral immunity, and innate resistance by neutrophils against the vaginal infection appear negligible, significant in vitro growth inhibition of Candida species by vaginal and oral epithelial cell-enriched cells has been observed. Both oral and vaginal epithelial cell anti-Candida activity has a strict requirement for cell contact to C. albicans with no role for soluble factors, and oral epithelial cells inhibit C. albicans through a cell surface carbohydrate moiety. The present study further evaluated the inhibitory mechanisms by murine vaginal epithelial cells and the fate of C. albicans by oral and vaginal epithelial cells. Similar to human oral cells, anti-Candida activity produced by murine vaginal epithelial cells is unaffected by enzymatic cleavage of cell surface proteins and lipids but sensitive to periodic acid cleavage of surface carbohydrates. Analysis of specific membrane carbohydrate moieties, however, showed no role for sulfated polysaccharides, sialic acid residues...

Effects of macrophage colony-stimulating factor (M-CSF) on anti-fungal activity of mononuclear phagocytes against Trichosporon asahii

Sasaki, E; Tashiro, T; Kuroki, M; Seki, M; Miyazaki, Y; Maesaki, S; Tomono, K; Kadota, J-I; Kohno, S
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
Publicado em /02/2000 EN
Relevância na Pesquisa
66.01%
Trichosporon asahii is an emerging opportunistic pathogen in immunocompromised patients. Little is known about the mechanisms of host defence against T. asahii. We investigated the fungicidal activity of human peripheral blood monocytes and murine peritoneal macrophages against T. asahii isolates, and the effects of M-CSF on the anti-fungal activity of mononuclear phagocytes. We also established a neutropenic mouse model of disseminated trichosporonosis with T. asahii. M-CSF enhanced the phagocytic fungicidal activity of mononuclear cells, and infected mice treated with human M-CSF at 10 × 106 U/kg showed a significant improvement in survival rate, with fewer fungal colony counts in the lung compared with control mice. Mice treated with human M-CSF showed higher concentrations of tumour necrosis factor-alpha (TNF-α) in the lung and plasma compared with control mice. The survival rate was significantly reduced in mice treated with anti-mouse TNF-α. Our results showed that M-CSF enhanced the fungicidal activity of mononuclear phagocytes partly by production of TNF-α, and suggest that the administration of M-CSF to patients with disseminated trichosporonosis may be a useful adjunct to conventional anti-microbial therapy and prophylaxis.

Synthesis and anti-microbial screening of novel schiff bases of 3-amino-2-methyl quinazolin 4-(3H)-one

Saravanan, Govindaraj; Pannerselvam, Perumal; Prakash, Chinnasamy Rajaram
Fonte: Medknow Publications & Media Pvt Ltd Publicador: Medknow Publications & Media Pvt Ltd
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
45.99%
In the present study, novel Schiff bases were synthesized by condensation of 3-amino-2-methyl quinazolin-4-(3H)-ones with different aromatic aldehydes. The 3-amino-2-methyl quinazolin-4-(3H)-one was synthesized from anthranilic acid via the 2-methyl benzoxazin-4-one. The chemical structures of the synthesized compounds were confirmed by means of Infrared (IR), 1H-NMR, 13C-NMR, Mass spectral, and Elemental analysis. These compounds were screened for anti-bacterial (Staphylococcus aureus ATCC 9144, Staphylococcus epidermidis ATCC 155, Micrococcus luteus ATCC 4698, Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2853, and Klebsiella pneumoniae ATCC 11298)) and anti-fungal (Aspergillus niger ATCC 9029 and Aspergillus fumigatus ATCC 46645) activities, using the paper disk diffusion technique. The minimum inhibitory concentrations (MIC) of the compounds were also determined by the agar streak dilution method. Most of the synthesized compounds exhibited significant anti-bacterial and anti-fungal activities. Among the synthesized compounds, 3-(4-hydroxy benzylideneamino)-2-methyl quinazolin-4(3H)-one 4g and 4c was found to exhibit the highest anti-bacterial activity and 3-(4-hydroxy-3-methoxy benzylideneamino)-2-methyl quinazolin-4(3H)-one 4k exhibited the highest anti-fungal activity.

The Synthetic Melanocortin (CKPV)2 Exerts Anti-Fungal and Anti-Inflammatory Effects against Candida albicans Vaginitis via Inducing Macrophage M2 Polarization

Ji, Hai-xia; Zou, Yu-lian; Duan, Jing-jing; Jia, Zhi-rong; Li, Xian-jing; Wang, Zhuo; Li, Li; Li, Yong-wen; Liu, Gen-yan; Tong, Ming-Qing; Li, Xiao-yi; Zhang, Guo-hui; Dai, Xiang-rong; He, Ling; Li, Zhi-yu; Cao, Cong; Yang, Yong
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/02/2013 EN
Relevância na Pesquisa
45.94%
In this study, we examined anti-fungal and anti-inflammatory effects of the synthetic melanocortin peptide (Ac-Cys-Lys-Pro-Val-NH2)2 or (CKPV)2 against Candida albicans vaginitis. Our in vitro results showed that (CKPV)2 dose-dependently inhibited Candida albicans colonies formation. In a rat Candida albicans vaginitis model, (CKPV)2 significantly inhibited vaginal Candida albicans survival and macrophages sub-epithelial mucosa infiltration. For mechanisms study, we observed that (CKPV)2 inhibited macrophages phagocytosis of Candida albicans. Meanwhile, (CKPV)2 administration inhibited macrophage pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) release, while increasing the arginase activity and anti-inflammatory cytokine IL-10 production, suggesting macrophages M1 to M2 polarization. Cyclic AMP (cAMP) production was also induced by (CKPV)2 administration in macrophages. These above effects on macrophages by (CKPV)2 were almost reversed by melanocortin receptor-1(MC1R) siRNA knockdown, indicating the requirement of MC1R in the process. Altogether, our results suggest that (CKPV)2 exerted anti-fungal and anti-inflammatory activities against Candida albicans vaginitis probably through inducing macrophages M1 to M2 polarization and MC1R activation.

Advances in targeting the vacuolar proton-translocating ATPase (V-ATPase) for anti-fungal therapy

Hayek, Summer R.; Lee, Samuel A.; Parra, Karlett J.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 27/01/2014 EN
Relevância na Pesquisa
45.96%
Vacuolar proton-translocating ATPase (V-ATPase) is a membrane-bound, multi-subunit enzyme that uses the energy of ATP hydrolysis to pump protons across membranes. V-ATPase activity is critical for pH homeostasis and organelle acidification as well as for generation of the membrane potential that drives secondary transporters and cellular metabolism. V-ATPase is highly conserved across species and is best characterized in the model fungus Saccharomyces cerevisiae. However, recent studies in mammals have identified significant alterations from fungi, particularly in the isoform composition of the 14 subunits and in the regulation of complex disassembly. These differences could be exploited for selectivity between fungi and humans and highlight the potential for V-ATPase as an anti-fungal drug target. Candida albicans is a major human fungal pathogen and causes fatality in 35% of systemic infections, even with anti-fungal treatment. The pathogenicity of C. albicans correlates with environmental, vacuolar, and cytoplasmic pH regulation, and V-ATPase appears to play a fundamental role in each of these processes. Genetic loss of V-ATPase in pathogenic fungi leads to defective virulence, and a comprehensive picture of the mechanisms involved is emerging. Recent studies have explored the practical utility of V-ATPase as an anti-fungal drug target in C. albicans...

Exploring the Anti-Cancer Activity of Novel Thiosemicarbazones Generated through the Combination of Retro-Fragments: Dissection of Critical Structure-Activity Relationships

Serda, Maciej; Kalinowski, Danuta S.; Rasko, Nathalie; Potůčková, Eliška; Mrozek-Wilczkiewicz, Anna; Musiol, Robert; Małecki, Jan G.; Sajewicz, Mieczysław; Ratuszna, Alicja; Muchowicz, Angelika; Gołąb, Jakub; Šimůnek, Tomáš; Richardson, Des R.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 16/10/2014 EN
Relevância na Pesquisa
45.94%
Thiosemicarbazones (TSCs) are an interesting class of ligands that show a diverse range of biological activity, including anti-fungal, anti-viral and anti-cancer effects. Our previous studies have demonstrated the potent in vivo anti-tumor activity of novel TSCs and their ability to overcome resistance to clinically used chemotherapeutics. In the current study, 35 novel TSCs of 6 different classes were designed using a combination of retro-fragments that appear in other TSCs. Additionally, di-substitution at the terminal N4 atom, which was previously identified to be critical for potent anti-cancer activity, was preserved through the incorporation of an N4-based piperazine or morpholine ring. The anti-proliferative activity of the novel TSCs were examined in a variety of cancer and normal cell-types. In particular, compounds 1d and 3c demonstrated the greatest promise as anti-cancer agents with potent and selective anti-proliferative activity. Structure-activity relationship studies revealed that the chelators that utilized “soft” donor atoms, such as nitrogen and sulfur, resulted in potent anti-cancer activity. Indeed, the N,N,S donor atom set was crucial for the formation of redox active iron complexes that were able to mediate the oxidation of ascorbate. This further highlights the important role of reactive oxygen species generation in mediating potent anti-cancer activity. Significantly...

Membrane-active derivatives of the frog skin peptide Esculentin-1 against relevant human pathogens

LUCA, VINCENZO
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
45.98%
Candida albicans represents one of the most prevalent species causing life-threatening fungal infections. Current treatments to defeat Candida albicans have become quite difficult, due to their toxic side effects and the emergence of resistant strains. Antimicrobial peptides (AMPs) are fascinating molecules with a potential role as novel anti-infective agents. However, only a few studies have been performed on their efficacy towards the most virulent hyphal phenotype of this pathogen. The purpose of this work is to evaluate the anti-Candida activity of the N-terminal 1–18 fragment of the frog skin AMP esculentin- 1b, Esc(1–18), under both in vitro and in vivo conditions using Caenorhabditis elegans as a simple host model for microbial infections. Our results demonstrate that Esc(1–18) caused a rapid reduction in the number of viable yeast cells and killing of the hyphal population. Esc(1–18)revealed a membrane perturbing effect which is likely the basis of its mode of action. Esc(1-18) is able (1) to kill both growing stages of Candida; (2) to promote survival of Candida-infected living organisms and (3) to inhibit transition of these fungal cells from the roundish yeast shape to the more dangerous hyphal form at sub-inhibitory concentrations. Pseudomonas aeruginosa is an opportunistic bacterial pathogen that forms sessile communities...

Complete ¹H and 13C NMR assignments and anti fungal activity of two 8-hydroxy flavonoids in mixture

Johann,Susana; Smânia-Jr,Artur; Pizzolatti,Moacir G.; Schripsema,Jan; Braz-Filho,Raimundo; Branco,Alexsandro
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2007 EN
Relevância na Pesquisa
55.69%
A mixture of the two new flavonols 8-hydroxy-3, 4', 5, 6, 7-pentamethoxyflavone (1) and 8-hydroxy-3, 3', 4', 5, 6, 7-hexamethoxyflavone (2) was isolated from a commercial sample of Citrus aurantifolia. An array of one- (¹HNMR, {¹H}-13C NMR, and APT-13C NMR) and two-dimensional NMR techniques (COSY, NOESY, HMQC and HMBC) was used to achieve the structural elucidation and the complete ¹H and 13C chemical shift assignments of these natural compounds. In addition, the antifungal activity of these compounds against phytopathogenic and human pathogenic fungi was investigated.

An endophytic fungus isolated from finger millet (Eleusine coracana) produces anti-fungal natural products

Mousa, Walaa K.; Schwan, Adrian; Davidson, Jeffrey; Strange, Philip; Liu, Huaizhi; Zhou, Ting; Auzanneau, France-Isabelle; Raizada, Manish N.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 21/10/2015 EN
Relevância na Pesquisa
46.03%
Finger millet is an ancient African cereal crop, domesticated 7000 years ago in Ethiopia, reaching India at 3000 BC. Finger millet is reported to be resistant to various fungal pathogens including Fusarium sp. We hypothesized that finger millet may host beneficial endophytes (plant-colonizing microbes) that contribute to the antifungal activity. Here we report the first isolation of endophyte(s) from finger millet. Five distinct fungal species were isolated from roots and predicted taxonomically based on 18S rDNA sequencing. Extracts from three putative endophytes inhibited growth of F. graminearum and three other pathogenic Fusarium species. The most potent anti-Fusarium strain (WF4, predicted to be a Phoma sp.) was confirmed to behave as an endophyte using pathogenicity and confocal microscopy experiments. Bioassay-guided fractionation of the WF4 extract identified four anti-fungal compounds, viridicatol, tenuazonic acid, alternariol, and alternariol monomethyl ether. All the purified compounds caused dramatic breakage of F. graminearum hyphae in vitro. These compounds have not previously been reported to have anti-Fusarium activity. None of the compounds, except for tenuazonic acid, have previously been reported to be produced by Phoma. We conclude that the ancient...