Quantitative structure-activity relationships (QSAR) studies of bisbenzamidines with antifungal activity

This paper describes 2D-QSAR and 3D-QSAR studies against Candida albicans and Cryptococcus neofarmans for a set of 20 bisbenzamidines. In the studies of 2D-QSAR with C. albicans it was obtained a correlation between log MIC-1 and lipolo component-Z (r² = 0.68; Q² = 0.51). In the case of C. neofarmans a correlation between log MIC-1 and lipolo component-Z and of Balaban index (r² = 0.85; Q² = 0.6) was obtained. 3D-QSAR studies using CoMFA showed that the steric fields contributed more to the predicted activities for Candida albicans (94.9%) and Cryptococcus neofarmans (97.9%).FAPEMIGCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNP

Sobre o uso de métodos quimiométricos em química combinatória The use of chemometric methods on combinatorial chemistry

<abstract language="eng">Combinatorial chemistry has emerged as a tool to circumvent a major problem of pharmaceutical industries to discover new lead compounds. A rapid and massive evaluation of a myriad of newly synthesised compounds can be carried out. Combinatorial synthesis leads to high throughput screening en masse towards another myriad of biological targets. The design of a set of compounds based upon combinatorial chemistry may be envisaged by using of QSPR-SIMCA and QSAR-SIMCA as tools for classification purposes. This work deals with the definition and establishment of a spanned substituent space (SSS) that reduces the analogue numbers with no exclusion of global content. The chemical diversity may be set properly within a specified pharmacological field. This allows a better use of its potentiality without loosing information

Bio-based nanocomposites obtained through covalent linkage between chitosan and cellulose nanocrystals

AbstractBio-based nanocomposites were obtained through covalent linkage between cellulose nanocrystals (CNCs) and the natural polymer chitosan (CH). The CNCs were first functionalized with methyl adipoyl chloride (MAC) and the reactive end groups on the surface of the CNCs were reacted with the amino groups of the CH biopolymer in an aqueous medium. The functionalized CNCs and the resulting nanocomposites were characterized using FTIR, TEM, XRD, and elemental analyses. Characterization of the functionalized CNCs showed that up to 8% of the hydroxyl groups in the nanocrystals were substituted by the MAC residue. The covalent linkage between the CNCs and CH was confirmed by FTIR spectroscopy. The nanocomposites demonstrated a significant improvement in the mechanical performance and a considerable decrease in the hydrophilicity relative to the neat chitosan. The approach used in this work can be extended to other natural polymers

Characterization of a Sulfonated Polycarbonate Resistive Humidity Sensor

sensor

Comparison of the Effect of Sol-Gel and Coprecipitation Routes on the Properties and Behavior of Nanocomposite Chitosan-Bioactive Glass Membranes for Bone Tissue Engineering

Recent studies in tissue engineering have highlighted the importance of the development of composite materials based on biodegradable polymers containing bioactive glasses, in particular, composites for high load support and excellent cell viability for potential application in bone regeneration. In this work, hybrid composite films were obtained by combining chitosan with bioactive glass in solution form and in nanoparticle dispersion form obtained by the two different synthesis routes: the sol-gel method and coprecipitation. The bioactive glass served both as a mechanical reinforcing agent and as a triggering agent with high bioactivity. The results of in vitro assays with simulated body fluid demonstrated the formation of a significant layer of fibrils on the surface of the film, with a typical morphology of carbonated hydroxyapatite, reflecting induction of a favorable bioactivity. Maximum tensile stress increased from 42 to 80 MPa to the sample with 5% wt bioactive glass. In addition, samples containing 5% and 10% wt bioactive glass showed a significant increase in cell viability, 18 and 30% increase compared to the control group. The samples showed significant response, indicating that they could be a potential material for use in bone regeneration through tissue engineering

Selective Sulfenylative Desulfonylation or Decarbalkoxylation of -Sulfonyl Malonates with DABCO or Bu3N: Reactivity and Conformational Analysis

The study on reactivity of several -substituted -sulfonyl malonates toward 1,4-diazabicyclo[2.2.2]octane (DABCO) and Bu3N is described. The reactivity with DABCO revealed the possible competition between decarbalkoxylation and unexpected desulfonylation, depending on the -substituent, because of sterical hindrance around the electrophilic centers (SO2 and CO2R). The derivatives with crowded -substituents suffer selective desulfonylation, and a novel and efficient desulfonylation method can be proposed. The dependence of the reactivity of -sulfonyl malonates on the sterical hindrance around the electrophilic centers is confirmed by conformational analysis (Macromodel/MM2* and Mopac/MP3). The carbanionic mechanism is proved because the corresponding protonated, deuterated, and sulfenylated products were obtained by addition of the corresponding electrophilic agents. Bu3N showed itself to be a novel selective decarbalkoxylation agent for any -substituted -sulfonyl malonate.FAPEMIG (Fundacao de Amparo a Pesquisa de Minas Gerais[EDT 479/07]Fundacao de Amparo a Pesquisa de Minas Gerais (FAPEMIG)FAPEMIG (Fundacao de Amparo a Pesquisa de Minas Gerais[CEX PPM III 0207/09]Fundacao de Amparo a Pesquisa de Minas Gerais (FAPEMIG)CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Arylfurans as potential Trypanosoma cruzi trypanothione reductase inhibitors

The natural lignans veraguensin and grandisin have been reported to be active against Trypanosoma cruzi bloodstream forms. Aiming at the total synthesis of these and related compounds, we prepared three 2-arylfurans and eight 2,5-diarylfurans. They were evaluated for their potential as T. cruzi trypanothione reductase (TR) inhibitors as well against the parasite's intracellular (amastigote) and bloodstream (trypomastigote) forms. Compound 12 was the most effective against TR with an IC50 of 48.5 μM while 7 and 14 were active against amastigotes, inhibiting the parasite development by 60% at 20 μg/ml (59 and 90 μM, respectively). On the other hand, none of the compounds was significantly active against the parasite bloodstream forms even at 250 μg/ml (0.6-1.5 mM)

Hybrid layer-by-layer assembly based on animal and vegetable structural materials: multilayered films of collagen and cellulose nanowhiskers

Layer-by-layer (LBL) assembly was used to combine crystalline rod-like nanoparticles obtained from a vegetable source, cellulose nanowhiskers (CNWs), with collagen, the main component of skin and connective tissue found exclusively in animals. The film growth of the multilayered collagen/CNW was monitored by UV-Vis spectroscopy and ellipsometry measurements, whereas the film morphology and surface roughness were characterized by SEM and AFM. UV-Vis spectra showed the deposition of the same amount of collagen, 5 mg m(-2), in each dipping cycle. Ellipsometry data showed an increment in thickness with the number of layers, and the average thickness of each bilayer was found to be 8.6 nm. The multilayered bio-based nanocomposites were formed by single layers of densely packed CNWs adsorbed on top of each thin collagen layer where the hydrogen bonding between collagen amide groups and OH groups of the CNWs plays a mandatory role in the build-up of the thin films. The approach used in this work represents a potential strategy to mimic the characteristics of natural extracellular matrix (ECM) which can be used for applications in the biomedical field.CNPqCAPES[04/2008]FAPEMIG[021/2008]FAPEMIG[PPM III 0207/09]FAPEMIG[PRONEX EDT 479/07]Pro-reitoria de Pesquisa-UFM