RESUMO
In this study, Schiff bases of chitosan (CS) were synthesized using citronellal, citral, and their derivatives containing selenium and sulfur. Organoselenium and organosulfur compounds show attractive biological and pharmaceutical activities, which can be beneficial to CS-based materials. From the characterization analyses, it was found that the CS-derivatives containing organoselenium and organosulfur compounds exhibited the highest conversion degrees (23 and 28%). Biological assays were conducted using films prepared by the blending of CS-derivatives and poly(vinyl alcohol). The antimicrobial evaluation indicated that the film prepared with the sulfur-containing CS was the most active against the tested pathogens (Escherichia coli, Staphylococcus aureus, and Candida albicans) since it reduced considerably their counts (42.5%, 17.4%, and 18.7%). Finally, in vivo assays revealed that this film attenuates atopic dermatitis-like symptoms in mice by suppressing the increase of myeloperoxidase (MPO) activity and reactive species (RS) levels induced by 2,4-dinitrochlorobenzene (DNCB). In summary, CS-derivatives containing chalcogens, mainly organosulfur, are potential candidates for biomedical applications such as for the treatment of chronic skin diseases.
Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Quitosana , Dermatite Atópica/tratamento farmacológico , Compostos Organosselênicos/farmacologia , Bases de Schiff/farmacologia , Animais , Candida albicans/efeitos dos fármacos , Calcogênios/farmacologia , Quitosana/análogos & derivados , Quitosana/farmacologia , Dermatite Atópica/induzido quimicamente , Dinitroclorobenzeno/química , Modelos Animais de Doenças , Escherichia coli/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Peroxidase/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacosRESUMO
Waste coffee-grounds (WCG), a poorly explored source of biocompounds, were combined with chitosan (Cs) and poly(vinyl alcohol) (PVA) in order to obtain composites. Overall, WCG showed a good interaction with the polymeric matrix and good dispersibility up to 10â¯wt-%. At 5â¯wt-% WCG, the composite exhibited a noticeable enhancement (from 10 to 44%) of the adsorption of pharmaceuticals (metamizol (MET), acetylsalicylic acid (ASA), acetaminophen (ACE), and caffeine (CAF)) as compared to the pristine sample. The highest removal efficiency was registered at pH 6 and the removal followed the order ASAâ¯>â¯CAFâ¯>â¯ACEâ¯>â¯MET. For all pharmaceuticals, the adsorption kinetics was found to follow the pseudo-second order model, while the adsorption mechanism was explained by the Freundlich isotherm. Reuse experiments indicated that the WCG-containing composite has an attractive cost-effectiveness since it presented a remarkable reusability in at least five consecutive adsorption/desorption cycles.
Assuntos
Quitosana/química , Café/química , Purificação da Água/métodos , Acetaminofen/química , Adsorção , Aspirina/química , Cafeína/química , Dipirona/química , Cinética , Preparações Farmacêuticas/químicaRESUMO
In this study, copper nanoparticles (CuNPs) were synthesized and stabilized into a chitosan/poly(vinyl alcohol) (CP) based film using a simple protocol under mild conditions. The polymeric matrix utilized in this study allows synthesizing stable nanoparticle with narrow size distribution within the film matrix. Further, this system showed very attractive properties, such as good mechanical properties, chemical resistance, easy handling during use and recovery, relatively low-cost as compared to other similar systems, among others. The catalytic performance of CP-Cu film was tested in the reduction reaction of nitrobenzene (NB) to aniline (AN). Our findings reveal that CP-Cu film catalyzes the reaction efficiently and also decreases the energy of activation (Ea) as compared to other catalysts. The catalytic efficiency of CP-Cu regarding this reaction was kept even after 6 consecutive reuse cycles. All these results rank this novel system as a promising catalyst in the reduction of aromatic nitro compounds to aromatic amines.