RESUMO
In chronic wound treatment, the debridement of devitalized tissue and the eradication of the biofilm must balance aggressiveness with care to protect regenerating tissues. In this study, urea, a potent chaotropic molecule, was modulated through the formation of a Natural Deep Eutectic Solvent (NADES) with betaine to develop a new debriding material (BU) suitable for application into injured dermal tissues. To evaluate BU's debriding capacity, along with its antibiofilm effect and biocompatibility, pre-clinical to clinical methods were employed. In vitro determinations using artificial and clinical slough samples indicate that BU has a high debriding capacity. Additionally, BU's de-structuring effects lead to a strong antibiofilm capability, demonstrated by a reduced bacterial load compared to the antiseptic PHMB-Betaine or medical honey, evaluated in artificial slough and ex vivo human skin. Furthermore, BU's efficacy was evaluated in a murine model of diabetic wound, demonstrating significant effects on debriding and antibiofilm capacity, similar to those observed in PHMB-Betaine and medical honey-treated animals. Finally, BU was clinically evaluated in leg ulcers, showing superiority in reduction of bacterial load and wound area compared to honey, with no adverse effects. Thus, BU represents a simple and non-biocidal option that could contributes to chronic wound care.
Assuntos
Betaína , Biofilmes , Desbridamento , Solventes , Cicatrização , Biofilmes/efeitos dos fármacos , Animais , Betaína/farmacologia , Betaína/química , Humanos , Solventes/química , Cicatrização/efeitos dos fármacos , Desbridamento/métodos , Camundongos , Masculino , Feminino , Ureia , Mel , Pele/microbiologia , Pele/efeitos dos fármacos , Doença Crônica , Antibacterianos/farmacologia , Antibacterianos/administração & dosagem , Antibacterianos/química , Pessoa de Meia-Idade , Diabetes Mellitus Experimental/tratamento farmacológico , IdosoRESUMO
The enzymatic synthesis of short-tailed alkyl glucosides is generally carried out in an aqueous-organic biphasic reaction medium with a rather low fatty alcohol concentration in the aqueous phase (where the synthesis occurs). Thus, hydrolytic reactions have a significant impact on the synthesis performance. Given this background, the use of acetone as cosolvent was studied for the synthesis of butyl-ß-galactoside with Aspergillus oryzae ß-galactosidase. The liquid-liquid equilibrium of the reaction mixture components (acetone/1-butanol/aqueous solution) was determined and the single- and two-phase regions were defined at 30, 40, and 50°C. It was observed that the liquid-liquid equilibrium of the ternary system acetone/1-butanol/water differs significantly from the one obtained using an aqueous solution (50 mM McIlvaine buffer pH 4.5; 5 g L-1) instead of water. This is mainly because of the salting-out effect of the buffer; nevertheless, the presence of lactose also altered the equilibrium. Having this in mind, the effects of temperature (30 and 50°C) and reaction mixture composition were assessed. Three general conditions were evaluated: single-phase ternary system (30% acetone), two-phase ternary system (10% acetone) and two-phase binary system (0% acetone). Acetone had a deleterious effect on enzyme stability at 50°C, leading to low reaction yields. However, no enzyme deactivation was detected at 30°C. Moreover, a reaction yield of 0.98 mol mol-1 was attained in the 30/50/20% (w/w) mixture of acetone/1-butanol/aqueous solution. This very high yield can be explained by the huge increase in the concentration of 1-butanol and the reduction of water activity. The synthesis was carried out using also the ß-galactosidase immobilized in glyoxal-agarose and amino-glyoxal-agarose, and by aggregation and crosslinking. In the case of agarose-derived catalysts, two average particle diameters were assessed to evaluate the presence of internal mass transfer limitations. Best yield (0.88 mol mol-1) was obtained with glyoxal-agarose derivatives and the particle size had non-effect on yield. The chemical structure of butyl-ß-galactoside was determined by NMR and FT-IR.
RESUMO
Homopolymannuronic and homopolyguluronic fractions were obtained by partial hydrolysis of the alkaline extracts from the brown seaweeds Ascoseira mirabilis, Desmarestia menziessi, Desmarestia ligulata and Durvillaea sp. collected in southern Chile. Full characterization of the fractions was achieved by FT-IR and NMR spectroscopy. Total hydrolysis with 90% formic acid of the homopolymeric fractions allowed the preparation of mannuronic and guluronic acids. Both monomers and homopolymeric fractions as neutral salts were studied by CD and ORD. Chiroptical spectra were similar in shape and sign to those previously published in the literature, and permitted to assign D configuration to mannuronic acid and L configuration to guluronic acid in alginic acids. Specific optical rotation values at the sodium D light for the homopolymannuronic (â¼-100°) and homopolyguluronic (â¼-110°) acid fractions were obtained. These high negative values are proposed for the assignment of the absolute configuration of monomers in homopolymeric fractions.