Carbohydrate-Derived Polytriazole Nanoparticles Enhance the Anti-Inflammatory Activity of Cilostazol.

Poly(amide-triazole) and poly(ester-triazole) synthesized from d-galactose as a renewable resource were applied for the synthesis of nanoparticles (NPs) by the emulsification/solvent evaporation method. The NPs were characterized as stable, spherical particles, and none of their components, including the stabilizer poly(vinyl alcohol), were cytotoxic for normal rat kidney cells. These NPs proved to be useful for the efficient encapsulation of cilostazol (CLZ), an antiplatelet and vasodilator drug currently used for the treatment of intermittent claudication, which is associated with undesired side-effects. In this context, the nanoencapsulation of CLZ was expected to improve its therapeutic administration. The carbohydrate-derived polymeric NPs were designed taking into account that the triazole rings of the polymer backbone could have attractive interactions with the tetrazole ring of CLZ. The activity of the nanoencapsulated CLZ was measured using a matrix metalloproteinase model in a lipopolysaccharide-induced inflammation system. Interestingly, the encapsulated drug exhibited enhanced anti-inflammatory activity in comparison with the free drug. The results are very promising since the stable, noncytotoxic NP systems efficiently reduced the inflammation response at low CLZ doses. In summary, the NPs were obtained through an innovative methodology that combines a carbohydrate-derived synthetic polymer, designed to interact with the drug, ease of preparation, adequate biological performance, and environmentally friendly production.

Concentration trend study on foaming properties for native soy protein isolate treated by ultrasound and heating.

Given the non-linearity of many protein properties with a short range of concentration which cannot be predicted a priori, and due to the lack of references in the food industry, we proceeded to analyze the foaming ones. The existing bibliography belongs to other fields of research but it is scarcely found for this area. For the food industry, ultrasound is considered one of the most environment-friendly processing. In addition, heating combination would alter their results considerably by synergistic or additive phenomena. Native soy protein isolate was obtained in our laboratory to use it as starting material; ultrasound with temperature was applied at 2, 4 and 6%w/w protein concentrations. Therefore, the objective of this paper was to determine the effect of ultrasound+temperature (50 or 90 °C) simultaneously applied, on the foamability by relating with the relative viscoelasticity, aggregates particle size distribution and their surface charge by zeta potential. The results indicated that treatments promoted changes on the functional parameters depending on the protein concentration. The analysis showed that at 4%wt/wt was adequate to improve foam formation and stability at same time. Dynamic rheology of continuous phase was relation with foamability showing the higher relative viscoelasticity at 4% of concentration after the combined treatment. Light scattering studies could partially explain this observation, taking into account both, the bulk viscosity and the low number of large particles formed after treating. Surface charge was increased for all concentrations equally leading to the aggregates formation of greater colloidal stability for all concentration and treatment conditions investigated. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-020-04954-w).

Combined Experimental and Molecular Simulation Study of Insulin-Chitosan Complexation Driven by Electrostatic Interactions.

Protein-polysaccharide complexes constructed via self-assembly methods are often used to develop novel biomaterials for a wide range of applications in biomedicine, food, and biotechnology. The objective of this work was to investigate theoretically and to demonstrate via constant-pH Monte Carlo simulations that the complexation phenomenon between insulin (INS) and the cationic polyelectrolyte chitosan (CS) is mainly driven by an electrostatic mechanism. Experimental results obtained from FTIR spectra and ζ-potential determinations allowed us to complement the conclusions. The characteristic absorption bands for the complexes could be assigned to a combination of signals from CS amide I and INS amide II. The second peak corresponds to the interaction between the polymer and the protein at the level of amide II. INS-CS complexation processes not expected when INS is in its monomeric form, but for both tetrameric and hexameric forms, incipient complexation due to charge regulation mechanism took place at pH 5. The complexation range was observed to be 5.5 < pH < 6.5. In general, when the number of INS units increases in the simulation process, the solution pH at which the complexation can occur shifts toward acidic conditions. CS's chain interacts more efficiently, i.e. in a wider pH range, with INS aggregates formed by the highest monomer number. The charge regulation mechanism can be considered as a previous phase toward complexation (incipient complexation) caused by weak interactions of a Coulombic nature.

Proteins as Nano-Carriers for Bioactive Compounds. The Case of 7S and 11S Soy Globulins and Folic Acid Complexation.

Isolated 7S and 11S globulins obtained from defeated soy flour were complexated with folic acid (FA) in order to generate nano-carriers for this important vitamin in human nutrition. Fluorescence spectroscopy and dynamic light scattering were applied to follow the nano-complexes formation and for their characterization. Fluorescence experimental data were modeled by the Stern-Volmer and a modified double logarithm approach. The results obtained confirmed static quenching. The number of binding sites on the protein molecule was ~1. The values obtained for the binding constants suggest a high affinity between proteins and FA. Particle size distribution allowed to study the protein aggregation phenomenon induced by FA bound to the native proteins. Z-average manifested a clear trend to protein aggregation. 11S-FA nano-complexes resulted in more polydispersity. ζ-potential of FA nano-complexes did not show a remarkable change after FA complexation. The biological activity of nano-complexes loaded with FA was explored in terms of their capacity to enhance the biomass formation of Lactobacillus casei BL23. The results concerning to nano-complexes inclusion in culture media showed higher bacterial growth. Such a result was attributed to the entry of the acid by the specific receptors concomitantly by the peptide receptors. These findings have technological impact for the use of globulins-FA based nano-complexes in nutraceutical, pharmaceutical and food industries.

Modification of foaming properties of soy protein isolate by high ultrasound intensity: Particle size effect.

The effect of high intensity ultrasound (HIUS) may produce structural modifications on proteins through a friendly environmental process. Thus, it can be possible to obtain aggregates with a determined particle size, and altering a defined functional property at the same time. The objective of this work was to explore the impact of HIUS on the functionality of a denatured soy protein isolate (SPI) on foaming and interfacial properties. SPI solutions at pH 6.9 were treated with HIUS for 20 min, in an ultrasonic processor at room temperature, at 75, 80 and 85°C. The operating conditions were: 20 kHz, 4.27 ± 0.71 W and 20% of amplitude. It was determined the size of the protein particles, before and after the HIUS treatment, by dynamic light scattering. It was also analyzed the interfacial behavior of the different systems as well as their foaming properties, by applying the whipping method. The HIUS treatment and HIUS with temperature improved the foaming capacity by alteration of particle size whereas stability was not modified significantly. The temperature of HIUS treatment (80 and 85°C) showed a synergistic effect on foaming capacity. It was found that the reduction of particle size was related to the increase of foaming capacity of SPI. On the other hand, the invariable elasticity of the interfacial films could explain the stability of foams over time.