Publications

Abstract The immune system is composed of organs, cells, and soluble factors, which together act to defend the organism against foreign invaders, and is divided into innate and adaptive immune system (or acquired). Antigens are substances (usually foreign macromolecules) recognized by adaptive immune system receptors as dangerous non-self and that immediately initiate a response. While, response against normal body components (itself reaction) may occur as a result of failure in self-tolerance mechanisms, producing different autoimmune diseases which are, in general, progressive, chronic, and self-perpetuating. The available treatments aim to ameliorate or treat symptoms but have serious side-effects due to the high doses needed, as used drugs have in general low water solubility and long treatment periods. Recent advances with resource of nanotechnology aiming to achieve better results in terms of drug bioavailability and targeting to the treatment site of action as well as reduction of side effects will be discussed. In this chapter, five autoimmune diseases were selected, due to their incidence to the general population: the organ-specific diseases diabetes mellitus type I, psoriasis, multiple sclerosis, lupus erythematosus, and rheumatoid arthritis that affect several organs.

Abstract Caffeic acid phenethyl ester (CAPE) is a bioactive polyphenolic compound obtained from propolis extract. Although it has a broad therapeutic potential, the bioavailability of CAPE is limited, due to reduced solubility and poor plasmatic stability. Efforts to reduce these pharmacokinetic drawbacks resulted in the synthesis of caffeic acid phenethyl amide (CAPA). Cyclodextrins have been proved as promising excipients for the formulation of active ingredients. Herein, we report the inclusion complexation behavior and binding ability of CAPE and CAPA with hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The supramolecular interactions were examined through UV and FTIR spectroscopy, DSC, H-1 NMR and 2D ROESY. The CAPE/HP-beta-CD and CAPA/HP-beta-CD inclusion complexes stability constants were determined to be, respectively, 2911.6 and 584.6 M-1 in water and 2866.2 and 700.1 M-1 at physiological pH. The aqueous solubility increased notably, proving that HP-beta-CD can be potentially useful to improve the biological, chemical and physical properties of CAPE and CAPA.

Abstract Gastric cancer is the third leading cause of cancer-related mortality worldwide and despite advances in prevention, diagnosis and therapy, it is still regarded as a global health concern. The efficacy of the therapies for gastric cancer is limited by a poor response to currently available therapeutic regimens. One of the reasons that may explain these poor clinical outcomes is the highly heterogeneous nature of this disease. In this sense, it is essential to discover new molecular agents capable of targeting various gastric cancer subtypes simultaneously. Here, we present a multi-objective approach for the ligand-based virtual screening discovery of chemical compounds simultaneously active against the gastric cancer cell lines AGS, NCI-N87 and SNU-1. The proposed approach relays in a novel methodology based on the development of ensemble models for the bioactivity prediction against each individual gastric cancer cell line. The methodology includes the aggregation of one ensemble per cell line using a desirability-based algorithm into virtual screening protocols. Our research leads to the proposal of a multi-targeted virtual screening protocol able to achieve high enrichment of known chemicals with anti-gastric cancer activity. Specifically, our results indicate that, using the proposed protocol, it is possible to retrieve almost 20 more times multi-targeted compounds in the first 1% of the ranked list than what is expected from a uniform distribution of the active ones in the virtual screening database. More importantly, the proposed protocol attains an outstanding initial enrichment of known multi-targeted anti-gastric cancer agents.

Abstract We used steady-state and time-resolved fluorescence techniques to study the excited-state proton transfer (ESPT) and the nonradiative properties of two irreversible photoacids, 1-naphthol-4-sulfonate (1N4S) and l-naphthol-5sulfonate (1N5S). We found that the ESPT rate constant of 1N4S in water is 2.2 x 10(10) s(-1), whereas in methanol, it is smaller by about 3 orders of magnitude and is not observed. The ESPT process of 1N5S competes with a major nonradiative process of equal rate and k(pt)of 2.2 x 10(10) s(-1). in methanol-water mixtures of X-H2o = 0.2, the fluorescence lifetime of the ROH form of 1N5S is lower by a factor of 10 than that in pure methanol. In the steady-state fluorescence spectra of 1N5S in methanol-water mixtures, there are two iso-emissive points, one for X-H2o < 0.2 and one for X-H2o > 0.3. This large reduction in fluorescence intensity and the two iso-emissive points are explained by the existence of a mixed water-methanol bridge of about three molecules that connects the proton donor 1-OH with the 5-sulfonate in mixtures of X-H20 < 0.2. The bridge enhances both the ESPT and the nonradiative processes. For 1N4S in methanol-water mixtures at X-H2o approximate to 0.2, the reduction in the fluorescence lifetime is only by similar to 30%, and only one iso-emissive point exists in the steady-state fluorescence spectra for 0 <X-H2o < 1. TD-DFT computations show that a mixed bridge of one water molecule and two methanol molecules that connects the 1-OH with 5-sulfonate is more stable by 7.7 kcal/mol than the 1-OH reactant in the S-1 state, and the barrier is only 8.0 kcal/mol. The nonradiative channel is because the S-2 dark state is about 4.6 kcal/mol higher than the S-1 state.

Abstract Herein, we present experimental evidence that protic ionic liquids (PILs), derived from 1:1 liquid mixtures of the organic superbases 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with carboxylic acids, form azeotropic mixtures with acid/base molar fractions different from 1:1. The ability of the carboxylic acids to form strong hydrogen bonds with the PIL ion pair leads to an azeotropic composition richer in the acid component. The results show that the azeotropic composition is ruled by the extent of acid-base equilibrium and the relative volatility of the neutral species in the PIL medium. The PILs show marked negative deviations from Raoult's Law with the stronger superbase (DBU) leading to an azeotropic composition closer to the equimolar 1:1 ratio.

Abstract Nanoscience and technology has generated an important area of research in the field of properties and functionality of ionic liquids (ILs) based materials and their thin films. This work explores the deposition process of ILs droplets as precursors for the fabrication of thin films, by means of physical vapor deposition (PVD). It was found that the deposition (by PVD on glass, indium tin oxide, graphene/nickel and gold-coated quartz crystal surfaces) of imidazolium [C(4)mim][NTf2] and pyrrolidinium [C(4)C(1)Pyrr][NTf2] based ILs generates micro/nanodroplets with a shape, size distribution and surface coverage that could be controlled by the evaporation flow rate and deposition time. No indication of the formation of a wettinglayer prior to the island growth was found. Based on the time-dependent morphological analysis of the micro/nanodroplets, a simple model for the description of the nucleation process and growth of ILs droplets is presented. The proposed model is based on three main steps: minimum free area to promote nucleation; first order coalescence; second order coalescence.

Abstract In this work, we studied the effect of anion and cation properties on the interaction of alcohols with ionic liquids (ILs), using propan-1-ol as a molecular probe. The enthalpies of solution at infinite dilution of propan-1-ol in several ILs were measured by isothermal titration calorimetry (ITC). The calorimetric results were analysed together with molecular dynamics simulation and quantum chemical calculations of the interaction of the hydroxyl group of propan-1-ol with the anions. The results evidenced the role of the anion's basicity in the intermolecular interactions of alcohols and ionic liquids and further revealed a secondary effect of the cation nature on the solvation process. The effect of the anion basicity on the strength of the interaction of alcohols with ionic liquids was evaluated by comparing the results obtained for ILs with the same cation and different anions, [C(4)C(1)im][anion] (anions NTf2, PF6, FAP, DCA and TFA). The effect of the cation (size, aromaticity, charge distribution, and acidity) was explored using five different cations of the NTf2 series, [cation][NTf2] (cations C(4)C(1)im, C(4)C(1)pirr, C(4)py, C(4)C(1)pip, and C(3)C(1)C(1)im).

Abstract The uptake and transport of dietary antioxidants remains the most important setback for their application in therapy. To overcome the limitations, a PEGylated-based platform was developed to improve the delivery properties of two dietary hydroxycinnamic (HCA) antioxidants caffeic and ferulic acids. The antioxidant properties of the new polymer antioxidant conjugates (PEGAntiOxs), prepared by linking poly(ethylene glycol) (PEG) to the cinnamic acids by a one-step Knovenagel condensation reaction, were evaluated. PEGAntiOxs present a higher lipophilicity than the parent compounds (caffeic and ferulic acids) and similar, or higher, antioxidant properties. PEGAntiOxs were not cytotoxic at the tested concentrations in SH-SYSY, Caco-2, and hCMEC/D3 cells. By contrast, cytotoxic effects in hCMEC/D3 and SH-SYSY cells were observed, at 50 and 100/3M, for caffeic and ferulic acids. PEGAntiOxs operate as antioxidants against several oxidative stress-cellular inducers in a neuronal cell-based model, and were able to inhibit glycoprotein-P in Caco-2 cells. PEGAntiOxs can cross hCMEC/D3 mono layer cells, a model of the blood-brain barrier (BBB) endothelial membrane. In summary, PEGAntiOxs are valid antioxidant prototypes that can uphold the antioxidant properties of HCAs, reduce their cytotoxicity, and improve their BBB permeability. PEGAntiOxs can be used in the near future as drug candidates to prevent or slow oxidative stress associated with neurodegenerative diseases.