Avaliação da atividade antioxidante e antiproliferativa do extrato aquoso de frutas tropicais

The antioxidant activity of aqueous extracts of five edible tropical fruits (Spondias lutea, Hancornia speciosa, Spondias purpurea, Manilkara zapota and Averrhoa carambola) was investigated using different methods. The amount of phenolic compounds was determined by the Folin-Ciocalteu reagent. The M. zapota had Total Antioxidant Capacity (TAC) higher than the other fruits. Extracts showed neither reducing power nor iron chelation (between 0.01 and 2.0 mg/mL). H. speciosa exhibited the highest superoxide scavenging activity (80%, 0.5 mg/mL). However, at high concentrations (8.0 mg/mL) only A. carambola, S. purpurea and S. lutea scavenging 100% of radicals formed. M. zapota and S. purpurea had higher phenolic compound levels and greater OH radical scavenging activity (92 %, 2.0 mg/mL). Antiproliferative activity was assessed with 3T3 fibroblasts and cervical tumor cells (HeLa). The most potent extract was S. purpurea (0.5 mg/mL), which inhibited HeLa cell proliferation by 52%. The most fruits showed antioxidant and antiproliferative properties, characterizing them as functional foods.

Síntese e caracterização de redes metalorgânicas baseadas em zinco e ácidos benzenodicarboxílicos

Metal Organic Frameworks (MOFs) are supramolecular structures consisted of ions or metal clusters coordinated to organic ligands which are repeated in two or three dimensions. These structures have atracted much attention due to their properties such as low density, high specific surface area and large volume of pores. In this work, MOFs consisted of zinc clusters connected by ditopic ligands, terephthalic acid (1,4- H2BDC) or isophthalic acid (1,3-H2BDC) were synthesized. To obtain the proposed materials, different routes and synthetic parameters were tested, such as the molar ratio of the precursors, the addition of template molecules, the type of solvente, the addition of organic base or the type of a counter-ion of Zn salt. It was found that the variation of these parameters led to the formation of different metalorganic structures. The solids obtained were characterized by XRD, SEM and IR. For the samples identified as MOF- 5, it was verified that the structure was composed of both interpenetrated and non interpenetrated structures. These samples showed a low stability, becoming totally transformed into another structure within less than 72 hours. The addition of the nickel and/or cobalt was found to be a promissing method for increasing the stability of MOF- 5, which in this case, still remained unconverted to another structure even after 15 days of exposure to air. The samples prepared from 1,3-H2BDC were probably new, still unknown Metal Organic Frameworks

Perfil imunológico associado à susceptibilidade, resistência e cura na infecção por Leishmania ( Leishmania ) infantum

Visceral Leishmaniasis (VL) is endemic in Brazil and the northeast region had the highest incidence of the disease , despite, in the last 30 years, it has spread to all geographic regions of the country. Leishmania infantum is the m ain etiological agent of VL in Latin America, Europe and North Africa. However, not all infected individuals develop the disease; in fact, the majority present spontaneous re solution of infection without symptoms. The evaluation of the immunological profil e has been mostly conducted stimulating, with Leishmania spp. antigen, peripheral blood mononuclear cells isolated from subjects with VL. These studies showed that VL patients had an inhibition of both, lymphocyte proliferation and proinflammatory response to Leishmania spp. antigen. Our study aimed to evaluate the immune response in active LV, cured post treatment and asymptomatic infection. To reach this aim, we analyzed immunophenotypic features related to activation, Treg and memory lymphocytes, by flow cytometry, as well as, evaluation of cytokine production, in ex vivo or in whole blood culture. In active VL volunteers, a longitu dinal study was conducted with reassessment at 4 and 14 months after clinical cure. The control group included individuals th at live d in endemic region and were either Positive Control, consisting of individuals with positive anti - L eishmania spp. serology and/or positive PCR for Leishmania  spp. and Negative Control composed by individuals with negative anti - Leishmania antibodie s serology and negative PCR for Leishmania . During VL, CD4 lymphocytes showed greater activation and memory profile s and were the major source of cytokines in culture when compared to CD8 lymphocytes , and these were not Leishmania specific. There were act ivated lymphocytes during VL (CD4 + CD69 + :4.9%) when compared to control groups, Positive (CD4 + CD69 + :1.96%, p=0.0045) and Negative (CD4 + CD69 + :1.35%, p=0.006), on the other hand, this was non - specific activation. The lymphocyte activation profile remain ed el evated even 14 months post treatmen t. A fter clinical cure , the activation was Leishmania specific (CD4 + CD25 + absence of SLA: 8.4%, and presence of SLA: 10.7% p=0.0279). CD8 + CD25 + lymphocytes were able to produce Leishmania specific IFN - γ in both, Positive Controls (absence of SLA 5.2% and presence of SLA: 9.5%, p=0.0391) and Cured 4 month (absence of SLA: 3.9%; presence of SLA: 10.7% p=0.0098). Whole blood culture cells, of VL patients, were able to produce IFN - γ, by SLA stimulation (absence of SLA: 28.0 pg ∕mL, and presence: 44.3 pg∕mL p=0.0020) as well as recovered groups (absence of SLA 2.3 pg∕mL and presence of SLA 139.8 pg∕mL, p=0.0005). However, the high level of IL - 10 seem ed to inhibit pro - inflammatory activity of IFN - γ and TNF - α during symptomatic dis ease . Unlike other pro - inflammatory cytokines, active VL group d id not produce Leishmania specific IL - 2 (absence of SLA 2.4 pg∕mL and presence of SLA: 2.6 pg∕mL). Based on these data we conclude that the restoration of lymphocyte activation and decreased i n IL - 10 Leishmania specific production were related to a protective immune profile.

Síntese, estrutura e propriedades de polímeros de coordenação à base de íons lantanídeos e ácidos benzenodicarboxílicos

Metal Organic Frameworks (MOFs) are hybrids materials, often crystalline, consisting of metal or metal clusters, connected by polytopic organic ligands repetitively, leading to structures, usually porous. In this work, MOFs based on lanthanide ions (La3+ and Gd3+) and dicarboxylate type of ligands (isophthalic and terephthalic acids), were synthesized by hydrothermal, solvothermal and hydro(solvo)thermal methods. The effects of the synthetic route as well as the type of heating, conventional or by microwave, on the structure and properties of MOFs were studied. The powder samples obtained were characterized by X-ray diffraction, infrared spectroscopy, thermal analysis and scanning electron microscopy. The results suggest that the addition of an organic or inorganic base is needed to promote the deprotonation of the ligand, since in the samples prepared by the hydrothermal method, without the use of a base, no formation of the metalorganic framework was observed. On the other hand, the presence of DMF as solvent or cosolvent, afforded the deprotonation of the ligand with the consequent formation of MOFs. At least two different crystalline structures were identified for the samples prepared with terephthalic acid. These samples are isostructural with those reported for phases Eu(1,3-BDC)DMF, Eu2(1,4-BDC)3 (DMF)2 and Tb(1,4-BDC)H2O. The presence of water in the reaction medium in the hydro(solvo)thermal method, provoked the growth of the structure different from that observed in the absence of water. This can be explained by the difference in the coordination mode of water and DMF to lanthanide ions. Although not identified by XRD, the samples prepared with isophthalic acid, also present metalorganic structures, which was confirmed by the presence of the characteristic displacement of the carbonyl group band in their infrared spectra, compared to the spectrum of the pure ligand. This shift was also observed in the samples prepared with terephthalic acid. Thermal analisys shows that the metal organic frameworks do not collapse occurs at a temperature below 430°C.The analysis of scanning electron microscopy suggests that the morphology of powders is highly dependent on the type of heating used, conventional or by microwave.