RESUMO
Urea is an essential molecule usually detected using spectroscopy, particularly ultraviolet and visible spectroscopy (UV-vis). However, its detection represents a not always fully acknowledged issue. Its concentration dependency has raised questions about the reliability of the UV-vis results. Derivatization reactions, common alternatives to achieve accuracy and precision with UV-vis measurements, still represent an additional step in the measurement process. Besides the problems mentioned earlier, urea forms complex mixtures in aqueous mediums. Therefore, this work proposes to investigate the accuracy and precision of urea determination by UV-vis spectroscopy in the pure form and derivatized with para-dimethylaminobenzaldehyde. The results show that UV-vis spectroscopy could not quantify urea in both forms with precision and accuracy. On the other hand, when applying multivariate curve resolution with alternating least squares (MCR-ALS) to the UV-vis data, the pure urea analytical signal is mathematically separated. Then, those parameters of merit were successfully achieved.
RESUMO
Colorectal cancer (CRC) has a high incidence and resistance to conventional treatments. Curcumin (CUR) is a promising natural product in the treatment of CRC with excellent in vitro results. However, its low bioavailability is a limiting factor in clinical applications. To overcome, CUR was incorporated into hydrogels constituted by chitosan (CHT) and chondroitin sulfate (CS), natural biopolymers, capable of controlled release. Hydrogels were synthesized in ionic liquids (ILs, [Hmim][HSO4]) improving the solubility of CHT and the hydrogel properties. Furthermore, CUR was combined with silver nanoparticles (AgNPs) and visible light by Photodynamic Therapy (PDT), which, through the MEO effect (Metal-Enhanced Singlet Oxygen), leads to cell death. It is highlighted the green synthesis of AgNPs using an ultrasound bath. The CHT/CS hydrogels loaded with CUR/AgNPs were properly characterized. Cellular assays showed that the hydrogels (CHT/CS) were not cytotoxic to healthy tissues. However, PDT selective illumination led to inhibition of Caco-2 human colon cancer cells by the CHT/CS/CUR-AgNPs (CC50 = 91.5 µg mL-1 of hydrogel). The cellular uptake assays showed, in addition to the therapeutic action, that the CUR can works as a diagnostic fluorescence probe (theranostic system). Finally, we highlight our commitment to work with reagents, solvents, and methodologies aiming at the principles of green chemistry.
Assuntos
Curcumina/química , Hidrogéis/química , Nanopartículas Metálicas/química , Polissacarídeos/química , Prata/química , Oxigênio Singlete/metabolismo , Apoptose/efeitos dos fármacos , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Sulfatos de Condroitina/química , Curcumina/metabolismo , Curcumina/farmacologia , Portadores de Fármacos/química , Humanos , Líquidos Iônicos/química , Luz , Nanopartículas Metálicas/toxicidade , SolubilidadeRESUMO
Visceral leishmaniasis, caused by Leishmania infantum, is a neglected tropical disease, to which efforts in the innovation of effective and affordable treatments remain limited, despite the rising incidence in several regions of the world. In this work, the antileishmanial effects of sugiol were investigated in vitro. This compound was isolated from the bark of Cupressus lusitanica and showed promising activity against L. infantum. In spite of the positive results, it is known that the compound is a poorly water-soluble diterpene molecule, which hinders further investigation, especially in preclinical animal studies. Thus, in an alternative delivery method, sugiol was entrapped in glucan-rich particles obtained from Saccharomyces cerevisiae yeast cell walls (YCWPs). To evaluate the activity of sugiol, the experiments were divided into two parts: (i) the in vitro investigation of antileishmanial activity of free sugiol against L. infantum promastigotes after 24, 48, and 72 h of treatment and (ii) the evaluation of antileishmanial activity of sugiol entrapped in glucan-rich particles against intracellular L. infantum amastigotes. Free sugiol induced the cell-death process in promastigotes, which was triggered by enhancing cytosolic calcium level and promoting the autophagy up to the first 24 h. Over time, the presence of autophagic vacuoles became rarer, especially after treatment with lower concentrations of sugiol, but other cellular events intensified, like ROS production, cell shrinkage, and phosphatidylserine exposure. Hyperpolarization of mitochondrial membrane potential was found at 72 h, induced by the mitochondria calcium uptake, causing an increase in ROS production and lipid peroxidation as a consequence. These events resulted in the cell death of promastigotes by secondary necrosis. Sugiol entrapped in glucan-rich particles was specifically recognized by dectin-1 receptor on the plasma membrane of macrophages, the main host cell of Leishmania spp. Electron micrographs revealed particles containing sugiol within the infected macrophages and these particles were active against the intracellular L. infantum amastigotes without affecting the host cell. Therefore, the YCWPs act like a Trojan horse to successfully deliver sugiol into the macrophage, presenting an interesting strategy to deliver water-insoluble drugs to parasitized cells.
Assuntos
Antiprotozoários/farmacologia , Morte Celular/efeitos dos fármacos , Diterpenos/farmacologia , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Animais , Autofagia/efeitos dos fármacos , Cálcio/metabolismo , Parede Celular , Modelos Animais de Doenças , Feminino , Glucanos , Lectinas Tipo C , Leishmania infantum/citologia , Leishmania infantum/patogenicidade , Macrófagos/metabolismo , Potencial da Membrana Mitocondrial , Camundongos Endogâmicos BALB C , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiaeRESUMO
The objective of this study was to encapsulate a synthetic compound, the 4-[(2E)-N'-(2,2'-bithienyl-5-methylene)hydra-zinecarbonyl]-6,7-dihydro-1-phenyl-1H-pyrazolo[3,4-d]pyridazin-7-one (T6) in glucan-rich particles mainly composed by the cell wall of Saccharomyces cerevisiae (GPs) and to study their individual and combined activity on Leishmania infantum. The possible mechanism of action of T6 was also investigated. Our results showed the activity of T6 compound in both promastigote (IC50â¯=â¯2.5⯵g/mL) and intracellular amastigote (IC50â¯=â¯1.23⯵g/mL) forms. We also found activity against intracellular amastigote forms (IC50â¯=â¯8.20⯵g/mL) when the T6 compound was encapsulated in GPs. Another interesting finding was the fact that T6 encapsulated in GPs showed a significant decrease in J774A1 macrophage toxicity (CC50â¯≥â¯18.53⯵g/mL) compared to the T6 compound alone (IC50â¯=â¯2.27⯵g/mL). Through electron microscopy and biochemical methodologies, we verified that the activity of T6 in promastigote forms of L. infantum was characterized by events of cell death by apoptosis like increased ROS production, cell shrinkage, phosphatidylserine exposure and DNA fragmentation. We conclude that T6 can be considered a promising anti-Leishmania compound, and that the use of GPs for drug encapsulation is an interesting approach to the development of new effective and less toxic formulations.
Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Leishmania infantum/efeitos dos fármacos , Pirazóis/química , Saccharomyces cerevisiae/química , beta-Glucanas/química , beta-Glucanas/farmacologia , Animais , Cápsulas , Camundongos , Proteoglicanas , Células RAW 264.7RESUMO
Thiosemicarbazones are an important class of compounds that have been extensively studied in recent years, mainly because of their broad profile of pharmacological activity. A new 4-nitrobenzaldehyde thiosemicarbazone compound (BZTS) that was derived from S-limonene has been demonstrated to have significant antiprotozoan activity. However, the hydrophobic characteristic of BZTS limits its administration and results in low oral bioavailability. In the present study, we proposed the synthesis of nanoparticle-based block copolymers that can encapsulate BZTS, with morphological evaluation of the nanoparticle suspensions being performed by transmission and cryo-transmission electronic microscopy. The mean particle sizes of the nanoparticle suspensions were determined by static light and dynamic light scattering (SLS/DLS), and the hydrodynamic radius (Rh) was determined using the Stokes-Einstein equation. The zeta potential (ζ) and polydispersity index (PDI) were also determined. The entrapment encapsulation efficiency of the BZTS nanoparticles was measured by ultraviolet spectrophotometry. In vitro activity of BZTS nanoparticle suspensions against intracellular amastigotes of Leishmania amazonensis and cytotoxic activity were also evaluated. The results showed the production of spherical nanoparticles with varied sizes depending on the hydrophobic portion of the amphiphilic diblock copolymers used. Significant concentration-dependent inhibitory activity against intracellular amastigotes was observed, and low cytotoxic activity was demonstrated against macrophages.
Assuntos
Antiprotozoários/química , Nanopartículas/química , Tiossemicarbazonas/química , Animais , Antiprotozoários/farmacologia , Benzaldeídos/química , Linhagem Celular , Difusão Dinâmica da Luz , Leishmania/efeitos dos fármacos , Camundongos , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Espectrofotometria UltravioletaRESUMO
This paper describes the concentration of organochloric pesticides found in water and soils. The samples were gathered in several places of Maringa, State of Parana, Brasil. In all surfgace samples analysed, there were found high concentrations of organochloric pesticides. This high level of pesticides was found in wells, mines, and almost all samples analysed. It may not be recomended for human consumption