Jerônimo Raimundo de Oliveira Neto

Electroanalytical tools for antioxidant evaluation of red fruits dry extracts

Red fruits are rich sources of antioxidant compounds with recognized health benefits. Since they are perishable, dried extracts emerge as more durable products and their quality control must include antioxidant capacity assays. In this study, the redox behavior of commercial dried products obtained from camu-camu, açai, acerola and cranberry red fruits was evaluated by electroanalytical approaches. The antioxidant potential was determined by 2,2-diphenyl-1-picrylhydrazyl free radical assay and the electrochemical index concept. The total phenol content was estimated by using a laccase based biosensor. A significant correlation was found between all methods and literature data. The voltammetric profile (cyclic, differential and square wave) obtained for each type of dried extract showed distinguishable features that were correlated with their main major markers, being also useful for identification purposes. The electrochemical methods were cheaper and more practical for evaluation of antioxidant properties and total phenol content in dried powders obtained from different red fruits.

Electroanalysis and laccase-based biosensor on the determination of phenolic content and antioxidant power of honey samples

Honey is a functional food widely consumed. Thus, the evaluation of honey samples to determine its phenolic content and antioxidant capacity (AOC) is relevant to determine its quality. Usually AOC is performed by spectrophotometric methods, which lacks reproducibility and practicality. In this context, the electroanalytical methods offer higher simplicity and accuracy. Hence, the aim of this work was to use of electroanalytical tools and laccase based biosensor on the evaluation of AOC and total phenol content (TPC) of honey samples from different countries. The antioxidant power established by electrochemical index presented good correlation with the spectrophotometric FRAP (Ferric Reducing Ability of Plasma) and DPPH (2,2-Diphenyl-1-Picrylhydrazyl) radical scavenging assays. Also, TPC results obtained by the biosensor agreed with the Folin-Ciocalteu (FC) assay. In addition to the semi quantitative results, the electroanalysis offered qualitative parameters, which were useful to indicate the nature of major phenolic compounds.

Study of Ethinylestradiol Degradation by Photolysis and Photocatalysis Heterogeneous

O etinilestradiol (EE2) vem sendo considerado um dos principais desreguladores endocrinos encontrados no meio ambiente. O EE2 nao e facilmente biodegradado, sendo somente cerca de 50% removido atraves de tratamentos de efluentes convencionais. Nesse contexto, os processos oxidativos sao opcoes relevantes no intuito de degradar tais substâncias. Com o exposto, o objetivo deste trabalho foi desenvolver e validar um metodo para a deteccao e quantificacao de EE2 em matrizes aquosas atraves de cromatografia liquida de alta eficiencia associada a fluorescencia (CLAE-FLD) e aplica-lo na avaliacao da degradacao do hormonio atraves de fotolise e fotocatalise heterogenea. O metodo desenvolvido e validado mostrou-se sensivel, seletivo, exato, preciso e eficiente. Os ensaios de degradacao fotocatalitica em regime de batelada apresentaram grande eficiencia na degradacao do etinilestradiol presente em agua (cerca de 99% em 120 minutos em relacao a fotocatalise e 75% em relacao a fotolise).

Improving peptide quantification in chitosan nanoparticles

Abstract The objective of the present study was to evaluate different methodologies for peptide quantification in the supernatant of chitosan nanoparticles by removing the unliked polymer in the suspension. The ionic gelation method was used to prepare the chitosan nanoparticles encapsulating a 5.3 kDa peptide. Three different methodologies for the processment of the solutions were compared before subjecting the samples to the Bradford protocol or Qubit® kit for protein detection. For the quantification, it was necessary to create a standard peptide curve using different peptide concentrations. The suitable standard curve would be one in which the peptide was diluted in the empty chitosan supernatant (obtained after nanoparticles centrifugation) or in the filtrate of the empty chitosan supernatant. Our results indicated the safest methodology tested for peptide quantification in the supernatant chitosan nanoparticles was filtering the solution before subjecting the sample to the Bradford assay.

Preclinical Assessment of Cardiovascular Alterations Induced by Birch Polypore Mushroom, Piptoporus betulinus (Agaricomycetes)

Piptoporus betulinus has been used in folk medicine for millennia. However, no data currently exist regarding its potential cardiovascular activity. In this work, the crude ethanolic extract and fractions (hexane, ethyl acetate, and water) with increased polarity from the partitioning process, as well as stigmasterol (the major metabolite isolated from P. betulinus), were administered orally at different doses to normotensive male Wistar rats an hour before recording mean arterial pressure, heart rate, renal blood flow, renal vascular conductance, arterial blood flow, and arterial vascular conductance. The acute oral administration of crude ethanolic extract and all fractions did not alter mean arterial pressure when compared with the control group, which received a vehicle. In addition, subchronic (14 days) oral administration of crude ethanolic extract, fractions, and stigmasterol did not alter cardiovascular parameters. In conclusion, our findings demonstrate that oral administration of organic extracts of P. betulinus did not induce cardiovascular alterations.