Daniela Moura de Oliveira

Phenolic acid concentrations in plasma and urine from men consuming green or black tea and potential chemopreventive properties for colon cancer

SCOPE Tea polyphenols are metabolized by the colonic microflora yielding phenolic metabolites, which may contribute to the health benefits of tea. We determined the serum and urine concentrations of phenolic acids, hippuric acid, and polyhydroxyphenyl-γ-valerolactones during green tea (GT) and black tea (BT) administration. The effects of (-)-epigallocatechin gallate (EGCG) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA) alone and in combination on bioavailability, intracellular metabolism, and antiproliferative activity were determined in HCT-116 colon cancer cells. METHODS AND RESULTS The concentration of phenolic metabolites was quantified by HPLC with electrochemical detection and MS. Urine concentrations of 4-hydroxyphenylacetic acid (4-HPAA), 3-hydroxyphenylacetic acid (3-HPAA), and polyhydroxy-γ-valerolactones were increased significantly in men drinking GT compared to control. Urine concentration of 3-O-methylgallic acid (3OMGA) was significantly increased in men drinking BT compared to control. Serum 3,4-DHPAA was significantly increased after consumption of GT and BT and 4-HPAA after GT consumption. In vitro treatment of HCT-116 colon cancer cells with 3,4-DHPAA and EGCG exhibited an additive antiproliferative effect, while methylation of 3,4-DHPAA was significantly decreased. 3OMGA exhibited the strongest antiproliferative activity among the phenolic acids. CONCLUSION The consumption of both, GT and BT, was associated with a significant increase in urinary and serum phenolic acids.

Yerba Maté (Ilex paraguariensis) aqueous extract decreases intestinal SGLT1 gene expression but does not affect other biochemical parameters in alloxan-diabetic Wistar rats.

Yerba maté (Ilex paraguariensis) is rich in polyphenols, especially chlorogenic acids. Evidence suggests that dietary polyphenols could play a role in glucose absorption and metabolism. The aim of this study was to evaluate the antidiabetic properties of yerba maté extract in alloxan-induced diabetic Wistar rats. Animals (n = 41) were divided in four groups: nondiabetic control (NDC, n = 10), nondiabetic yerba maté (NDY, n = 10), diabetic control (DC, n = 11), and diabetic yerba maté (DY, n = 10). The intervention consisted in the administration of yerba maté extract in a 1 g extract/kg body weight dose for 28 days; controls received saline solution only. There were no significant differences in serum glucose, insulin, and hepatic glucose-6-phosphatase activity between the groups that ingested yerba maté extract (NDY and DY) and the controls (NDC and DC). However, the intestinal SGLT1 gene expression was significantly lower in animals that received yerba maté both in upper (p = 0.007) and middle (p < 0.001) small intestine. These results indicate that bioactive compounds present in yerba maté might be capable of interfering in glucose absorption, by decreasing SGLT1 expression.

Determination of binding constant Kb of biocompatible, ferrite-based magnetic fluids to serum albumin

In this work, we investigated the interaction between molecular-coated magnetic nanoparticles (MC-MNPs) and serum albumin proteins (BSA) through the fluorescence quenching of the tryptophan residue present in BSA after the binding of MC-MNPs to specific sites. Three different biocompatible magnetic fluid (BMF) samples based on magnetite or cobalt–ferrite MNPs coated with citric acid or dextran were used. The binding constant and the stoichiometry of the investigated MNPs indicate that the BMF based on cobalt–ferrite is more site specific and more strongly bound to the BSA than the BMFs based on magnetite. The results may direct the design of new magnetic drug-carriers based on BMFs.In this work, we investigated the interaction between molecular-coated magnetic nanoparticles (MC-MNPs) and serum albumin proteins (BSA) through the fluorescence quenching of the tryptophan residue present in BSA after the binding of MC-MNPs to specific sites. Three different biocompatible magnetic fluid (BMF) samples based on magnetite or cobalt–ferrite MNPs coated with citric acid or dextran were used. The binding constant and the stoichiometry of the investigated MNPs indicate that the BMF based on cobalt–ferrite is more site specific and more strongly bound to the BSA than the BMFs based on magnetite. The results may direct the design of new magnetic drug-carriers based on BMFs.

Biodisponibilidade de ácidos fenólicos

The daily intake of phenolic compounds does not necessarily reflect the dose at which they reach the physiological targets in the organisms. The biological activity of phenolic compounds metabolites found in blood, organs and target tissues, as a result of digestive and hepatic activity, may differ from those of the native forms of the substances. This review discusses the absorption and metabolism of phenolic acids, a class of phenolic compounds abundant in food, and the methodologies used for evaluation of bioavailability.

The effect of bovine serum albumin on the binding constant and stoichiometry of biocompatible magnetic fluids

In this work, we investigated the interaction between different molecular-coated magnetite nanoparticles and the serum albumin protein. The investigation was based on the fluorescence quenching of the tryptophan residue of the serum albumin protein after the binding with the molecular-coated magnetite nanoparticles to specific sites. Three different biocompatible magnetic fluid samples based on magnetite nanoparticles surface-coated with carboxymethyldextran, tartrate, and polyaspartic were used. Significant differences in the values of binding constant (K/sub b/) and stoichiometry (n) were found as the surface-coating species are changed. The results obtained from the molecular-coated magnetite nanoparticles having different coatings indicate the effect of the coating material in the biological association of magnetite nanoparticles to biological macromolecules.

Effects of Mate Tea Intake on ex Vivo LDL Peroxidation Induced by Three Different Pathways

Yerba maté (Ilex paraguariensis) is a native South America plant widely consumed as different beverages. Yerba maté leaves contains high concentrations of polyphenols that are responsible for its high in vitro and in vivo antioxidant activity. The in vivo antioxidant properties vis a vis LDL particles has not yet been studied for maté tea, the roasted yerba maté product. The aim of this study was to evaluate the antioxidant activity of maté tea ingestion ex vivo on human LDL. Fasting peripheral venous blood samples of healthy women were taken in three different times: before drinking the tea, one hour later and after one week (7 days) of daily consumption of maté tea. The isolated LDL was oxidized by three different pathways [copper (CuSO4), lipoxygenase and peroxynitrite (SIN-1)]. Conjugated dienes and structural modifications on LDL were evaluated. Ingestion of maté tea increased LDL resistance towards ex vivo copper oxidation, but did not alter the peroxidation pattern when SIN-1 or lipoxygenase were used as oxidants

Evaluation of new complexes of biocompatible magnetic fluid and 3/sup rd/ generation of photosensitizer useful to cancer treatment

This paper introduces a new class of complex materials that combine the action of photodynamic therapy (PDT) and hyperthermia (HPT) therapies, designed to work in a synergic way, leading to an expected enhancement of the tumor damage after minimum doses of heat dissipation and/or visible light photosensitization . In this study, we evaluated comparative dark and light toxicity of the photosensitisers (PS), biocompatible magnetic fluids(BMF) and BMF/PS complex in the J774-A cell line. Maghemite nanoparticles are surface coated with phosphate (PPT) and chlorine e/sub 6/ (Chle/sub 6/) is used as a PS drug. In the dark toxicity studies, five different concentration of Chle/sub 6/ were evaluated at the lower dark toxicity concentration (5 /spl mu/M). The same studies were developed in the presence of BMFs. No change was observed upon the addition of BMFs. Light toxicity studies were performed with three different fluence of visible light irradiation (2, 5 and 10 J/cm/sup 2/). The methodology used to investigate the cell toxicity in both protocol was the classical MTT assay. All the results presented here allow the development of a new drug generation for cancer treatment extending the possibility of the use of the Chle6/PPT complex as a candidate for maximum tumor damage, acting via photoactivation and/or magnetic field exposure.

Characterization of the estrous cycle in Galea spixii(Wagler, 1831)

The Galea spixii inhabits semiarid vegetation of Caatinga in the Brazilian Northeast. They are bred in captivity for the development of researches on the biology of reproduction. Therefore, the aim of this study is characterize the estrous cycle of G. spixii, in order to provide information to a better knowledge of captive breeding of the species. The estrous cycle was monitored by vaginal exfoliative cytology in 12 adult females. After the detection of two complete cycles in each animal, the same were euthanized. Then, histological study of the vaginal epithelium, with three females in each phase of the estrous cycle was performed; five were paired with males for performing the control group for estrous cycle phases, and three other were used to monitor the formation and rupture of vaginal closure membrane. By vaginal exfoliative cytology, predominance of superficial cells in estrus, large intermediate cells in proestrus, intermediate and parabasal cells, with neutrophils, in diestrus and metestrus respectively was found. Estrus was detected by the presence of spermatozoa in the control group. By histology, greater proliferation of the vaginal epithelium in proestrus was observed. We conclude that the estrous cycle of G. spixii lasts 15.8 ± 1.4 days and that the vaginal closure membrane develops until complete occlusion of the vaginal ostium, breaking after few days. Future studies may reveal the importance of this fact for the reproductive success of this animal.

Development and Validation of Methods for the Extraction of Phenolic Acids from Plasma, Urine, and Liver and Analysis by UPLC-MS

This study developed and validated a method for the extraction and determination of 11 phenolic acids in rat plasma, urine, and liver by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). A system suitability test (instrumental linearity, area, and retention time precision) was performed and recovery, intraday and between-day precisions, detection limits (LOD), and quantification limits (LOQ) were determined for all compounds in each biological matrix. Recoveries varied between 88 and 117% in plasma, between 87 and 102% in urine, and between 38 and 100% in liver. Precision was higher than 13.7% intraday and 14.0% interday in all matrices, at three concentration levels. To demonstrate the applicability, the method was used to estimate the concentrations of phenolic acids in samples from animals that received 5-caffeoylquinic acid (5-CQA) by gavage. The excellent validation results and the applicability of the method to real samples confirmed the suitability for studies on absorption, bioavailability, and pharmacokinetics of phenolic acids derived from foods rich in phenolic compounds.

Investigation of pheophorbide∕magnetic fluid complex as a promising system for early cancer detection and treatment

The present work reports on a class of materials for the combined action of photodynamic therapy (PDT) and hyperthermia therapy (HPT). These materials are designed to work in a synergic way, leading to an expected enhancement of the tumor damage after minimum doses of heat dissipation and∕or light photosensitization. Pheophorbide-a (Pheo) has been studied and used for PDT with total absence of dark toxicity to cell by itself. Studies using biocompatible magnetic fluids (MFs) also indicate absence of toxicity without the application of ac magnetic field. The spectroscopic and photophysical properties of the Pheo∕MF were investigated to evaluate their photodynamic and HPT characteristics. The results clearly indicate that Pheo presents similar spectroscopic properties associated or not with the MF sample, working efficiently as a photodynamic drug in both conditions.