Cibele Marli Cação Paiva Gouvêa

Effect of processing and roasting on the antioxidant activity of coffee brews

The aim of this work was to evaluate the effect of processing and roasting on the antioxidant activity of coffee brews. Brews prepared with light, medium and dark roasted coffees were analyzed. The pH, total solids content, polyphenols content, reducing substances and chlorogenic acids content were determined. The antioxidant activity of aqueous extracts, the guaicol decolorizing and the capacity to inhibit lipid peroxidation were also analyzed. The antioxidant activity of coffee brews were concentration-dependent. A progressive antioxidant activity and polyphenols content was observed decreasing with roasting. The light roasted coffee showed the highest antioxidant activity and dark roasted coffee showed the lowest antioxidant activity. The results indicate that the ingestion of coffee brews prepared with light and medium roasted coffees might protect cells from oxidative stress damages.

Extraction, purification and biochemical characterization of a peroxidase from Copaifera langsdorffii leaves

The aim of this work is to obtain, purify and characterize biochemically a peroxidase from Copaifera langsdorffii leaves (COP). COP was obtained by acetone precipitation followed by ion-exchange chromatography. Purification yielded 3.5% of peroxidase with the purification factor of 46.86. The COP optimum pH is 6.0 and the temperature is 35 oC. COP was stable in the pH range of 4.5 to 9.3 and at temperatures below 50.0 oC. The apparent Michaelis-Menten constants (Km) for guaiacol and H2O2 were 0.04 mM and 0.39 mM respectively. Enzyme turnover was 0.075 s-1 for guaiacol and 0.28 s-1 for hydrogen peroxide. Copaifera langsdorffii leaves showed to be a rich source of active peroxidase (COP) during the whole year. COP could replace HRP, the most used peroxidase, in analytical determinations and treatment of industrial effluents at low cost.

Avaliação in vitro da atividade antioxidante do extrato hidroalcoólico de folhas de bardana

A atividade antioxidante do extrato hidroalcoolico de folhas de bardana (EEB), das fracoes acetato de etila (ACE) e hexano (HEX) foi avaliada por meio de testes in vitro. O EEB e fracoes inibiram a peroxidacao lipidica em homogeneizado de cerebro de rato, com IC50 de 0,136 ± 0,015; 0,218 ± 0,049 e 0,628 ± 0,092 mg/mL para o EEB, ACE e HEX respectivamente. O EEB, ACE e HEX apresentaram atividade sequestrante de radicais DPPH, com IC50 de 0,029 ± 0,006; 0,089 ± 0,003 e 0,837 ± 0,160 mg/mL respectivamente. A capacidade antioxidante total do EEB foi significativamente maior (p<0,001) que a das fracoes sendo de 267,20; 55,49 e 50,02 mM de acido ascorbico, respectivamente, para o EEB, ACE e HEX. O EEB apresentou 7,88 ± 0,25 % (m/m) de compostos fenolicos, que foi significativamente (p<0,001) diferente das ACE e HEX. Os resultados indicam que os extratos analisados apresentam atividade antioxidante, sendo que o EEB foi o mais eficiente. Este e o primeiro trabalho demonstrando a atividade antioxidante de folhas de bardana.

The cytotoxic and growth inhibitory effects of palladium(II) complexes on MDA-MB-435 cells

The antitumorigenic potential of two palladium(II) complexes, [Pd(ca2-o-phen)Cl2] – C1 and [Pd(dmba)(dppp)Cl] – C2, was evaluated, using MDA-MB-435 cells, a human breast adenocarcinoma cell-line that does not express the estrogen receptor α (ER−). Growth inhibition and induced alterations in cell-morphology were analyzed. The sulforhodamine B test showed that, compared to control cells, both C1 and C2 significantly inhibited (p < 0.5) cell growth. The maximum effect with both was achieved with 1 μM complexes, after 24 h of treatment. No further cell-growth inhibition was achieved by increasing concentration or incubation time. Cell morphology was analyzed after staining with hematoxylin-eosin (HE). The morphological changes noted in the treated cells were cell rounding-up, shrinkage, nuclear condensation and reduction of cell length (p < 0.05), thereby indicating that both C1 and C2 are cytotoxic to breast adenocarcinoma cells. All together, there was every indication that, by decreasing cell growth and inducing morphological changes, the tested complexes are cytotoxic, hence their potentiality as promising candidates for antineoplastic drug development.

INFLUÊNCIA DO PROCESSAMENTO E DA TORREFAÇÃO SOBRE A ATIVIDADE ANTIOXIDANTE DO CAFÉ (Coffea arabica)

The aim of this work is to evaluate the influence of processing (semi-dry and dry) and roasting (light, medium and dark) on the antioxidant activity of coffee brews, using tests to determine the reducing power and the DPPH scavenging, Fe+2 chelating and lipid peroxidation inhibition activities. All of the coffee brews presented concentration-dependent antioxidant activity. The light coffee samples presented the higher reducing power and DPPH scavenging activity. Its ion chelating capacity was similar to the medium samples, but was less than the green coffee chelating capacity. The semi-dry processing was more efficient than the dry processing only for the reducing power. All of the samples presented high lipid peroxidation inhibition activity. Based on the results the degree of coffee roasting seems to be more important than the processing to determine the antioxidant activity of brews.

Rat skin wound healing induced by alternagin-C, a disintegrin-like, Cys-rich protein from Bothrops alternatus venom

Alternagin‐C (ALT‐C) is a disintegrin‐like, Cys‐rich protein isolated from Bothrops alternatus snake venom, which has been shown to induce in vivo angiogenesis. Therefore, this protein could be interesting as a new approach for tissue regeneration studies. Here the effects of ALT‐C on fibroblasts and inflammatory cells, collagen type III and type I and TGF‐α expression in a rat wounded skin model were studied. Thirty‐five male Wistar rats (weight 270 ± 20 g) were divided into seven groups with five animals in each of the following groups: a control group which wounded animals received treatment with natrozol® gel only; ALT‐C10, ALT‐C60 and ALT‐C100 groups of wounded animals that were treated with the same amount of gel containing 10, 60 and 100 ng of ALT‐C, respectively. Animals were treated once a day with 20 µl of gel associated or not with ALT‐C for 1, 3, 5 or 7 days. ALT‐C treatment increased the fibroblast density, collagen deposition and accelerated the inflammatory process, mostly in the ALT‐C60 group. These results indicate that ALT‐C improves wound repair process in rat skin. Thus, ALT‐C could be a candidate to the development of a novel therapeutic strategy for wounded skin repair.

Angiogenesis and growth factor modulation induced by alternagin C, a snake venom disintegrin-like, cysteine-rich protein on a rat skin wound model

In this work, we show that alternagin-C (ALT-C) and ALT-C PEP, a peptide derived from its sequence, were able to induce angiogenesis in wounded rat skin. A spherical cutaneous excision was made in the back of each animal and treated with three different concentrations of ALT-C or ALT-C PEP. After that, the skin was removed and analyzed to verify the presence of new vessels and the expression of growth factors. ALT-C and ALT-C PEP induced the formation of new vessels and modulated the expression of growth factors, mainly VEGF and FGF1. The expression of VEGF increased and it could be detected up to 7 days after injury. FGF1 also significantly increased, but at a lesser extent than VEGF. In conclusion, the present study shows for the first time the stimulation of angiogenesis in an injured tissue by a disintegrin-like protein and that ALT-C may exert this effect by modulating the expression of growth factors.

Obtenção de nova fonte de peroxidase de folha de Copaifera langsdorffii Desf. com alta atividade

Objetivou-se neste trabalho extrair peroxidase de folha de Copaifera langsdorffii (COP), medir sua atividade, compara-la com a peroxidase de raiz forte (Horseradish peroxidase - HRP) e determinar o pH otimo, a melhor solucao extratora e o efeito de aditivos sobre a atividade da COP. Os resultados mostraram que a COP atingiu 81,6% da atividade de HRP e a faixa de pH otimo foi de 5,5 a 6,0. A melhor solucao extratora da enzima foi o tampao fosfato de sodio 50 mM, pH 6,0 e o melhor aditivo foi o PVPP. Concluindo, a COP apresenta atividade mais alta que outras peroxidases de diferentes fontes citadas na literatura.

Extração e caracterização parcial de peroxidase de folhas de Copaifera langsdorffii Desf.

In the literature, several processes have been described to obtain peroxidases. The purpose of this work was to obtain peroxidase from Copaifera langsdorffii leaves and characterize it partially using a factorial design of experiments and univaried tests, to confirm the results obtained by the factorial design of experiments. Peroxidase activity was measured using the guaiacol: hydrogen peroxide system. The isolated peroxidase presented 81.6% of horseradish peroxidase activity and was easy to obtain from leaves of an abundant tree distributed all over the country. Semi-purified peroxidase (COP) was precipitated with acetone 65% (v.v-1) of the crude extract, obtaining the acetone powder. The COP optimum reaction pH values were between 5.0-7.0 and the temperatures between 5 and 45 °C, with a maximum activity at pH 6.0 and 35 °C. The enzyme was stable in temperatures below 50 °C and pH from 4.5 to 9.0 for up to 24 hours. The peroxidase was inactivated after 4 hours at 80 °C and after 3 minutes at 96 °C. This enzyme can possibly be used as a diagnostic reagent, biosensor and for other analytical methods in several fields of Sciences.