Ivan Castelar

Antibacterial and cytotoxic properties of some plant crude extracts used in Northeastern folk medicine

In the present study, 32 hexane and ethanol extracts of Protium bahianum, P. heptaphyllum, Croton sellowii, C. rhamnifolius, C. jacobinensis, C. micans and Muntingia calabura were screened for antibacterial activity by the disc-diffusion method. Cytotoxicity assays using the brine shrimp Artemia salina Leach as a model were performed to determine lethal doses for 50% of individuals (LC50 µg/mL). Antibacterial activity was found in flowers hexane extracts of M. calabura against B. subtilis, and leaves ethanol extracts against S. aureus and B. subtilis at concentration of 1mg/mL. Among 32 extracts, 19 showed low or no toxicity (LC50 > 250 µg/mL), 6 showed moderate toxicity (LC50 between 80 µg/mL and 250µg/mL), and 7 were highly toxic (LC50 < 80 µg/mL).

Previsão da demanda por energia elétrica para classes de consumo na região Nordeste, usando OLS dinâmico e mudança de regime

The objective of this research is to estimate the residential, commercial and industrial demand for electric energy in the Northeast of Brazil during the period 1970-2003. Two different methodologies were used to compute price and income elasticities of demand: i) DOLS, proposed by Stock and Watson (1993); and ii) Regime Switching, by Gregory and Hansen (1996). Error Correction Models were estimated using the cointegrating vectors. These models are used to perform long-run forecasts of demand for the period 2004-2010. The main results are then compared to those from other studies about Brazilians price and income elasticities of demand for electric energy. Furthermore, an analysis of forecast performance shows that these models predict as good or better than Eletrobras and Siqueira, Cordeiro Jr. e Castelar (2006).

Polyphenol Composition, Antioxidant Activity and Cytotoxicity of Seeds from Two Underexploited Wild Licania Species: L. rigida and L. tomentosa

Studies have shown the benefit of antioxidants in the prevention or treatment of human diseases and promoted a growing interest in new sources of plant antioxidants for pharmacological use. This study aimed to add value to two underexploited wild plant species (Licania rigida) and L. tomentosa) from Brazilian flora. Thus, the phenolic compounds profile of their seed ethanol extract and derived fractions were elucidated by HPLC, the antioxidant capacity was assessed by in vitro chemical tests and the cytotoxicity determined using the human carcinoma cell lines MCF-7 and Caco-2. Eleven phenolic compounds were identified in the extracts of each species. The extracts and fractions showed excellent antioxidant activity in the DPPH assay (SC50, ranging from 9.15 to 248.8 µg/mL). The aqueous fraction of L. rigida seeds was most effective in preventing lipid peroxidation under basal conditions (IC50 60.80 µg/mL) whereas, in the presence of stress inducer, the methanolic fraction of L. tomentosa performed best (IC50 8.55 µg/mL). None of the samples showed iron chelating capacity. Ethanolic seed extracts of both species did not reveal any cytotoxicity against MCF-7 and Caco-2 cells. Both plant species showed a promising phenolic profile with potent antioxidant capacity and deserve attention to be sustainably explored.

Análise da área desmatada municipal na Amazônia brasileira no período 2000-2004: uma abordagem com modelos não lineares

Existe uma certa assimetria na distribuicao do desmatamento da Amazonia Legal brasileira, concentrando-se particularmente nos estados do Mato Grosso, Para e Rondonia, o que estaria, em principio, associado a certas caracteristicas comuns de suas atividades produtivas predominantes, como a pecuaria, a exploracao madeireira e, mais recentemente, a expansao da producao de graos. Todavia, pode-se indagar se e possivel a formacao de grupos de economias municipais com caracteristicas semelhantes, quanto as causas ligadas ao desmatamento. Com este objetivo em mente, procura-se neste artigo testar a hipotese de convergencia em clubes a partir das areas desmatadas dos municipios da Amazonia Legal no periodo de 2000 a 2004. A fim de alcancar o objetivo proposto foi utilizado um modelo com efeito limiar (threshold) baseado em Hansen (2000). Os resultados empiricos corroboram a hipotese levantada, no que concerne a formacao de quatro clubes de convergencia.

Increased Levels of Antinutritional and/or Defense Proteins Reduced the Protein Quality of a Disease-Resistant Soybean Cultivar.

The biochemical and nutritional attributes of two soybean (Glycine max (L.) Merr.) cultivars, one susceptible (Seridó) and the other resistant (Seridó-RCH) to stem canker, were examined to assess whether the resistance to pathogens was related to levels of antinutritional and/or defense proteins in the plant and subsequently affected the nutritional quality. Lectin, urease, trypsin inhibitor, peroxidase and chitinase activities were higher in the resistant cultivar. Growing rats were fed with isocaloric and isoproteic diets prepared with defatted raw soybean meals. Those on the Seridó-RCH diet showed the worst performance in terms of protein quality indicators. Based on regression analysis, lectin, trypsin inhibitor, peroxidase and chitinase appear to be involved in the resistance trait but also in the poorer nutritional quality of Seridó-RCH. Thus, the development of cultivars for disease resistance may lead to higher concentrations of antinutritional compounds, affecting the quality of soybean seeds. Further research that includes the assessment of more cultivars/genotypes is needed.