Luciana Lopes Silva Pereira

Inhibition of pancreatic lipase by extracts of Baccharis trimera (Less.) DC., Asteraceae: evaluation of antinutrients and effect on glycosidases

In order to confirm the traditional use of Baccharis trimera (Less.) DC., Asteraceae, for the reduction of weight, plant extracts were evaluated on the activity of pancreatic lipase (PL), an enzyme responsible for hydrolysis of triacylglycerols in the diet for its subsequent absorption. The aqueous and infused extracts did not show inhibitory activity on the PL, the ethanol inhibited 16% (66 ALI/g) and methanol extract inhibited 78% (241 ALI/g). The methanol extract of B. trimera (MEB) was subjected to a wash with decreasing solvent polarity (n-hexane, ethyl acetate and methanol) and only the methanol fraction inhibited the lipase by 72% (230 ALI/g). We evaluated the MEB and infused inhibitory activity on the enzymes α-amylase and α and β-glycosidases. The α-amylase was not inhibited by any of the extracts, the enzyme α-glucosidase was inhibited by both extracts in the same proportion (46.9±0.1) and β-glucosidase was inhibited by 73% by the methanol extract and 65% by the infused. We also evaluated the presence of anti-nutrients. We detected the presence of saponins, polyphenols and trypsin inhibitors in the two samples. Tests performed in vivo can assess at which therapeutic concentration the presence of these anti-nutrients can be harmful to health.

Genotoxic effect of Bothrops snake venoms and isolated toxins on human lymphocyte DNA.

In the present study, micronucleus with cytokinesis blocking and comet assays were used to evaluate the genotoxic potential of Bothrops jararacussu, Bothrops atrox, Bothrops moojeni, Bothrops alternatus (Rhinocerophis alternatus) and Bothrops brazili snake venoms, and also of some isolated toxins (MjTX-I, BthTX-I and II myotoxins, BjussuMP-II metalloprotease, and BatxLAAO l-amino acid oxidase) on human lymphocytes. Significant DNA damages were observed, indicating genotoxic potential after exposure of the lymphocytes to the toxins BthTX-I, II and BatxLAAO compared to untreated and Cisplatin-treated controls, which were able to induce greater formation of micronuclei. B. brazili, B. jararacussu and B. atrox crude venoms also presented genotoxic potential, and the latter two induced DNA breakage 5 times more often than in normal environmental conditions (control without treatment). B. jararacussu venom and its isolated toxins, as well as an LAAO from B. atrox, were able to cause lymphocyte DNA breakage in the comet test with more than 85% damage levels. The DNA damage evaluation allows a widening of the toxic-pharmacological characterization of snake venoms and their toxins and also contributes to the understanding of the mechanisms of action of these molecules in several human pathologies.

Seleção de extratos brutos de plantas com atividade antiobesidade

The prevalence of obesity has been increasing at an alarming rate and only a few medications are currently available in the market. Pancreatic lipase inhibition is one of the most widely studied mechanisms for determining the efficacy of natural products as anti-obesity agents. The aim of this study was to evaluate in vitro the inhibition of nineteen aqueous and methanol extracts on pancreatic lipase. Kinetic assays were performed in four periods with the absence and the presence of the inhibitor extract. We also tested the action of these extracts after gastric fluid simulation. Cymbopogon citratus showed the highest inhibition, followed by Costus spicatus and Baccharis trimera. The extracts have the potential to act as adjuvants in the treatment of obesity.

Application of Comet assay to assess the effects of white bean meal on DNA of human lymphocytes

This study was conducted to evaluate the potential induction of genotoxic effects of white bean flour using the Comet assay. The test was conducted with human lymphocytes present in whole blood immediately after collection, by incubation with white bean flour in three concentrations (3.92, 9.52 and 18.18 mg/mL) at 37 oC for 4 h followed by preparation of slides. Samples were considered positive (above 20% damage) when the damage observed to cellular DNA was higher than the negative control. No genotoxic potential was found at the doses tested. However, it would be premature to suggest absence of risk to human health of DNA damage since the exposure of cells to the extract was restricted to four hours rather than a whole cell cycle. Additionally, further information on toxicology should be obtained in future studies.

Evaluation of the Hypoglycemic Properties of Anacardium humile Aqueous Extract.

The antihyperglycemic effects of several plant extracts and herbal formulations which are used as antidiabetic formulations have been described and confirmed to date. The main objective of this work was to evaluate the hypoglycemic activity of the aqueous extract of Anacardium humile. Although the treatment of diabetic animals with A. humile did not alter body weight significantly, a reduction of the other evaluated parameters was observed. Animals treated with A. humile did not show variation of insulin levels, possibly triggered by a mechanism of blood glucose reduction. Levels of ALT (alanine aminotransferase) decreased in treated animals, suggesting a protective effect on liver. Levels of cholesterol were also reduced, indicating the efficacy of the extract in reestablishing the balance of nutrients. Moreover, a kidney protection may have been achieved due to the partial reestablishment of blood glucose homeostasis, while no nephrotoxicity could be detected for A. humile. The obtained results demonstrate the effectiveness of A. humile extracts in the treatment of alloxan-induced diabetic rats. Therefore, A. humile aqueous extract, popularly known and used by diabetic patients, induced an improvement in the biochemical parameters evaluated during and following treatment of diabetic rats. Thus, a better characterization of the medicinal potential of this plant will be able to provide a better understanding of its mechanisms of action in these pathological processes.

Syzygium sp (Myrtaceae) extracts: inhibition of alpha amylase.

Aims: The aims of this study were: a) prepare crude extracts of commercial teas Syzygium sp by different methods (maceration, decoction and infusion) in different proportions (1:20, 1:50 and 1:100) and b) submit them the inhibition assays digestive enzyme alpha-amylase before and after exposure to a simulated gastric fluid. Place and Duration of Study: Laboratorio de Bioquimica, Instituto de Ciencias Biologicas e Naturais, Universidade Federal do Triângulo Mineiro, Brazil, between August 2012 and July 2013. Methodology: Five samples of Syzygium sp teas were purchased commercially from pharmacies, drugstores and health food stores. Results: In the first step inhibition of enzymatic extracts of the teas without simulated gastric fluid the results showed significant inhibition of alpha-amylase (mean 92.84%, CV = 3.86%). However, when these extracts were placed in contact with the simulated gastric fluid was observed decreased inhibition of alpha – amylase, suggesting a possible Original Research Article European Journal of Medicinal Plants, 4(1): 116-125, 2014 117 reduction of hypoglycemic potential of these teas under physiological conditions. Conclusion: Aqueous extract Syzygium sp have high percentages of inhibition of the enzyme amylase, suggesting a potential hypoglycemic effect. Additional studies aiming at elucidating the chemical compounds present in the extracts of Syzygium sp using chromatographic techniques will be performed.

Atividade das glicosidases na presença de chá verde e de chá preto

Varias plantas tem sido consideradas produtos terapeuticos, dentre elas destacam-se os chas verde e preto, popularmente utilizados para controle da hiperglicemia e obesidade. Objetivou-se neste trabalho avaliar o potencial inibitorio sobre as enzimas α-amilase, α e β-glicosidases e o teor de compostos fenolicos do cha verde e do cha preto. O teor de compostos fenolicos encontrados foram de 80,8 ± 0,43 mg g-1 no cha preto e 32,0 ± 0,12 mg g-1 no cha verde. O cha verde e o cha preto, em condicoes de consumo, inibiram as enzimas em estudo, porem, apos a simulacao do fluido gastrico o inibidor presente no cha verde perdeu a acao. O cha preto deixou de inibir a α-amilase e apresentou inibicao inalterada para α e β-glicosidases. Tais resultados sugerem que o cha preto pode ser auxiliar em dietas de restricao de carboidratos.

Eficácia e toxicidade do pó comercial de Hoodia gordonii (Masson) swet ex decne utilizado no tratamento da obesidade

A obesidade e atualmente o principal problema de saude em paises desenvolvidos e em desenvolvimento. Diversos recursos terapeuticos tem sido empregados para o tratamento da obesidade destacando-se os fitoterapicos, consagrados pelo conhecimento popular. Nesse contexto, a planta Hoodia gordonii tem despertado atualmente grande interesse mundial, principalmente pelas recentes descobertas e comprovacoes cientificas da inibicao do apetite e da sede pelo glicosideo ativo P57 isolado de especies da planta. Apesar disso, tais efeitos ainda nao foram avaliados e comprovados em amostras comerciais do po de H. gordonii (PHG), nao existindo evidencias cientificas que garantam a sua eficacia e seguranca. Portanto, o objetivo deste trabalho foi realizar ensaios biologicos com ratos para avaliar a atividade farmacologica e a toxicidade de amostras comerciais do po de H. gordonii. As amostras foram administradas por gavagem em doses equivalentes a 20 vezes as recomendadas para humanos em ratas Wistar durante 4 semanas sendo avaliados os parâmetros indicadores do efeito terapeutico. Apos as 4 semanas, os animais foram sacrificados, e amostras de sangue e orgaos foram coletados e submetidos a avaliacao dos indicadores metabolicos, endocrinos, hematologicos e histopatologicos. Os resultados demonstraram que para todos os parâmetros avaliados nao houve diferencas significativas entre o grupo controle que recebeu somente solucao salina esteril e os grupos tratados com PHG indicando que os mesmos, apesar de nao apresentarem quaisquer indicios de toxicidade, sao incapazes de produzir os supostos efeitos de inibicao de apetite e consequente tratamento da obesidade.

PADRONIZAÇÃO DA EXTRAÇÃO DO INIBIDOR PROTEICO DE ALFA-AMILASE DE FEIJÃO BRANCO

The Alpha-Amylase inhibitors have been indicated as auxiliariesto loss of weight and to the management of diabetes mellitus type 2through the reduction of starch absorption. This work standardized theprocess of extraction of white beans alpha-amylase inhibitor determiningthe extractor, the time of agitation and the conditions for thermal treatment.The results indicate that the methodology used the water as extracting, inthe ratio of 1:5, followed for 3 consecutives extractions under agitation for15 minutes and 70°C thermal treatment for 5 minutes as faster and moreefficient option in the extraction of inhibitor.