Acetylcholinesterase and α-Amylase inhibitors from Mouriri elliptica Martius leaf extract / Inibidores da acetilcolinesterase e α-amilase do extrato da folha de Mouriri elliptica Martius

Population growth has raised food production, and new sources are needed to increase quantity and quality of agricultural products. Carbamates and organophosphates are insecticide classes used worldwide as acetylcholinesterase (AChE) inhibitors. Plants have a natural resistance to insects, which can be employed in pest control as a new alternative to reduce the use of chemicals. An alternative may be the use of α-amylase inhibitors, which are digestive enzymes that impair pest species growth and development. Another would be acetylcholinesterase inhibitors since they damage the normal functioning of the central and peripheral nervous system, by releasing high concentrations of acetylcholine in cholinergic synapses. This substance accumulation increases stimulations that lead to behavioral changes, asphyxia, hyperactivity, and death. Botanical agrochemicals are believed to have advantages over synthetic ones, as they are rapidly degraded in the environment. In this scenario, plants have played an important role in pest control as sources of interest for the synthesis of new molecules for agricultural use. The present study evaluated acetylcholinesterase and α-amylase inhibition by microplate method, from leaf extracts of Mouriri elliptica Martius with different polarities.

O crescimento populacional tem aumentado a quantidade de produção alimentícia, sendo necessárias novas fontes para o aumento da quantidade e qualidade dos produtos agrícolas. Os carbamatos e organofosforados são classes de inseticidas utilizadas em todo o mundo, são inibidores da acetilcolinesterase (AChE). Os vegetais possuem uma resistência natural aos insetos, e esse método de resistência pode ser utilizado no controle das pragas como uma nova alternativa para redução do uso de inseticidas químicos, tais como os inibidores da α-amilase, enzima digestiva, a qual sua inibição prejudica o crescimento e desenvolvimento de espécies de pragas. E os inibidores da acetilcolinesterase que danificam o funcionamento normal do Sistema Nervoso Central e Periférico, através de elevadas concentrações da acetilcolina que ficam depositadas nas sinapses colinérgicas. Este acúmulo de ACh provoca uma grande estimulação que leva á alterações comportamentais, asfixia, hiperatividade e a morte. Estudos já realizados mostraram que os agrotóxicos botânicos têm vantagens sobre os sintéticos, sendo degradados rapidamente no meio ambiente. Neste cenário os vegetais têm desempenhado um importante papel no controle de pragas, através da síntese de novas moléculas para uso na agricultura. O presente trabalho avaliou a inibição das enzimas acetilcolinesterase e α-amilase através do método da microplaca a partir dos extratos das folhas de Mouriri elliptica Martius em diferentes polaridades.

Total Antioxidant Activity and Enzymatic Inhibition against Alpha-Amylase, Alpha-Glucosidase and Pancreatic Lipase of Irradiated Archidendron bubalinum

@#Introduction: Archidendron bubalinum is an underutilised plant with numerous antioxidant properties and has a great potential to inhibit enzymes linked with diabetes and obesity. Food irradiation is an advanced technology to prolong the lifespan of plant, prevent physical spoilage and eradicate food borne disease. Present study was aimed to determine the total antioxidant activity, enzymatic inhibition against alpha-amylase, alpha-glucosidase and pancreatic lipase and the toxicity levels of non-irradiated and irradiated (3, 6, 9 & 12 kGy) hot aqueous extract of A. bubalinum. Methods: The antioxidant ability of the extract was determined by total phenolic content (TPC), total flavanoid content (TFC), Diphenyl-1-Picrylhydrazyl (DPPH), β-carotene assay and ferric reducing antioxidant potential (FRAP) assay. The inhibitory activities were evaluated using α-amylase, α-glucosidase, and pancreatic lipase inhibition assay. The toxicity levels of A. bubalinum extract were determined using Brine shrimp and Zebra-fish assays. Results: Results showed that irradiated A. bubalinum at 12 kGy demonstrated the highest TFC (448.99 ± 5.02 mg GAE/g), FRAP (2.55 ± 0.40 mmol Fe2+/g) and β-carotene bleaching activity (79.49%). Whereas, non-irradiated A. bubalinum samples expressed the highest TPC (2517.07 ± 15.81 mg GAE/g) and exhibited the lowest IC50 values of α-amylase (31.99 ± 3.15 μg/ml), α-glucosidase (23.40 ± 0.69μg/ml) and pancreatic lipase (32.81 ± 7.96 μg/ml) activity. The toxicity assays also showed no significant different between irradiated and non-irradiated samples. Conclusion: The study suggests that gamma irradiation has the prospective future to increase antioxidant properties and maintaining the enzyme inhibitory activities to preserve the sample of A. bubalinum for commercial purposes

Heavy metal tolerance (Cr, Ag and Hg) in bacteria isolated from sewage

Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr), silver (Ag) and mercury (Hg). Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%). Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerantBacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr). Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.

White Bean Flour (Phaseolus vulgaris): Therapeutic and Toxicological Research in Wistar Rats.

The objective was to evaluate the possible therapeutic and toxic effects resulting from administration of white bean flour (WBF) in Wistar rats for 21 days. The assay was performed to assess the consequences of using WBF crude, at a the concentration corresponding to the recommended daily dose to cause weight loss and hypoglycemic effect, which is 1,000 mg of phaseolamin/day. The administration of WBF at 1 mg/g body weight in Wistar rats with diabetes induced by STZ in a period of 21 days, did not alter physiological parameters (consumption of food and water, urine volume), biochemical markers (total cholesterol, HDL cholesterol and triglycerides), liver enzymes (gamma-GT, AST and ALT), and weight of organs (liver and pancreas) as well as fecal excretion of proteins and lipids. An increased excretion of carbohydrate fecal confirms the results of inhibition of α-amylase. Despite the tendency to decrease blood glucose from 20 days of treatment, there was no significant reduction during the period evaluated in the treated group. It can be concluded that despite the decreasing tendency of hyperglycemia and possibly aid in weight loss by decreasing absorption of carbohydrates in the diet, high doses of WBF may have deleterious effects on the body resulting from chronic use.

Atividade das glicosidases na presença de chá verde e de chá preto / Activity of glycosidases in the presence of green tea and black tea

Várias plantas têm sido consideradas produtos terapêuticos, dentre elas destacam-se os chás verde e preto, popularmente utilizados para controle da hiperglicemia e obesidade. Objetivou-se neste trabalho avaliar o potencial inibitório sobre as enzimas α-amilase, α e β-glicosidases e o teor de compostos fenólicos do chá verde e do chá preto. O teor de compostos fenólicos encontrados foram de 80,8 ± 0,43 mg g-1 no chá preto e 32,0 ± 0,12 mg g-1 no chá verde. O chá verde e o chá preto, em condições de consumo, inibiram as enzimas em estudo, porém, após a simulação do fluido gástrico o inibidor presente no chá verde perdeu a ação. O chá preto deixou de inibir a α-amilase e apresentou inibição inalterada para α e β-glicosidases. Tais resultados sugerem que o chá preto pode ser auxiliar em dietas de restrição de carboidratos.

Several plants have been considered therapeutic products, including green and black tea, popularly used to control hyperglycemia and obesity. This study aimed to evaluate the inhibitory potential of the enzymes α-amylase, α and β-glycosidases, as well as the content of phenolic compounds in green tea and black tea. The concentrations of phenolic compounds found were 80.8 ± 0.43 mg g-1 in black tea and 32.0 ± 0.12 mg g-1 in green tea. Under the tested conditions of use, green and black tea inhibited the enzyme under study. However, after simulation of the gastric fluid, the inhibitor present in green tea lost its action. Black tea no longer inhibited a-amylase and showed unaltered inhibition for α and β-glycosidases. These results suggest that black tea can be helpful in diets restricting carbohydrates.

Interference of a commercial catalase preparation in laccase and peroxidase activities

The influence of commercial catalase preparations (fungal and bovine origin) on laccase and peroxidase activity assays was evaluated using enzymatic extracts obtained from several basidiomycetes grown under different culture conditions. No hydrogen peroxide was detected in the extracts. Inhibition of laccase activity by 40 to 80 percent was related to the catalase source. In addition, oxidation of the substrate (ABTS) by fungal catalase in the absence of the enzymatic extract from basidiomycetes was observed. The results demonstrated the need for the evaluation of interference of the commercial catalase preparation when its use was required in the reaction mixture.

A influência da preparação comercial de catalase (origem fúngica e bovina) nos ensaios de atividade absence and presence of a fungal or bovine de lacase e de peroxidases foi avaliada empregando-se extratos enzimáticos obtidos do crescimento de diversos basidiomicetos em diferentes condições de cultivo. Não foi detectado H2O2 nos extratos. Inibição de 40 a 80 por cento da atividade de lacase foi relacionada à fonte de catalase. Além disso, foi observada oxidação do substrato (ABTS) pela catalase fúngica, na ausência de extrato enzimático do basidiomiceto. Os resultados evidenciaram a necessidade de se proceder a uma avaliação da interferência da preparação comercial de catalase, quando o seu uso se fizer necessário na mistura reacional.