Walter A. Roman Junior

Subchronic atrazine exposure changes defensive behaviour profile and disrupts brain acetylcholinesterase activity of zebrafish

Animal behaviour is the interaction between environment and an individual organism, which also can be influenced by its neighbours. Variations in environmental conditions, as those caused by contaminants, may lead to neurochemical impairments altering the pattern of the behavioural repertoire of the species. Atrazine (ATZ) is an herbicide widely used in agriculture that is frequently detected in surface water, affecting non-target species. The zebrafish is a valuable model organism to assess behavioural and neurochemical effects of different contaminants since it presents a robust behavioural repertoire and also all major neurotransmitter systems described for mammalian species. The goal of this study was to evaluate the effects of subchronic ATZ exposure in defensive behaviours of zebrafish (shoaling, thigmotaxis, and depth preference) using the split depth tank. Furthermore, to investigate a putative role of cholinergic signalling on ATZ-mediated effects, we tested whether this herbicide alters acetylcholinesterase (AChE) activity in brain and muscle preparations. Fish were exposed to ATZ for 14days and the following groups were tested: control (0.2% acetone) and ATZ (10 and 1000μg/L). The behaviour of four animals in the same tank was recorded for 6min and biological samples were prepared. Our results showed that 1000μg/L ATZ significantly increased the inter-fish distance, as well as the nearest and farthest neighbour distances. This group also presented an increase in the shoal area with decreased social interaction. No significant differences were detected for the number of animals in the shallow area, latency to enter the shallow and time spent in shallow and deep areas of the apparatus, but the ATZ 1000 group spent significantly more time near the walls. Although ATZ did not affect muscular AChE, it significantly reduced AChE activity in brain. Exposure to 10μg/L ATZ did not affect behaviour or AChE activity. These data suggest that ATZ impairs defensive behaviours of zebrafish, which could be related to its action on brain cholinergic neurotransmission. Moreover, the use of the split depth tank could be an alternative strategy to assess group behaviour and depth preference after exposure to chemical compounds.

Avaliação in vivo do efeito hipoglicemiante de extratos obtidos da raiz e folha de bardana Arctium minus (Hill.) Bernh.

The objective of the present study was to analyze in vivo the hypoglycemiant potential of the extracts from the root and leaf of the medicinal plant bardana, Arctium minus (Asteraceae). It was also carried out through pharmacognostics analysis of quality control. In the biological assays, 60 rats were induced to the experimental diabetes through endovenous injection of alloxan administration, in an only dose of 42 mg/kg. On the seventh day after the induction, the fast glycemia was dosed. The animals with glycemia superior to 190 mg/dL were redistributed in four groups to receive, for 21 days, some kind of treatment. Group 1: Glibenclamide in the dose of 0.071 mg/kg; Group 2: pure lyophilized extract of bardana root, 500 mg/kg; Group 3: pure lyophilized extract of bardana leaf, 200 mg/kg; and Group 4: physiological serum. After treatment, the pure extract of bardana root reduced in 34.6 ± 5.8% the glycemic levels, the pure extract of the leaf reduced in 22.9 ± 6.2% and the Glibenclamide 34.5 ± 6.2%. The placebo group kept the glicemy. This study suggests that the pure extract of Arctium minus, mainly the root extract, is able to reduce the plasmatic levels of glucose, with similar power to the synthetic medicine of Glibenclamide reference.

Hypolipidemic effects of Solidago chilensis hydroalcoholic extract and its major isolated constituent quercetrin in cholesterol-fed rats

Abstract Context: Despite several studies on the effects of Solidago chilensis Meyen (Asteraceae), the phytochemical and hypolipidemic properties remain underappreciated. Objective: This study evaluates the hypolipidemic and antioxidant effects of hydroalcoholic extract (HE) and quercetrin from S. chilensis aerial parts in cholesterol-fed rats. Materials and methods: The HE was analyzed by high-performance liquid chromatography, followed by quercetrin isolation. Hypercholesterolemic rats (1% cholesterol and 0.5% cholic acid for 15 d) were treated with HE (150, 300, and 600 mg/kg p.o.; n = 6), simvastatin (4 mg/kg p.o.; n = 6), or quercetrin (10 mg/kg p.o.; n = 6) once a day for 30 d. During this period, a high-cholesterol diet was maintained until the 30th day of treatment. Results: Rats treated with HE (150, 300, and 600 mg/kg) and quercetrin showed decreased serum levels of total cholesterol (−19.9, −27.5, −31.0, and −39.4%), lipoprotein-cholesterol (−36.0, −37.5, −43.3, and −59.4%), and triacylglycerides (−15.6, −23.5, −29.8, and −27.2%) when compared with the control group similar to simvastatin. Moreover, treatment with HE and quercetrin decreased hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity (35.1% on average) and increased fecal cholesterol levels (38.2% on average). Discussion and conclusions: Our results suggest that hypolipidemic effects of HE are associated with it modulating the activity of HMG-CoA reductase and its interference in the reabsorption and/or excretion of intestinal lipids. Solidago chilensis and its main constituent, quercetrin, may thus be effective as cholesterol-lowering agents and in preventing atherosclerosis.

Assessment of plant development, morphology and flavonoid content in different cultivation treatments of Calendula officinalis L: , Asteraceae

O objetivo deste estudo foi avaliar a influencia dos tratos culturais no desenvolvimento vegetal, morfologia e teor de flavonoides para Calendula officinalis L., Asteraceae. Os tratos culturais foram: calagem (CA), calagem + adubacao orgânica (CAO) e calagem + adubacao quimica NPK (CAQ). O experimento foi inteiramente casualizado com sessenta repeticoes e a comparacao das medias realizada por ANOVA e teste de Duncan (significância de 95%). Os resultados apontam que CAO e CAQ apresentaram maior desenvolvimento vegetal comparados com tratamento CA. O tratamento CAO produziu ainda, plantas com maior homogeneidade, massa fresca e numero de capitulos florais por planta, mas menor biomassa de flores produzidas por cada individuo. Observou-se tambem, variacoes morfoanatomicas com flores tubulares com centro amarelado (TCA) e tubulares com centro acastanhado (TAC) que produziram maior teor de flavonoides (1,41 e 1,44% respectivamente) comparadas com flores ligulares com centro amarelado (LCA) e ligulares com centro acastanhado (LAC) (0,89 e 0,95% respectivamente). Os compostos quimicos nas flores de calendula, visualizados por cromatografia em camada delgada, demonstraram que os tratamentos nao tem influencia sobre o perfil quimico qualitativo do vegetal. Entretanto, cultivares de calendula submetidas ao tratamento CAQ produziram maior quantidade de flavonoides totais (1,14%) contra 1,04% do CAO e 1,03% de CA.

Antidepressant-Like and Antioxidant Effects of Plinia trunciflora in Mice

The jaboticaba tree, Plinia trunciflora (O. Berg) Kausel, is popularly named “jabuticabeira” in Brazil and is used in folk medicine to treat diabetes and chronic inflammation of the tonsils, but studies evaluating the central effects of this species are limited. This study evaluated the antidepressant-like and antioxidant effects of P. trunciflora (PT) aqueous extract, in which five different anthocyanins were identified. PT showed significant ferric-reduction power and DPPH radical scavenging activity in vitro and reduced lipid peroxidation both in vitro and ex vivo. At the behavioural level, PT (400 and 800 mg/kg, i.p.) dose-dependently reduced immobility time in the tail suspension test in Swiss male mice. The identification of bioactive compounds accompanied by the in vitro and ex vivo antioxidant activity of PT suggests that these activities might be related to the antidepressant-like activity of P. trunciflora.