RESUMO: "Efeitos cardiovasculares induzidos pelo extrato hidroalcoólico das cascas de Xylopia cayennensis em ratos". Os efeitos cardiovasculares induzidos pelo extrato hidroalcoólico do caule de Xylopia cayennensis (EHXC) foram estudados em ratos, utilizando uma abordagem combinada in vivo e in vitro. Em ratos não anestesiados, EHXC induziu uma hipotensão não dependente de dose associada com um aumento da freqüência cardíaca. Esta resposta hipontesora não foi atenuada depois do bloqueio com L-NAME (20 mg/Kg, i.v.). Em anéis de aorta isolados de rato, EHXC foi capaz de relaxar o tônus induzido por fenilefrina (1 μM) e KCl (80 mM), (CE 50 = 85±13 e 62±5 μg/mL, respectivamente). A atividade vasorelaxante do HEXC não foi inibida pela remoção do endotélio vascular (CE 50 = 58±6 μg/mL). HEXC antagonizou as contrações induzidas por CaCl 2 em meio despolarizante nominalmente sem Ca +2 . EHXC antagonizou de maneira dependente de concentração as contrações transientes induzidas por cafeína (20 mM), em meio livre de Ca 2+ , contudo não alterou aquelas induzidas por noradrenalina (1 μM). Em átrio isolado de rato, EHXC induziu um efeito inotrópico e cronotrópico negativo (CI 50 = 534±42 μg/mL e 259±22 μg/mL; respectivamente). Os resultados obtidos demonstram que EHXC apresenta um potente efeito hipotensor, provavelmente conseqüência da diminuição da resistência periférica total que parece ser, em parte, devido a uma ação inibitória sobre o infl uxo de Ca +2 através de canais de cálcio dependentes de voltagem e também através da inibição da liberação de Ca +2 dos estoques intracelulares sensíveis à cafeína. HEXC atua diretamente no coração diminuindo a contratilidade e a freqüência cardíaca, estes efeitos têm importância pequena na expressão da resposta hipotensiva induzida por HEXC.Unitermos: Xylopia cayennensis, Annonaceae, efeitos cardiovasculares, átrio isolado de rato, anéis aórticos isolado de rato, infl uxo de Ca 2+ . ABSTRACT:The cardiovascular effects induced by the hydroalcoholic extract of the stem of Xylopia cayennensis (HEXC) were studied in rats using a combined in vivo and in vitro approach. In non-anesthetized rats, HEXC injections produced a signifi cant and dose-dependent hypotension associated with an increase in heart rate. The hypotensive response was not attenuated after nitric oxide (NO) synthase blockade, L-NAME (20 mg/Kg, i.v.). In isolated rat superior aortic rings, HEXC was able to relax the tonus induced by phenylephrine (1 μM) and KCl (80 mM), (EC 50 = 85±13 and 62±5 μg/mL, respectively). The smooth muscle-relaxant activity of HEXC was not inhibited by removal of vascular endothelium (EC 50 = 58±6 μg/mL). HEXC antagonized CaCl 2 -induced contractions in depolarizing medium nominally without Ca 2+ . HEXC inhibited the intracellular calcium-dependent transient contractions induced by caffeine (20 mM) in Ca 2+ -free solution, but not those induced by norepinephrine (1 μM). In isolated rat atrial preparations, HEXC produced negative inotropic and chronotropic responses (IC 50 = 534±42 and 259±22 μg/...
RESUMOParahancornia amapa é uma espécie endêmica do Estado do Amapá, na região Amazônica. Este estudo teve como objetivo avaliar a toxicidade aguda do extrato metanólico das cascas do caule de P. amapa. Diferentes concentrações do extrato foram adicionadas aos camarões de salmoura (Artemia salina) e a concentração letal média (CL 50 Preclinical acute toxicological evaluation of the methanolic stem bark extract of Parahancornia amapa (Apocynaceae)ABSTRACT Parahancornia amapa is an endemic plant species of Amapá in the Amazon region. This study aimed to evaluate the acute toxicity of methanol extract of the bark of P. amapa. Different concentrations of the extract were added to the brine shrimps (Artemia salina) and 50% lethality concentration (LC 50 ) was assessed. The results of the brine-shrimp assay indicated that the extract was found to be non-toxic. Acute toxicity was studied in Wistar rats (males and females) after single dose (2000 mg kg -1 ) by oral gavage. Food and water intake, body weight, general behavioral changes and mortality of animals were noted. Blood samples were collected for haematological and serum biochemical parameters measurements. Subsequently, they were euthanized and their organs (heart, kidneys, liver and lungs) subjected to macroscopic and histopathological analysis. There was no mortality or any sign of behavioral change or toxicity observed after oral administration of the extract. Nevertheless, it was observed a significant increase (p<0.05) on water intake of female rats treated with the extract of P. amapa (127.64 mL) when compared to control group (101.93 mL). A significant increase (p<0.05) in platelet count was also observed in both male (288.00x10 3 mm 3 ) and female (220.83x10 3 mm 3 ) rats that received the extract when compared to their respective control groups (128.33x10 3 mm 3 ; 109.50x10 3 mm 3 ). Histopathological changes were not related to the treatment with extract in any of the analyzed organs. These results suggest that P. amapa extract has a non-toxic effect.
The Licania macrophylla Benth species, popularly known as "anauerá", "anuera", "anoerá", "ana-wyra" and "wayãpi", is widely found in the Amazon. Here, riverine communities use different parts of the plant for the treatment of amoebiasis, dysenteric disorders, wound healing and anti-inflammatory actions. The present study aims to investigate the gastroprotective activity of ethanolic extract of L. macrophylla stem bark in experimental animals. For this purpose, different experimental models for gastric ulcer induction were performed, such as absolute ethanol (99.5%), acidified ethanol (60%/0.3M HCl), and the non-steroidal anti-inflammatory drug model (indomethacin). In this study, 25-30g female Swiss mice were used for the absolute and acidified ethanol experimental models, and 200-300g female Wistar rats were used for the non-steroidal anti-inflammatory drug model. Each experimental model was divided into groups of five (5) animals for each tested dose of L. macrophylla extract (100, 250 and 625 mg/kg), as well as for the negative (vehicle) and positive (carbenoxolone) control groups. All administrations were performed orally, with a volume ratio of a maximum of 10 ml/kg body weight for mice and 100 ml/kg for rats. After each experiment, stomachs were evaluated to determine the following parameters: total lesion area, ulcer percentage, ulcerative lesion index, cure percentage. Statistical analysis was performed by one-way ANOVA followed by Dunnett post-test, considering significant values when p<0.05. The ethanolic extract of L. macrophylla showed gastroprotective effect against gastric lesions induced by absolute ethanol, significantly reducing the established parameters (250 and 625 mg/kg), promoting a cure rate of 53.76±5.71% and 84.15±1.89%, respectively. For the experimental protocol performed with acidified ethanol the results showed that the animals treated with the L. macrophylla ethanolic extract at the doses of 250 and 625 mg/kg, lesions decreased significantly when analyzing the established parameters, obtaining as a cure percentage of 52.34±4.83% and 83.86±2.46%, respectively. The ethanolic extract of L. macrophylla in the non-steroidal anti-inflammatory gastric lesion induction model was able to significantly reduce lesions for all doses tested (100, 250 and 625 mg/kg) in the established parameters, with a cure percentage (%) of 84.46±1.33%, 75.00±3.71% and 72.27±2.06%, respectively. In conclusion, L. macrophylla extract demonstrates antiulcerogenic activity in the acid and absolute ethanol induction models, as well as in the ulcer model induced by non-steroidal anti-inflammatory drugs with significant gastroprotective activity.
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