O presente trabalho descreve a atividade do extrato etanólico (EE) dos frutos de Combretum leprosum, do triterpeno 3b, 6b, 16b-triidroxilup-20(29)-eno (1) e seus derivados sintéticos (1a-1d), sobre promastigotas de Leishmania amazonensis. O EE apresentou atividade leishmanicida e o valor de IC 50 foi de 24,8 mg mL -1 . Já o triterpeno 3b, 6b, 16b-trihidroxilup-20(29)-eno (1), na concentração de 5,0 mg mL -1 , apresentou uma potente ação inibitória sobre a proliferação das promastigotas (IC 50 = 3,3 mg mL -1 ). Entre os derivados sintéticos, apenas 1b e 1d apresentaram atividade contra as promastigotas (IC 50 = 3,48 mg mL -1 e 5,8 mg mL -1 , respectivamente). Por outro lado, o derivado sintético 1a não apresentou atividade sobre as promastigotas de L. amazonensis. O EE, (1) e os derivados sintéticos 1a-1d não apresentaram efeito citotóxico sobre macrófagos peritoneais de camundongos. Estes resultados fornecem evidencias de que o extrato etanólico e o lupano isolado de C. leprosum possui atividade contra promastigotas de L. amazonensis, podendo ser utilizados como ferramentas no estudo de novas drogas leishmanicidas. This paper describes the activity of the ethanolic extract (EE), obtained from the fruits of Combretum leprosum, the triterpene 3b, 6b, 16b-trihydroxylup-20(29)-ene (1) and its synthetic derivatives 1a-1d on Leishmania amazonensis promastigotes. The EE displayed leishmanicidal activity and the IC 50 was 24.8 mg mL -1 . However, the triterpene 3b, 6b, 16b-trihydroxylup-20(29)-ene (1), at a concentration of 5.0 mg mL -1 , showed a potent inhibitory activity on promastigotes proliferation (IC 50 = 3.3 mg mL -1 ). Among the synthetic derivatives, only (1b) and (1d) were active against promastigotes (IC 50 = 3.48 mg mL -1 and 5.8 mg mL -1 , respectively). Moreover, the synthetic derivative 1a showed no activity on promastigotes of L. amazonensis. EE, (1) and the synthetic derivatives 1a-1d showed no cytotoxic effect on mice peritoneal macrophages. These results provide evidence that the ethanolic extract and the lupane isolated from C. leprosum was active against promastigotes of L. amazonensis, and may be used as a tool in the studies of new antileishmanial drugs. The clinical manifestations of leishmaniasis are often divided in cutaneous, diffuse cutaneous, mucocutaneous and visceral leishmaniasis. Keywords3,4 Cutaneous leishmaniasis can Teles et al. 937 Vol. 22, No. 5, 2011 be spontaneously healed after a few months, or, depending on the Leishmania species, develop into diffuse cutaneous, relapsing cutaneous or mucocutaneous leishmaniasis. Visceral leishmaniasis, if untreated, leads to death in most patients. 5,6 This disease causes considerable morbidity and severe face-disfigurement lesions on the affected people.Nowadays, chemotherapy for leishmaniasis is still based on pentavalent antimonials (Glucantime and Pentostam), diamines (Pentamidine) and antifungal polyene (Amphotericin B). These are only a few of the drugs available since 1940. Unfortunately, they are generally toxic, expensive, s...
The analysis of reinforced concrete structures until failure requires the consideration of geometric and material nonlinearities. However, nonlinear analysis is much more complex and costly than linear analysis. In order to obtain a computationally efficient approach to nonlinear analysis of reinforced concrete structures, this work presents the formulation of a nonlinear plane frame element. Geometric nonlinearity is considered using the co-rotational approach and material nonlinearity is included using appropriate constitutive relations for concrete and steel. The integration of stress resultants and tangent constitutive matrix is carried out by the automatic subdivision of the cross-section and the application of the Gauss quadrature in each subdivision. The formulation and computational implementation are validated using experimental results available in the literature. Excellent results were obtained.
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