Recebido em 5/12/02; aceito em 7/7/03 NATURAL PRODUCTS FOR DENGUE TRANSMISSION CONTROL-LARVICIDAL ACTIVITY OF Myroxylon balsamum (RED OIL) AND OF TERPENOIDS AND PHENYLPROPANOIDS. The bioassay-guided fractionation of the hexane extract obtained from the medicinal plant Myroxylon balsamum (red oil) was conducted in preparative thin layer chromatography on silica gel. The obtained fractions and some terpenoids and phenylpropanoids were assayed as larvicidal on third instar Aedes aegypti larvae, NPPN colony. The results indicate that the sesquiterpene nerolidol was the active constituent in the extract and that the sesquiterpenes were more active than the monoterpenes and phenylpropanoids utilized in this study. Lipophilicity seems to be an important property for the activity since the compounds with hydroxyl, carbonyl and methoxyl groups were less active. The results confirm also that essential oils can be a good tool for the control of dengue.Keywords: essential oil constituents; Aedes aegypti; Myroxylon balsamum. INTRODUÇÃOO dengue é uma infecção reemergente que vem preocupando as autoridades sanitárias de todo o mundo em virtude de sua circulação nos cinco continentes e grande potencial para assumir formas graves e letais. No período compreendido entre 1955 e 1995 foram registrados cerca de 3 milhões de casos de febre hemorrágica do dengue e 58 mil mortes 1 . Com o surgimento de formas resistentes do mosquito aos inseticidas convencionais utilizados, tem crescido a procura por extratos vegetais e substâncias naturais que sejam efetivas no combate ao mosquito adulto e/ou à larva de Aedes aegypti e que sejam isentas de toxicidade para o meio ambiente. Resistência a inseticidas convencionais é um dos principais obstáculos ao controle de insetos pestes de importância na agricultura e na medicina. A resistência resulta no aumento da freqüência de aplicação de inseticida, dosagens crescentes, rendimentos diminuídos, danos ambientais e surgimento de doenças, quando os vetores não podem ser controlados. Segundo a Organização Mundial de Saúde (OMS), o custo da resistência de insetos a inseticidas pode alcançar anualmente US$ 1,4 bilhões nos Estados Unidos 2 . Plantas, como organismos que co-evoluem com insetos e outros microorganismos, são fontes naturais de substâncias inseticidas e antimicrobianas, já que as mesmas são produzidas pelo vegetal em resposta a um ataque patogênico. Inúmeras substâncias acumulamse no vegetal para sua defesa contra microorganismos, algumas delas sendo denominadas de fitoalexinas 3 . As plantas sintetizam e emitem inúmeros compostos voláteis (ácidos, aldeídos e terpenos) para atrair polinizadores e se defender de herbívoros 4 . No que concerne à defesa contra herbívoros, as plantas desenvolveram dois tipos de defesa, a direta e a indireta. Na defesa direta estão envolvidas substâncias como sílica, metabólitos secundários, enzimas e proteínas, além de órgãos como tricomas e espinhos que afetam diretamente a performance do inseto. Na defesa indireta estão envolvidas substân-cias emitidas pela p...

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More than 94% of colorectal cancer cases have mutations in one or more Wnt/β-catenin signaling pathway components. Inactivating mutations in APC or activating mutations in β-catenin ( CTNNB1 ) lead to signaling overactivation and subsequent intestinal hyperplasia. Numerous classes of medicines derived from synthetic or natural small molecules, including alkaloids, have benefited the treatment of different diseases, including cancer, Piperine is a true alkaloid, derived from lysine, responsible for the spicy taste of black pepper ( Piper nigrum ) and long pepper ( Piper longum ). Studies have shown that piperine has a wide range of pharmacological properties; however, piperine molecular mechanisms of action are still not fully understood. By using Wnt/β-catenin pathway epistasis experiment we show that piperine inhibits the canonical Wnt pathway induced by overexpression of β-catenin, β-catenin S33A or dnTCF4 VP16, while also suppressing β-catenin nuclear localization in HCT116 cell line. Additionally, piperine impairs cell proliferation and migration in HCT116, SW480 and DLD-1 colorectal tumor cell lines, while not affecting the non-tumoral cell line IEC-6. In summary, piperine inhibits the canonical Wnt signaling pathway and displays anti-cancer effects on colorectal cancer cell lines.

RESUMO:A espécie Calceolaria chelidonioides (Scrophulariaceae), até então inédita nas citações científi cas, foi estudada sob o ponto de vista farmacológico buscando-se identifi car possíveis atividades antimicrobiana e antioxidante em metodologia in vitro. As partes aéreas dessa espécie demonstraram atividade antioxidante em modelo usando o radical livre DPPH. As fl ores de C. chelidonioides mostraram grande potencial antibacteriano frente à bactéria Staphylococcus aureus resistente a meticilina MRSA, um dos principais responsáveis em casos de infecção hospitalar.Unitermos: Calceolaria chelidonioides, Scrophulariaceae, MRSA, DPPH.ABSTRACT: "Antioxidant and anti-microbial activity from Calceolaria chelidonioides Humb. Bonpl. & Kunth." The species Calceolaria chelidonioides (Scrophulariaceae), not scientifi c described so for, was studied in pharmacological aspects aiming to identify some anti-microbial and antioxidant activity. The aerial parts showed antioxidant activity using in vitro DPPH model. The fl owers from C. chelidonioides showed strong antibacterial potential against meticiline resistant Staphylococcus aureus (MRSA) strains the main responsible for hospital infection complications.

Maternal Wnt/β-Catenin signaling is essential to establish dorsal-specific gene expression required for axial patterning in Xenopus. Deregulation of this pathway causes axis phenotypes in frog embryos. In adult life, mutations in the Wnt pathway components are associated with many diseases, such as polyposis coli; osteoporosis-pseudoglioma syndrome (OPPG); skeletal dysplasia; neural tube defects, cancer and many others. Thus, a better understanding of Wnt/β-catenin signaling will have great and significant impact on Biology and Medicine. In this aspect, natural compounds are potential targets as novel molecules that could modulate the Wnt pathway. For instance, flavonoids are a large group of natural compounds found in plants that modulate important cellular and molecular mechanisms related to diseases, but the specific in vivo mechanism of action of most flavonoids remain unknown. In this way, Xenopus embryos may provide an efficient model, since it is frequently used to test and identify the role of molecules that affect Wnt/β-catenin signaling. Here, we describe a combination of approaches to outline and characterize the role of two flavonoids, quercetin and rutin, on Wnt/β-catenin signaling, using Xenopus embryos as an experimental model. Our data support that quercetin is potential in vivo modulator of canonical Wnt signaling and that this effect might depend on the structure of this molecule, as we did not observe any effect with rutin treatment, a flavonol structurally-related to quercetin. This model is useful to analyze effects of quercetin and other flavonoids in vivo and to provide further understanding of how natural compounds can modulate signaling pathways, using Xenopus embryos as a fast and efficient reading of in vivo effects of those compounds.