The goal of this work is to evaluate the chemical composition and the larvicidal activity of an extract from the nutshell (Anacardium occidentale L.) against Aedes aegypti and Culex quinquefasciatus larvae. A Hydro-ethanolic extract was prepared by maceration using 1 g of cashew nutshell in 3 mL of ethanol 70 %. The larvicidal effect and the acetylcholinesterase inhibitory activity of the extract were evaluated. The extract content includes phenolic compounds, coumarins, quinones, anthocyanidins, triterpenes, steroids, flavonoids, saponins, lipid compounds, aliphatic acids, and terpenoids. The larvicidal activity of the extract (LC50) for A.aegypti was 35,81 ppm and 40,21 ppm for A. aegypti (Macapá and Rockefeller strains), and 21,47 ppm for C.quinquefasciatus. The IC50 for the AChE inhibitory test was 43,27 ± 2,22 ppm. The evaluated extract presents a good AChE inhibitory activity and a potent larvicidal activity. The larvicidal effect could be associated with the AChE inhibitory activity of the extract.

El objetivo de este trabajo es evaluar la composición química, así como la actividad larvicida contra mosquitos Aedes Aegypti y Culex quinquefasciatus de un extracto de la cáscara de nuez de Anacardium Occidentale L. o marañón. Con esta intención, un extracto hidro-etanólico es preparado por maceración y en proporción de 1 g de corteza seca en 3 ml de etanol al 70 %. Al extracto se le determinó la presencia de compuestos fenólicos, cumarinas, quinonas, antocianidinas, triterpenos, esteroides, flavonoides y saponinas. La actividad larvicida mostró una concentración letal media (LC50) de 35,81 ppm y 40,21 ppm para larvas de A. aegypti (cepas Macapá y Rockefeller respectivamente) y 21,47 ppm para C. quinquefasciatus. La LC50 para la actividad anticolinesterásica fue de 43,27 ± 2,22 ppm, pudiendo asociarse la actividad larvicida del extracto a su capacidad inhibitoria sobre esta enzima.

Analisou-se a sobrevivência de mudas plantadas em 400 clareiras causadas por exploração florestal de impacto reduzido, em floresta de terra firme na Amazônia Oriental. Foram plantadas 3.818 mudas de 17 espécies, das quais apenas Schizolobium amazonicum não ocorre na área de estudo. A distância entre as mudas plantadas foi de aproximadamente 5m. As avaliações ocorreram em 2005 e 2006. Com base na sobrevivência das mudas aos 11 meses após o plantio, as espécies indicadas para o enriquecimento de clareiras são: Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa e Schefflera morototoni. Estudos sobre a taxa de crescimento, em períodos mais longos, são necessários para confirmar a utilização dessas espécies em plantios de enriquecimento de clareiras oriundas de exploração florestal, como alternativa para aumentar a produtividade e o valor econômico das florestas naturais manejadas na Amazônia brasileira.

Survival of seedlings planted in 400 gaps created by reduced impact logging in a terra firme forest in the Eastern Amazonia was evaluated. 3,818 seedlings from 17 species occurring in the study area, except for Schizolobium amazonicum (paricá), which is rare in natural forests of Paragominas region, were planted in the gaps. Spacing of planted seedlings was 5m. According to survival of seedlings during 11 months after planting, the species Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa and Schefflera morototoni can be suggested for enriching in gaps created by reduced impact logging. Complementary studies, mainly related to growth rates of seedlings, must be carried out and in a period longer than the present study to confirm the benefits of enrichment planting in gaps as an alternative to boost forest productivity and economic value of managed natural forest in the Brazilian Amazon.