Atividade larvicida de Anacardium occidentale como alternativa ao controle de Aedes aegypti e sua toxicidade em Rattus norvegicus

Abstract

RESUMO:A busca por substitutos para os inseticidas sintéticos tem estimulado muitos trabalhos científicos contemplando inclusive a utilização de óleos, extratos, ou constituintes ativos provenientes de plantas. Esta procura pode ser justificada pelo potencial inseticida associado à fácil degradação de seus constituintes, menor toxicidade ao homem e uma alternativa mais segura para o meio ambiente. Após a coleta e aquecimento dos frutos de Anacardium occidentale (Anacardiaceae) a 40°C, obteve-se um líquido da castanha de caju (LCC) que, depois de testado quanto à sua atividade larvicida, foi fracionado em coluna de sílica gel dando origem a oito frações, as quais foram codificadas como AO 1 a AO 8 e submetidas a ensaios larvicidas. Avaliou-se também sua toxicidade oral aguda em Rattus norvegicus. O LCC e as frações AO 2 e AO 3 apresentaram atividade larvicida para Aedes aegypti. As concentrações letais, CL 50 e CL 90 do LCC foram, respectivamente, de 6,55 e 10,98 ppm. Para AO 2 e AO 3, as CL 50 e CL 90 foram de 3,18 e 7,80 ppm, e de 3,57 e 10,47 ppm, respectivamente. Não foi observada nenhuma toxicidade do LCC e das frações para R. norvegicus. O LCC e as frações foram administrados por via oral na dose de 2000 mg/kg. Esses produtos apresentaram potencial larvicida sobre Ae. aegypti e nenhum sinal de toxicidade foi evidenciado nos parâmetros analisados. Palavras-chave:Anacardium occidentale, Aedes aegypti, larvicida, toxicidade aguda. ABSTRACT: Larvicidal activity of Anacardium occidentale as an alternative to controlAedes aegypti and its toxicity in Rattus norvegicus. The search for substitutes for synthetic pesticides has been the subject of many scientific publications, including considering the use of oils, extracts and active constituents from plants. This demand can be justified by the insecticide potential associated with an easy degradation of its constituents, lower toxicity to humans and, consequently, a safer alternative for the environment. After collecting and heating the Anacardium occidentale (Anacardiaceae) fruits at 40°C, they were tested to confirm their larvicidal activity. Then, it was fractionated in a silica gel column. The fractionation resulted in eight fractions, which were coded as AO 1 to AO 8 . In this paper, the cashew nut shell liquid (CNSL) and its fractions were evaluated as to their biological activity in the third instar larvae of Aedes aegypti. The acute oral toxicity in Rattus norvegicus also was evaluated. CNSL and the AO 2 and AO 3 fractions presented larvicidal activity. The lethal concentrations, LC 50 and LC 90 , of CNSL were, respectively, 6.55 and 10.98 ppm. The active fractions, AO 2 and AO 3 , presented LC 50 and LC 90 of 3.18 and of 7.80 ppm, and 3.57 and 10.47 ppm, respectively. The LCC and the fractions were orally administered at a dose of 2000 mg/kg. These products showed larvicidal potential against Ae. aegypti and no sign of toxicity was evident in the parameters analyzed.

Larvicidal effect of hydroethanolic extract from the leaves of Acmella oleracea L. R. K. Jansen in Aedes aegypti and Culex quinquefasciatus

“…The search for alternatives to synthetic insecticides stimulates the development of new technologies. In the Amazon, due to its rich biodiversity, oils, extracts, or active constituents from certain plants are being exploited for their uses as bioactive products (Guissoni et al, 2013).…”

Fatty Acid Profile and Anti-Inflammatory Activity of Fixed Plant Oils

“…Some seed oils displays anti-inflammatory properties administred by ingestion or topical application, such as sunflower oil (Helianthus annus), which is used frequently as anti-inflammatory, antiseptic and healing agent [1]. Some other fixed oil extracts have been also employed to treat inflammation and among them the following species are in Northeastern Brazil: Ouratea fieldingiana popularly known as Batiputá [18]; Caryocar coreaceum, which yields a fruit common known as Pequi, used widely in Araripe, southern Ceará and the fixed oil has been employed in the treatment of skin inflammation, respiratory affections [7], wound healing and muscle pain; Byrsonima crassifolia fruit oil showed anti-inflammatory action in a pharmacological study [10,16]; Anacardium occidentale, popularly known as cashew, has a great economic importance in Brazil and cashew nut is one of the main exportation products [6]; Cocus nucifera (coconut) kernel and tender coconut water have numerous medicinal properties such as antibacterial, antifungal, antiviral, antiparasitic, antidermatophytic, antioxidant, hypoglycemic, hepatoprotective, immunostimulant [13,14]; Elaeis guineensis, common name palm, in the Amazon region, is widely used in the treatment of wounds and inflammations [2].…”

The mixture of cashew nut shell liquid and castor oil results in an efficient larvicide against Aedes aegypti that does not alter embryo-fetal development, reproductive performance or DNA integrity

“…CNSL exhibits larvicidal activity, as previously described [ 11 , 13 , 16 ]. In addition, preliminary data from Galdino and Beatriz [ 14 ] and Beatriz et al [ 15 ] demonstrated that mixtures of sodium surfactants from natural CNSL and castor bean oil exhibit larvicidal activity; among the various tests that were performed, the best results were observed at a ratio of 20:80.…”

“…Accordingly, there is a critical need for new larvicidal compounds that do not exhibit toxicity to humans or the environment. One attractive organic raw material is cashew nut ( Anarcadium occidentale L.) shell liquid (CNSL), which contains phenolic compounds with great biological potential, such as in treatments for asthenia, respiratory problems, genital infections, and skin diseases [ 9 – 12 ] and for use in larvicidal compounds [ 11 , 13 – 16 ].…”