Chemical profile and allelopathic potential of Anacardium humile St. Hill. (cajuzinho-do-cerrado) leaf aqueous extract in the seed germination and seedling growth of lettuce, tomato and sicklepod / Perfil químico e potencial alelopático do extrato aquoso de Anacardium humile St. Hill. (cajuzinho-do-cerrado) na germinação e formação de plântulas de alface, tomate e fedegoso

Anacardium genus, Anacardiaceae, stands out for the presence of phenolic compounds. One of its species, investigated for its different potential uses, is Anacardium humile; however, little is known about its allelopathic effects. Therefore, the present study aimed to determine the chemical profile and evaluate the herbicide potential of your leaves in the germination of seeds and growth of seedlings of Lactuca sativa(lettuce), Lycopersicon esculentum (tomato) and Senna obtusifolia (sicklepod), both in vitro and in greenhouse. Leaves of A. humile were obtained from 20 matrices of Cerrado fragments in the municipality of Campo Grande, Mato Grosso do Sul state, Brazil. A voucher specimen was deposited at the herbarium (no. 8448). The aqueous extract was obtained from dried and crushed leaves using the extraction method of ultrasonic bath (30 min) with subsequent static maceration. After solvent evaporation, 12.78 g of extract were obtained. The chemical profile of the aqueous extract included determination of total phenolic and flavonoid contents, pH, electrical conductivity, and soluble solids concentration. For the in vitro bioassays, the extract was used at different concentrations, namely, 25, 50, 100, 150, and 200 mg mL-1. In greenhouse, the substrates were prepared using 950 g of vermiculite and 50 g of A. humile leaf powder at the following ratios: (950/50) (5%), 900/100 (10%), 800/200 (20%), and a control (100% vermiculite), under a completely randomized experimental design. Phenolic compounds and anthraquinones were predominant in the chemical profile of the extract, which presented different levels of allelopathic effect on seed germination and seedling growth of plants both ingermination chamber and in greenhouse, indicating strong allelopathic activity associated with the different compounds found in the leaves. Therefore, the results showed germination and growth inhibition at different levels, indicating that the substances contained in the leaves of Anacardium humile may be a promising alternative for the control of invasive species.

O gênero Anacardium, Anacardiaceae, destaca-se pela presença de compostos fenólicos. Uma de suas espécies, investigada pelos diferentes potenciais de uso, é Anacardium humile. No entanto, pouco se sabe sobre seus efeitos alelopáticos. Portanto, o presente trabalho objetivou determinar o perfil químico e avaliar o potencial herbicida de suas folhas sobre a germinação e crescimento de Lactuca sativa (alface), Lycopersicon esculentum (tomate) e Senna obtusifolia (fedegoso) in vitro e em casa de vegetação. Folhas de A. humile foram obtidas de 20 matrizes de Cerrado, município de Campo Grande/MS, Brasil. Uma espécime foi depositada no herbário (N. 8448). O extrato aquoso foi obtido das folhas secas e trituradas e o método de extração foi banho de ultrassom (30 minutos) seguido de maceração estática, sendo o solvente evaporado e 12,78 g de extrato obtido. O extrato foi submetido ao perfil químico e determinado: teor de fenóis totais e flavonóides, pH, condutividade elétrica e concentração de sólidos solúveis. Para os bioensaios in vitro, o extrato foi utilizado em diferentes concentrações (25, 50, 100, 150 e 200 mg mL-1). Em casa de vegetação, os substratos foram preparados com 950 g do substrato vermiculita e 50 g do pó das folhas de A. humile (950/50) (5%); 900/100 (10%); 800/200 (20%), além do controle, 100% vermiculita, com delineamento experimental inteiramente casualizado. O extrato apresentou como perfil químico predominante os compostos fenólicos e antraquinonas, com efeito alelopático sobre a germinação e crescimento em câmara de germinação e estufa, em diferentes graus, indicando que há uma forte atividade alelopática associada aos diferentes compostos encontrados nas folhas. Portanto, os resultados indicaram germinação e inibição do crescimento, em diferentes níveis, demonstrando que as substâncias contidas nas folhas de A. humile podem ser uma alternativa promissora para o controle de espécies invasoras.

A potent larvicidal agent against Aedes aegypti mosquito from cardanol

ABSTRACT Cardanol is a constituent of Cashew Nut Shell Liquid that presents larvicidal activity against Aedes aegypti. The isolation of cardanol is somewhat troublesome, however, in this work we describe an efficient and inexpensive method to obtain it as a pure material. The compound was used as starting material to make chemical transformation leading to saturated cardanol, epoxides and, halohydrins. These derivatives were tested for toxicity against Aedes aegypti larvae. The results showed that iodohydrins are very promising compounds for making commercial products to combat the vector mosquito larvae presenting a LC50 of 0.0023 ppm after 72 h of exposure.