Antifeedant and allelopathic activities of the hydroalcoholic extract obtained from Neem (Azadirachta indica) leaves

Abstract

RESUMO: "Atividades antialimentar e alelopática do extrato hidroalcoólico obtido das folhas de Nim (Azadirachta indica)". A espécie vegetal Azadirachta indica, popularmente chamada de Nim, é conhecida em muitos países devido a suas inúmeras propriedades biológicas. O presente estudo teve como objetivo investigar a propriedade antialimentar do extrato hidroalcoólico das folhas de Nim sobre Zabrotes fasciatus (Coleoptera: Bruchidae), um inseto conhecido como carucho-do-feijão e que atua como praga durante o processo de estocagem do feijão comum (Phaseolus vulgaris). Este inseto provoca danos tais como perda de peso, redução do valor nutritivo e do grau de higiene do feijão. Quando adicionado a sua dieta, usando sementes de Phaseolus vulgaris, o extrato hidroalcoólico das folhas de Nim demonstrou efeito antialimentar, ocasionando assim, uma signifi cativa redução nos danos. Os efeitos inibitórios deste extrato sobre a germinação e o crescimento de Phaseolus vulgaris também foram avaliados. O extrato de Nim afetou a germinação das sementes e o crescimento das radículas de Phaseolus vulgaris de uma maneira dose-dependente. Unitermos: Azadirachta indica, Phaseolus vulgaris, Zabrotes fasciatus, Nim, atividade antialimentar, alelopatia.ABSTRACT: Azadirachta indica, the so-called Neem or Nim, is well-known for its biological activities in many countries. The present study aimed at investigating the antifeedant properties of the hydroalcoholic extract obtained from the leaves of Neem on Zabrotes fasciatus (Coleoptera: Bruchidae), an insect pest that commonly feeds on common bean (Phaseolus vulgaris) during seed storage. We observed that the hydroalcoholic extract obtained from Neem leaves displayed signifi cant antifeedant activity when it was added to the insect diet via Phaseolus vulgaris seeds. Additionally, the inhibitory effects of this extract on Phaseolus vulgaris germination and growth were also evaluated, indicating that both seed germination and radicle growth were affected in a concentration-dependent manner.

Control of the Mexican bean weevil Zabrotes subfasciatus with kaolin

“…Although neem oil is reported as effective against Z. subfasciatus (BARBOSA et al, 2002;SILVA et al, 2007), antagonistic effects probably Table 2 -Cumulative mortality (%) of Zabrotes subfasciatus weevils males in common bean grains treated with kaolin, kaolin + neem and diatomaceous earth in the laboratory (25±2ºC, 70% RH; 12: 2 L: D). - occurred when it was mixed with kaolin (Tables 1, 2 and 3).…”

Effects of ground cover from branches of arboreal species on weed growth and maize yield

“…Chemical effects are related to allelopathic phenomena, changes in the carbon to nitrogen ratio (C/N), and the immobilization and recycling of nutrients (QUEIROZ et al, 2010). Allelopathic effects have been seen in the species studied in this work, i.e., in gliricidia (RAMAMOORTHY; PALIWAL, 1993), leucaena (CHOU; KUO, 1986), neem (SILVA et al, 2007) and sabiá (FERREIRA et al, 2010).…”

Chromatographic evaluation and antimicrobial activity of Neem (Azadirachta indica A. Juss., Meliaceae) leaves hydroalcoholic extracts

“…Other active substances are salanin, 14-epoxiazadiradione, meliantrol, melianone, gedunin, nimboline, nimbin, deacetilasalanin, azadiractol, azadirone, vilosinin, meliacarpine, over 300 isolated and characterized components (Dai et al, 1999;Sharma et al, 2003;Silva, 2005 (Khan & Wassilew, 1987). The activity in inhibiting the protease of Trichophyton (Iyer & Williamson, 1991), the production of aflatoxin of A. parasiticus (Allamed et al, 2001), antifeedant activity (Silva et al, 2007) and the antifungal activity against Penicillium expansum (Mossini et al, 2004) have been confirmed. The Neem seed oil also showed a wide spectrum activity against Gram-negative and Grampositive microorganisms, including M. tuberculosis and streptomicine resistant strains (Chopra et al, 1952).…”