Bioactivity of neem nanoformulations on tomato pinworm

O uso de plantas inseticidas é uma importante ferramenta para o manejo de insetos-praga. Visando ao controle de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), nanoformulações de nim foram avaliadas. Após a estimativa de uma CL50 para uma formulação de óleo comercial de nim, bioensaios de seleção foram realizados com 22 nanoformulações. Para isso, lagartas neonatas foram alimentadas sobre folíolos tratados com soluções das nanoformulações durante 10 dias. Com as duas nanoformulações mais promissoras, NC40 aquoso e NC40 pó (NC 40=nanocápsulas de Poli- β-hidroxibutirato), foi avaliado o efeito sobre o desenvolvimento e a longevidade do inseto. A CL50 para o óleo de nim foi estimada em 0,20% ou 1,31mgL-1 de azadiractina. As nanoformulações NC40 aquoso e NC40 pó afetaram o desenvolvimento do inseto

Formulaciones de nim para el control de larvas de Diabrotica speciosa (Coleoptera: Chrysomelidae) en maíz.

Las larvas de Diabrotica speciosa (Germar) son una de las principales plagas subterráneas de varios cultivos y su principal hospedero es el maíz (Zea mays). Este estudio tuvo como objetivo evaluar los efectos de extracto de nim formulado en aceite y extracto de nim en micro encapsulación para el control de larvas de D. speciosa, así como el efecto de la aplicación de las distintas formulaciones en el desarrollo de las plantas de maíz. En el primer experimento, las dosis 0,25; 0,5; 1,0; 2,0; y 4,0 mL de extracto de nim formulado en aceite fueron aplicadas por 25 g de suelo y comparadas con el insecticida fipronil WG y agua desionizada (control). En el segundo experimento, las dosis 160, 80, 40, 20 y 10 mg de extracto de nim en formulación micro encapsulada fueron aplicadas por 25 g de suelo, y comparadas con los controles. Ambas formulaciones de nim fueron tan eficientes como el insecticida fipronil WG en el control de larvas de D. speciosa. Las dosis evaluadas de las formulaciones de nim no interfieren negativamente en el desarrollo de las plantas de maíz. Se concluye que, a partir de los resultados de esta investigación y bajo condiciones de laboratorio, las formulaciones extracto de nim formulado en aceite y extracto de nim en micro encapsulación son promisoras para el control de larvas de D. speciosa en maíz, beneficiando el manejo sustentable de plagas

Preparation and characterization of polymeric nanoparticles loaded with the flavonoid luteolin, by using factorial design.

Nanoparticles containing luteolin flavonoid were prepared by using interfacial polymer deposition following solvent displacement. The formulation was optimized using factorial design. The parameters studied were the type of polymer [poly(ε-caprolactone) and poly(lactic-co-glycolic acid)], nature oil (isodecyl oleate and oleic acid) and the quantity of luteolin. Nanocapsules and nanospheres were also prepared and evaluated. Colloidal suspensions were characterized by evaluating pH, the particle size, the zeta potential, the morphological aspect and the kinetic release. A new High Performance Liquid Chromatography method was developed and validated in order to quantify luteolin in colloidal suspension allowing the analyses of the absolute recovery, entrapment efficiency and the kinetic release. The luteolin-absolute recovery ranged from 61.6% to 95%; entrapment efficiency was nearly 100% in all formulations and the particle sizes were smaller than 185.5 nm. The nanoparticles prepared with isodecyl oleate show a negative zeta potential. On the other hand, when oleic acid was utilized, the zeta potential was positive. The nanoparticles prepared by using isodecyl oleate have a more perfect spherical shape with a regular surface and form, homogeneity, and lower size dispersion. Nanocapsules and nanospheres have a similar release mechanism of pure diffusion according with Korsmeyer-Peppas’s model

New Limonoids from Dictyoloma vandellianum and Sohnreyia excelsa: Chemosystematic considerations

Molecular phylogenetic studies separated and united a group of genera that constituted the Spathelia-Ptaeroxylon clade, in which Dictyoloma and Sohnreyia have been included. Our taxonomic interest in the Dictyoloma vandellianum and Sohnreyia excelsa stimulated an investigation of both species searching for limonoids. Leaves from D. vandellianum afforded the new limonoid 1,2-dihydro-1α-hydroxy-8,30-epoxy-cneorin R, and heartwood yielded the new rearranged limonoid dictyolomin. Leaves from S. excelsa afforded the new protolimonoid 3β-angeloyloxy-7α,24,25-trihydroxy-21,23-oxide-14,18-cycloapotirucall-21-methoxycetal and the new cycloheptanyl ring C limonoid with carbonate substituent and named as sohnreyolide. The new limonoids from Sohnreyia and Dictyoloma show similarities with those from Rutaceae and Meliaceae, providing support for moving Spathelia-Ptaeroxylon clade near to these associated large families. ©2019 Sociedade Brasileira de Química

Uso de CLAE no controle de qualidade em produtos comerciais de Nim: reprodutibilidade da ação inseticida

The Neem tree, Azadirachta indica, provides many useful compounds that are used as pesticides. However, the efficiency in field of products like neem oil can be committed because they have not been observed reproductive content of secondary metabolic like azadirachtin. Based on reverse-phase high-performance liquid chromatography (HPLC) a new method was developed to permit the rapid quantitative analysis of azadirachtin from seeds, extracts and oil of Neem. In the present study it was evaluated the azadirachtin quantitative variation among various Neem's extracts and seeds showing the importance of quality control for reproduction of the insecticide efficiency, using S. frugiperda as target insect

Preparation and characterization of polymeric nanoparticles loaded with the flavonoid luteolin, by using factorial design

Nanoparticles containing luteolin flavonoid were prepared by using interfacial polymer deposition following solvent displacement. The formulation was optimized using factorial design. The parameters studied were the type of polymer [poly(-caprolactone) and poly(lactic-co-glycolic acid)], nature oil (isodecyl oleate and oleic acid) and the quantity of luteolin. Nanocapsules and nanospheres were also prepared and evaluated. Colloidal suspensions were characterized by evaluating pH, the particle size, the zeta potential, the morphological aspect and the kinetic release. A new High Performance Liquid Chromatography method was developed and validated in order to quantify luteolin in colloidal suspension allowing the analyses of the absolute recovery, entrapment efficiency and the kinetic release. The luteolin-absolute recovery ranged from 61.6% to 95%; entrapment efficiency was nearly 100% in all formulations and the particle sizes were smaller than 185.5 nm. The nanoparticles prepared with isodecyl oleate show a negative zeta potential. On the other hand, when oleic acid was utilized, the zeta potential was positive. The nanoparticles prepared by using isodecyl oleate have a more perfect spherical shape with a regular surface and form, homogeneity, and lower size dispersion. Nanocapsules and nanospheres have a similar release mechanism of pure diffusion according with Korsmeyer-Peppas’s model.CNPqCAPESFAPES

Evaluation of an Experimental Gel Containing Euclea natalensis: An In Vitro Study

Objective. To evaluate the effect of an experimental gel containing Euclea natalensis extract on dentin permeability. Methods. Thirty-six dentin discs, 1-mm-thick. The discs were prepared from the coronal dentin of extracted human third molars that were divided into 3 groups (n = 10). The dentin discs in each group were treated with the groups following experimental materials: (FG): 1.23% fluoride gel, pH 4.1; (EG): Euclea natalensis extract gel, pH 4.1; (CG): control gel, pH 4.1. The gels were applied to the occlusal slide of the dentin under the following conditions: after 37% phosphoric acid and before 6% citric acid. The hydraulic conductance (HC) of each condition was determined four times using a fluid flow apparatus (Flodec). The data were analyzed using Two-way ANOVA and Tukey's test (P < 0.05). Results. The greatest mean reduction in HC was produced in group EG dentin discs (61.2%; P < 0.05). Even after acid challenge with 6% citric acid the great reduction occurred in group EG (66.0%; P < 0.05) than other groups (CG-77.1%, FG-90.8%). Conclusion. E. natalensis gel not only reduced dentin permeability, but also resisted posttreatment citric acid challenge without changing its permeability. Further research has to confirm this promising result in the clinical situation.FAPESPFAPESP [2009/16079-0, 2010/09951-0

Preparation and characterization of polymeric nanoparticles loaded with the flavonoid luteolin, by using factorial design.

Nanoparticles containing luteolin flavonoid were prepared by using interfacial polymer deposition following solvent displacement. The formulation was optimized using factorial design. The parameters studied were the type of polymer [poly(ε-caprolactone) and poly(lactic-co-glycolic acid)], nature oil (isodecyl oleate and oleic acid) and the quantity of luteolin. Nanocapsules and nanospheres were also prepared and evaluated. Colloidal suspensions were characterized by evaluating pH, the particle size, the zeta potential, the morphological aspect and the kinetic release. A new High Performance Liquid Chromatography method was developed and validated in order to quantify luteolin in colloidal suspension allowing the analyses of the absolute recovery, entrapment efficiency and the kinetic release. The luteolin-absolute recovery ranged from 61.6% to 95%; entrapment efficiency was nearly 100% in all formulations and the particle sizes were smaller than 185.5 nm. The nanoparticles prepared with isodecyl oleate show a negative zeta potential. On the other hand, when oleic acid was utilized, the zeta potential was positive. The nanoparticles prepared by using isodecyl oleate have a more perfect spherical shape with a regular surface and form, homogeneity, and lower size dispersion. Nanocapsules and nanospheres have a similar release mechanism of pure diffusion according with Korsmeyer-Peppas’s model