RESUMO
This work evaluated the insecticidal, antifeedant and AChE inhibitory activity of compounds with eudesmane skeleton. The insecticidal activity was tested against larvae of Drosophila melanogaster and Cydia pomonella, the compounds 3 and 4 were the most active (LC50 of 104.2 and 106.7 µM; 82.0 and 84.4 µM, respectively). Likewise, the mentioned compounds were those that showed the highest acetylcholinesterase inhibitory activity, with IC50 of 0.26 ± 0.016 and 0.77 ± 0.016 µM, respectively. Enzyme kinetic studies, as well as molecular docking, show that the compounds would be non-competitive inhibitors of the enzyme. The antifeedant activity on Plodia interpunctella larvae showed an antifeedant index (AI) of 99% at 72 h for compounds 16, 27 and 20. The QSAR studies show that the properties associated with the polarity of the compounds would be responsible for the biological activities found.
Assuntos
Acetilcolinesterase , Inibidores da Colinesterase , Drosophila melanogaster , Inseticidas , Larva , Simulação de Acoplamento Molecular , Relação Quantitativa Estrutura-Atividade , Sesquiterpenos de Eudesmano , Animais , Inseticidas/farmacologia , Inseticidas/química , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/química , Larva/efeitos dos fármacos , Drosophila melanogaster/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Sesquiterpenos de Eudesmano/farmacologia , Sesquiterpenos de Eudesmano/química , Mariposas/efeitos dos fármacos , Sesquiterpenos/farmacologia , Sesquiterpenos/químicaRESUMO
Persicaria maculosa (Polygonaceae) (known as lady's thumb) is an annual morphologically variable weed that is widely distributed in Chile. The purpose of this study was to investigate the antifeedant potential of methanolic (MeOH), ethanolic (EtOH), and dichloromethane (DCM) extracts from the aerial parts of this plant collected in the Valparaíso and Curicó provinces (Chile) and relate this activity to the antioxidant capacity and the presence of phenolic compounds in the extracts. A phenolic profile based on HPLC-ESI-MS/MS allowed the identification of 26 phenolic compounds, most of them glycosyl derivatives of isorhamnetin, quercetin, and kaempferol. In addition, the total phenolic content (TP), total flavonoids (TF), and antioxidant activity measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion scavenging (O2-), ferric-reducing antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) of the extracts are reported. The antifeedant potentials of the plant extracts were tested against Epilachna paenulata, Pseudaletia adultera, Macrosiphum euphorbiae, and Diaphorina citri insects for the first time. The activity against the aphid M. euphorbiae was significant for the DCM extracts of plants from Valparaíso and Curicó (settling % = 23% ± 4% and 23% ± 5%, respectively). The antifeedant activities against the beetle E. paenulata and the lepidoptera P. adultera were significant for Valparaíso extracts, especially when tested against E. Paenulata (IFP = 1.0 ± 0.0). Finally, the MeOH and EtOH extracts from Valparaíso plants reduced the diet consumption of the psilid D. citri (p < 0.05). The results showed that P. maculosa is a good source of flavonoids with some antioxidant capacities and has potential interest as botanical eco-friendly alternative with deterrent activity.
Assuntos
Antioxidantes/análise , Flavonoides/análise , Fenóis/química , Extratos Vegetais/análise , Polygonaceae/química , Antioxidantes/metabolismo , Flavonoides/metabolismo , Extratos Vegetais/metabolismoRESUMO
Micromycetes from unexplored sources represent an opportunity to discover novel natural products to control insect pests. With this aim, a strain of Acremonium masseei CICY026 isolated from a tropical sinkhole was identified, cultured on fermented rice, and its ethyl acetate extract (EAE) was evaluated against three serious phytophagous insects (Bemisia tabaci, Myzus persicae, and Rhopalosiphum padi). DNA from A. masseei CICY026 was used to confirm its identity. EAE caused settling inhibition (SI) of M. persicae and R. padi (67.5% and 75.3%, respectively). Bioassay-guided fractionation of the active EAE led to the isolation of a novel metabolite, named hexahydroacremonintriol (1), and of acremonin A glucoside (2). The structures of 1 and 2 were determined using IR, one- and two-dimensional NMR, HRMS, and confirmed by theoretical data. The aphid M. persicae was noticeably sensitive to 1 and 2 (SI: 55.6% and 67.2%, respectively), whereas R. padi was only slightly affected by 1 (SI: 59%). This new knowledge about mycobiota from these special sinkhole ecosystems will inform the development of new biorational pesticides.
RESUMO
The anti-acetylcholinesterase, larvicidal, antifeedant activities and general toxicity of 15 semisynthetic eugenol derivatives based on clove oil (including the own oil), were evaluated against the maize armyworm, Spodoptera frugiperda (J.E. Smith). Therefore, promising eugenol molecules were classified with larvicidal, anti-acetylcholinesterase and antifeedant activities for controlling this pest. During structure-activity relationship studies and physicochemical profile analysis, it was found that among tested molecules 1-15, eugenol 1, prenyl eugenol 4, isoeugenol 8 and isoeugenol acetate 11 exhibited lethal effects LD50 at concentrations <1â¯mg/g of insect. On the other hand, eugenol 1, metallyl eugenol 3, isoeugenol 8 and isoeugenol acetate 11 showed a good antifeedant activity (CE50â¯=â¯158-209⯵g/mL) with a high antifeedant index (70-78%) at concentration 1000⯵g/mL, possessing a weak anti-acetylcholinesterase activity (IC50â¯=â¯21-31⯵g/mL). According to their ecotoxicological profiles (LC50â¯=â¯2033.1-6303.8⯵g/mL on Artemia salina larvae), isoeugenol 8 and its acetate derivative 11 could be potential used in control of the growth, feeding, or reproduction of S. frugiperda larvae, acting as moderate insecticidal acetylcholinesterase inhibitors and/or antifeedant molecules. Such structure-activity relationship studies could stimulate the identification of lead structures from natural sources for the development of larvicidal and deterrent products against S. frugiperda and related insect pests.
RESUMO
The insecticidal and antifeedant activities of five 7-chloro-4-(1H-1,2,3-triazol-1-yl)quinoline derivatives were evaluated against the maize armyworm, Spodoptera frugiperda (J.E. Smith). These hybrids were prepared through a copper-catalyzed azide alkyne cycloaddition (CuAAC, known as a click reaction) and displayed larvicidal properties with LD50 values below 3 mg/g insect, and triazolyl-quinoline hybrid 6 showed an LD50 of 0.65 mg/g insect, making it 2-fold less potent than methomyl, which was used as a reference insecticide (LD50 = 0.34 mg/g insect). Compound 4 was the most active antifeedant derivative (CE50 = 162.1 µg/mL) with a good antifeedant index (56-79%) at concentrations of 250-1000 µg/mL. Additionally, triazolyl-quinoline hybrids 4-8 exhibited weak inhibitory activity against commercial acetylcholinesterase from Electrophorus electricus (electric-eel AChE) (IC50 = 27.7 µg/mL) as well as low anti-ChE activity on S. frugiperda larvae homogenate (IC50 = 68.4 µg/mL). Finally, molecular docking simulations suggested that hybrid 7 binds to the catalytic active site (CAS) of this enzyme and around the rim of the enzyme cavity, acting as a mixed (competitive and noncompetitive) inhibitor like methomyl. Triazolyl-quinolines 4-6 and 8 inhibit AChE by binding over the perimeter of the enzyme cavity, functioning as noncompetitive inhibitors. The results described in this work can help to identify lead triazole structures from click chemistry for the development of insecticide and deterrent products against S. frugiperda and related insect pests.
Assuntos
Inseticidas/síntese química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Quinolinas/química , Quinolinas/farmacologia , Spodoptera/efeitos dos fármacos , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Animais , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Química Click , Simulação por Computador , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Inseticidas/química , Larva/enzimologia , Larva/crescimento & desenvolvimento , Simulação de Acoplamento Molecular , Doenças das Plantas/parasitologia , Spodoptera/enzimologia , Spodoptera/crescimento & desenvolvimento , Zea mays/parasitologiaRESUMO
Several representatives of Meliaceae contain biologically active compounds that are toxic to insects with few negative effects on the environment and humans. Our study evaluated the activity of ethyl acetate and ethanol extracts from the fruit and seeds of Cabralea canjerana (Vellozo) Mart (Sapindales: Meliaceae) on Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae). Limonoids and triterpenes were detected in fruit and seed extracts. Each extract was added to an artificial diet at three concentrations and tested after 24, 48, and 72 hr of extract application. Ethyl acetate extracts were the most active ones and showed the effect of both dose and time elapses after application on the insects. The highest toxic effect on A. fraterculus adults was from ethyl acetate extracts from fruit, followed by extracts from seeds. These extracts showed antifeedant activities. Extract solutions sprinkled on fruits of Carica papaya (L.) (Brassicales: Caricaceae) caused oviposition repellency and negatively affected the biological development of A. fraterculus. Ethyl acetate extracts highly hampered oviposition, but seed extracts showed lesser oviposition deterrence. The fruit and seed extracts diminished pupal viability. Particularly, the ethyl acetate fruit extract caused malformed adults. The sex ratio was also affected, resulting in female predominance for the fruit extract, while the seed extract showed a dose-dependent effect. Low doses caused male abundance, but at higher concentrations the effect was reversed. These encouraging results showed that the C. canjerana extracts have great potential as new tools to be used in integrated pest management programs to protect fruits against A. fraterculus.
Assuntos
Controle de Insetos/métodos , Meliaceae/química , Extratos Vegetais/farmacologia , Tephritidae/efeitos dos fármacos , Animais , Brasil , Comportamento Alimentar/efeitos dos fármacos , Feminino , Frutas/química , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/fisiologia , Limoninas/farmacologia , Masculino , Oviposição/efeitos dos fármacos , Óvulo/efeitos dos fármacos , Óvulo/fisiologia , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Sementes/química , Tephritidae/crescimento & desenvolvimento , Tephritidae/fisiologia , Triterpenos/farmacologiaRESUMO
Introducción: los estudios fitoquímicos y propiedades biológicas de la especie Pernettya prostrata (Cav.) DC. (Ericaceae) han sido preliminares, y muchos de los resultados publicados no son muy confiables. Por lo anterior, la planta se convierte en objeto de estudio promisorio e interesante. Objetivo: realizar el análisis fitoquímico preliminar y la evaluación de algunas propiedades biológicas de extractos y fracciones de la especie P. prostrata. Métodos: a los extractos etanólicos de parte aérea y frutos se les determinaron los posibles constituyentes mediante un análisis fitoquímico preliminar, y se evaluó la actividad antioxidante mediante la captación del radical libre DPPH, la actividad tóxica frente a Artemia salina y antialimentaria frente a Sitophilus zeamais y Tribolium castaneum. Resultados: las pruebas fitoquímicas preliminares sugieren la presencia de flavonoides, taninos triterpenos y/o esteroides en los extractos etanólicos de frutos y parte aérea, obtenidos de P. prostata. Del estudio fitoquímico realizado sobre el extracto etanólico de frutos se aisló e identificó escualeno y β-1-O-metoxiglucopiranosa. Los compuestos aislados e identificados no arrojaron resultados promisorios frente a los ensayos biológicos realizados. Los extractos etanólico de frutos (72,8 ppm) y parte aérea (60,9 ppm) presentan similar actividad antioxidante. La fracción metanólica es la de mayor actividad antioxidante con CI50 (86,2 ± 8,8 ppm) y PI (89,8 %), mayores a los del ácido ascórbico usado como patrón (CI50 = 49,3 ± 0,2 ppm). No se observó actividad tóxica y antialimentaria de los extractos y fracciones evaluados. Conclusiones: el presente trabajo realiza aportes al conocimiento químico y de las propiedades biológicas de la especie P. prostrata, mediante el aislamiento e identificación de dos sustancias nuevas y la determinación de la actividad antioxidante de algunos extractos y fracciones.
Introduction: studies about the phytochemistry and biological properties of the species Pernettya prostrata (Cav.) DC. (Ericaceae) conducted so far have been preliminary and many of the results published are not totally reliable. Therefore, the plant is an interesting and promising object of study. Objective:carry out the preliminary phytochemical analysis and evaluation of some biological properties of extracts and fractions of P. prostrata. Methods: preliminary phytochemical analysis was conducted of ethanolic extracts from the aerial parts and fruits for determination of possible constituents. Antioxidant activity was evaluated by DPPH free radical capture. Toxic activity against Artemia salina and antifeedant activity against Sitophilus zeamais and Tribolium castaneum were also determined. Results: preliminary phytochemical tests suggest the presence of flavonoids, tannins, triterpenes and/or steroids in ethanolic extracts from fruits and aerial parts of P. prostrata. Squalene and β-1-O-methoxy-glucopyranose were isolated and identified from the phytochemical study of the fruit ethanolic extract. The compounds isolated and identified did not reveal any promising results in the biological assays performed. Ethanolic extracts from fruits (72.8 ppm) and aerial parts (60.9 ppm) exhibited similar antioxidant activity. The methanolic fraction showed the highest antioxidant activity with IC 50 (86.2 ± 8.8 ppm) and IP (89.8 %), greater than those in the ascorbic acid used as a standard (IC50 = 49.3 ± 0.2 ppm). No toxic or antifeedant activity was found in the extracts and fractions evaluated. Conclusions: the present paper makes a contribution to knowledge about the chemical composition and biological properties of the species P. prostrata through isolation and identification of two new substances, and determination of the antioxidant activity of some extracts and fractions.
RESUMO
Antifeedant and growth regulating activities of PONNEEM, an oil formulation containing neem and pungam (karanj) oils were evaluated along with individual neem and karanj oils and Nimbicidine, a commercial neem-based pesticide against fourth instar larvae of Spodoptera litura (Fab.). Among all the treatments, PONNEEM recorded the maximum antifeedant activity (88.6%) at 0.6%. Neem and karanj individual treatments as well as PONNEEM extended larval duration compared to control. Pupal weight and fecundity were significantly reduced and pupal period was greatly increased by PONNEEM treatment compared to other treatments. The PONNEEM was found to be compatible with Trichogramma chilonis Ishii, an egg parasitoid of many lepidopteran pests, at 0.15, 0.3 and 0.5% concentrations. PONNEEM did not affect the parasitoid emergence significantly at 0.3% concentration compared to control. PONNEEM also showed growth disruption activity against fourth instar larvae.
RESUMO
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 significant 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.
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 significativa 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.