Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 182
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
J Agric Food Chem ; 67(49): 13544-13549, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725276

RESUMO

With the ultimate goal of addressing pest-related constraints on global agricultural production, we used combination principles to design and synthesize 2,4-diphenyl-1,3-oxazolines containing a sulfonate moiety at the para-position of the 4-phenyl group. The target compounds, which have strong affinity for lipids and can be expected to traverse cell membranes, were characterized by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry. Their activities against the larvae and eggs of carmine spider mites (Tetranychus cinnabarinus) were determined by a leaf-dipping method and compared with the activity of the commercial acaricide etoxazole. Most of the test compounds displayed good ovicidal and larvicidal activities. In particular, a tert-butylphenyl-substituent compound possessed better larvicidal activity (LC50 = 0.022 ± 0.009 mg/L) and ovicidal activity (0.044 ± 0.020 mg/L) than etoxazole (0.091 ± 0.051 and 0.095 ± 0.059 mg/L, respectively). Given its outstanding bioactivities, this compound deserves further attention as a pesticide candidate.


Assuntos
Acaricidas/química , Acaricidas/farmacologia , Oxazóis/química , Oxazóis/farmacologia , Acaricidas/síntese química , Animais , Desenho de Drogas , Larva/efeitos dos fármacos , Dose Letal Mediana , Estrutura Molecular , Oxazóis/síntese química , Relação Estrutura-Atividade , Ácidos Sulfônicos/química , Tetranychidae/efeitos dos fármacos
2.
J Agric Food Chem ; 67(44): 12182-12190, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31609606

RESUMO

In continuation of our program to develop natural-product-based pesticidal candidates, matrinic/oxymatrinic amides were obtained through structural optimization of matrine. N'-(4-Fluoro)phenyl-N-(4-bromo)phenylsulfonyloxymatrinic amide (IIm) showed potent insecticidal activity against Mythimna separata. N-(Un)substituted phenylsulfonylmatrinic acids (3a-c) exhibited promising acaricidal activity against Tetranychus cinnabarinus. By qRT-PCR analysis of nAChR subunits and AChE genes and determination of AChE activity of (un)treated T. cinnabarinus, it suggested that the open lactam ring of matrine and carboxyl group and (4-methyl)phenylsulfonyl of N-(4-methyl)phenylsulfonylmatrinic acid (3b) were necessary for action with α2, α4, α5, and ß3 nAChR subunits; compound 3b was an inhibitor of AChE in T. cinnabarinus, and AChE was one possible target of action in T. cinnabarinus against 3b; and compound 3b may be an antagonist of nAChR and AChE in T. cinnabarinus.


Assuntos
Acaricidas/química , Alcaloides/química , Amidas/química , Inseticidas/química , Quinolizinas/química , Acaricidas/síntese química , Acaricidas/farmacologia , Acetilcolinesterase/genética , Acetilcolinesterase/metabolismo , Alcaloides/farmacologia , Amidas/farmacologia , Animais , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Feminino , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Inseticidas/síntese química , Inseticidas/farmacologia , Estrutura Molecular , Mariposas/efeitos dos fármacos , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Mariposas/metabolismo , Quinolizinas/farmacologia , Relação Estrutura-Atividade , Tetranychidae/efeitos dos fármacos , Tetranychidae/genética , Tetranychidae/crescimento & desenvolvimento , Tetranychidae/metabolismo
3.
Pestic Biochem Physiol ; 160: 11-19, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31519244

RESUMO

The mite Varroa destructor is an ectoparasite and has been identified as a major cause of worldwide honey bee colony losses. The use of yearly treatments for the control of varroosis is the most common answer to prevent collapses of honey bee colonies due to the mite. However, the number of effective acaricides is small and the mite tends to become resistant to these few active molecules. In this study, we have been looking for a new original varroacide treatment inhibiting selectively Varroa destructor AChE (vdAChE) with respect to Apis mellifera AChE (amAChE). To do this an original drug design methodology was used applying virtual screening of the CERMN chemolibrary, starting from a vdAChE homology sequence model. By combining the in silico screening with in vitro experiments, two promising compounds were found. In vitro tests of AChE inhibition for both species have confirmed good selectivity toward the mite vdAChE. Moreover, an in vivo protocol was performed and highlighted a varroacide activity without acute consequences on honey bee survival. The two compounds discovered have the potential to become new drug leads for the development of new treatments against the mite varroa. The method described here clearly shows the potential of a drug-design approach to develop new solutions to safeguard honey bee health.


Assuntos
Acaricidas/farmacologia , Varroidae/efeitos dos fármacos , Acaricidas/química , Animais , Simulação por Computador , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia
4.
Vet Parasitol ; 269: 53-56, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31079828

RESUMO

Infestations of Rhipicephalus microplus cause significant damage to cattle breeding and their control is primarily based on chemical products. There are extensive reports of efficacy losses of acaricid products over time, as well as resistance of the parasites to them, thereby making it necessary to search for new alternatives. The present work aimed to determine the in vitro and in vivo acaricidal activity of organo-modified siloxanes with and without piperonyl butoxide (PBO) in southern Brazil. For the in vitro test, engorged females of R. microplus were collected and submitted to the immersion test. The formulation containing organo-modified siloxanes was tested at 4 different concentrations: 0.6, 1.0, 2.5, and 5.0%. The lowest dilutions (0.6, 1.0, and 2.5%) were also tested with the inclusion of 10% PBO. The in vivo test was performed by applying 2.5% organo-modified siloxanes, and the addition of 10% PBO was applied by spraying. The results showed high acaricidal activity (100%) in vitro in the concentration of 5% on non-associated forms, and in combinations of concentrations of 0.6, 1.0, 2.5% with PBO. The in vivo results also increased the efficacy with the association of PBO. In view of the current multi-resistance scenario of the R. microplus tick to the different commercially available acaricidal products, this study investigated the use of this product in association with PBO as an alternative to R. microplus control and found positive results. To the authors' knowledge, this is the first study to use organo-modified siloxanes against ticks.


Assuntos
Acaricidas/farmacologia , Doenças dos Bovinos/parasitologia , Butóxido de Piperonila/farmacologia , Rhipicephalus/efeitos dos fármacos , Siloxanas/farmacologia , Infestações por Carrapato/veterinária , Acaricidas/química , Animais , Bovinos , Resistência a Medicamentos , Feminino , Siloxanas/química , Infestações por Carrapato/parasitologia
5.
J Agric Food Chem ; 67(24): 6708-6715, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31140799

RESUMO

This is the first systemic assessment of the stereoselectivity of etoxazole enantiomers. Etoxazole's stereoselective bioactivity was assessed against target organisms ( Tetranychus urticae eggs and Tetranychus cinnabarinus eggs), and its acute toxicity was assessed toward nontarget aquatic organisms ( Daphnia magna and Danio rerio). Additionally, stereoselective elimination was investigated in three species of fruits (grape and strawberry grown in a greenhouse and apple grown in an open field) and in field soil. The ovicidal activity of (+)-( S)-etoxazole against Tetranychus urticae and Tetranychus cinnabarinus eggs was about 16 and 24 times higher, respectively, than that of (-)-( R)-etoxazole. Inconsistent order of etoxazole isomer toxicity was found toward different aquatic organisms: (+)-( S)-etoxazole showed nearly 8.7 times higher acute toxicity than (-)-( R)-etoxazole toward Daphnia magna, whereas (-)-( R)-etoxazole was ∼4.5 times more toxic to Danio rerio than (+)-( S)-etoxazole. Stereoselective degradation of etoxazole enantiomers showed significant variation in various fruits and field soil. The (+)-( S)-etoxazole was preferentially dissipated in grape and strawberry fruits grown under greenhouse condition, whereas (-)-( R)-etoxazole degraded faster than its antipode in apple fruits and soils under open-field condition. Overall, the stereoselectivity of etoxazole enantiomers should be fully considered in comprehensive environmental health risk in future work.


Assuntos
Acaricidas/química , Acaricidas/toxicidade , Frutas/química , Oxazóis/química , Oxazóis/toxicidade , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Animais , Fragaria/química , Fragaria/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Malus/química , Malus/crescimento & desenvolvimento , Solo/química , Estereoisomerismo , Tetranychidae/efeitos dos fármacos , Vitis/química , Vitis/crescimento & desenvolvimento
6.
Molecules ; 24(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999695

RESUMO

Beeswax is useful for the beekeeping sector but also for the agro-food, pharmaceutical or cosmetics sectors. Frequently, this bee product is contaminated with pesticides reducing its utility and causing the decline in its market. This study aimed to prove the effectiveness of an industrial-scale decontamination method in removing acaricides from beeswax. Chlorfenvinphos and coumaphos decrease was higher than 90%, whereas tau fluvalinate decrease was only 30%. No changes were observed in the beeswax content of hydrocarbons and monoesters, whereas a decrease in the concentrations of Ca, Fe, Zn, Hg, Mn and P, and an increase in the concentrations of As and Si were found after the decontamination. Filtration reduced total phenolics, flavonoids and the antioxidant capacity of the lipophilic extract. These results demonstrate that the industrial method used was as effective as the method previously tested on a laboratory scale. The study also contributes to a better knowledge and characterization of beeswax, specially related to trace and ultra-trace elements and antioxidant capacity. Moreover, it offers the chance to further develop a method to effectively detect wax adulterations based on the chemical elements profile.


Assuntos
Acaricidas/química , Antioxidantes/química , Descontaminação , Metais Pesados/química , Ceras/química , Animais , Abelhas
7.
An Acad Bras Cienc ; 91(1): e20180381, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30994766

RESUMO

As a part of our continuing search for insect and arthropod development regulators from Brazilian restinga vegetation of the Rio de Janeiro State, crude extracts, purified fractions and essential oils were submitted to screening tests seeking for biological activities on the development of the insects Rhodnius prolixus, Dysdercus peruvianus, Oncopeltus fasciatus and Rhipicephalus (Boophilus) microplus. Up to now, 102 secondary metabolites have been detected in the fractions, among them monoterpenes, sesquiterpenes and two triterpenes which were obtained from the species, Eugenia sulcata, Pilocarpus spicatus, Manilkara subsericea, Myrciaria floribunda and Zanthoxylum caribaeum. These secondary plant metabolites are considered of interest for the use of studies related to arthropod endocrinology, vector-parasite interaction system, and population control of vector insect and agricultural pest. The observed biological activities were surprisingly high, involving increased mortality, molting and metamorphosis inhibition, paralysis, corporeal deformities, apparition of permanent nymphs, of adultoids and juvenoids, partial or total inhibition of oviposition and egg hatching. These compounds are now being studied further to determine if they may or may not be useful in controlling insect populations and/or interfere with the life cycle and vector transmission of parasites to animal and human populations.


Assuntos
Acaricidas/química , Inseticidas/química , Óleos Voláteis/química , Controle Biológico de Vetores/métodos , Extratos Vegetais/química , Agricultura , Animais , Brasil , Insetos/efeitos dos fármacos , Monoterpenos/química , Reprodutibilidade dos Testes , Sesquiterpenos/química
8.
Vet Parasitol ; 268: 61-66, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30981307

RESUMO

The emergence of resistance to chemical acaricides in Dermanyssus gallinae, together with their toxicity and high costs, has prompted investigations into the use of plant extracts as alternatives to chemical acaricidal treatments. Drimia maritima bulbs and Dittrichia viscosa (D. viscosa) leaf extracts were here characterized by HPLC-PDA-ESI-MS/MS, and their toxicity against D. gallinae was evaluated using contact methods. Twenty-nine compounds were identified in D. maritima extracts, with glucoscilliphaeoside derivatives (i.e., quercetin, kaempferol and bufadienolides) as the major components. Twenty-four phenolic compounds, mainly caffeic acid derivatives, were detected in D. viscosa extracts. D. maritima extracts displayed a significantly higher (p < 0.05) acaricidal activity than D. viscosa extracts, with 100% of D. gallinae mortality at a concentration of 100 mg/mL following 24 h exposure. The mortality rate of D. gallinae induced by D. viscosa extracts ranged from 25 to 45% following 48 h exposure at a concentration of 200 mg/mL. The acetonic extract of D. viscosa and D. maritima displayed the highest efficacy against D. gallinae. This study provides evidence of the diversity of bioactive compounds present in D. maritima bulbs and D. viscosa leaf extracts, which are both efficacious against D. gallinae. The higher efficacy of D. maritima bulb extracts might be linked to the presence of bufadienolides in its extracts.


Assuntos
Acaricidas/farmacologia , Asteraceae/química , Drimia/química , Ácaros/efeitos dos fármacos , Extratos Vegetais/farmacologia , Acaricidas/química , Animais , Feminino , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/química , Folhas de Planta/química , Raízes de Plantas/química
9.
J Agric Food Chem ; 67(17): 4782-4792, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30973721

RESUMO

Polyketides represent an important class of biologically active and structurally diverse compounds found in nature. They are biosynthesized from acyl CoA precursors by polyketide synthases (PKSs). The use of combinatorial biosynthesis to form hybrid PKSs is considered to be an excellent approach for the development of novel polyketides. Here, 10 new 16-membered macrolide compounds were isolated from the broth of the genetically engineered strain Streptomyces avermitilis TM24, in which the PKS gene aveA3 was seamlessly replaced by the milbemycin PKS gene milA3. Their structures were elucidated on the basis of NMR and MS spectroscopic analyses. The acaricidal and nematicidal activities of them against Tetranychus cinnabarinus and Bursaphelenchus xylophilus were tested. The results indicated that compound 1 had potent acaricidal activity against adult mites with an LC50 value of 0.0022 mg L-1, while compounds 5 and 7 possessed potent nematicidal activity with LC50 values of 4.56 and 4.30 mg L-1, respectively.


Assuntos
Acaricidas/farmacologia , Antinematódeos/farmacologia , Proteínas de Bactérias/genética , Macrolídeos/farmacologia , Streptomyces/química , Streptomyces/genética , Acaricidas/química , Acaricidas/isolamento & purificação , Acaricidas/metabolismo , Animais , Antinematódeos/química , Antinematódeos/isolamento & purificação , Antinematódeos/metabolismo , Proteínas de Bactérias/metabolismo , Feminino , Engenharia Genética , Macrolídeos/química , Macrolídeos/isolamento & purificação , Macrolídeos/metabolismo , Masculino , Estrutura Molecular , Streptomyces/metabolismo , Tetranychidae/efeitos dos fármacos , Tylenchida/efeitos dos fármacos
10.
J Agric Food Chem ; 67(15): 4224-4231, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30905158

RESUMO

Sulfimides and sulfoximines are highly relevant for medicinal chemistry and crop protection, as the resulting products can reveal interesting bioactivities. Herein, we report the design and synthesis of a series of novel 2,4-diphenyl-1,3-oxazolines containing sulfiliminyl and sulfoximinyl moieties. The acaricidal and insecticidal activities of the new compounds were evaluated and indicated that these compounds exhibited excellent acaricidal activities against spider mite larvae and eggs. The LC50 values of 6a-7, 6b-3, 6b-4, 6c-2, and 6c-4 against spider mite larvae were about 4 to 6 times lower than that of the commercial insecticide etoxazole (0.0221 mg L-1), and the LC50 value of 6a-4 against spider mite eggs was 0.0006 mg L-1, which was 10 times lower than that of etoxazole (0.0063 mg L-1). At the same time, most of the compounds showed insecticidal activity though their structure-activity relationships that were different. Oxazolines containing an N-cyano sulfiliminyl moiety at the para position of the 4-phenyl group exhibited better insecticidal activities against cotton bollworm and corn borer than etoxazole, whereas the compounds containing groups derived from sulfiliminyl and sulfoximinyl had weak insecticidal activities. This research again proved that the substituent type at the para site of the 4-phenyl moiety has a decisive role on the biological activity and insecticidal spectrum.


Assuntos
Acaricidas/síntese química , Inseticidas/síntese química , Acaricidas/química , Acaricidas/farmacologia , Animais , Desenho de Drogas , Avaliação de Medicamentos , Inseticidas/química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Estrutura Molecular , Mariposas/efeitos dos fármacos , Mariposas/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tetranychidae/efeitos dos fármacos , Tetranychidae/crescimento & desenvolvimento
11.
Colloids Surf B Biointerfaces ; 173: 632-638, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30368210

RESUMO

Synergistic combination of pesticides and nanomaterials has been rarely reported in pest management science at present. In this work, graphene oxide (GO) was synergistically used with three types of pesticides (pyridaben (Pyr), chlorpyrifos (Chl) and beta-cyfluthrin (Cyf) respectively as acaricide against two economically important spider mites Tetranychus truncatus and T. urticae Koch. The results demonstrated that GO can enhance the activity of three types of pesticides. Compared with pesticides, the GO-Cyf, GO-Pyr and GO-Chl mixtures exhibited 1.77-, 1.56- and 1.55-fold higher contact toxicity against T. truncatus, and 1.50-, 1.75-, and 1.78-fold higher contact toxicity against T. urticae. SEM results showed that pesticide can adsorbed on the surface of GO. The synergistic mechanism may be that GO can serve as a carrier of pesticides, which can be adsorbed on the surface of mites and thus improve efficacy and utilization efficiency of pesticides. This kind of GO-based nanoscale pesticide delivery system may find widespread application in the field of plant protection in the future.


Assuntos
Acaricidas/toxicidade , Clorpirifos/toxicidade , Grafite/toxicidade , Nitrilos/toxicidade , Piretrinas/toxicidade , Piridazinas/toxicidade , Tetranychidae/efeitos dos fármacos , Acaricidas/química , Adsorção , Animais , Clorpirifos/química , Grafite/química , Longevidade/efeitos dos fármacos , Nanocompostos/química , Nanocompostos/toxicidade , Nitrilos/química , Óxidos , Piretrinas/química , Piridazinas/química , Tetranychidae/anatomia & histologia , Tetranychidae/fisiologia
12.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 56(2): [e157595], ago. 2019. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1025110

RESUMO

Tick infestation causes major problems in cattle. Tick parasitism accounts for significant economic losses in many beef and dairy herds in the vast majority of the states in the Brazilian territory including the State of Santa Catarina in the southern region of the country. Tick resistance to several active principles occurs due to a number of factors including the indiscriminate, injudicious and inadequate use of tick insecticides. Considering the great importance of fighting off tick infestations in cattle, we evaluated the efficiency of 8 different topical active principles against the ixodid tick R. microplus and identified the main factors that contribute to the development of ticks that are resistant to acaricides in the farms and bovine herds studied. For such purpose, R. microplus telegionae were collected in 39 farms locates in different municipalities of the West of Santa Catarina, south Brazil. At the time of sample collection, information about the management, the history of the acar used in the herd, the number of annual applications of these pesticides, the frequency of acaricide rotation, and the frequency of technical monitoring for strategic tick control were retrieved. We collected this data in order determine contributing factors to the development resistant R. microplus populations. For the sensitivity profile of these ticks to a number of different acaricides tested, 10 engorged females for each principle and a control were used. The results of our study show that most associations between pyrethroids and organophosphates had an efficiency between 96.6% and 100% in the control of R. microplus except for the combination of Alfacipermetrine 15%, Ethion 16%, and Chlorpyrifos 8.5% that had 93.4% of efficiency. Among the chemicals not associated with any other type of compound, Amitraz 12.5% ​​was effective in 98.3% of the cases. In contrast, Cypermethrin 15% had an efficiency in only 25.8% of the farms/herds analyzed. Based on the results of the present study, we may infer that the methods of control and management used by producers may be related to the low indexes of resistance to topical acaricides in the different populations of ticks in the study area.(AU)


A infestação por carrapatos em bovinos gera grandes problemas, sendo esse parasito responsável por elevados prejuízos econômicos em diversos rebanhos de produção de corte e também de leite na maioria das regiões brasileiras, inclusive em Santa Catarina. A resistência dos carrapatos frente aos diversos princípios ativos pode ser decorrente de fatores como o uso indiscriminado de carrapaticidas, bem como a inadequada forma de aplicação dos mesmos. Tendo em vista a grande importância em combater essas infestações, buscou-se avaliar a eficiência de oito diferentes princípios ativos de contato contra o carrapato Rhipicephalus microplus, bem como identificar os principais fatores que possam contribuir com a seleção de carrapatos resistentes nas propriedades avaliadas. Para isso, teleóginas de R. microplus foram coletadas em 39 propriedades de diferentes municípios do Oeste de Santa Catarina. No momento da coleta também foram obtidas informações referentes ao sistema de manejo dos animais, histórico dos carrapaticidas utilizados, número de aplicações anuais, frequência de rodízios de acaricidas, e frequência de acompanhamento técnico para controle estratégico, com a finalidade de evidenciar os diferentes fatores que possam estar contribuindo para o surgimento de eventual resistência das populações do R. microplus. A avaliação de suscetibilidade foi realizada através da técnica de biocarrapaticidograma, utilizando 10 teleóginas ingurgitadas para cada princípio e mais o controle. Dentre os principais resultados obtidos, a maioria das associações entre piretróides e organofosforados demonstraram ter eficiência entre 96,6% e 100%, com exceção da associação de Alfacipermetrina 15%, Ethion 16% e Clorpirifós 8,5% com 93,4% de eficiência. Dentre as bases químicas sem nenhum tipo de associação o Amitraz 12,5% demonstrou ser eficaz em 98,3%, em contrapartida a Cipermetrina 15% teve eficiência em apenas 25,8% das propriedades analisadas. A partir dos resultados obtidos, pode se afirmar que as formas de controle e manejo adotados pelos produtores podem estar relacionadas com os baixos índices de resistência aos carrapaticidas de contato, nas diferentes populações de carrapato na região do estudo.(AU)


Assuntos
Animais , Bovinos , Bovinos/parasitologia , Rhipicephalus , Acaricidas/administração & dosagem , Acaricidas/química
13.
J Agric Food Chem ; 66(49): 12898-12910, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30452245

RESUMO

To discover new natural-product-based potential pesticides, 85 matrinic acid/alcohol/ester derivatives were synthesized by structural modifications of a quinolizidine alkaloid matrine. N-(4-Methyl)benzylmatrinyl n-decylate (76) and N-(2-chloro)benzylmatrinyl n-undecylate (86) exhibited greater than seven-fold more pronounced acaricidal activity than matrine against Tetranychus cinnabarinus; N-(2-chloro)benzylmatrinyl benzoate (80) showed the most promising insecticidal activity against Mythimna separata. The carboxyl group of matrinic acids and introduction of n-decyl/ n-undecylcarbonyl into matrinic alcohols were important for the acaricidal activity; introduction of alkyloxy into the carboxyl of matrinic acids and introduction of the electron-withdrawing groups on the N-benzyl of matrinic esters were necessary for the insecticidal activity. Through RT-PCR and qRT-PCR analysis, it was shown that the lactam ring of matrine was vital for action on VGSC; opening the lactam ring of matrine and the alkylcarbonyl of side-chain were two important factors for acting with α1, α2, and α4 nAChR subunits; α1, α2, α4, and ß3 subunits may be the target of action of compound 86 against T. cinnabarinus.


Assuntos
Álcoois/química , Alcaloides/química , Ésteres/química , Praguicidas/síntese química , Praguicidas/farmacologia , Quinolizinas/química , Tetranychidae/efeitos dos fármacos , Acaricidas/química , Animais , Anti-Helmínticos , Produtos Biológicos/química , Inseticidas/química , Estrutura Molecular , Mariposas , Sophora/química , Relação Estrutura-Atividade
14.
Vet Parasitol ; 263: 23-26, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30389020

RESUMO

The leaf latex of Aloe yavellana Reynolds is traditionally used for the treatment of various illnesses of humans and domestic animals in Ethiopia. In the present study, the latex and two major compounds isolated from it, namely, aloin A/B and microdontin A/B were assessed for their larvicidal activity against Amblyomma variegatum tick larvae using a larval packet test (LPT). The LC50 and LC99 of the latex were found to be 35.82 ± 2.27 and 83.48 ± 3.95 mg/ml, respectively. Although microdontin A/B showed better larvicidal activity (LC50 = 89.40 ± 4.45 mg/ml) than aloin A/B (LC50 = 257.69 ± 6.31 mg/ml), neither of the isolated compounds was as active as the latex suggesting that the compounds acted synergistically or minor compounds with potent larvicidal activity may exist in the latex. The results confirmed that the leaf latex of A. yavellana and its isolated compounds could have the potential to be used as larvicidal against A. variegatum ticks.


Assuntos
Acaricidas/administração & dosagem , Aloe/química , Ixodidae/efeitos dos fármacos , Larva/efeitos dos fármacos , Látex/administração & dosagem , Folhas de Planta/química , Acaricidas/química , Acaricidas/isolamento & purificação , Animais , Bovinos/parasitologia , Doenças dos Bovinos/parasitologia , Emodina/análogos & derivados , Emodina/farmacologia , Humanos , Ixodidae/fisiologia , Látex/química , Látex/isolamento & purificação
15.
Vet Parasitol ; 263: 5-9, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30389024

RESUMO

Rhipicephalus (Boophilus) microplus is one of the most important ectoparasites in cattle breeding worldwide, causing direct and indirect losses to animals and producers. Chemical acaricides are utilized in the control of cattle tick and the increase in the development of resistance by ectoparasites makes new alternative necessary. Therefore, research studies have been carried out using bioactive molecules that are quickly degraded and that reduce poisoning to appliers and non-target organisms, environmental contamination and development of resistance. Thus, this study aimed to isolate piperovatine from the roots of Piper corcovadensis, a native species to Brazil, and to evaluate the larvicidal activity against Rhipicephalus (Boophilus) microplus by larval packet test and in ex situ in an open environment. Piperovatine was isolated by classical column chromatography, and identified by 1H and 13C NMR. The lethal concentration (LC) of piperovatine that killed 50% (LC50) and 99% (LC99) of the larvae was determined by Probit analysis. The results indicated LC50 5.17 and LC99 25.41 µg/mL. LC99 was tested in ex situ in an open environment, and an efficiency of 96.63% was found, indicating that piperovatine kept the larvicidal action determined in in vitro test and in open environment. Therefore, this study shows new perspectives to develop products that can be applied in natural conditions to control this ectoparasite.


Assuntos
Acaricidas/administração & dosagem , Ectoparasitoses/veterinária , Larva/efeitos dos fármacos , Ácido Sórbico/análogos & derivados , Acaricidas/química , Acaricidas/isolamento & purificação , Animais , Produtos Biológicos/administração & dosagem , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/epidemiologia , Descoberta de Drogas , Ectoparasitoses/tratamento farmacológico , Ectoparasitoses/epidemiologia , Feminino , Piper/anatomia & histologia , Piper/química , Ácido Sórbico/administração & dosagem , Ácido Sórbico/química , Ácido Sórbico/isolamento & purificação , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/tratamento farmacológico , Infestações por Carrapato/veterinária , Carrapatos/efeitos dos fármacos , Carrapatos/fisiologia
16.
J Agric Food Chem ; 66(39): 10163-10168, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30200767

RESUMO

Bioassay-guided fractionation of the supernatant of the biocontrol strain Bacillus amyloliquefaciens W1 led to the isolation of eight acaricidal cyclodipeptides from the active fractions by column chromatography separation and HPLC purification. The chemical structures of these compounds were identified as cyclo-(Gly-l-Phe), 2, cyclo-(l-Phe- trans-4-OH-l-Pro), 3, cyclo-(Gly-l-Tyr), 4, cyclo-(l-Ala-l-Pro), 5, cyclo-(l-Pro- trans-4-OH-l-Pro), 6, cyclo-(Gly-l-Pro), 7, cyclo-(l-Pro-l-Pro), 8, and cyclo-(l-Tyr- trans-4-OH-l-Pro), 9. Those cyclodipeptides displayed significant acaricidal activities with LC50 values of 13.85-98.24 µM. Cyclo-(l-Tyr- trans-4-OH-l-Pro) (LC50 13.85 µM) was five times more effective than the positive control abamectin (LC50 72.06 µM). The results indicated that the hydroxyl group is an important component. This is the first report on the acaricidal capabilities of cyclodipeptides against Tetranychus urticae. The results revealed that the acaricidal activity of the biocontrol strain B. amyloliquefaciens W1 was dependent on its constituent cyclodipeptides, which have the potential to be safe and environmentally friendly acaricides.


Assuntos
Acaricidas/toxicidade , Bacillus amyloliquefaciens/química , Peptídeos Cíclicos/toxicidade , Tetranychidae/efeitos dos fármacos , Acaricidas/química , Acaricidas/metabolismo , Animais , Bacillus amyloliquefaciens/metabolismo , Dose Letal Mediana , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Controle Biológico de Vetores , Tetranychidae/crescimento & desenvolvimento
17.
Bioorg Med Chem Lett ; 28(20): 3338-3341, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30217413

RESUMO

In continuation of our program aimed at the development of new natural product-based pesticides, a series of novel pyrazolomatrine derivatives were prepared by structural modifications of matrine, isolated as a quinolizidine alkaloid from the roots of Sophora flave. Their structures were confirmed by 1H NMR, HRMS, etc. Moreover, the steric structures of three compounds were determined by single-crystal X-ray diffraction. Among all derivatives, 19-(naphthyl-2-oyl)pyrazolomatrine (5y) showed 3.13-fold more potent acaricidal activity than its precusor matrine against Tetranychus cinnabarinus; 19-(4-methylbenzoyl)pyrazolomatrine (5j) and 19-(3,5-dimethylbenzoyl)pyrazolomatrine (5k) displayed the promising aphicidal activity against Aphis citricola van der. Their structure-activity relationships were also observed.


Assuntos
Acaricidas/toxicidade , Alcaloides/toxicidade , Pirazóis/toxicidade , Quinolizinas/toxicidade , Acaricidas/síntese química , Acaricidas/química , Alcaloides/síntese química , Alcaloides/química , Animais , Afídeos/efeitos dos fármacos , Cristalografia por Raios X , Feminino , Estrutura Molecular , Pirazóis/síntese química , Pirazóis/química , Quinolizinas/síntese química , Quinolizinas/química , Relação Estrutura-Atividade , Tetranychidae/efeitos dos fármacos
18.
Vet Parasitol ; 260: 1-4, 2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30197007

RESUMO

This study reports the comparative evaluation of the activity of carvacrol, thymol, eugenol and their respective acetylated derivatives (carvacrol acetate, thymol acetate and eugenol acetate) on Rhipicephalus microplus, to verify the possible influence of the acetate group. The acetylated derivatives were prepared from reactions of the phenolic compounds with acetic anhydride/pyridine. The formation of the products was confirmed by analysis of hydrogen and carbon-13 nuclear magnetic resonance (1H and 13C NMR) spectra. The larval packet test was used to evaluate the acaricidal activity, with concentrations of 0.312, 0.625, 1.25, 2.5, 5.0, 7.5, 10.0 and 15.0 mg/mL. Thymol and carvacrol resulted in 100% mortality starting at the concentration of 2.5 mg/mL, while the same was observed for carvacrol acetate starting at the concentration of 5.0 mg/mL. For the other treatments, 100% mortality was only achieved in the groups treated with the highest concentration (15.0 mg/mL). The LC50 and LC90 values (mg/mL) of carvacrol acetate (2.49, 4.21), thymol acetate (2.97, 8.52) and eugenol acetate (4.25, 13.10) were higher than those for the corresponding precursor molecules carvacrol (0.83, 2.02), thymol (1.26, 2.21) and eugenol (2.77, 5.35). The acetylation process did not enhance the activity of these substances on unengorged larvae of R. microplus, since the precursor substances (carvacrol, thymol and eugenol) had greater efficacy.


Assuntos
Acaricidas/farmacologia , Anti-Infecciosos/farmacologia , Eugenol/farmacologia , Monoterpenos/farmacologia , Rhipicephalus/efeitos dos fármacos , Timol/farmacologia , Acaricidas/química , Acetilação , Animais , Bovinos/parasitologia , Eugenol/química , Técnicas In Vitro , Larva/efeitos dos fármacos , Monoterpenos/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Timol/química
19.
Bioorg Chem ; 81: 88-92, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30118989

RESUMO

In continuation of our program aimed at the development of natural product-based pesticidal agents, a series of matrinic amide derivatives containing 1,3,4-thiadiazole scaffold were prepared, and their insecticidal and acaricidal activities were evaluated against Mythimna separata and Tetranychus cinnabarinus. Some compounds exhibited potent insecticidal and acaricidal activities. It suggested that R1 as a nitro group and R2 as a fluorine atom, were important for the insecticidal activity; R1 as the electron-donating groups and R2 as the methyl group, were necessary for the acaricidal activity.


Assuntos
Acaricidas/farmacologia , Alcaloides/farmacologia , Amidas/farmacologia , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Quinolizinas/farmacologia , Tetranychidae/efeitos dos fármacos , Tiadiazóis/farmacologia , Acaricidas/síntese química , Acaricidas/química , Alcaloides/síntese química , Alcaloides/química , Amidas/síntese química , Amidas/química , Animais , Relação Dose-Resposta a Droga , Inseticidas/síntese química , Inseticidas/química , Estrutura Molecular , Quinolizinas/síntese química , Quinolizinas/química , Relação Estrutura-Atividade , Tiadiazóis/química
20.
Int J Parasitol Drugs Drug Resist ; 8(2): 350-360, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29957333

RESUMO

A novel L-glutamate-gated anion channel (IscaGluCl1) has been cloned from the black-legged tick, Ixodes scapularis, which transmits multiple pathogens including the agents of Lyme disease and human granulocytic anaplasmosis. When mRNA encoding IscaGluCl1 was expressed in Xenopus laevis oocytes, we detected robust 50-400 nA currents in response to 100 µM L-glutamate. Responses to L-glutamate were concentration-dependent (pEC50 3.64 ±â€¯0.11). Ibotenate was a partial agonist on IscaGluCl1. We detected no response to 100 µM aspartate, quisqualate, kainate, AMPA or NMDA. Ivermectin at 1 µM activated IscaGluCl1, whereas picrotoxinin (pIC50 6.20 ±â€¯0.04) and the phenylpyrazole fipronil (pIC50 6.90 ±â€¯0.04) showed concentration-dependent block of the L-glutamate response. The indole alkaloid okaramine B, isolated from fermentation products of Penicillium simplicissimum (strain AK40) grown on okara pulp, activated IscaGluCl1 in a concentration-dependent manner (pEC50 5.43 ±â€¯0.43) and may serve as a candidate lead compound for the development of new acaricides.


Assuntos
Acaricidas/farmacologia , Azetidinas/farmacologia , Azocinas/farmacologia , Canais de Cloreto/efeitos dos fármacos , Canais de Cloreto/genética , Alcaloides Indólicos/farmacologia , Ixodes/metabolismo , Abelmoschus/metabolismo , Acaricidas/química , Acaricidas/isolamento & purificação , Animais , Azetidinas/isolamento & purificação , Azocinas/isolamento & purificação , Vetores de Doenças , Descoberta de Drogas , Ácido Glutâmico/farmacologia , Alcaloides Indólicos/isolamento & purificação , Ivermectina/farmacologia , Ixodes/genética , Doença de Lyme/parasitologia , Oócitos/efeitos dos fármacos , Penicillium/química , Penicillium/crescimento & desenvolvimento , Penicillium/metabolismo , Xenopus laevis/genética , Xenopus laevis/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA