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1.
Molecules ; 28(2)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36677552

RESUMO

Pulse beetle is the most harmful pest attacking stored grains and affecting quality and marketability. Continuous use of chemical-based pesticides against pulse beetle led to the development of insecticidal resistance; essential oils (EOs) can be an effective natural alternative against this pest. The main objective was to study the chemical composition of seven EOs viz., Acorus calamus, Hedychium spicatum, Lavandula angustifolia, Juniperus recurva, Juniperus communis, Cedrus deodara and Pinus wallichiana, their insecticidal and enzyme inhibition activities against pulse beetle. The primary compounds present in these EOs were cis-asarone, 1,8-cineole, linalyl isobutyrate, 2-ß-pinene, camphene, α-dehydro-ar-himachalene and camphene. A. calamus oil showed promising fumigant toxicity to Callosobruchus maculatus and C. chinensis (LC50 = 1357.86 and 1379.54 µL/L, respectively). A combination of A. calamus + L. angustifolia was effective against C. maculatus and C. chinensis (LC50 = 108.58 and 92.18 µL/L, respectively). All the combinations of EOs showed synergistic activity. In the repellency study, A. calamus showed more repellence to C. maculatus and C. chinensis (RC50 = 53.98 and 118.91 µL/L, respectively). A. calamus and L. angustifolia oil at 2500, 5000 and 10,000 µL/L significantly inhibited the AChE and GST enzymes in C. maculatus and C. chinensis after 24 and 48 h.


Assuntos
Besouros , Repelentes de Insetos , Inseticidas , Óleos Voláteis , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/química , Inseticidas/farmacologia , Inseticidas/química , Monoterpenos Bicíclicos/farmacologia , Eucaliptol/farmacologia , Repelentes de Insetos/farmacologia
2.
J Agric Food Chem ; 71(4): 2152-2159, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36649540

RESUMO

The use of skin repellents against hematophagous mosquitoes is an important personal protection practice wherever these insects are abundant and where they are vectors of diseases. DEET and Icaridin are the major synthetic insect repellents in commercial formulations and are considered the most effective. Here, we tested against the mosquito Aedes albopictus several cyclic hydroxyacetals synthesized by acetalization of commercially available aliphatic carbonyl compounds (ranging from C3 to C15) with either glycerol, 1,1,1-trismethyloletane, or 1,1,1-trismethylolpropane and compared their efficacy with commercial repellents. We found that several hydroxyacetals were comparable with DEET and Icaridin both in terms of the required dose and repellence duration, while a few performed better. For those most active, toxicity was investigated, finding that a few of them were less cytotoxic than DEET and less prone to permeate through cell layers. Therefore, such results indicate that novel safe mosquito repellents could be developed among cyclic hydroxyacetals.


Assuntos
Aedes , Repelentes de Insetos , Animais , Repelentes de Insetos/farmacologia , DEET , Acetais , Mosquitos Vetores
3.
Sci Rep ; 13(1): 1705, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36717735

RESUMO

Cases of mosquito- and tick-borne diseases are rising worldwide. Repellent products can protect individual users from being infected by such diseases. In a previous study, we identified five essential oils that display long-distance mosquito repellency using a Y-tube olfactometer assay. In the current study, the contact repellent efficacy of 20 active ingredients from the Environmental Protection Agency's (EPA) Minimum Risk Pesticides list were tested using Aedes aegypti and Ixodes scapularis. We utilized an arm-in-cage assay to measure complete protection time from mosquito bites for these active ingredients. To measure tick repellency, we used an EPA-recommended procedure to measure the complete protection time from tick crossings. We found that of the 20 ingredients tested, 10% v/v lotion emulsions with clove oil or cinnamon oil provided the longest protection from both mosquito bites and tick crossings. We conclude that in a 10% v/v emulsion, specific active ingredients from the EPA Minimum Risk Pesticides list can provide complete protection from mosquito bites and tick crossings for longer than one hour.


Assuntos
Aedes , Mordeduras e Picadas de Insetos , Repelentes de Insetos , Ixodes , Óleos Voláteis , Animais , Humanos , Óleos Voláteis/farmacologia , Repelentes de Insetos/farmacologia
5.
Braz. j. biol ; 83: e244647, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1278527

RESUMO

Abstract The essential oil of citronella (Cymbopogon winterianus) has several biological activities, among them the insect repellent action. Some studies showed that cinnamic acid esters can be applied as natural pesticides, insecticides and fungicides. In this context, the objective of the present work was to evaluate the production of esters from citronella essential oil with cinnamic acid via enzymatic esterification. Besides, the essential oil toxicity before and after esterification against Artemia salina and larvicidal action on Aedes aegypti was investigated. Esters were produced using cinnamic acid as the acylating agent and citronella essential oil (3:1) in heptane and 15 wt% NS 88011 enzyme as biocatalysts, at 70 °C and 150 rpm. Conversion rates of citronellyl and geranyl cinnamates were 58.7 and 69.0% for NS 88011, respectively. For the toxicity to Artemia salina LC50 results of 5.29 μg mL-1 were obtained for the essential oil and 4.36 μg mL-1 for the esterified oils obtained with NS 88011. In the insecticidal activity against Aedes aegypti larvae, was obtained LC50 of 111.84 μg mL-1 for the essential oil of citronella and 86.30 μg mL-1 for the esterified oils obtained with the enzyme NS 88011, indicating high toxicity of the esters. The results demonstrated that the evaluated samples present potential of application as bioinsecticide.


Resumo O óleo essencial de citronela (Cymbopogon winterianus) possui diversas atividades biológicas, entre elas a ação repelente a insetos. Alguns estudos mostraram que os ésteres do ácido cinâmico podem ser aplicados como pesticidas naturais, inseticidas e fungicidas. Nesse contexto, o objetivo do presente trabalho foi avaliar a produção de ésteres a partir do óleo essencial de citronela com ácido cinâmico via esterificação enzimática. Além disso, foi investigada a toxicidade do óleo essencial antes e após a esterificação contra Artemia salina e a ação larvicida sobre Aedes aegypti. Os ésteres foram produzidos utilizando ácido cinâmico como agente acilante e óleo essencial de citronela (3: 1) em heptano e 15% em peso da enzima NS 88011 como biocatalisadores, a 70 ° C e 150 rpm. As taxas de conversão de cinamatos de citronelil e geranil foram 58,7 e 69,0% para NS 88011, respectivamente. Para a toxicidade sobre Artemia salina foram obtidos CL50 de 5,29 μg mL-1 para o óleo essencial e 4,36 μg mL-1 para os óleos esterificados com NS 88011. Na atividade inseticida contra larvas de Aedes aegypti, obteve-se CL50 de 111,84 μg mL-1 para o óleo essencial de citronela e 86,30 μg mL-1 para os óleos esterificados com a enzima NS 88011, indicando alta toxicidade dos ésteres. Os resultados demonstraram que as amostras avaliadas apresentam potencial de aplicação como bioinseticida.


Assuntos
Animais , Óleos Voláteis/toxicidade , Aedes , Cymbopogon , Repelentes de Insetos , Inseticidas/toxicidade , Esterificação , Larva
6.
SAR QSAR Environ Res ; 33(12): 969-986, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36548121

RESUMO

Cockroaches are urban pests that are very difficult to control. Using repellents is a green, safe and effective strategy for their control. In order to find novel cockroach repellents, the repellent activity of 45 bridged-ring terpenoid derivatives synthesized from ß-pinene against Blattella germanica was tested. The relationship between the molecular structure of these bridged-ring terpenoid derivatives and their repellent activity against Blattella germanica was also analysed. The results show that some of the bridged-ring terpenoid derivatives exhibit good repellent activity against Blattella germanica, and six compounds (RR = 60.44-87.32%) show higher repellent activity against Blattella germanica than DEET (RR = 54.77%), making them promising for development as new cockroach repellents. Quantitative structure-activity relationship (QSAR) analysis revealed that the HOMO-1 energy, Kier and Hall index (order 2), Balaban index, and relative positive charged surface area of bridged-ring terpenoid derivatives have effects on repellent activity against Blattella germanica. The present study may provide a theoretical basis for the high-value use of ß-pinene and can be helpful to the development of novel repellents against Blattella germanica.


Assuntos
Blattellidae , Repelentes de Insetos , Animais , Terpenos/farmacologia , Relação Quantitativa Estrutura-Atividade , Repelentes de Insetos/farmacologia , Repelentes de Insetos/química
7.
Sci Rep ; 12(1): 21410, 2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36496475

RESUMO

Mosquitoes are unquestionably the most medic arthropod vectors of disease. Culex pipiens, usually defined as a common house mosquito, is a well-known carrier of several virus diseases. Crude ethanol extracts of different organs of Agratum houstonianum are tested with Culex pipiens Linnaeus (Diptera: Culicidae) to determine their larvicidal, antifeedant, and repellency effects. Alongside biochemical analysis, the activity of the AChE, ATPase, CarE, and CYP-450 is detected in the total hemolymph of the C. pipiens larvae to examine the enzymatic action on the way to explain their neurotoxic effect and mode of action. Through HPLC and GC-MS analysis of the phytochemical profile of A. houstonianum aerial parts is identified. The larvicidal activity of aerial parts; flower (AF), leaf (AL), and stem (AS) of A. houstonianum extracts are evaluated against the 3rd instar larvae of C. pipiens at 24-, 48- and 72-post-treatment. A. houstonianium AF, AL, and AS extracts influenced the mortality of larvae with LC50 values 259.79, 266.85, and 306.86 ppm, respectively after 24 h of application. The potency of AF and AL extracts was 1.69- and 1.25-folds than that of AS extract, respectively. A high repellency percentage was obtained by AF extract 89.10% at a dose of 3.60 mg/cm2. A. houstonianium AF prevailed inhibition on acetylcholinesterase and decrease in carboxylesterase activity. Moreover, a significant increase in the ATPase levels and a decrease in cytochrome P-450 monooxegenase activity (- 36.60%) are detected. HPLC analysis prevailed chlorogenic and rosmarinic acid as the major phenolic acids in AL and AF, respectively. GC-MS analysis of A. houstonianum results in the identification of phytol as the major makeup. Precocene I and II were detected in AF. Linoleic, linolenic, and oleic acid were detected in comparable amounts in the studied organs. Overall, results suggest that the A. houstonianum flower extract (AF) exhibits significant repellent, antifeedant, and larvicidal activities.


Assuntos
Aedes , Ageratum , Culex , Repelentes de Insetos , Inseticidas , Animais , Acetilcolinesterase , Inseticidas/farmacologia , Extratos Vegetais/farmacologia , Mosquitos Vetores , Repelentes de Insetos/farmacologia , Larva , Adenosina Trifosfatases
8.
Insect Biochem Mol Biol ; 151: 103866, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36347453

RESUMO

The cornerstone of the reverse chemical ecology approach is the identification of odorant receptors (OR) sensitive to compounds in a large panel of odorants. In this approach, we de-orphanize ORs and, subsequently, measure behaviors elicited by these semiochemicals. After that, we evaluate behaviorally active compounds for applications in insect vector management. Intriguingly, multiple ORs encoded by genes highly expressed in mosquito antennae do not respond to any test odorant. One such case is CquiOR125 from the southern house mosquito, Culex quinquefasciatus Say. To better understand CquiOR125's role in Culex mosquito olfaction, we have cloned a CquiOR125 orthologue in the genome of the yellow fever mosquito, Aedes aegypti (L.), AaegOR11. Unlike the unresponsive nature of the orthologue in Cx. quinquefasciatus, oocytes co-expressing AaegOR11 and AaegOrco elicited robust responses when challenged with fenchone, 2,3-dimethylphenol, 3,4-dimethylphenol, 4-methycyclohexanol, and acetophenone. Interestingly, AaegOR11 responded strongly and equally to (+)- and (-)-fenchone, with no chiral discrimination. Contrary to reports in the literature, fenchone did not show any repellency activity against Ae. aegypti or Cx. quinquefasciatus. Laboratory and field tests did not show significant increases in egg captures in cups filled with fenchone solutions compared to control cups. The second most potent ligand, 2,3-dimethylphenol, showed repellency activity stronger than that elicited by DEET at the same dose. We, therefore, concluded that AaegOR11 is a mosquito repellent sensor. It is feasible that CquiOR125 responds to repellents that remain elusive.


Assuntos
Aedes , Culex , Repelentes de Insetos , Receptores Odorantes , Febre Amarela , Animais , Repelentes de Insetos/farmacologia , Receptores Odorantes/genética , Mosquitos Vetores/genética , Culex/genética , Aedes/genética
9.
Parasit Vectors ; 15(1): 422, 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36369215

RESUMO

BACKGROUND: Mosquitoes are responsible for disease transmission worldwide. They possess the ability to discriminate between different ecological resources, including nectar sources, animal hosts and oviposition sites, a feature mediated by their olfactory system. Insect repellents, such as N,N-diethyl-meta-toluamide (also called DEET), have been shown to activate and inhibit mosquito odorant receptors, resulting in behavioral modulation. This and other repellents currently available for personal protection against mosquitoes are topically applied to the skin and operate at a short range. In our search for potential long-range inhibitors of attractants to human hosts, we have hypothesized that the shared chemical similarities between indole and DEET may confer the former with the ability to block odorant receptor function and inhibit human host attraction in a similar way as DEET. METHODS: We used the two-electrode voltage clamp system to assay Xenopus laevis oocytes as a platform to compare the pharmacological effect of commercially available insect repellents and indole on the Aedes aegypti (R)-1-octen-3-ol receptor, OR8, a receptor involved in the decision-making of female mosquitoes to identify human hosts. We also conducted arm-in-a-cage and wind-tunnel bioassays to explore the effect of indole on human host-seeking female Aedes aegypti mosquitoes. RESULTS: Our results demonstrate that indole inhibited the Aedes aegypti (R)-1-octen-3-ol receptor OR8. In our arm-in-a-cage assay, 1 M of DEET reduced mosquito visits on average by 69.3% while the same indole concentration achieved 97.8% inhibition. This effect of indole on flight visits was dose-dependent and disappeared at 1 µM. In the flight tunnel, indole elicited on average 27.5% lower speed, 42.3% lower upwind velocity and 30.4% higher tortuosity compared to the control. CONCLUSIONS: Indole significantly inhibits OR8 activation by (R)-1-octen-3-ol, mosquito visits to a human hand and long-range human host-seeking. The volatility of indole may be leveraged to develop a novel insect repellent in the context of personal mosquito protection.


Assuntos
Aedes , Indóis , Repelentes de Insetos , Receptores Odorantes , Animais , Feminino , Humanos , Aedes/fisiologia , DEET/farmacologia , Indóis/farmacologia , Repelentes de Insetos/farmacologia
10.
PLoS One ; 17(11): e0276783, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36374859

RESUMO

Malaria vector control interventions in Sumba, Indonesia, have not been able to eliminate malaria. Human drivers of exposure to Anopheles bites were investigated as part of a larger clinical trial evaluating the impact of a spatial repellent product on malaria incidence. Human behavioral observations (HBOs) evaluating temporal and spatial presence, sleeping behaviors, and insecticide treated net (ITN) use, were collected parallel to entomological collections-indoor and outdoor human landing catches (HLCs), and house hold surveys. Data demonstrates that mosquito access to humans, enabled by structurally open houses, is evident by the similar entomological landing rates both inside and outside households. The presence of animals inside houses was associated with increased mosquito entry-however, the number of humans present inside houses was not related to increased mosquito landing. Analyzing mosquito landing rates with human behavior data enables the spatial and temporal estimation of exposure to Anopheles bites, accounting for intervention (ITN) presence and usage. Human behavior adjusted exposure to Anopheles bites was found to be highest in the early in the evening, but continued at lower levels throughout the night. Over the night, most exposure (53%) occurred when people were indoors and not under the protection of nets (asleep or awake) followed by exposure outside (44%). Characterized gaps in protection are outdoor exposure as well as exposure indoors-when awake, and when asleep and not using ITNs. Interestingly, in the primary trial, even though there was not a significant impact of the spatial repellent on vector biting rates by themselves (16%), when factoring in human behavior, there was approximately 28% less exposure in the intervention arm than in the placebo arm. The treated arm had less human behavior adjusted bites in all spaces evaluated though there was proportionally higher exposure indoors. This analysis points to the importance of using HBOs both towards understanding gaps in protection as well as how interventions are evaluated. To mitigate ongoing transmission, understanding context specific spatial and temporal exposure based on the interactions of vectors, humans and interventions would be vital for a directed evidence-based control or elimination strategy.


Assuntos
Anopheles , Mordeduras e Picadas de Insetos , Repelentes de Insetos , Inseticidas , Malária , Humanos , Animais , Malária/epidemiologia , Malária/prevenção & controle , Controle de Mosquitos , Indonésia/epidemiologia , Mosquitos Vetores , Mordeduras e Picadas de Insetos/epidemiologia , Repelentes de Insetos/farmacologia , Inseticidas/farmacologia , Comportamento Alimentar
11.
PLoS One ; 17(11): e0269150, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36346809

RESUMO

Repellents serve an important role in bite protection. Tick repellents largely rely on biomechanisms that induce responses with direct contact, but synthetic pyrethroids used as spatial repellents against insects have received recent attention for potential use in tick protection systems. An in vitro vertical climb assay was designed to assess spatial repellency against Dermacentor variabilis, Amblyomma americanum, and Ixodes scapularis adult, female ticks. Climbing behavior was assessed with and without the presence of two spatial repellents, transfluthrin and metofluthrin. Repellency parameters were defined to simulate the natural questing behavior of ambushing ticks, including measures of detachment, pseudo-questing duration, climbing deterrence, and activity. Significant effects were observed within each parameter. D. variabilis showed the greatest general susceptibility to each repellent, followed by A. americanum, and I. scapularis. The most important and integrative measure of repellency was climbing deterrence-a measure of the spatial repellent's ability to disrupt a tick's natural propensity to climb. Transfluthrin deterred 75% of D. variabilis, 67% of A. americanum, and 50% of I. scapularis. Metofluthrin was slightly more effective, deterring 81% of D. variabilis, 73% of A. americanum, and 72% of I. scapularis. The present study poses a novel paradigm for repellency and reports a preliminary assessment of spatial repellent effect on tick behavior. Further research will assess spatial repellency in a more natural setting, scale exposure conditions, and incorporate host cues.


Assuntos
Dermacentor , Repelentes de Insetos , Ixodes , Ixodidae , Animais , Feminino , Amblyomma , Repelentes de Insetos/farmacologia
12.
Sci Rep ; 12(1): 20397, 2022 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-36437275

RESUMO

Natural-based compounds with repellent activity arise nowadays with the possibility to replace commercial synthetic repellents wholly or partially, such as N,N-Diethyl-m-toluamide (DEET). It is due to DEET's demonstrated toxicity and cutaneous irritation for human beings. Besides, research recommends avoiding using it with kids and pregnant women. The search for a repellent product implies early stages of detailed research that resolve the modes of action against the target insect. Therefore the objective of the current study was to analyze neuronal electrophysiological signals and olfactory system protein expression when the Aedes aegypti mosquito with exposition to natural-based repellents. Adult females of Ae. aegypti of Rockefeller strain were exposed to specific concentrations of repellent compounds like geranyl acetate, α-bisabolol, nerolidol, and DEET. The neuronal effect was measured by electroantennography technique, and the effect of exposure to either DEET or a mixture of natural molecules on protein expression was determined with 2D-PAGE followed by MALDI-TOF-mass spectrometry (MS). This approach revealed that DEET affected proteins related to synapses and ATP production, whereas natural-based repellents increased transport, signaling, and detoxification proteins. The proteomic and electrophysiology experiments demonstrated that repellent exposure disrupts ionic channel activity and modifies neuronal synapse and energy production processes.


Assuntos
Aedes , Repelentes de Insetos , Gravidez , Adulto , Animais , Feminino , Humanos , Proteômica , DEET/farmacologia , Repelentes de Insetos/farmacologia , Eletroforese em Gel Bidimensional
13.
Cell ; 185(22): 4099-4116.e13, 2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36261039

RESUMO

Some people are more attractive to mosquitoes than others, but the mechanistic basis of this phenomenon is poorly understood. We tested mosquito attraction to human skin odor and identified people who are exceptionally attractive or unattractive to mosquitoes. These differences were stable over several years. Chemical analysis revealed that highly attractive people produce significantly more carboxylic acids in their skin emanations. Mutant mosquitoes lacking the chemosensory co-receptors Ir8a, Ir25a, or Ir76b were severely impaired in attraction to human scent, but retained the ability to differentiate highly and weakly attractive people. The link between elevated carboxylic acids in "mosquito-magnet" human skin odor and phenotypes of genetic mutations in carboxylic acid receptors suggests that such compounds contribute to differential mosquito attraction. Understanding why some humans are more attractive than others provides insights into what skin odorants are most important to the mosquito and could inform the development of more effective repellents.


Assuntos
Aedes , Anopheles , Repelentes de Insetos , Animais , Humanos , Ácidos Carboxílicos/farmacologia , Odorantes/análise , Repelentes de Insetos/farmacologia , Repelentes de Insetos/análise
14.
Exp Appl Acarol ; 88(2): 153-163, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36282439

RESUMO

Spider mites become easy prey for ants when they leave their protective webs; therefore, the ability to avoid traces of ongoing ant activity should confer a selective advantage to mites. We examined avoidance of ant traces by the spider mites Tetranychus kanzawai and Tetranychus urticae. Both mite species avoided host plant leaves with active traces of Pristomyrmex punctatus or Formica japonica ants. Pristomyrmex punctatus trace avoidance by T. kanzawai lasted for more than 1 h, but not more than 3 h. Tetranychus kanzawai also avoided P. punctatus traces on plant stems, along which the mites access leaves. Moreover, T. kanzawai avoided hexane extracts of P. punctatus or F. japonica applied to a filter paper pathway. This study represents the first demonstration of a repellent effect of ant chemical traces on spider mites. Considering the substantial abundance and global distribution of ants in nature, such repellent effects may help to answer the long-standing question of why only a small fraction of available plant resources is used by herbivores. Although spider mites have developed resistance against many synthetic pesticides, natural compounds that simulate ant chemical traces may repel spider mites from agricultural crops.


Assuntos
Formigas , Repelentes de Insetos , Tetranychidae , Animais , Repelentes de Insetos/farmacologia , Produtos Agrícolas , Folhas de Planta
15.
Molecules ; 27(20)2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36296371

RESUMO

The Aedes aegypti mosquito is the main hematophagous vector responsible for arbovirus transmission in Brazil. The disruption of A. aegypti hematophagy remains one of the most efficient and least toxic methods against these diseases and, therefore, efforts in the research of new chemical entities with repellent activity have advanced due to the elucidation of the functionality of the olfactory receptors and the behavior of mosquitoes. With the growing interest of the pharmaceutical and cosmetic industries in the development of chemical entities with repellent activity, computational studies (e.g., virtual screening and molecular modeling) are a way to prioritize potential modulators with stereoelectronic characteristics (e.g., pharmacophore models) and binding affinity to the AaegOBP1 binding site (e.g., molecular docking) at a lower computational cost. Thus, pharmacophore- and docking-based virtual screening was employed to prioritize compounds from Sigma-Aldrich® (n = 126,851) and biogenic databases (n = 8766). In addition, molecular dynamics (MD) was performed to prioritize the most potential potent compounds compared to DEET according to free binding energy calculations. Two compounds showed adequate stereoelectronic requirements (QFIT > 81.53), AaegOBP1 binding site score (Score > 42.0), volatility and non-toxic properties and better binding free energy value (∆G < -24.13 kcal/mol) compared to DEET ((N,N-diethyl-meta-toluamide)) (∆G = -24.13 kcal/mol).


Assuntos
Aedes , Repelentes de Insetos , Receptores Odorantes , Animais , Receptores Odorantes/metabolismo , DEET/química , Simulação de Acoplamento Molecular , Mosquitos Vetores , Repelentes de Insetos/farmacologia , Repelentes de Insetos/química , Preparações Farmacêuticas/metabolismo
16.
Molecules ; 27(20)2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36296645

RESUMO

In our natural product screening program, we screened natural products for their repellency and toxicity against insect vectors. Methanolic extract of aerial parts of Stenaria nigricans (Lam.), with no published chemistry, was tested for repellency against mosquitoes and imported hybrid fire ants. Methanolic extracts showed biting deterrence similar to DEET (N,N-diethyl-3-methylbenzamide) against Aedes aegypti L. Based on this activity, the crude extract was fractionated into chloroform, ethyl acetate, and methanol subfractions. The active methanolic subfraction was further fractionated into 13 subfractions. These fractions were tested for their biting deterrence against Ae. Aegypti. Active subfractions were further characterized to identify the compounds responsible for this activity. Four undescribed iridoid glucosides (1-4) and three previously reported compounds (5-7) were isolated from active subfractions and tested for their biting deterrent activity. Based on BDI values, compounds 2, 3, 6, and 7, with biting deterrence similar to DEET, showed the potential to be used as repellents against mosquitoes. In an in vitro digging bioassay, none of these compounds showed any repellency against hybrid imported fire ants at a dose of 125 µg/g. This is the first report of biting deterrence and repellency of S. nigricans extract and its pure compounds, iridoid glucosides against mosquitoes and imported fire ants. Further studies will be conducted to explore the repellent potential of these compounds in different formulations under field conditions.


Assuntos
Aedes , Formigas , Produtos Biológicos , Culicidae , Repelentes de Insetos , Rubiaceae , Animais , DEET , Glucosídeos Iridoides , Metanol , Clorofórmio , Mosquitos Vetores , Repelentes de Insetos/farmacologia , Bioensaio , Misturas Complexas
17.
Am J Primatol ; 84(11): e23438, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36193566

RESUMO

Animal self-medication is thought to provide an adaptive advantage, as species would actively respond to a disease state or homeostatic imbalances. In wild nonhuman primates, it is challenging to differentiate plant use as part of the diet or as medication, especially because self-medication can be preventive or therapeutic. Here, we aimed to compile the available potential evidence on primate self-medication modes, investigating which proposed requirements are fulfilled for each plant species reported to date. We systematically reviewed the scientific literature on plant use for potential self-medication in wild nonhuman primates. To construct the extensive database, we extracted data on the primate species, study area, plant/plant's part used, the requirement(s) met for demonstrating self-medication modes, and self-medicative behavioral patterns. We also updated available information on plant's biological compounds and/or physical characteristics, pharmacological properties, and ethnomedical uses. We identified 575 plant species (135 families), used by 25 primate species (9 families). Plants were used by Old World monkeys (46.5%, n = 268 plant species), followed by apes (41%, n = 235), New World monkeys (13.4%, n = 77), and prosimians (1%, n = 6). We found three general types of self-medicative behaviors: ingestion (including, but not limited to, leaf-swallowing, seed-swallowing, and bitter pith chewing), topical (fur-rubbing), and nest fumigation. Plant uses were associated with antiparasitic, antibacterial, antimalarial, anti-inflammatory, insect repellent, among other properties. Self-medication is widespread in nonhuman primate species across Central and South America, Africa, Madagascar, and Asia. Long-term field research efforts and studies integrating different research sites and topics are urgent to advance our knowledge into the evolution of plant selection, medical traditions, and to bring insights into potentially novel medicinal plants and bioactive compounds to treat emergent or established primate and human diseases.


Assuntos
Antimaláricos , Hominidae , Repelentes de Insetos , Plantas Medicinais , Animais , Antibacterianos , Humanos , Medicina Tradicional , Primatas
18.
Molecules ; 27(18)2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36144685

RESUMO

Aphids are one of the most damaging agricultural pests. For the sake of novel eco-friendly compounds with good activity for aphid control, a series of novel geranic acid esters containing substituted aromatic rings were designed by inverting ester groups of lead compounds. All compounds were characterized by HRMS, 1H-NMR, and 13C-NMR. In order to identify the effect of inversion ester groups on activity, a bioassay was conducted. The results showed that the repellent activity against Acyrthosiphon pisum (A. pisum) and the binding affinity with the odorant-binding protein 9 from A. pisum (ApisOBP9) of the compounds were increased after inversion of the ester groups. Particularly, 5f showed the best repellent activity (repellency proportion: 55.6%) and binding affinity (1/Ki: 0.49 µM). Meanwhile, the structure-activity relationships revealed that the introduction of meta-substitution of the benzene ring and halogen atoms, such as Cl and Br, facilitated the biological activity. The further molecular docking results demonstrated that hydrogen bonding interactions and hydrophobic interactions were vital for the binding affinity with ApisOBP9. Additionally, all compounds were predicted to be eco-friendly and their volatile physicochemical properties have been enhanced compared to the leads. The present results provide valuable clues for the further rational design of aphids' behavioral control agents.


Assuntos
Afídeos , Repelentes de Insetos , Animais , Benzeno , Ésteres/farmacologia , Halogênios , Repelentes de Insetos/química , Repelentes de Insetos/farmacologia , Simulação de Acoplamento Molecular , Terpenos
19.
PLoS Negl Trop Dis ; 16(9): e0010765, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36137005

RESUMO

Lymphatic filariasis (LF) is a mosquito-borne parasitic neglected tropical disease. In 2000, WHO launched the Global Programme to Eliminate Lymphatic Filariasis (GPELF) as a public health problem. In 2020, new goals for 2030 were set which includes a reduction to 0 of the total population requiring Mass Drug Administrations (MDA), a primary tool of GPELF. We develop a mathematical model to study what can happen at the end of MDA. We use a game-theoretic approach to assess the voluntary use of insect repellents in the prevention of the spread of LF through vector bites. Our results show that when individuals use what they perceive as optimal levels of protection, the LF incidence rates will become high. This is in striking difference to other vector-borne NTDs such as Chagas or zika. We conclude that the voluntary use of the protection alone will not be enough to keep LF eliminated as a public health problem and a more coordinated effort will be needed at the end of MDA.


Assuntos
Filariose Linfática , Repelentes de Insetos , Infecção por Zika virus , Zika virus , Animais , Filariose Linfática/tratamento farmacológico , Filariose Linfática/epidemiologia , Filariose Linfática/prevenção & controle , Humanos , Administração Massiva de Medicamentos , Modelos Teóricos , Saúde Pública , Infecção por Zika virus/tratamento farmacológico
20.
BMC Infect Dis ; 22(1): 747, 2022 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-36153501

RESUMO

BACKGROUND: Countries of the Greater Mekong Sub-region aim to achieve malaria elimination by 2030. In the region, malaria is concentrated in high-risk areas and populations such as forest-going mobile and migrant populations (MMPs). However, routine protective measures such as long-lasting insecticidal nets do not prevent all infectious bites in these high-risk populations. Evidence for the effectiveness of a personal protection package tailored to forest-going MMPs which is acceptable, feasible, and cost-effective for reducing malaria transmission is required to inform the malaria elimination toolkit in the region. METHODS: A personal protection package consisting of long-lasting insecticidal hammock net, insect repellent and health communication pamphlet was developed in consultation with relevant implementing partners from Cambodia and Lao PDR. An open stepped-wedge cluster-randomised controlled trial will be conducted over a period of 12 months in a minimum of 488 villages (~ 428 in Lao PDR and ~ 60 in Cambodia) to evaluate the effectiveness of the personal protection package. Villages will be randomised into 11 blocks, with blocks transitioned in random order from control to intervention states at monthly intervals, following a 1-month baseline period. The primary outcome of the trial is the prevalence of Plasmodium spp. infection diagnosed by rapid diagnostic test. Difference in prevalence of malaria infection will be estimated across intervention and control periods using generalized linear mixed modelling. Nested within the stepped-wedge cluster-randomised controlled trial is a mixed-methods study to explore the acceptability of the personal protection package, feasibility of implementing a personal protection package as a vector control intervention, and knowledge, attitude and practice of MMPs regarding malaria prevention; and cost-analysis to determine the cost-effectiveness of implementing a personal protection package. DISCUSSION: This study, using a rigorous design and mixed-methods methodology, will evaluate whether a personal protection package can reduce residual malaria transmission among forest-going MMPs in Cambodia and Lao PDR. It will also measure implementation research outcomes such as effectiveness of the intervention package, cost-effectiveness, acceptability, and feasibility, in order to inform potential national and regional policy. Trial registration This trial was prospectively registered on ClinicalTrials.gov (NCT05117567) on 11th November 2021.


Assuntos
Repelentes de Insetos , Inseticidas , Malária , Migrantes , Camboja/epidemiologia , Florestas , Humanos , Laos/epidemiologia , Malária/epidemiologia , Malária/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto
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