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2.
J Agric Food Chem ; 69(37): 11095-11109, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34514794

RESUMO

Vector-borne diseases cause around 700,000 deaths every year. Insect repellents are one of the strategies to limit them. Para-menthane-3,8-diol (PMD), a natural compound, is one of the most promising alternatives to conventional synthetic repellents. This work describes a diastereodivergent method to synthesize each diastereoisomer of PMD from enantiopure citronellal and studies their repellence activity against Aedes albopictus. We found that cis-PMD is the kinetic control product of the cyclization of citronellal, while trans-PMD is the thermodynamic control product. X-ray diffraction analysis of crystals highlighted some differences in hydrogen-bond patterns between cis or trans isomers. The present paper demonstrates that (1R)-(+)-cis-PMD has the highest repellency index using a new evaluation system for 24 h. (1S)-(-)-cis-PMD has somewhat lower and (1S)-(+)-trans-PMD and (1R)-(-)-trans-PMD have a slight effect. Volunteer tests show that (1R)-(+)-cis-PMD is the most efficient. This effect could be ascribed to the interaction of PMD/insect odorant receptors and their physical properties, that is, the evaporation rate.


Assuntos
Aedes , Repelentes de Insetos , Animais , Monoterpenos Cicloexânicos , Humanos , Mentol/análogos & derivados , Mosquitos Vetores
3.
Molecules ; 26(15)2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34361547

RESUMO

Essential oils of aromatic plants represent an alternative to classical pest control with synthetic chemicals. They are especially promising for the alternative control of stored product pest insects. Here, we tested behavioral and electrophysiological responses of the stored product pest Tribolium confusum, to the essential oil of a Brazilian indigenous plant, Varronia globosa, collected in the Caatinga ecosystem. We analyzed the essential oil by GC-MS, tested the effects of the entire oil and its major components on the behavior of individual beetles in a four-way olfactometer, and investigated responses to these stimuli in electroantennogram recordings (EAG). We could identify 25 constituents in the essential oil of V. globosa, with anethole, caryophyllene and spathulenole as main components. The oil and its main component anethole had repellent effects already at low doses, whereas caryophyllene had only a repellent effect at a high dose. In addition, the essential oil abolished the attractive effect of the T. confusum aggregation pheromone. EAG recordings revealed dose-dependent responses to the individual components and increasing responses to the blend and even more to the entire oil. Our study reveals the potential of anethole and the essential oil of V. globosa in the management of stored product pests.


Assuntos
Antenas de Artrópodes/fisiologia , Comportamento Animal/efeitos dos fármacos , Repelentes de Insetos , Magnoliopsida/química , Óleos Voláteis , Tribolium/fisiologia , Animais , Repelentes de Insetos/química , Repelentes de Insetos/farmacologia , Óleos Voláteis/química , Óleos Voláteis/farmacologia
4.
Molecules ; 26(12)2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34208408

RESUMO

Essential oils have been widely used as an active ingredient in mosquito repellent products. However, essential oils are highly unstable and prone to degradation when exposed to the environment during storage. Microencapsulation techniques help to maintain the stability of molecules in essential oils that are sensitive to environmental stress, and therefore improve shelf life. In this study, the physical stability and efficacy of a repellent formulation consisting of encapsulated Citrus grandis essential oil (CGEO) were evaluated under different storage conditions over a 12-month period by comparing the formulation with a non-encapsulated formulation. The formulations were both stored under two different storage conditions, i.e., 25 ± 2 °C/60% ± 5% relative humidity (RH) and 40 ± 2 °C/75% RH ± 5%, for 12 months. Droplet size, zeta potential, and pH value were measured after 1, 6, and 12 months of storage to determine their stability. For the study of efficacy, each formulation was tested against Aedes aegypti under laboratory conditions. We found that the microencapsulated formulation's physical characteristics showed insignificant changes as compared with the non-encapsulated formulation during storage. The microencapsulated formulation demonstrated better repellent effects, sustaining high protection (>80%) for 4 more hours of exposure after 12 months of storage as compared with the non-encapsulated formulation that demonstrated high protection for only an hour post application. Microencapsulation helped to preserve the stability of the formulation, which resulted in high protection being maintained for over 12 months of storage.


Assuntos
Aedes/efeitos dos fármacos , Citrus/química , Repelentes de Insetos/química , Óleos Voláteis/química , Aedes/fisiologia , Animais , Composição de Medicamentos , Avaliação de Medicamentos , Estabilidade de Medicamentos
5.
Molecules ; 26(13)2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34279396

RESUMO

The main strategies against Triatoma infestans (primary vector responsible for the Chagas disease transmission) are the elimination or reduction of its abundance in homes through the application of insecticides or repellents with residual power, and environmental management through the improvement of housing. The use of plant-derived compounds as a source of therapeutic agents (i.e., essential oils from aromatic plants and their components) is a valuable alternative to conventional insecticides and repellents. Essential oil-based insect repellents are environmentally friendly and provide reliable personal protection against the bites of mosquitoes and other blood-sucking insects. This study investigates, for the first time to our knowledge, the potential repellent activity of Zuccagnia punctata essential oil (ZEO) and poly(ε-caprolactone) matrices loaded with ZEO (ZEOP) prepared by solvent casting. The analysis of its essential oil from aerial parts by GC-FID and GC-MS, MS allowed the identification of 25 constituents representing 99.5% of the composition. The main components of the oil were identified as (-)-5,6-dehydrocamphor (62.4%), alpha-pinene (9.1%), thuja-2, 4 (10)-diene (4.6%) and dihydroeugenol (4.5%). ZEOP matrices were homogeneous and opaque, with thickness of 800 ± 140 µm and encapsulation efficiency values above 98%. ZEO and ZEOP at the lowest dose (0.5% wt./wt., 96 h) showed a repellency of 33 and 73% respectively, while at the highest dose (1% wt./wt., 96 h) exhibited a repellent activity of 40 and 66 %, respectively. On the other hand, until 72 h, ZEO showed a strong repellent activity against T. infestans (88% repellency average; Class V) to both concentrations, compared with positive control N-N diethyl-3-methylbenzamide (DEET). The essential oils from the Andean flora have shown an excellent repellent activity, highlighting the repellent activity of Zuccagnia punctata. The effectiveness of ZEO was extended by its incorporation in polymeric systems and could have a potential home or peridomiciliary use, which might help prevent, or at least reduce, Chagas' disease transmission.


Assuntos
Fabaceae/química , Repelentes de Insetos/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Óleos Voláteis/farmacologia , Triatoma/efeitos dos fármacos , Animais , Cânfora/análogos & derivados , Cânfora/análise , Eugenol/análogos & derivados , Eugenol/análise , Repelentes de Insetos/química , Óleos Voláteis/química , Poliésteres/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-34199797

RESUMO

The overuse of synthetic pesticides in plant protection strategies has resulted in numerous side effects, including environmental contamination, food staff residues, and a threat to non-target organisms. Several studies have been performed to assess the pesticidal effects of plant-derived essential oils and their components, as partially safe and effective agents, on economically important pests. The essential oils isolated from Satureja species are being used in medicinal, cosmetic, and food industries. Their great potential in pest management is promising, which is related to high amounts of terpenes presented in this genus. This review is focused on the acute and chronic acaricidal, insecticidal, and nematicidal effects of Satureja essential oil and their main components. The effects of eighteen Satureja species are documented, considering lethality, repellency, developmental inhibitory, and adverse effects on the feeding, life cycle, oviposition, and egg hatching. Further, the biochemical impairment, including impairments in esterases, acetylcholinesterase, and cytochrome P450 monooxygenases functions, are also considered. Finally, encapsulation and emulsification methods, based on controlled-release techniques, are suggested to overcome the low persistence and water solubility restrictions of these biopesticides. The present review offers Satureja essential oils and their major components as valuable alternatives to synthetic pesticides in the future of pest management.


Assuntos
Acaricidas , Repelentes de Insetos , Inseticidas , Óleos Voláteis , Satureja , Acaricidas/toxicidade , Feminino , Humanos , Inseticidas/toxicidade , Óleos Voláteis/toxicidade
7.
Zoonoses Public Health ; 68(6): 658-665, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34160897

RESUMO

Tick bite prevention practices, knowledge of Lyme disease (LD) symptoms and transmission, and patterns of LD diagnoses among Hispanic persons have been reported but not comprehensively evaluated. In 2014, CDC examined questions from a prospective nationwide survey of U.S. Hispanic adults conducted via the Offerwise QueOpinas panel regarding ticks and LD. From October to November, a total of 2,649 surveys were released and 1,006 completed surveys returned. Overall, 44% of respondents reported routinely practising at least one form of personal protection against tick bites, and wearing repellent was the most commonly reported method (29%). Approximately 6% of respondents reported a tick bite for either themselves or someone in their household during the previous 12 months. An individual or household diagnosis of LD in the previous year was reported by 2% of respondents, with the highest proportion of diagnoses reported by respondents from high LD incidence states. The annual incidence of healthcare provider-diagnosed LD in the survey population was higher than national surveillance estimates for reported LD among U.S. Hispanic persons during 2000-2013. As annual incidence of LD continues to increase, it is important to ensure equitable access to information about LD, including disease transmission, manifestations, and prevention recommendations. Results from this survey can help inform public health outreach focused on effective tick bite prevention methods and early recognition of LD.


Assuntos
Hispano-Americanos , Doença de Lyme/epidemiologia , Picadas de Carrapatos/epidemiologia , Picadas de Carrapatos/psicologia , Adulto , Animais , Coleta de Dados , Feminino , Humanos , Repelentes de Insetos , Inseticidas , Doença de Lyme/transmissão , Masculino , Pessoa de Meia-Idade , Razão de Chances , Picadas de Carrapatos/prevenção & controle , Estados Unidos/epidemiologia , Adulto Jovem
8.
Ticks Tick Borne Dis ; 12(5): 101760, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34130147

RESUMO

Rhipicephalus sanguineus sensu lato (s.l.), commonly known as brown dog tick, is a widely distributed tick species that is substantially important for human and veterinary medicine. Therefore, it is the target of different control methods. Carvacrol and its semisynthetic derivative, acetylcarvacrol, are promising chemical compounds for alternative tick control. Thus, this study aimed to compare the repellent activities of carvacrol and acetylcarvacrol at different concentrations and drying times. Additionally, morphological alterations found in salivary glands were evaluated through histological techniques after exposure to acetylcarvacrol. The impact of the morphological changes on the development and survival of acini/cells in salivary glands was measured by a semiquantitative analysis. The repellent action of both compounds did not differ when evaluated at different concentrations, although acetylcarvacrol increased its effects as the concentration raised. Regarding the different drying times, acetylcarvacrol maintained its effects after 3 hours of exposure, while the efficacy of carvacrol decreased during this time period. Salivary glands of unfed R. sanguineus s.l. females showed dose-dependent alterations in the size and shape of acini as well as cytoplasmic vacuolization. Loss of the acinar cell limit, rupture of secretory granules and nuclear changes in the cells were also observed in the treated groups. Thus, our results demonstrated the potential of acetylcarvacrol to act as repellent against R. sanguineus s.l. Additionally, the morphological alterations found in salivary glands may interfere with the feeding process of ticks, which contributes to mitigate infestation by this species.


Assuntos
Cimenos/farmacologia , Ixodidae/efeitos dos fármacos , Glândulas Salivares/efeitos dos fármacos , Acaricidas/farmacologia , Animais , Cães , Repelentes de Insetos/farmacologia , Rhipicephalus sanguineus/efeitos dos fármacos , Glândulas Salivares/patologia , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/veterinária
9.
Braz J Biol ; 83: e244647, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34190758

RESUMO

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.


Assuntos
Aedes , Cymbopogon , Repelentes de Insetos , Inseticidas , Óleos Voláteis , Animais , Esterificação , Inseticidas/toxicidade , Larva , Óleos Voláteis/toxicidade
10.
Molecules ; 26(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34063887

RESUMO

The present work describes the use of Centrifugal Partition Chromatography (CPC) for the bio-guided isolation of repellent active volatile compounds from essential oils. Five essential oils (EOs) obtained from three Pinus and two Juniperus species were initially analyzed by gas chromatography-mass spectrometry (GC/MS) and evaluated for their repellent properties against Aedes albopictus. The essential oil from needles of P. pinea (PPI) presented the higher activity, showing 82.4% repellency at a dose of 0.2 µL/cm2. The above EO, together with the EO from the fruits of J. oxycedrus subsp. deltoides (JOX), were further analyzed by CPC using the biphasic system n-Heptane/ACN/BuOH in ratio 1.6/1.6/0.2 (v/v/v). The analysis of PPI essential oil resulted in the recovery of (-)-limonene, guaiol and simple mixtures of (-)-limonene/ß-pheladrene, while the fractionation of JOX EO led to the recovery of ß-myrcene, germacrene-D, and mixtures of α-pinene/ß-pinene (ratio 70/30) and α-pinene/germacrene D (ratio 65/45). All isolated compounds and recovered mixtures were tested for their repellent activity. From them, (-)-limonene, guaiol, germacrene-D as well the mixtures of (-)-limonene/ß-pheladrene presented significant repellent activity (>97% repellency) against Ae. albopictus. The present methodology could be a valuable tool in the effort to develop potent mosquito repellents which are environmentally friendly.


Assuntos
Aedes/efeitos dos fármacos , Cromatografia/métodos , Repelentes de Insetos/isolamento & purificação , Animais , Bioensaio , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Repelentes de Insetos/administração & dosagem , Repelentes de Insetos/farmacologia , Juniperus/química , Óleos Voláteis/química , Pinus/química , Volatilização
11.
Malar J ; 20(1): 226, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-34016099

RESUMO

BACKGROUND: Malaria vector control relies upon the use of insecticide-treated nets and indoor residual spraying. However, as the emergency of insecticide resistance in malaria vectors grows, the effectiveness of these measures could be limited. Alternative tools are needed. In this context, repellents can play an important role against exophagic and exophilic mosquitoes. This study evaluated the efficacy of MAÏA®, a novel repellent ointment, in laboratory and field conditions in Burkina Faso. METHODS: For laboratory and field assessment, 20 volunteers were enrolled and trained for nocturnal collection of mosquitoes using human landing catches (HLC). In the laboratory tests, 2 mg/sq cm of treatment (either MAIA® or 20 % DEET) were used to assess median complete protection time (CPT) against two species: Anopheles gambiae and Aedes aegypti, following WHO guidelines. For both species, two strains consisting of susceptible and local strains were used. The susceptible strains were Kisumu and Bora Bora for An. gambiae and Ae. aegypti, respectively. For the field test, the median CPT of MAÏA® was compared to that of a negative (70 % ethanol) and positive (20 % DEET) after carrying out HLCs in rural Burkina Faso in both indoor and outdoor settings. RESULTS: Laboratory tests showed median Kaplan-Meier CPT of 6 h 30 min for An. gambiae (Kisumu), 5 h 30 min for An. gambiae (Goden, local strain), and 4 h for Ae. aegypti for both the local and sensitive strain. These laboratory results suggest that MAÏA® is a good repellent against the three mosquito species. During these field tests, a total of 3979 mosquitoes were caught. In this population, anophelines represented 98.5 %, with culicines (Aedes) making up the remaining 1.5 %. Among anopheline mosquitoes, 95 % belonged to the An. gambiae complex, followed by Anopheles funestus and Anopheles pharoensis. The median CPT of 20 % DEET and MAÏA® were similar (8 h) and much longer than that of the negative control (2 h). CONCLUSIONS: Results from the present studies showed that MAÏA® offers high protection against anophelines biting indoors and outdoors and could play an important role in malaria prevention in Africa.


Assuntos
Aedes/efeitos dos fármacos , Anopheles/efeitos dos fármacos , DEET/farmacologia , Repelentes de Insetos/farmacologia , Adulto , Animais , Burkina Faso , Feminino , Humanos , Malária/prevenção & controle , Masculino , Pomadas , Adulto Jovem
12.
Environ Pollut ; 287: 117359, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34020258

RESUMO

Ants are eusocial insects and have evolved sensitive chemosensory systems for social communication. However, the effect of heavy metal contamination on the olfactory sensitivity of ants remains largely unknown. Here, we investigated the survival and olfactory response of Solenopsis invicta under cadmium (Cd) exposure. As a result, exposure to dietary Cd at different concentrations (100, 300 and 500 mg/L) caused higher Cd accumulation and lower survival of the ants compared with the control (0 mg/L). Cd exposure induced diverse expression patterns of odor binding protein genes (SiOBPs) in S. invicta antenna. Specifically, the expression of SiOBP4, SiOBP11, SiOBP12 and SiOBP16 was increased by 1.84-, 1.14-, 0.83- and 1.76-fold, respectively, at 300 mg/L Cd, while SiOBP7 and SiOBP9 were suppressed as Cd concentration increased. Electroantennography (EAG) and behavioral bioassays were performed to further evaluate the effect of Cd contamination on the olfactory sensitivity of S. invicta workers to 2, 4, 6-trimethylpyridine (TMP) and 2-ethyl-3,6(5)-dimethylpyrazine (EDP), the two frequent functional semiochemicals for S. invicta. The results showed that under no Cd exposure, S. invicta workers exhibited strong EAG response and apparent residing repellence to TMP and EDP, but Cd exposure suppressed EAG response and deprived the behavioral repellence to TMP and EDP of the workers, suggesting that Cd exposure decreases the olfactory sensitivity of S. invicta to these two functional semiochemicals. Further fluorescence competitive binding assay revealed that SiOBP7 had strong binding affinity to TMP and EDP, suggesting that the decrease in olfactory sensitivity may be attributed to the inhibitory effect of Cd exposure on SiOBP7. Overall, our results suggest that Cd exposure may not only directly decrease the survival of ants, but also affect their olfactory recognition.


Assuntos
Formigas , Repelentes de Insetos , Animais , Cádmio/toxicidade , Humanos , Feromônios
13.
Nat Commun ; 12(1): 2553, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33953207

RESUMO

Pyrethrum extracts from flower heads of Chrysanthemum spp. have been used worldwide in insecticides and repellents. While the molecular mechanisms of its insecticidal action are known, the molecular basis of pyrethrum repellency remains a mystery. In this study, we find that the principal components of pyrethrum, pyrethrins, and a minor component, (E)-ß-farnesene (EBF), each activate a specific type of olfactory receptor neurons in Aedes aegypti mosquitoes. We identify Ae. aegypti odorant receptor 31 (AaOr31) as a cognate Or for EBF and find that Or31-mediated repellency is significantly synergized by pyrethrin-induced activation of voltage-gated sodium channels. Thus, pyrethrum exerts spatial repellency through a novel, dual-target mechanism. Elucidation of this two-target mechanism may have potential implications in the design and development of a new generation of synthetic repellents against major mosquito vectors of infectious diseases.


Assuntos
Chrysanthemum cinerariifolium/metabolismo , Culicidae/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Inseticidas/farmacologia , Piretrinas/farmacologia , Aedes/efeitos dos fármacos , Animais , Chrysanthemum cinerariifolium/genética , Técnicas de Inativação de Genes , Controle de Mosquitos , Mosquitos Vetores , Neurônios , Receptores Odorantes/genética , Canais de Sódio Disparados por Voltagem
15.
Parasit Vectors ; 14(1): 190, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827658

RESUMO

BACKGROUND: Plant-based mosquito control methods may use as a supplementary malaria vector control strategy. This study aimed to evaluate the effect of smoking ethno-medicinal plants on indoor density and feeding activity of malaria vectors at early hours of the night and its residual effect after midnight in southern Ethiopia. METHODS: Both field and tent trials were conducted to evaluate the impact of smoking Juniperus procera leaves, Eucalyptus globulus seeds and Olea europaea leaves in Kolla Shara Village from July 2016 to February 2017. For the field trial, five grass-thatched traditional huts (three for ethno-medicinal plants and two as control [only charcoal smoking and non-charcoal smoking]) were used. Indoor host-seeking mosquitoes were collected by CDC light traps. A Latin square design was employed to minimize the bias due to the variation in house location and different sampling nights. For the tent experiment, 25 3-5-day-old starved wild female Anopheles mosquitoes reared from the larvae were released into the tents where a calf was tethered at the mid-point of each tent. RESULTS: A total of 614 Anopheles mosquitoes belonging to 5 species were collected from 5 huts, of which 93.4% was An. arabiensis; O. europaea, E. globulus and J. procera reduced the indoor density of An. arabiensis, with the mean percentage drop of 80%, 73% and 70%, respectively. In the tent trial, smoking of these plants had significant knockdown effects and inhibited feeding on the calves (F = 383.5, DF = 3, P < 0.01). The mean knockdown effect due to O. europaea was relatively high (17.7 ± 0.54; 95% CI 16.8-18.6), while it was only 0.9 ± 0.1 (95% CI 0.29-1.52) in the control tents. All the test plants used in the tent trial caused significantly inhibited feeding activity of An. arabiensis on the host (F = 383.5, DF = 3, P < 0.01). About 94.5%, 89.5% and 86% of mosquitoes were unfed because of the smoking effect of O. europaea, E. globulus and J. procera, respectively, whereas only 19.5% were unfed in the control tent. CONCLUSIONS: Smoking ethno-medicinal plant materials reduced indoor density of malaria vectors and inhibited feeding on calves inside the tents. Thus, plant-based mosquito control methods may play a vital role in reducing mosquito bites in the early hours of the night and thereby reduce residual malaria transmission.


Assuntos
Anopheles/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Repelentes de Insetos/normas , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/fisiologia , Plantas Medicinais/química , Animais , Etiópia , Feminino , Habitação , Repelentes de Insetos/análise , Malária/transmissão , Folhas de Planta/química , Sementes/química , Fatores de Tempo
16.
Pest Manag Sci ; 77(9): 4034-4039, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33896101

RESUMO

BACKGROUND: Movement of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), in stored products is mediated by food volatiles and other semiochemicals. RESULTS: In two-way olfactometer assays, T. castaneum was more attracted to wheat bran previously infested with conspecifics than to uninfested bran. Chemical analysis showed that 1-pentadecene was present in the headspace of T. castaneum-infested wheat bran, but not detectable in the headspace of uninfested bran. An olfactometer was used to test the effect on T. castaneum behaviour of 1-pentadecene, and of volatiles from wheat bran with and without 1-pentadecene. The lowest concentration of 1-pentadecene exhibited an attractive effect, compared to the control (n-hexane). Slightly higher concentrations showed a neutral effect, while the highest concentrations repelled T. castaneum. Wheat bran with a low 1-pentadecene concentration was more attractive than wheat bran alone, whereas higher concentrations of 1-pentadecene were repellent. CONCLUSION: The results provide important information on intraspecific, semiochemical-mediated behaviour in T. castaneum, which could potentially be used to develop new methods to monitor the flour beetles in stored products. © 2021 Society of Chemical Industry.


Assuntos
Besouros , Repelentes de Insetos , Tribolium , Animais , Humanos , Repelentes de Insetos/farmacologia , Feromônios/farmacologia
17.
SAR QSAR Environ Res ; 32(5): 395-410, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33870800

RESUMO

The fumigant and topical activities exhibited by 27 plant-derived essentials oils (EOs) on adult M. domestica housefly are predicted through the Quantitative Structure-Activity Relationship (QSAR) theory. These molecular structure based calculations are performed on 253 structurally diverse compounds from the EOs, where the number of constituents in each essential oil mixture varies between 2 to 24. A large number of 86,048 non-conformational mixture descriptors are derived as linear combinations of the molecular descriptors of the EO components. Two strategies are compared for the mixture descriptor formulation, which consider or avoid the use of the chemical composition. The multivariable linear regression QSAR models of the present work are useful for fumigant and topical applications, describing predictive parallelisms for the insecticidal activity of the analysed complex mixtures.


Assuntos
Moscas Domésticas/efeitos dos fármacos , Inseticidas/farmacologia , Óleos Voláteis/farmacologia , Animais , Fumigação , Repelentes de Insetos/química , Repelentes de Insetos/farmacologia , Inseticidas/química , Óleos Voláteis/química , Relação Quantitativa Estrutura-Atividade
18.
Artigo em Inglês | MEDLINE | ID: mdl-33803910

RESUMO

Mass-participation events in temperate forests are now well-established features of outdoor activities and represent high-risk activities regarding human exposition to tick bites. In this study we used a citizen science approach to quantify the space-time frequency of tick bites and undetected tick bites among orienteers that participated in a 6-day orienteering competition that took place in July 2018 in the forests of Eastern France, and we looked at the use and efficacy of different preventive behaviors. Our study confirms that orienteers are a high-risk population for tick bites, with 62.4% of orienteers bitten at least once during the competition, and 2.4 to 12.1 orienteers per 100 orienteers were bitten by ticks when walking 1 km. In addition, 16.7% of orienteers bitten by ticks had engorged ticks, meaning that they did not detect and remove their ticks immediately after the run. Further, only 8.5% of orienteers systematically used a repellent, and the use of repellent only partially reduced the probability of being bitten by ticks. These results represent the first attempt to quantify the risk of not immediately detecting a tick bite and provide rare quantitative data on the frequency of tick bites for orienteers according to walking distance and time spent in the forest. The results also provide information on the use of repellent, which will be very helpful for modeling risk assessment. The study also shows that prevention should be increased for orienteers in France.


Assuntos
Mordeduras e Picadas , Repelentes de Insetos , Picadas de Carrapatos , Carrapatos , Animais , França/epidemiologia , Humanos , Picadas de Carrapatos/epidemiologia , Picadas de Carrapatos/prevenção & controle
19.
Molecules ; 26(9)2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-33923002

RESUMO

Artemisia abrotanum L. (southern wormwood) is a plant species with an important position in the history of European and Asian medicine. It is a species famous as a medicinal plant in Central Asia, Asia Minor, and in South-East and Central Europe. The raw materials obtained from this species are Abrotani herba and Abrotani folium. In the traditional European medicine, they have been used successfully most of all in liver and biliary tract diseases, in parasitic diseases in children and as antipyretic medication. In the official European medicine, this plant species is recommended by the French Pharmacopoeia for use in homeopathy. In many European countries, it is used traditionally in allopathy. The latest studies on the biological activity of extracts from the aboveground parts of the plant and/or the leaves, and/or the essential oil have provided evidence of other possible applications related to their antibacterial, antifungal, antioxidant, anticancer, and antiallergic properties. The latest studies have also focused on the repellent activity of the essential oil of this species and the possibility to use it in the prevention of diseases in which insects are the vectors. The main substances obtained from the plant that are responsible for this activity are: the essential oil, coumarins, phenolic acids, and flavonoids. Some of the latest investigations emphasize the large differences in the composition of the essential oil, determined by the geographical (climatic) origin of the plant. A. abrotanum is recommended by the European Cosmetic Ingredients Database (CosIng) as a source of valuable cosmetic ingredients. Additionally, the leaves of this species possess a well-established position in the food industry. This plant species is also the object of biotechnological studies.


Assuntos
Antioxidantes/uso terapêutico , Artemisia/química , Medicina Tradicional , Óleos Voláteis/química , Antifúngicos/química , Antifúngicos/uso terapêutico , Antioxidantes/química , Cosméticos , Humanos , Repelentes de Insetos/química , Repelentes de Insetos/uso terapêutico , Óleos Voláteis/uso terapêutico , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta/química
20.
Pest Manag Sci ; 77(8): 3706-3712, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33798266

RESUMO

BACKGROUND: Pyrethrum from dry flowers of Chrysanthemum is a well-known botanical insecticide and repellent. Its insecticidal activity attributes to its six insecticidal esters, collectively known as pyrethrins. Pyrethrins and its synthetic analogs pyrethroids exert their toxic action by modifying the function of voltage-gated sodium channels. Aside from insecticidal activity, pyrethrum has also been used to repel mosquitoes for centuries. Today, pyrethrum continues to be used as an active ingredient in mosquito coils and other mosquito-repellent devices globally. However, the mechanism of pyrethrum repellency remains largely unknown. RESULTS: Here we report that pyrethrum vapor induced spatial (non-contact) repellency in Aedes albopictus, a major vector of dengue and West Nile viruses. Using electroantennogram (EAG) recordings from adult antennae, we found that pyrethrum elicited EAG response in a dose-dependent manner. We then isolated the six insecticidal esters, pyrethrins I and II, cinerins I and II, jasmolins I and II from pyrethrum extract and discovered that five of the six esters, except jasmolin I, all elicited EAG responses. Furthermore, pyrethrins I and II, cinerin II and jasmolin II induced repellency, whereas cinerin I and jasmolin I did not. CONCLUSION: Of the six pyrethrins, four of them, pyrethrins I and II, cinerin II and jasmolin II, activate olfactory-receptor neurons and elicit spatial repellency in Ae. albopictus. Our study provided a foundation for future structure-function studies of pyrethrins, their cognate olfactory receptors and efficacies of repellency and for the development of new and more effective mosquito repellents for controlling vector-borne human diseases. © 2021 Society of Chemical Industry.


Assuntos
Aedes , Chrysanthemum cinerariifolium , Repelentes de Insetos , Inseticidas , Piretrinas , Animais , Humanos , Mosquitos Vetores
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