In Vitro Characterization and Mosquito (Aedes aegypti) Repellent Activity of Essential-Oils-Loaded Nanoemulsions (original) (raw)
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Insects
Negative impacts on the environment from the continuous use of synthetic insecticides against mosquitoes has driven research towards more ecofriendly products. Phytochemicals, classified as low-risk substances, have been recognized as potential larvicides of mosquitoes; however, problems related to water solubility and stability are limiting factors for their use in mosquito control programs in the field. In this context, many researchers have focused on formulating essential oils in nanoemulsions, exploiting innovative nanotechnology. In the current study, we prepared 4 (R)-(+)-limonene oil-in-water nanoemulsions using low and high energy methods, and we evaluated their physicochemical characteristics (e.g., viscosity, stability, mean droplet diameter, polydispersity index) and their bioactivity against larvae of two mosquito species of great medical importance, namely, Cx. pipiens molestus and Ae. albopictus. According to the dose–response bioassays with the limonene-based nanoemu...
Ayapana triplinervis is a plant species used in traditional medicine and in mystical-religious rituals by traditional communities in the Amazon. The aim of this study are to develop a nano-emulsion containing essential oil from A. triplinervis morphotypes, to evaluate larvicidal activity against Aedes aegypti and acute oral toxicity in Swiss albino mice (Mus musculus). The essential oils were extracted by steam dragging, identified by gas chromatography coupled to mass spectrometry, and nano-emulsions were prepared using the low energy method. Phytochemical analyses indicated the major compounds, expressed as area percentage, β-Caryophyllene (45.93%) and Thymohydroquinone Dimethyl Ether (32.93%) in morphotype A; and Thymohydroquinone Dimethyl Ether (84.53%) was found in morphotype B. Morphotype A essential oil nano-emulsion showed a particle size of 101.400 ± 0.971 nm (polydispersity index = 0.124 ± 0.009 and zeta potential =-19.300 ± 0.787 mV). Morphotype B essential oil nano-emulsion had a particle size of 104.567 ± 0.416 nm (polydispersity index = 0.168 ± 0.016 and zeta potential =-27.700 ± 1.307 mV). Histomorphological analyses showed the presence of inflammatory cells in the liver of animals treated with morphotype A essential oil nano-emulsion (MAEON) and morphotype B essential oil nano-emulsion (MBEON). Congestion and the presence of transudate with leukocyte infiltration in the lung of animals treated with MAEON were observed. The nano-emulsions containing essential oils of A. triplinervis morphotypes showed an effective nanobiotechnological product in the chemical control of A. aegypti larvae with minimal toxicological action for non-target mammals.
Revista Brasileira de Farmacognosia, 2020
Diseases transmitted by the mosquito Aedes aegypti, Culicidae, are a serious public health problem worldwide, especially because of the increasing resistance to synthetic insecticides. Volatile oils are botanicals with interesting multi-target properties, but with reduced applications due to its volatility and water solubility. For this reason, nanoemulsions containing volatile oils are an important alternative for the mosquito control. The volatile oil of leaves Piper alatipetiolatum Yunck., Piperaceae, was characterized mostly by sesquiterpenes, such as ishwarone (78.6%), ishwarol B (8.2%), β-elemene (6.9%), selin-11-en-4α-ol (2.9%), and ishwarane (2.4%). The volatile oil showed lower ovicidal activity (19 to 100%), larvicidal activity (LC 50 33.74 ppm), and pupicidal activity (LC 50 65.06 ppm) as compared with its nanoemulsion that presented higher ovicidal activity (47.7 to 100%), larvicidal activity (LC 50 6.37 ppm), and pupicidal activity (LC 50 9.33 ppm) against Ae. aegypti. The volatile oil nanoemulsion was characterized with approximately spherical morphology, with an average size of 316 ± 8 nm, PDI of 0.44 ± 0.01, zeta potential of − 8.5 ± 0.1 mV, and pH of 5.3 ± 0.1. These results indicated that the nanoemulsion containing the encapsulated volatile oil was effective to interrupt the development of immature forms of Ae. aegypti and represents an efficient alternative tool to control this vector, contributing to vector control of dengue and other related diseases.
The Open Biotechnology Journal, 2020
Introduction: The present study aimed to prepare Nanoemulsions of Mentha piperita and Eucalyptus globulus essential oils and comparison of the repellant activity of them with normal essential oils and DEET in the field conditions. Methods: To determine the protection and failure time of the essential oils and DEET in the field condition against natural population of night biting culicid mosquitoes, 4 human volunteers participated in night biting test. GC-MS was used to determine the essential oil components and the Dynamic Light Scattering device was used to measure droplet size and zeta potential. Results: The relative abundance of more common species captured in this study was 40.09% and 31.65% for Anopheles superpictus, and Culex pipiens, respectively. Based on the results, the protection time of nanoemulsions of M. piperita 50% against night biting mosquitoes was 4.96±0.21 h. Also, the protection for nanoemulsions essential oil 50% of E. globulus was 6.06±0.20 h. Comparison of t...
Indian Journal of Biochemistry and Biophysics
Mentha piperita (peppermint) essential oil nanoemulsion was prepared by low energy spontaneous emulsification method. GC-MS analysis revealed the composition of peppermint essential oil and menthol (45.2%) was the major bioactive compound along with menthone (15.39%), neomethol (8.1%), menthyl acetate (7.7%) and isomenthone (7.4%). Optimization of the nanoemulsion preparation process was done by Response Surface Methodology (RSM) with Central Composite Design (CCD). The droplet diameter and polydispersity index at optimized conditions (15% oil concentration, 25% surfactant concentration and Tween80 as surfactant) were 39.2 nm and 0.22 respectively. Optimized peppermint oil nanoemulsion (OPNE) was optically transparent, spherical in morphology and was stable for 6 months. OPNE formulation demonstrated dose, time and size-dependent larvicidal activity against malaria vectors with LC 50 value of 48 ppm and 123 ppm against Anopheles culicifacies and Anopheles stephensi respectively. The LC 50 values were 90 ppm and 163 ppm against Anopheles culicifacies and Anopheles stephensi correspondingly for the bigger droplet size formulation (PNE, droplet diameter: 129.6 nm) confirming the droplet size-dependent larvicidal activity of the nanoemulsion. The results of this study propose that peppermint oil-based nanoemulsion possibly be used as an eco-friendly larvicide for mosquito vector control strategies.
Journal of Medical Entomology, 2019
Siparuna guianensis (Laurales: Siparunaceae) has a terpene-rich essential oil with great potential for larvicides. The poor water miscibility of their compounds makes nano-emulsions of great interest for novel bioactive systems, including for control of Aedes aegypti (Diptera: Culicidae). This species is adapted to urban environments with important role in the epidemiology of some arboviruses such as dengue, chikungunya fever, zika, and urban yellow fever. The aim of the present study was to evaluate the feasibility of nano-emulsification to affect Ae. aegypti larvae. An optimal system was achieved by using a nonionic single surfactant, highlighted by its satisfactory size distribution profile. Moreover, improved larvicidal activity in comparison to bulk essential oil can be observed for the nano-emulsions. The estimated LC50 and LC90 values after 24 h of treatment of larvae with the essential oil were, respectively, 86.5232 and 134.814 µg/ml, while the estimated LC50 and LC90 value...
Journal of Pest Science, 2021
Carlina acaulis root essential oil (EO) is one of the most potent mosquito larvicides (LC50 90%). Poor water solubility and rapid degradation from UV light and oxygen in the environment limit the real-world use of this EO. Herein, we developed nanocarrier-based formulations, namely micro- and nanoemulsions (ME and NE, respectively) containing C. acaulis EO or carlina oxide (both at 0.5%) as active ingredients (a.i.). The larvicidal activity of ME and NE was evaluated against Culex quinquefasciatus. The highest larvicidal activity was achieved by the ME containing 0.5% of the EO (M1); its LC50(90) was 579.1 (791.3) µL L−1. Sublethal effects of this ME and its a.i. were assessed testing both at the LC16, LC30, LC50 and LC90 on mosquito larvae exposed to each product for 1–7 h, and then monitoring mortality for 18 days. At variance with the EO, ME application, even at LC16, led to 100% mortality at 18 days. The EO and its encapsulated form were scarcely toxic to human keratinocytes (H...