RESUMO
Mosquitoes can be vectors of pathogens and transmit diseases to both animals and humans. Species of the genus Culex are part of the cycle of neglected diseases, especially Culex quinquefasciatus, which is an anthropophilic vector of lymphatic filariasis. Natural products can be an alternative to synthetic insecticides for vector control; however, the main issue is the poor water availability of some compounds from plant origin. In this context, nanoemulsions are kinetic stable delivery systems of great interest for lipophilic substances. The objective of this study was to investigate the larvicidal activity of the Hyptis suaveolens essential oil nanoemulsion on Cx. quinquefasciatus. The essential oil showed a predominance of monoterpenes with retention time (RT) lower than 15 min. The average size diameter of the emulsions (sorbitan monooleate/polysorbate 20) was ≤ 200 nm. The nanoemulsion showed high larvicidal activity in concentrations of 250 and 125 ppm. CL50 values were 102.41 (77.5253−149.14) ppm and 70.8105 (44.5282−109.811) ppm after 24 and 48 h, respectively. The mortality rate in the surfactant control was lower than 9%. Scanning micrograph images showed changes in the larvae's integument. This study achieved an active nanoemulsion on Cx. quinquefasciatus through a low-energy-input technique and without using potentially toxic organic solvents. Therefore, it expands the scope of possible applications of H. suaveolens essential oil in the production of high-added-value nanosystems for tropical disease vector control.
Assuntos
Aedes , Culex , Culicidae , Inseticidas , Lamiaceae , Óleos Voláteis , Humanos , Animais , Óleos Voláteis/farmacologia , Óleos Voláteis/análise , Larva , Mosquitos Vetores , Inseticidas/química , Extratos Vegetais/química , Folhas de Planta/químicaRESUMO
BACKGROUND: From the fruits and seeds of the species of Pterodon, it is possible to obtain two main products: essential oil and oleoresin. In oleoresin, numerous vouacapan compounds have been demonstrated to have biological potential, including insecticidal activity. OBJECTIVE: In silico studies were performed to identify potential candidates for natural insecticides among the vouacapans present in the genus Pterodon. MATERIALS AND METHODS: Molecular docking and molecular dynamics studies were performed to analyze the interaction of vouacapan compounds with acetylcholinesterase of Drosophila melanogaster. Pharmacokinetic parameters regarding physicochemical properties, plasma protein binding, and activity in the central nervous system were evaluated. The toxicological properties of the selected molecules were predicted using malathion as the reference compound. RESULTS: 6α,7ß-dimethoxivouacapan-17-ene (15) showed a high number of interactions and scores in molecular docking studies. These results suggested that this compound exhibits an inhibitory activity of the enzyme acetylcholinesterase. This compound showed the best results regarding physicochemical properties, besides presenting low cutaneous permeability values, suggesting null absorption. Molecular dynamics studies demonstrated few conformational changes in the structure of the complex formed by compound 4 and acetylcholinesterase enzyme throughout the simulation time. CONCLUSION: It was determined that compound 4 (vouacapan 6α,7ß,17ß,19-tetraol) could be an excellent candidate for usage as a natural insecticide.
Assuntos
Fabaceae , Inseticidas , Acetilcolinesterase , Animais , Diterpenos , Drosophila melanogaster , Fabaceae/química , Inseticidas/farmacologia , Simulação de Acoplamento Molecular , Patentes como AssuntoRESUMO
Pectis elongata is found in the northern and northeastern regions of Brazil. It is considered a lemongrass due to its citric scent. The remarkable citral content and the wide antimicrobial properties and bioactive features of this terpene make this essential oil (EO) eligible for several industrial purposes, especially in cosmetics and phytotherapics. However, to address the problems regarding citral solubility, nano-emulsification is considered a promising strategy thanks to its improved dispersability. Thus, in this paper we propose a low-energy approach for the development of citral-based nano-emulsions prepared with P. elongata EO. The plant was hydrodistillated to produce the EO, which was characterized with a gas chromatograph coupled to mass spectrometry. The nano-emulsion prepared by a non-heated water titrating (low-energy) method was composed of 5% (w/w) EO, 5% (w/w) non-ionic surfactants and 90% (w/w) deionized water and was analyzed by dynamic light scattering. Levels of citral of around 90% (neral:geranial-4:5) were detected in the EO and no major alteration in the ratio of citral was observed after the nano-emulsification. The nano-emulsion was stable until the 14th day (size around 115 nm and polydispersity index around 0.2) and no major alteration in droplet size was observed within 30 days of storage. Understanding the droplet size distribution as a function of time and correlating it to concepts of compositional ripening, as opposing forces to the conventional Ostwald ripening destabilization mechanism, may open interesting approaches for further industrial application of novel, low-energy, ecofriendly approaches to high citral essential oil-based nano-emulsions based on lemongrass plants.
Assuntos
Monoterpenos Acíclicos/isolamento & purificação , Emulsões/química , Óleos Voláteis/isolamento & purificação , Monoterpenos Acíclicos/química , Brasil , Cymbopogon/química , Cromatografia Gasosa-Espectrometria de Massas , Monoterpenos/química , Óleos Voláteis/química , Extratos Vegetais/isolamento & purificação , Tensoativos/química , Água/químicaRESUMO
Cutaneous leishmaniasis (CL) is a neglected tropical skin disease caused by the protozoan genus Leishmania. The treatment is restricted to a handful number of drugs that exhibit toxic effects, limited efficacy, and drug resistance. Additionally, developing an effective topical treatment is still an enormous unmet medical challenge. Natural oils, e.g. the oleoresin from P. emarginatus fruits (SO), contain various bioactive molecules, especially terpenoid compounds such as diterpenes and sesquiterpenes. However, its use in topical formulations can be impaired due to the natural barrier of the skin for low water solubility compounds. Nanoemulsions (NE) are drug delivery systems able to increase penetration of lipophilic compounds throughout the skin, improving their topical effect. In this context, we propose the use of SO-containing NE (SO-NE) for CL treatment. The SO-NE was produced by a low energy method and presented suitable physicochemical characteristic: average diameter and polydispersity index lower than 180 nm and 0.2, respectively. Leishmania (Leishmania) amazonensis-infected BALB/c mice were given topical doses of SO or SO-NE. The topical use of a combination of SO-NE and intraperitoneal meglumine antimoniate reduced lesion size by 41 % and tissue regeneration was proven by histopathological analyses. In addition, a reduction in the parasitic load and decreased in the level of IFN-γ in the lesion may be associated, as well as a lower level of the cytokine IL-10 may be associated with a less intense inflammatory process. The present study suggests that SO-NE in combination meglumine antimoniate represents a promising alternative for the topical treatment of CL caused by L. (L.) amazonensis.
Assuntos
Fabaceae , Leishmania mexicana/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Extratos Vegetais/farmacologia , Pele/efeitos dos fármacos , Tripanossomicidas/farmacologia , Administração Tópica , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Composição de Medicamentos , Quimioterapia Combinada , Emulsões , Fabaceae/química , Feminino , Interações Hospedeiro-Parasita , Leishmania mexicana/crescimento & desenvolvimento , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Antimoniato de Meglumina/farmacologia , Mesocricetus , Camundongos Endogâmicos BALB C , Nanopartículas , Carga Parasitária , Extratos Vegetais/isolamento & purificação , Pele/parasitologia , Pele/patologia , Tripanossomicidas/isolamento & purificaçãoRESUMO
Rhipicephalus microplus, the cattle tick, is a major cause of economic losses in bovine production. Due to the widespread acaricidal resistance to commercially available products, as well as their toxicity and environmental impact, alternative control methods are required. Nanoformulations produced from plant extracts as bioactive substances are very promising as innovative acaricidal agents. Thus, the aim of this study was to evaluate the in vitro repellent activity of Pilocarpus spicatus essential oil and its nanoemulsion against R. microplus, using larval repellent test (RT). The essential oil was extracted by hydrodistillation, using a Clevenger-type apparatus. The nanoemulsion was prepared with 5% essential oil, 5% tween 80, and 90% water, using the phase inversion method (50 mg/mL). Limonene was the major component (46.8%) of the essential oil, as determined by gas chromatography-mass spectrometry (GC/MS) and confirmed by flame ionization detection (GC/FID). According to the RT results, the essential oil had a repellent activity greater than 69%, from concentrations of 3.12 mg/mL (69.81 ± 10%) to 50 mg/mL (98.10 ± 0.6%), whereas the nanoemulsion at 50 mg/mL presented repellent activities of 97.14 ± 1.37% and 97.89 ± 0.52% 6 and 10 h after treatment, respectively. These values regarding to total repellency were very close to those calculated for mortality corrected by Abbott's formula. The phase inversion method preserved the chemical and physical characteristics of the essential oil since both reached an equal repellent effect at the same concentration. Therefore, P. spicatus essential oil and nanoemulsion had excellent repellent activities against R. microplus larvae, demonstrating its potential for future use as an alternative for tick control.
Assuntos
Óleos Voláteis/farmacologia , Pilocarpus/química , Óleos de Plantas/farmacologia , Rhipicephalus/efeitos dos fármacos , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Emulsões/farmacologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Larva/efeitos dos fármacos , Limoneno/análise , Modelos Lineares , Óleos Voláteis/isolamento & purificação , Folhas de Planta/química , Óleos de Plantas/isolamento & purificação , Distribuição Aleatória , Controle de Ácaros e Carrapatos/métodos , Infestações por Carrapato/parasitologia , Infestações por Carrapato/prevenção & controle , Infestações por Carrapato/veterináriaRESUMO
Metal nanoparticles are a promising approach for the development of new antimicrobial systems. Silver nanoparticles (AgNP) have a significant antibacterial activity through bacterial surface adsorption and oxidative stress induction, as indicated by recent observations. This research aimed to use endophytic fungi from the genus Trichoderma spp. isolated from the Bertholletia excelsa (Brazil-nut) seeds and the soil to biosynthesize AgNPs and also test their antibacterial activity. The use of these fungi for this purpose not only valorizes the Amazon biodiversity but it also uses cleaner and cheaper processes, being part of the Green Chemistry concept. The particles were analyzed through Ultraviolet-Visible Spectroscopy and ZetaSizer and the band of absorption at 420 nm was analyzed through Localized Surface Plasmon Resonance. After characterization, the AgNP were tested for antibacterial activity against several bacterial strains, when it was observed that their antibacterial activity was superior in Gram-negative bacteria.
Assuntos
Antibacterianos/farmacologia , Nanopartículas Metálicas/química , Prata/farmacologia , Trichoderma/crescimento & desenvolvimento , Antibacterianos/química , Bertholletia/microbiologia , Biodiversidade , Brasil , Bactérias Gram-Negativas/efeitos dos fármacos , Química Verde , Testes de Sensibilidade Microbiana , Prata/química , Microbiologia do Solo , Ressonância de Plasmônio de Superfície , Trichoderma/metabolismoRESUMO
ABSTRACT Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson, Verbenaceae, is considered a great source of a bioactive volatile oil. Due to the wide range of known chemotypes, its chemical analysis is very important. Among the several activities of this volatile oil, a potential larvicidal action against Culicidae species is highlighted. However, the low water miscibility of volatile oils limits their application in aqueous media. Oil in water nano-emulsions are in the spotlight of novelty to solve this main problem. Thus, the aim of the present study was to obtain this nanostructured system with L. alba volatile oil (citral chemotype) and evaluate its larvicidal activity against Aedes aegypti and Culex quinquefasciatus larvae. The major compounds were geranial (30.02%) and neral (25.26%). Low mean droplet size (117.0 ± 1.0 nm) and low polydispersity index (0.231 ± 0.004) were observed and no major changes were observed after seven days of storage. LC50 values against C. quinquefasciatus and A. aegypti third-instar larvae were respectively 38.22 and 31.02 ppm, while LC90 values were, respectively, 59.42 and 47.19 ppm. The present study makes use of a low energy, solvent-free and ecofriendly method with reduced costs. Thus, this paper contributes significantly to phyto-nanobiotechnology of larvicidal agents, opening perspectives for the utilization of L. alba volatile oil in integrated practices of vector control.
RESUMO
Jaboticaba (Myrciaria cauliflora) is considered a "super fruit" due to its remarkable phenolic content and antioxidant capacity. Despite the great potential of its peels, to our knowledge the investigation of novel nanostructured systems with this natural raw material, still considered an industrial residue, is scarce. The present study aimed to obtain nanodispersions with its peel's extract through a low energy method. Antioxidant assays were performed, showing positive results for DPPH (IC50â¯=â¯0.89⯵g/mL) and FRAP (225.53⯵mol equivalent ferrous sulphate/g). The chemical characterization in terms of flavonoids (2.56%) and total monomeric anthocyanins (0.80%) contents were also performed. Overall, the nanodispersion prepared with the non-ionic surfactant polysorbate 85 and the hydroalcoholic extract standardized in ellagic acid (129⯵g/mL) presented the best properties regarding particle size distribution and zeta potential. Thus, it opens perspectives for the generation of novel food-grade nanodispersions through an ecofriendly approach that is in accordance to sustainable concepts.
Assuntos
Myrtaceae/química , Extratos Vegetais/química , Antocianinas/análise , Antioxidantes/química , Cromatografia Líquida de Alta Pressão , Ácido Elágico/química , Flavonoides/análise , Frutas/química , Frutas/metabolismo , Myrtaceae/metabolismo , Nanotecnologia , Tamanho da Partícula , Polissorbatos/químicaAssuntos
Antioxidantes/uso terapêutico , Doenças Metabólicas/prevenção & controle , Doenças Neurodegenerativas/prevenção & controle , Ácido Ascórbico/uso terapêutico , Carotenoides/uso terapêutico , Suplementos Nutricionais , Humanos , Doenças Metabólicas/metabolismo , Doenças Metabólicas/patologia , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/patologia , Polifenóis/uso terapêuticoRESUMO
Baccharis reticularia DC. is a plant species from the Asteraceae family that is endemic to Brazil. Despite the great importance of Baccharis genus, no study has been carried out regarding either the phytochemical composition of B. reticularia or the evaluation of its larvicidal potential. Considering the intrinsic immiscibility of essential oils, this study shows larvicidal nanoemulsions containing the B. reticularia phytochemically characterized essential oil and its main constituent against Aedes aegypti. The major compound found was d-limonene (25.7%). The essential oil inhibited the acetylcholinesterase, one of the main targets of insecticides. The required hydrophile-lipophile balance of both nanoemulsions was 15.0. The mean droplet sizes were around 90.0 nm, and no major alterations were observed after 24 h of preparation for both formulations. After 48 h of treatment, the estimated LC50 values were 118.94 µg mL-1 and 81.19 µg mL-1 for B. reticularia essential oil and d-limonene nanoemulsions, respectively. Morphological alterations evidenced by scanning electron micrography were observed on the larvae treated with the d-limonene nanoemulsion. This paper demonstrated a simple and ecofriendly method for obtaining B. reticularia essential oil and d-limonene aqueous nanoemulsions by a non-heating and solvent-free method, as promising alternatives for Aedes aegypti control.