Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
J Biomol Struct Dyn ; 38(16): 4687-4709, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31674282

RESUMO

Models validation in QSAR, pharmacophore, docking and others can ensure the accuracy and reliability of future predictions in design and selection of molecules with biological activity. In this study, pyriproxyfen was used as a pivot/template to search the database of the Maybridge Database for potential inhibitors of the enzymes acetylcholinesterase and juvenile hormone as well. The initial virtual screening based on the 3D shape resulted in 2000 molecules with Tanimoto index ranging from 0.58 to 0.88. A new reclassification was performed on the overlapping of positive and negative charges, which resulted in 100 molecules with Tanimoto's electrostatic score ranging from 0.627 to 0.87. Using parameters related to absorption, distribution, metabolism and excretion and the pivot molecule, the molecules selected in the previous stage were evaluated regarding these criteria, and 21 were then selected. The pharmacokinetic and toxicological properties were considered and for 12 molecules, the DEREK software not fired any alert of toxicity, which were thus considered satisfactory for prediction of biological activity using the Web server PASS. In the molecular docking with insect acetylcholinesterase, the Maybridge3_002654 molecule had binding affinity of -11.1 kcal/mol, whereas in human acetylcholinesterase, the Maybridge4_001571molecule show in silico affinity of -10.2 kcal/mol, and in the juvenile hormone, the molecule MCULE-8839595892 show in silico affinity value of -11.6 kcal/mol. Subsequent long-trajectory molecular dynamics studies indicated considerable stability of the novel molecules compared to the controls.AbbreviationsQSARquantitative structure-activity relationshipsPASSprediction of activity spectra for substancesCommunicated by Ramaswamy H. Sarma.


Assuntos
Inseticidas , Simulação de Dinâmica Molecular , Acetilcolinesterase , Humanos , Hormônios Juvenis , Simulação de Acoplamento Molecular , Relação Quantitativa Estrutura-Atividade , Reprodutibilidade dos Testes
2.
Rev. bras. farmacogn ; 29(6): 778-784, Nov.-Dec. 2019. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1057844

RESUMO

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.

3.
Artigo em Inglês | MEDLINE | ID: mdl-28798803

RESUMO

Andiroba (Carapa guianensis) seeds are the source of an oil with a wide range of biological activities and ethnopharmacological uses. However, few studies have devoted attention to innovative formulations, including nanoemulsions. The present study aimed to obtain a colloidal system with the andiroba oil using a low-energy and organic-solvent-free method. Moreover, the preliminary residual larvicidal activity of the nanoemulsion against Aedes aegypti was evaluated. Oleic and palmitic acids were the major fatty acids, in addition to the phytosterol ß-sitosterol and limonoids (tetranortriterpenoids). The required hydrophile-lipophile was around 11.0 and the optimal nanoemulsion was obtained using polysorbate 85. The particle size distribution suggested the presence of small droplets (mean diameter around 150 nm) and low polydispersity index (around 0.150). The effect of temperature on particle size distribution revealed that no major droplet size increase occurred. The preliminary residual larvicidal assay suggested that the mortality increased as a function of time. The present study allowed achievement of a potential bioactive oil in water nanoemulsion that may be a promising controlled release system. Moreover, the ecofriendly approach involved in the preparation associated with the great bioactive potential of C. guianensis makes this nanoemulsion very promising for valorization of this Amazon raw material.

4.
J Nanobiotechnology ; 15(1): 2, 2017 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-28049483

RESUMO

BACKGROUND: Preparation of nanoformulations using natural products as bioactive substances is considered very promising for innovative larvicidal agents. On this context, oil in water nanoemulsions develop a main role, since they satisfactorily disperse poor-water soluble substances, such as herbal oils, in aqueous media. Pterodon emarginatus, popularly known as sucupira, has a promising bioactive oleoresin. However, to our knowledge, no previous studies were carried out to evaluate its potential against Culex quinquefasciatus, the main vector of the tropical neglected disease called lymphatic filariasis or elephantiasis. Thus, we aimed to investigate influence of different pairs of surfactants in nanoemulsion formation and investigate if a sucupira oleoresin-based nanoemulsion has promising larvicidal activity against this C. quinquefasciatus. We also evaluated morphological alteration, possible mechanism of insecticidal action and ecotoxicity of the nanoemulsion against a non-target organism. RESULTS: Among the different pairs of surfactants that were tested, nanoemulsions obtained with polysorbate 80/sorbitan monooleate and polysorbate 80/sorbitan trioleate presented smallest mean droplet size just afterwards preparation, respectively 151.0 ± 2.252 and 160.7 ± 1.493 nm. They presented high negative zeta potential values, low polydispersity index (<0.300) and did not present great alteration in mean droplet size and polydispersity index after 1 day of preparation. Overall, nanoemulsion prepared with polysorbate 80/sorbitan monooleate was considered more stable and was chosen for biological assays. It presented low LC50 value against larvae (34.75; 7.31-51.86 mg/L) after 48 h of treatment and some morphological alteration was observed. The nanoemulsion did not inhibit acetylcholinesterase of C. quinquefasciatus larvae. It was not toxic to green algae Chlorella vulgaris at low concentration (25 mg/L). CONCLUSIONS: Our results suggest that optimal nanoemulsions may be prepared with different surfactants using a low cost and low energy simple method. Moreover, this prototype proved to be effective against C. quinquefasciatus, being considered an ecofriendly novel nanoproduct that can be useful in integrated control programs of vector control.


Assuntos
Culicidae/efeitos dos fármacos , Emulsões/toxicidade , Fabaceae/química , Controle de Insetos , Inseticidas/toxicidade , Extratos Vegetais/toxicidade , Animais , Chlorella vulgaris/efeitos dos fármacos , Chlorella vulgaris/fisiologia , Culicidae/fisiologia , Emulsões/química , Feminino , Inseticidas/química , Larva/efeitos dos fármacos , Larva/fisiologia , Extratos Vegetais/química
5.
PLoS One ; 11(1): e0145835, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26742099

RESUMO

Pterodon emarginatus Vogel is a Brazilian species that belongs to the family Fabaceae, popularly known as sucupira. Its oil has several biological activities, including potent larvicidal property against Aedes aegypti. This insect is the vector of dengue, a tropical disease that has been considered a critical health problem in developing countries, such as Brazil. Most of dengue control methods involve larvicidal agents suspended or diluted in water and making active lipophilic natural products available is therefore considered a technological challenge. In this context, nanoemulsions appear as viable alternatives to solve this major problem. The present study describes the development of a novel nanoemulsion with larvicidal activity against A. aegypti along with the required Hydrophile Lipophile Balance determination of this oil. It was suggested that the mechanism of action might involve reversible inhibition of acetylcholinesterase and our results also suggest that the P. emarginatus nanoemulsion is not toxic for mammals. Thus, it contributes significantly to alternative integrative practices of dengue control, as well as to develop sucupira based nanoproducts for application in aqueous media.


Assuntos
Aedes/efeitos dos fármacos , Fabaceae/química , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Nanoestruturas/química , Óleos Voláteis/farmacologia , Acetilcolinesterase/metabolismo , Aedes/enzimologia , Aedes/crescimento & desenvolvimento , Animais , Comportamento Animal/efeitos dos fármacos , Dengue/prevenção & controle , Emulsões , Feminino , Interações Hidrofóbicas e Hidrofílicas , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/metabolismo , Inseticidas/isolamento & purificação , Larva/enzimologia , Larva/crescimento & desenvolvimento , Dose Letal Mediana , Camundongos , Controle de Mosquitos/métodos , Óleos Voláteis/isolamento & purificação , Extratos Vegetais/química , Folhas de Planta/química
6.
Rev. bras. farmacogn ; 24(6): 699-705, Nov-Dec/2014. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: lil-741837

RESUMO

Copaiba (Copaifera duckei Dwyer, Fabaceae) oleoresin is an important Amazonian raw material. Despite its insecticidal potential, poor water solubility remains a challenge for the development of effective and viable products. Nanotechnology has emerged as a promising area to solve this problem, especially oil-in-water nanoemulsions. On this context, the aim of the present study was to develop oil-in-water nanoemulsions using copaiba oleoresin dispersed through a high internal phase; and evaluate its potential insecticidal action against Aedes aegypti larvae. Overall, 31 formulations were prepared, ranging from 11.5 ± 0.2 to 257.3 ± 4.1 nm after one day of manipulation. Some of them reached small mean droplet sizes (< 200 nm) and allowed achievement of a nanoemulsion region. The formulation consisted of 5% (w/w) of copaiba oil, 5% (w/w) of surfactant and 90% (w/w) of water, which presented mean droplet size of 145.2 ±0.9 nm and polidispersity of 0.378 ± 0.009 after one day of manipulation, and these were evaluated for larvicidal potential. According to mortality level (250 ppm - 93.3 after 48 h), this nanoemulsion was classified as a promising insecticidal agent against Aedes aegypti larvae. The present study allowed the development of low-cost ecofriendly green natural-based nanoformulations with potential larvicidal activity, using a nanobiotechnology approach.

7.
Molecules ; 19(1): 367-99, 2013 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-24381053

RESUMO

The Hartree-Fock method and the 6-31G** basis set were employed to calculate the molecular properties of artemisinin and 20 derivatives with antimalarial activity. Maps of molecular electrostatic potential (MEPs) and molecular docking were used to investigate the interaction between ligands and the receptor (heme). Principal component analysis and hierarchical cluster analysis were employed to select the most important descriptors related to activity. The correlation between biological activity and molecular properties was obtained using the partial least squares and principal component regression methods. The regression PLS and PCR models built in this study were also used to predict the antimalarial activity of 30 new artemisinin compounds with unknown activity. The models obtained showed not only statistical significance but also predictive ability. The significant molecular descriptors related to the compounds with antimalarial activity were the hydration energy (HE), the charge on the O11 oxygen atom (QO11), the torsion angle O1-O2-Fe-N2 (D2) and the maximum rate of R/Sanderson Electronegativity (RTe+). These variables led to a physical and structural explanation of the molecular properties that should be selected for when designing new ligands to be used as antimalarial agents.


Assuntos
Antimaláricos/química , Antimaláricos/farmacologia , Artemisininas/química , Artemisininas/farmacologia , Análise por Conglomerados , Heme/química , Modelos Moleculares , Conformação Molecular , Simulação de Acoplamento Molecular , Estrutura Molecular , Testes de Sensibilidade Parasitária , Análise de Componente Principal , Relação Quantitativa Estrutura-Atividade , Eletricidade Estática , Relação Estrutura-Atividade
8.
Chem Biodivers ; 6(9): 1427-34, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19774604

RESUMO

The essential oils of the specimens of Piper aduncum that occur in deforested areas of Brazilian Amazon, North Brazil, are rich in dillapiole (35-90%), a derivative of phenylpropene, to which are attributed biological properties. On the other hand, the oils of the specimens with occurrence in the Atlantic Forest, and Northeastern and Southeastern Brazil, do not contain dillapiole, but only terpene compounds such as (E)-nerolidol and linalool. One specimen existing in the Amazon was hydrodistilled. The obtained oil was fractioned on a silica chromatographic column, resulting in fractions rich in dillapiole (95.0-98.9%) utilized for analyses by GC and GC/MS, structural characterization by NMR, confirmation of their biological properties, and to obtain the isomer isodillapiole. Dillapiole showed a fungicide action against the fungus Clinipellis perniciosa (witches' broom) by inhibition of its basidiospores, in concentrations ranging from 0.6 to 1.0 ppm. The larvicide and insecticide actions of dillapiole were tested against the larvae and the adult insects of Anopheles marajoara and Aedes aegypti (malaria and dengue mosquitoes), resulting in mortality of the larvae (48 h, 100%) at a concentration of 100 ppm, and mortality of the insects (30 min, 100%) at a concentration of 600 ppm. The isomeric isodillapiole showed no significant activity in the same biological tests.


Assuntos
Compostos Alílicos/química , Antifúngicos/química , Dioxóis/química , Inseticidas/química , Óleos Voláteis/química , Piper/química , Compostos Alílicos/farmacologia , Animais , Antifúngicos/farmacologia , Culicidae/efeitos dos fármacos , Dioxóis/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Inseticidas/farmacologia , Larva/efeitos dos fármacos , Espectroscopia de Ressonância Magnética
9.
Ciênc. cult. (Säo Paulo) ; 48(4): 261-3, July-Aug. 1996. tab
Artigo em Inglês | LILACS | ID: lil-186388

RESUMO

The Pacora virus (PAC: Bunyaviridae: Bunyavirus - like), was known only through some isolates obtained from mosquitoes (culex dunni) in Panama, and two isolates obtained in the Brasilian Amazon region from the sylvatic birds Phlegopsis nigromaculata and Automolus ochrolaemus. In order to add to the knowledge of the arboviruses' cycles, mosquitoes were colected in the Zoobotanical Park of Macapá (Amapá State), from August, 18th to September, 11th, in areas of rain forest and savannah. The collections were done at both ground and canopy levels in the savannah, with human bait and light traps. 5642 mosquitoes have been collected, of which 5580 (or 184 pools) have been inoculated intracerebrally in newborn mice. Two strains of PAC virus have been isolated from unidentified Culex mosquitoes. This result is the first report of PAC virus in Amapá State. The virus has also been isolated for the first time from mosquitoes in Brazil. Thus, the presence of the complete cycle of sylvatic transmission of this agent is confirmed in Brazilian Amazonia. The ecological data available for the host show that the virus circulates at the lower level in the rain forest (0-5 m) with mostly nocturnal mosquitoes as vectors.


Assuntos
Animais , Camundongos , Ecossistema Amazônico , Bunyaviridae/isolamento & purificação , Culex/virologia , Insetos Vetores/virologia , Arbovírus/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...