RESUMO

Phytomonas serpens is a trypanosomatid phytoparasite, found in a great variety of species, including tomato plants. It is a significant problem for agriculture, causing high economic loss. In order to reduce the vegetal infections, different strategies have been used. The biological activity of molecules obtained from natural sources has been widely investigated to treat trypanosomatids infections. Among these compounds, chalcones have been shown to have anti-parasitic and anti-inflammatory effects, being described as having a remarkable activity on trypanosomatids, especially in Leishmania species. Here, we evaluated the antiprotozoal activity of the chalcone derivative (NaF) on P. serpens promastigotes, while also assessing its mechanism of action. The results showed that treatment with the derivative NaF for 24 h promotes an important reduction in the parasite proliferation (IC50/24 h = 23.6 ± 4.6 µM). At IC50/24 h concentration, the compound induced an increase in reactive oxygen species (ROS) production and a shortening of the unique flagellum of the parasites. Electron microscopy evaluation reinforced the flagellar phenotype in treated promastigotes, and a dilated flagellar pocket was frequently observed. The treatment also promoted a prominent autophagic phenotype. An increased number of autophagosomes were detected, presenting different levels of cargo degradation, endoplasmic reticulum profiles surrounding different cellular structures, and the presence of concentric membranar structures inside the mitochondrion. Chalcone derivatives may present an opportunity to develop a treatment for the P. serpens infection, as they are easy to synthesize and are low in cost. In order to develop a new product, further studies are still necessary.

RESUMO

Chalcone is a molecule with known biological activities. Based on this, a series of chalcone derivatives bearing methyl, phenyl or furanyl substituents at different positions of A and B rings were synthesised, characterised, and evaluated regarding antiprotozoal activity. Molecules were synthesised via base catalyzed Claisen-Schmidt condensation and characterised by IR and NMR spectral data. Antiprotozoal activity against Phytomonas serpens, Leishmania amazonensis and Acanthamoeba polyphaga was performed. All compounds inhibited more than 50% of the growth of P. serpens while five had this effect on L. amazonensis and all of them no more than 35% of inhibition on A. polyphaga. Remarkably interesting antiprotozoal effects were recorded with compound 5, with IC50 of 1.59 µM for P. serpens and 11.49 µM for L. amazonensis. The addition of a naphthyl group to the B ring can be postulated to be the cause of the 10 times increase observed in its trypanocidal activity.

RESUMO

The essential oils obtained by hydrodistillation from fresh leaves of Vitex agnus-castus and Ocimum campechianum, and from fresh inflorescences of Ocimum carnosum were analysed by GC-FID and GC-MS. The major components of V. agnus-castus essential oil were identified as 1,8-cineole (47.9%), terpinyl α-acetate (11.6%), sabinene (11.2%) and caryophyllene oxide (9.7%), while in the O. campechianum essential oil were eugenol (72.1%), ß-elemene (6.8%), (E)-caryophyllene (6.4%) and bicyclogermacrene (5.2%). Linalool (79.0%), α-epi-cadinol (5.4%), terpinen-4-ol (3.2%) and 1,8-cineole (2.8%) were the major constituents in the O. carnosum essential oil. The essential oils were subsequently evaluated for their larvicidal and cytotoxic activities. Larval bioassay against Aedes aegypti of V. agnus-castus, O. campechianum and O. carnosum essential oils showed LC50 values of 97.55 ± 0.35, 81.45 ± 0.35 and 109.49 ± 0.35 µg/mL, respectively. The in vitro cytotoxic activities of the essential oils has been evaluated on breast adenocarcinoma (MCF-7), lung carcinoma (NCI-H292), pro-myelocytic leukemia (HL-60), and cervical adenocarcinoma (HEP-2) human cell lines, and pro-myelocytic leukemia cells lines (HL-60) were found to be the most sensitive to all the essential oils tested than the others. This is the first report on larvicidal and cytotoxic activities of these essential oils.

Assuntos

RESUMO

BACKGROUND: One of the most efficient ways to prevent arboviruses, such as dengue fever, yellow fever, chikungunya and Zika, is by controlling their vector, the Aedes aegypti. Because this vector is becoming resistant to most larvicides used, the development of new larvicides should be considered. ß-Cyclodextrin (ß-CD) complexes have been investigated as an interesting way of enabling the use of essential oils in water as larvicides. This study comprised the development of Lippia gracilis essential oil (LGEO) and ß-CD inclusion complexes for control of Ae. aegypti. RESULTS: Thermal analysis clearly showed the formation of complexes using kneading and co-evaporation methods. Gas chromatography analysis showed that kneading without co-solvent (KW) gave the highest content (∼ 15%) of the LGEO major component. Moreover, KW showed that the complex had a 50% lethal concentration (LC50 ; 33 ppm) lower than that of pure LGEO (39 ppm); in other words, complexing LGEO with ß-CD improved the larvicidal activity. In addition, LGEO complexed with ß-CD (KW) was not harmful to non-target organisms at the concentrations needed to control Ae. aegypti larvae. CONCLUSION: The inclusion complex with LGEO was a feasible formulation, being economically viable, easy-to-apply and without impact on non-target organisms and, therefore, is a potential alternative larvicide for Ae. aegypti control. © 2018 Society of Chemical Industry.

Assuntos

RESUMO

BACKGROUND: The mosquito Aedes aegypti is intensively controlled because it is a vector of viruses that cause numerous diseases, especially in tropical regions. As a consequence of the indiscriminate use of insecticides, populations from different regions have become resistant to pyrethroids. Here, we analyzed the lethal and sublethal effects of essential oil of Aristolochia trilobata and its major compounds on A. aegypti from susceptible and pyrethroid-resistant populations. RESULTS: Our results showed that the toxicity of the different compounds and behavioral changes in response to them are dependent on the stage of the insect life cycle. The monoterpene ρ-cymene caused high mortality in both larvae and adult females of A. aegypti, including those from the pyrethroid-resistant population. The monoterpenes limonene and linalool caused a sublethal effect in the larvae, triggering changes in the swimming pattern. CONCLUSION: This study highlights the potential of the essential oil of A. trilobata and its major compounds ρ-cymene and limonene for the control of A. aegypti and reveals the importance of analyzing sublethal effects on the population dynamics of the A. aegypti mosquito. © 2017 Society of Chemical Industry.

Assuntos

RESUMO

Leaf-cutting ants are pests of great economic importance due to the damage they cause to agricultural and forest crops. The use of organosynthetic insecticides is the main form of control of these insects. In order to develop safer technology, the objective of this work was to evaluate the formicidal activity of the essential oils of two Hyptis pectinata genotypes (chemotypes) and their major compounds on the leaf-cutting ants Acromyrmex balzani Emery and Atta sexdens rubropilosa Forel. Bioassays of exposure pathways (contact and fumigation) and binary mixtures of the major compounds were performed. The major compounds identified in the essential oils of H. pectinata were ß-caryophyllene, caryophyllene oxide and calamusenone. The essential oils of H. pectinata were toxic to the ants in both exposure pathways. Essential oils were more toxic than their major compounds alone. The chemotype calamusenone was more toxic to A. balzani in both exposure pathways. A. sexdens rubropilosa was more susceptible to the essential oil of the chemotype ß-caryophyllene in both exposure pathways. In general, the binary mixtures of the major compounds resulted in additive effect of toxicity. The essential oils of H. pectinata is a raw material of great potential for the development of new insecticides.

Assuntos

RESUMO

Plants of the genus Aristolochia have been frequently reported as important medicinal plants. Despite their high bioactive potential, to date, there are no reports of their effects on leaf-cutting ants. Therefore, the present study aimed to evaluate the insecticidal activity of the essential oil of Aristolochia trilobata and its major components on Atta sexdens and Acromyrmex balzani, two species of leaf-cutting ants. The bioassays were performed regarding routes of exposure, acute toxicity, binary mixtures of the major components and behavioral effects. Twenty-five components were identified in the essential oil of A. trilobata using a gas chromatographic system equipped with a mass spectrometer and a flame ionization detector. The components found in higher proportions were sulcatyl acetate, limonene, p-cymene and linalool. The essential oil of A. trilobata and its individual major components were efficient against A. balzani and A. sexdens workers when applied by fumigation. These components showed fast and efficient insecticidal activity on ants. The components acted synergistically and additively on A. balzani and A. sexdens, respectively, and caused a strong repellency/irritability in the ants. Thus, our results demonstrate the great potential of the essential oil of A. trilobata and its major components for the development of new insecticides.

Assuntos

RESUMO

The aim of this study was to evaluate the volatile profile as a result of hybridization. Data were analyzed by ANOVA, Tukey test and Principal Component Analysis. Hybridization provided the appearance of compounds in hybrids, and these compounds are absent in the parental volatile profile. The new compounds were: camphor, neral, geranial, beta-selinene, bicyclogermacrene, (E)-caryophyllene and methyl chavicol, for the hybrid 'Genovese' x 'Maria Bonita'; and camphor, for the hybrid 'Sweet Dani' x 'Genovese'.

El objetivo de este estudio fue evaluar el perfil de volátiles como resultado de la hibridación. Los datos fueron analizados por ANOVA, prueba de Tukey y Análisis de Componentes Principales. La hibridación proporcionó la aparición de nuevos compuestos híbridos que no están presentes en el perfil de volátiles de los parentales, como por ejemplo el alcanfor, el neral, el geranial A, el beta-selineno, el biciclogermacrene, el (E)-cariofileno y el metil chavicol para el híbrido 'Genovese' x 'Maria Bonita', y el alcanfor para el híbrido 'Sweet Dani' x 'Genovese'.

Assuntos

RESUMO

This study aimed to evaluate the orofacial antinociceptive effect of the Cymbopogon winterianus essential oil (LEO) complexed in ß-cyclodextrin (LEO-CD) and to assess the possible involvement of the central nervous system (CNS). The LEO was extracted, chromatographed, and complexed in ß-cyclodextrin. The complex was characterized by differential scanning calorimetry (DSC) and thermogravimetry derivative (TG/DTG). Male Swiss mice (2-3 months) were treated with LEO-CD (50-200 mg/kg, p.o.), vehicle (distilled water, p.o.), or standard drug (i.p.) and subjected to the orofacial nociception formalin-, capsaicin-, and glutamate-induced. After the formalin test, the animals were perfused and the brains subjected to immunofluorescence for Fos. The rota-rod test (7 rpm/min) was carried out. Geraniol (37.57%) was the main compound of LEO. DSC and TG/DTG proved the complexation. The orofacial nociceptive behavior was significantly (p < 0.05) reduced. The number of Fos-positive cells was significantly changed in the dorsal raphe nucleus (p < 0.01), locus coeruleus (p < 0.001), trigeminal nucleus (p < 0.05), and trigeminal thalamic tract (p < 0.05). LEO-CD did not cause changes in motor coordination in the rota-rod test. Thus, our results suggested that LEO-CD has an orofacial antinociceptive profile, probably mediated by the activation of the CNS without changing the motor coordination.

RESUMO

Ocimum selloi is an herbal species popularly used in Brazil as antispasmodic. Herein, we report the antispasmodic effect of O. selloi essential oil (OS) in segments of guinea-pig ileum. OS did not reduce the tonus of the ileum. In contrast, OS reduced the contraction induced by carbachol (100 µM), BaCl2 (0.03 M) and low- and high-K(+) concentrations (25 and 60 mM, respectively). OS shifted the concentration-response curve for calcium to the right in a parallel manner. GC/MS analysis showed that OS consists mostly of methyl chavicol (97.57%). These results suggest that OS antispasmodic effect is mediated through calcium channel blockade. In addition, OS effect and mode of action could be accounted for methyl chavicol.

Assuntos