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In this study, nanoemulsions of essential oil from Ocimumgratissimum (Linn) (EO) were produced using low and high energy techniques using cashew gum (CG) as a co-surfactant. The main constituents of the EO were determined by Gas Chromatography coupled with Mass Spectrometry (GC-MS), and their presence in the EO and in the formulations verified by Fourier Transform Infrared Spectroscopy (FTIR) and UV-visible spectrophotometry was observed the encapsulation efficiency (EE%), with colloidal stability. Nuclear magnetic resonance (NMR) was used to study cashew gum. Dynamic light scattering analysis (DLS) determined the nanoemulsion Z means, polydispersity index and the Zeta potential value, nanoparticle tracking analysis (NTA) were determined. The nanostructured EO showed better antibacterial action against the pathogenic gastroenteritis species Staphylococcus aureus, Escherichia coli and Salmonella enterica when compared to free EO. Atomic Force Microscopy (AFM) was used for morphological analysis of the nanoparticle and study of the action of the nanoemulsion through images of the cellular morphology of S. enterica. The antioxidant activity was evaluated against the ABTS radical (2,2'-azino-bis diazonium salt (3-ethylbenzothiazoline-6-sulfonic acid)). The encapsulation of EO in a nanostructured system improved its antibacterial and antioxidant activity, the low energy synthesis showed greater storage stability, remaining stable for 37 days.

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The present study investigated the effects of different concentrations of Acmella oleracea extract on the germinative cells and digestive processes of semi-engorged Rhipicephalus sanguineus females. For this experiment, 150 ticks were divided into five groups (30 individuals each). The animals were immersed for 5 min in different concentrations of the extract, distilled water, or ethanol 50%/DMSO 1%, dried, and kept in biological oxygen demand incubator for 7 days. The alterations were associated with the size of germinative cells and yolk granules; presence, size, and location of vacuoles in the cytoplasm of germinative cells; nuclear modifications in the germinative cells; damages to the nucleus and cytoplasm of the midgut generative cells; size of digestive cells; number of captured blood elements; accumulated digestive residues and digestive vacuoles in the digestive cells cytoplasm; and the number and distribution of proteins and polysaccharides in all the cells of both organs. The concentrations used in this study prevented an efficient and complete blood digestion by the midgut epithelial cells of the treated animals, resulting in the absence of the necessary nutrients to maintain the physiological events in the ectoparasites. In advanced stages, This can lead the ectoparasite to death. The germinative cells were highly impaired and probably not able to advance developmental stages (I-V) or complete vitellogenesis to be released during ovulation, which would prevent the females from originating a new individual. Thus, it can be concluded that the effects of A. oleracea are similar to those caused by chemical products widely recognized as effective to control ticks.

RESUMEN

The present study analyzed the effects of different concentrations of the hexane extract of A. oleraceae (HEAO) (Jambú) on the germ cells of semi-engorged Rhipicephalus microplus female ticks, through a morpho-histological study, evaluating the effectiveness of the extract in the genesis of the individuals. To perform this analysis, 100 semi-engorged females were divided into five groups with 20 individuals each: groups I and II, respectively constituted by distilled water control and 50% ethanol + 1% DMSO, and groups III, IV, and V constituted by treatment with HEAO in the concentrations of 12.5, 25.0 and 50.0 mg/mL, respectively. All the ticks were immersed in the different concentrations of the extract or in distilled water for 5 minutes, dried and conditioned in BOD incubator for 7 days. The individuals of the treatment groups revealed the action of this extract showing alterations in the germ cells of the females from the different groups when compared with those from the groups I and II (control groups). These alterations were mainly related to the size and shape of the oocytes; number of yolk granules; presence, number, size and location of vacuoles in the cytoplasm of all the germ cells; and the presence of nuclear alterations in these cells as well. Thus, it was demonstrated that the concentrations of HEAO affected the germ cells of R. microplus ticks. The effects of the extract are similar to those caused by renowned and efficient chemical products used to control these ticks. Microsc. Res. Tech. 79:744-753, 2016. © 2016 Wiley Periodicals, Inc.

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