BackgroundPlants have been recognized as a good source of insecticidal agents, since they are able to produce their own defensives to insect attack. Moreover, there is a growing concern worldwide to develop pesticides with low impact to environment and non-target organisms. Hexane-soluble fraction from ethanolic crude extract from fruits of Manilkara subsericea and its triterpenes were considered active against a cotton pest (Dysdercus peruvianus). Several natural products with insecticidal activity have poor water solubility, including triterpenes, and nanotechnology has emerged as a good alternative to solve this main problem. On this context, the aim of the present study was to develop an insecticidal nanoemulsion containing apolar fraction from fruits of Manilkara subsericea.ResultsIt was obtained a formulation constituted by 5% of oil (octyldodecyl myristate), 5% of surfactants (sorbitan monooleate/polysorbate 80), 5% of apolar fraction from M. subsericea and 85% of water. Analysis of mean droplet diameter (155.2 ± 3.8 nm) confirmed this formulation as a nanoemulsion. It was able to induce mortality in D. peruvianus. It was observed no effect against acetylcholinesterase or mortality in mice induced by the formulation, suggesting the safety of this nanoemulsion for non-target organisms.ConclusionsThe present study suggests that the obtained O/A nanoemulsion may be useful to enhance water solubility of poor water soluble natural products with insecticidal activity, including the hexane-soluble fraction from ethanolic crude extract from fruits of Manilkara subsericea.

Medicinal plants such as Aloysia polystachya are often used in the treatment of psychiatric diseases, including anxiety- and depression-related humor disturbances. In folk medicine, A. polystachya is used to treat digestive and respiratory tract disturbances, as a sedative and antidepressant agent, and as a tonic for the nerves. This study aimed to evaluate the antidepressant and anxiolytic effect from the hydroethanolic extract from the leaves of Aloysia polystachya (HELAp) in zebrafish. The extract was analyzed through ultra-performance liquid chromatography-mass spectroscopy (UPLC-MS) and the main compound detected was acteoside. HELAp was administered orally (10 mg/kg) and through immersion (mg/L). The anxiolytic activity was evaluated through the scototaxis (light–dark) test using caffeine as an anxiogenic agent and buspirone as a positive control. The parameters assessed were: period spent in the white compartment (s), latency (s), alternations (n), erratic swims (n), period of freezing (s), thigmotaxis (s), and risk evaluation (n). The antidepressant effect was evaluated through the novel tank diving test using 1% ethanol, unpredictable chronic stress, and social isolation as depressors; fluoxetine was used as a positive control. The parameters assessed were: period spent at the top of the tank, latency, quadrants crossed, erratic swim, period of freezing, and distance of swam. The main chemical compound of HELAp was acteoside. The administration of the extract on zebrafish managed to revert the anxiogenic effect of caffeine without impairing their locomotion. Additionally, the treatment exerted antidepressant activity similarly to fluoxetine. Overall, the results suggest a significant anxiolytic and antidepressant activity to the extract, which is probably due to the presence of the major compound, acteoside.

Hydroethanolic preparations of Acmella oleracea is used in the north of Brazil as a female aphrodisiac. Thus, the objective of this study was to evaluate the action of the hydroethanolic extract of Acmella oleracea (EHFAo) flowers (21.873 and 44.457 mg/kg) and spilanthol (3 mg/kg) administered orally on reproductive performance and effects on the embryonic development of zebrafish F1 generation. It was observed that in the groups in which males and females received EHFAo and spilanthol, the spawning was interrupted, whereas in the groups in which only the females were treated, spawning occurred during the 21 days. Thus, in the histopathological evaluation of the gonads, it was possible to observe that the percentage of mature cells in the spermatozoa and females was significantly reduced. Only the embryo groups in which parental generation was treated with EHFAo showed lethal and teratogenic effects. On the other hand, the parental groups treated with the spilanthol presented only the lethality. Spilanthol and some metabolites showed good oral availability and important toxicological properties. Thus, it is suggested that the treatment of parental generation of zebrafish with EHFAo and spilanthol caused severe changes in the gonads and on fertility. However, on the embryo, the most striking effects in the development were recorded in the groups in which the parental generation was treated with the EHFAo, while the spilanthol influenced the lethality of the embryos.

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Seizures affect about 50 million people around the world. Approximately 30% of seizures are refractory to the current pharmacological arsenal, so, the pursuit of new therapeutic alternatives is essential. Clarified Euterpe oleracea (EO) juice showed anticonvulsant properties similar to diazepam in an in vivo model with pentylenetetrazol, a GABAA receptor blocker. This study investigated the effects of EO on the main GABAergic targets for anticonvulsant drugs, analyzing the effect on the GABA receptor's benzodiazepine and picrotoxinin binding sites and the GABA uptake. Primary cultures of cortical neurons and astrocytes were treated with EO (0–25%) for up to 90 min. [3H]Flunitrazepam and [3H]TBOB binding, [3H]GABA uptake, cell viability, and morphology were assayed. Nonlethal concentrations of EO increased agonist binding and decreased antagonist binding in cortical neurons. Low concentrations significantly inhibited GABA uptake, especially in astrocytes, suggesting an accumulation of endogenous GABA in the synaptic cleft. The results demonstrate, for the first time, that EO can improve GABAergic neurotransmission via interactions with GABAA receptor and modulation of GABA uptake. Understanding these molecular mechanisms will help in the treatment of seizures and epilepsy, especially in developing countries where geographic isolation and low purchasing power are the main barriers to access to adequate treatment.