Anna E.M.F.M. Oliveira

Development of a Larvicidal Nanoemulsion with Pterodon emarginatus Vogel Oil.

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.

Preparation of aqueous nanodispersions with annatto (Bixa orellana L.) extract using an organic solvent-free and low energy method

The seeds of Bixa orellana L. is widely used in food industry as a natural colorant. A major technological challenge for its utilization on aqueous food products is the low water solubility. Therefore, the present study aimed to obtain aqueous nanodispersions using this natural raw material by using a simple organic solvent-free and low energy method. Bixin and geranylgeraniol were found on the extract. The nanodispersions were prepared by addition of water on a mixture of extract and surfactant (s). The effect of the surfactants and dilution on the nanodispersions were also evaluated. Best results were achieved using polysorbate 80/sorbitan monooleate (HLB 13) (diluted in water, 1:10). The results shows the potential of this ecofriendly approach, in contrast to common methods that make use of potentially toxic organic solvents and high input of energy, which elevate the costs for further industrialization.

Preparation of a Nanoemulsion with Carapa guianensis Aublet (Meliaceae) Oil by a Low-Energy/Solvent-Free Method and Evaluation of Its Preliminary Residual Larvicidal Activity

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 β-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.

Action of AferBio (fermented food) in a rat inflammatory model

Background AferBio is a fermented prebiotic food that contains beta-glucans, which are oligosaccharides capable of stimulating the proliferation of beneficial bacteria in the gastrointestinal tract. The aim of this study was to evaluate the possible effects of this functional food on the inflammatory response in rats. Methods and results AferBio (900 mg/kg) inhibited edema formation by 34% compared to the control group. We also observed inhibition of the primary and secondary reactions of inflammation after the injection of Freund’s adjuvant in the animals fed AferBio. Daily administration of AferBio for 6 d inhibited the formation of granulomatous tissue by 37%; additionally, inhibition of 31% of neutrophil migration downstream of carrageenan-induced peritonitis was observed. An ulcerogenic potency assay revealed that indomethacin produced a higher number of lesions compared to treatment with AferBio. Anti-inflammatory potency analysis showed that indomethacin inhibited 39% of carrageenan-induced edema but produced a higher number of lesions. However, animals treated with AferBio had areas of hyperemia without ulcerative lesions and 21% of edema was inhibited. Conclusion Based on the results obtained in this study, AferBio appears to have anti-inflammatory activity during acute and chronic inflammatory processes.