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.
Mosquitoes can be vectors of pathogens and transmit diseases to both animals and humans. Species of the genus Culex are part of the cycle of neglected diseases, especially Culex quinquefasciatus, ...which is an anthropophilic vector of lymphatic filariasis. Natural products can be an alternative to synthetic insecticides for vector control; however, the main issue is the poor water availability of some compounds from plant origin. In this context, nanoemulsions are kinetic stable delivery systems of great interest for lipophilic substances. The objective of this study was to investigate the larvicidal activity of the Hyptis suaveolens essential oil nanoemulsion on Cx. quinquefasciatus. The essential oil showed a predominance of monoterpenes with retention time (RT) lower than 15 min. The average size diameter of the emulsions (sorbitan monooleate/polysorbate 20) was ≤ 200 nm. The nanoemulsion showed high larvicidal activity in concentrations of 250 and 125 ppm. CL50 values were 102.41 (77.5253−149.14) ppm and 70.8105 (44.5282−109.811) ppm after 24 and 48 h, respectively. The mortality rate in the surfactant control was lower than 9%. Scanning micrograph images showed changes in the larvae’s integument. This study achieved an active nanoemulsion on Cx. quinquefasciatus through a low-energy-input technique and without using potentially toxic organic solvents. Therefore, it expands the scope of possible applications of H. suaveolens essential oil in the production of high-added-value nanosystems for tropical disease vector control.
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.
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 LC
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).
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.
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.
Kefir is an acidic and low alcohol beverage obtained from the fermentation of milk at ambient temperature and, in form of biofilm, it can be used for several purposes, e.g., as an antimicrobial ...against a wide variety of gram-positive and gram-negative bacteria and against some fungi. However, some pharmaceutical applications require materials both antibacterial and antioxidant at same time. Herein, we obtain the first fundamental insights into the chemical production of antibacterial and antioxidant biofilms using brown sugar, kefir grains, açaí (
Euterpe oleracea
Mart.) pulp and cupuaçu (
Theobroma grandiflorum
Schum) pulp. Four essays were performed to obtain the biofilms, namely a without kefir film, a kefir biofilm, a biofilm of kefir with Cupuaçu extract, and a biofilm of kefir with Açaí extract. The crystallinity of the biofilms was analyzed using X-ray diffraction, which revealed a semicrystalline structure. These results were explained by the biofilms microstructure, which was analyzed by atomic force microscopy, demonstrating a growing dependence of roughness on the substrate concentration, mainly for the Cupuaçu and Açaí biofilms. The homogeneity of the surface of the biofilms was determined, revealing that all the biofilms have uniform distribution of heights on their surfaces. This research showed that the surfaces of the kefir, kefir with Açaí extract and kefir with Cupuaçu extract biofilms are characterized to be amorphous, without any diffraction peak associated with the crystal structure, and having high roughness, indicating that the films have good adhesion, and are uniform in the distribution of surface peaks, thus emphasizing that, once adhered to some surface, there will be no formation of bubbles on their surface. Therefore, considering their potential application in the pharmaceutical industry, the biofilms can be used as natural healing materials.
•Annatto is an industrial food colorant.•Its seeds extract has low water solubility.•Nanodispersions preparation often use organic solvents.•A low-energy and solvent-free method was used in this ...study.•The present annatto nanoemulsions is a green-product.
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.
...it is noteworthy that the antioxidants play a crucial role in both food systems and in the human body to reduce oxidative processes and, consequently, neurodegenerative diseases and metabolic ...dysfunctions. According to these authors, E. oleracea can improve GABAergic neurotransmission via interactions with the GABAA receptor and modulation of GABA uptake, possibly leading to the accumulation of endogenous GABA in the synaptic cleft and enhancing the inhibitory neurotransmission in the brain. ...the Guest Editors are very grateful to the authors who submitted their precious research to this special issue, and they would also like to warmly acknowledge the reviewers for their excellent contribution to improve the quality of this work.
Manilkara subsericea (Mart.) Dubard (Sapotaceae) is popularly known in Brazil as “guracica.” Studies with Manilkara spp. indicated the presence of triterpenes, saponins, and flavonoids. Several ...activities have been attributed to Manilkara spp. such as antimicrobial, antiparasitic and antitumoral, which indicates the great biological potential of this genus. In all, 87.19% of the hexanic extract from fruits relative composition were evaluated, in which 72.81% were beta- and alpha-amyrin esters, suggesting that they may be chemical markers for M. subsericea. Hexadecanoic acid, hexadecanoic acid ethyl ester, (E)-9-octadecenoic acid ethyl ester, and octadecanoic acid ethyl ester were also identified. Ethanolic crude extracts from leaves, stems, and hexanic extract from fruits exhibited antimicrobial activity against Staphylococcus aureus ATCC25923. These extracts had high IC50 values against Vero cells, demonstrating weak cytotoxicity. This is the first time, to our knowledge, that beta- and alpha-amyrin caproates and caprylates are described for Manilkara subsericea.
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