ABSTRACT
ABSTRACT Lippia alba (Mill.) N.E.Br. ex Britton & P. Wilson, Verbenaceae, is considered a great source of a bioactive volatile oil. Due to the wide range of known chemotypes, its chemical analysis is very important. Among the several activities of this volatile oil, a potential larvicidal action against Culicidae species is highlighted. However, the low water miscibility of volatile oils limits their application in aqueous media. Oil in water nano-emulsions are in the spotlight of novelty to solve this main problem. Thus, the aim of the present study was to obtain this nanostructured system with L. alba volatile oil (citral chemotype) and evaluate its larvicidal activity against Aedes aegypti and Culex quinquefasciatus larvae. The major compounds were geranial (30.02%) and neral (25.26%). Low mean droplet size (117.0 ± 1.0 nm) and low polydispersity index (0.231 ± 0.004) were observed and no major changes were observed after seven days of storage. LC50 values against C. quinquefasciatus and A. aegypti third-instar larvae were respectively 38.22 and 31.02 ppm, while LC90 values were, respectively, 59.42 and 47.19 ppm. The present study makes use of a low energy, solvent-free and ecofriendly method with reduced costs. Thus, this paper contributes significantly to phyto-nanobiotechnology of larvicidal agents, opening perspectives for the utilization of L. alba volatile oil in integrated practices of vector control.
ABSTRACT
Abstract Pterodon emarginatus Vogel, Fabaceae, is a great source of bioactive compounds. The most known and studied herbal derivative from this species is an ambar-colored oleoresin that contains vouacapane diterpenes and volatile terpenoids, such as β-caryophyllene. Some recent papers aimed to generate nanoemulsions using this oleoresin for biological applications. However, they used high-energy methods that elevate costs of the process or heating procedures, which offer the disadvantage of possible volatile substances loss. Thus, as part of our ongoing studies with nanobiotechnology of natural products, especially regarding preparation of nanoemulsions with promising plant-based oils by low cost and low energy methods, we decided to evaluate the ability of non-heating and solvent-free method to generate P. emarginatus oleoresin-based nanoemulsions. Two non-ionic surfactants were used to generate the nanoemulsions by a simple homogenization method with vortex stirrer. Low mean droplet size (<180 nm) and low polydispersity index (<0.200) were observed even after one day of preparation. The low coefficient of variation for the analyzed parameters of different batches and similar profile for droplet size distribution suggested reproducibility of the method. After 30 days, some degree of droplet growth was observed on nanoemulsion prepared with polyethyleneglycol 400 monooleate, while almost no alteration was observed for nanoemulsion prepared with polysorbate 85. Programmed temperature ramp analysis revealed that no major effects on droplet size and polydispersity index were observed, suggesting the robustness of formed nanoemulsions. Thus, the present study shows for the first time the formation of sucupira-based nanoemulsions by a simple, low cost and ecofriendly method. This study opens new perspectives for bioactive evaluation of this novel nano-product.
ABSTRACT
Copaiba (Copaifera duckei Dwyer, Fabaceae) oleoresin is an important Amazonian raw material. Despite its insecticidal potential, poor water solubility remains a challenge for the development of effective and viable products. Nanotechnology has emerged as a promising area to solve this problem, especially oil-in-water nanoemulsions. On this context, the aim of the present study was to develop oil-in-water nanoemulsions using copaiba oleoresin dispersed through a high internal phase; and evaluate its potential insecticidal action against Aedes aegypti larvae. Overall, 31 formulations were prepared, ranging from 11.5 ± 0.2 to 257.3 ± 4.1 nm after one day of manipulation. Some of them reached small mean droplet sizes (< 200 nm) and allowed achievement of a nanoemulsion region. The formulation consisted of 5% (w/w) of copaiba oil, 5% (w/w) of surfactant and 90% (w/w) of water, which presented mean droplet size of 145.2 ±0.9 nm and polidispersity of 0.378 ± 0.009 after one day of manipulation, and these were evaluated for larvicidal potential. According to mortality level (250 ppm - 93.3 after 48 h), this nanoemulsion was classified as a promising insecticidal agent against Aedes aegypti larvae. The present study allowed the development of low-cost ecofriendly green natural-based nanoformulations with potential larvicidal activity, using a nanobiotechnology approach.
ABSTRACT
Artemisia annua has been used as a traditional plant for the treatment of malaria and fever in China because of the presence of its active compound, artemisinin. The present study evaluated the central activity of the essential oil and the crude ethanol extract of A. annua L. in animals as a part of a psychopharmacological screening of this plant. The extract was prepared in ethanol (AEE) and the essential oil (AEO) obtained by hydrodistillation, both with fresh leaves. Induced immobility, the forced swimming test (FST) and the open-field test (OFT) are well-known animal models to study drug-induced depression. The administration of A. annua essential oil or crude ethanol extract increased the immobility time in the FST and decreased other activities (ambulation, exploration, rearing and grooming) in the OFT in animals. Both AEO and AEE prolonged pentobarbital-induced sleep as well, but the essential oil had a marked effect. Observing these results, it is possible to suggest that A. annua crude ethanol extract and essential oil could act as depressors on the Central Nervous System (CNS).
Artemisia annua tem sido utilizada tradicionalmente para o tratamento de malária e febre na China devido à presença do princípio ativo, artemisinina. O presente trabalho avaliou a atividade central de do óleo essencial obtido por hidrodestilação e do extrato etanólico bruto de folhas frescas de A. annua em modelo in vivo como parte de um screening farmacológico dessa espécie. Sono induzido por pentobarbital, nado forçado e o ensaio de campo aberto são modelos de estudo conhecidos para o estudo de fármacos sobre depressão induzida. A administração do óleo essencial ou extrato bruto etanólico de A. annua aumentaram o tempo de imobilidade no teste do nado forçado. Por outro lado, diminuíram outros parâmetros no campo aberto, como ambulação, exploração, o ato de lamber as patas ou se lamber. Ambos produtos aumentaram o tempo de sono induzido por pentobarbital, com o óleo essencial apresentando um efeito superior ao do extrato. Pela análise dos resultados, é possível sugerir que tanto o extrato bem como o óleo essencial podem atuar como depressores do Sistema Nervoso Central (SNC).
ABSTRACT
O cogumelo tibetano (CT) é uma bebida probiótica fermentada por um grande conjunto de bactérias e leveduras, algumas das quais de conhecida atividade antimicrobiana, imunomodulatória, pró-digestiva e auxiliar da peristalse intestinal. Neste sentido, este trabalho teve como objetivo avaliar a possível ação da suspensão produzida pelo CT sobre a motilidade intestinal de ratos. Foram utilizados grupos de animais (ratos Wistar albinos machos, n = 6/grupo) pesando 200 ± 20 g. Os diferentes grupos foram tratados v.o. durante 15 dias (1,5 mL/animal de fermentado de 24 h de CT em cultivo contínuo em 50 g/l de açúcar mascavo comercial em água destilada), e os demais grupos tratados com água destilada (1,5 mL/animal). Após 15 dias os animais foram mantidos em jejum por 24 hs, e tratados com suspensão de CT (1,5 mL/animal/v.o), água destilada (controle, 1,5mL/animal/v.o), acetilcolina (1mg/kg/s.c.) e atropina (1mg/kg/i.m.). Após 30 min, os animais receberam uma suspensão de carvão ativo 10 por cento (0,1 mL/10 g, v.o), seguindo-se eutanásia após 45 min, excisão da porção do piloro até o início do ceco, e determinação da distância percorrida pelo carvão. A administração da suspensão de CT aumentou o trânsito intestinal em 68,7 por cento e os demais tratamentos apresentaram as seguintes percentagens: atropina 20,2 por cento, acetilcolina 78,7 por cento e controle 42,9 por cento (p < 0,05, ANOVA seguido de teste de Tukey-Kramer). Esses resultados mostraram que a suspensão de CT estimulou o peristaltismo nos animais, o que sugere um efeito positivo na digestão e absorção alimentar para o consórcio microbiano.
The Tibetan mushroom (CT) is a probiotic beverage fermented by a big group of bacteria and yeasts, some of which of well-known anti-bacterial activity, immunomodulatory, pro-digestive and to aid of the intestinal peristalsis. In this sense, this work had the aim of evaluating the possible action of the suspension produced by CT on the peristalsis intestinal of rats. Animal groups weighing 200 ± 20 g were used (Wistar rats (male, n = 6/group)). The different groups were treated v.o. for 15 days (1,5 mL/animal of 24h fermented of CT in continuously cultured into molasses solutions (50 g/l)), and the other groups treated with distilled water (1,5 mL/animal). After 15 days the animals were maintained in fast for 24h, and treated with suspension CT (1,5 mL/animal/v.o), distilled water (control, 1,5mL/animal/v.o), acetylcholine (1mg/kg/s.c) and atropine (1mg/kg/i.m). After 30 min, the animals received a suspension of active coal 10 percent (0,1 mL/10g, v.o), after the euthanasia, excision of the portion of the pylorus to the beginning of the cecum, and determination of the distance traveled by the coal. The administration of the CT suspension increased the intestinal peristalsis in 68,7 percent and the other treatments presented the following percentages: atropine 20,2 percent, acetylcholine 78,7 percent and control 42,9 percent (p < 0,05, ANOVA followed by Tukey-Kramer test). Those results showed that the CT suspension stimulated the peristalsis in the animals, what suggests a positive effect in the digestion and alimentary absorption for the microbial consortium.