Department of Pharmaceutical Technology, Faculty of Pharmacy, Fluminense Federal University, Rua Dr. Mário Viana, 523, Santa Rosa, Niterói 24.241-000, RJ, Brazil
Dr. Leandro Machado Rocha
Department of Pharmaceutical Technology, Faculty of Pharmacy, Fluminense Federal University, Rua Dr. Mário Viana, 523, Santa Rosa, Niterói 24.241-000, RJ, Brazil
Plants 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.
Essential oils are used primarily as natural preservatives, flavourants and fragrances in cosmetic products. Several pharmacopeias possess monographs of plants which are good sources of essential oils, such as Brazilian Pharmacopeia, including Illicium verum Hook. f., Schisandraceae and Rosmarinus officinalis. Since determination of Hydrophile-Lipophile Balance (HLB) value of essential oils appears as a critical step for development of emulsions and other semi-solid formulations, evaluation of required HLB values for I. verum and R. officinalis essential oils is the aim of this study. They were obtained by hydrodistillation and several emulsions were prepared by changing emulsii ers. The couple sorbitan oleate/polysorbate 20 provided best emulsions and was used at different ratios, at a total blend concentration of 5% w/w. The lowest mean droplet diameters for R. officinalis and I. verum emulsions were obtained at HLB 16.5 (97.12nm) and 16.7 (246.6nm), respectively. Moreover, emulsions with R. officinalis were i ner and presented some bluish rel ection, characteristic of nanoemulsions. The lowest turbidity value for R. officinalis emulsion was also obtained at HLB 16.5 (0.33). Thus, the present study describes for the first time HLB values for R. officinalis (16.5) and I. verum (16.7) essential oils, contributing to their physicochemical characterization and technology development of phytopharmaceutical
Baccharis reticularia DC. is a plant species from the Asteraceae family that is endemic to Brazil. Despite the great importance of Baccharis genus, no study has been carried out regarding either the phytochemical composition of B. reticularia or the evaluation of its larvicidal potential. Considering the intrinsic immiscibility of essential oils, this study shows larvicidal nanoemulsions containing the B. reticularia phytochemically characterized essential oil and its main constituent against Aedes aegypti. The major compound found was d-limonene (25.7%). The essential oil inhibited the acetylcholinesterase, one of the main targets of insecticides. The required hydrophile-lipophile balance of both nanoemulsions was 15.0. The mean droplet sizes were around 90.0 nm, and no major alterations were observed after 24 h of preparation for both formulations. After 48 h of treatment, the estimated LC50 values were 118.94 μg mL−1 and 81.19 μg mL−1 for B. reticularia essential oil and d-limonene nanoemulsions, respectively. Morphological alterations evidenced by scanning electron micrography were observed on the larvae treated with the d-limonene nanoemulsion. This paper demonstrated a simple and ecofriendly method for obtaining B. reticularia essential oil and d-limonene aqueous nanoemulsions by a non-heating and solvent-free method, as promising alternatives for Aedes aegypti control.