RESUMEN
Essential oils are known for their insect control potential, which is mainly attributed to the presence of terpenes that interfere with hormonal and physiological processes of arthropods. The aim of the present study was to evaluate the effects of essential oil from the leaves of Eugenia sulcata Spring ex Mart., Myrtaceae, on the development of two species of agricultural pest insects, Dysdercus peruvianus and Oncopeltus fasciatus. Results showed that the essential oil induced mortality, and reduced numbers of adults. Topical treatment of Oncopeltus fasciatus using pure essential oil caused significant mortality rates (96.67%), while Dysdercus peruvianus had a higher tolerance, with 80% mortality at the end of the experiments. Results suggest that essential oil from the leaves of Eugenia sulcata may be used in agriculture for insect pest control.
RESUMEN
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 offi cinalis. 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. offi cinalis essential oils is the aim of this study. They were obtained by hydrodistillation and several emulsions were prepared by changing emulsifiers. 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. offi cinalis and I. verum emulsions were obtained at HLB 16.5 (97.12 nm) and 16.7 (246.6 nm), respectively. Moreover, emulsions with R. offi cinalis were finer and presented some bluish reflection, characteristic of nanoemulsions. The lowest turbidity value for R. offi cinalis emulsion was also obtained at HLB 16.5 (0.33). Thus, the present study describes for the first time HLB values for R. offi cinalis (16.5) and I. verum (16.7) essential oils, contributing to their physicochemical characterization and technology development of phytopharmaceuticals.