Desenvolvimento de nanoformulações do óleo essencial de Lippia sidoides Cham

• Autor(a) principal: Pinto, Nayra de Oliveira Frederico
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/28502
• topic: Engenharia química; Nanocápsulas; Emulsão - Difusão; Alecrim - Pimenta; Timol

The plant Lippia sidoides (Verbenaceae), popularly known as alecrim-pimenta, is a native species from the Brazilian Caatinga. Its essential oil is rich in thymol, a phenol compound with proven antifungal and antibacterial activities. Due to its biological effects, the essential oil of L. sidoides has attracted great interest for applications against phytopathogens. However, essential oils are susceptible to degradation by physical (such as light, temperature, pH) and chemical agents (oxygen, humidity, etc). Thus, suspensions of polycaprolactone- coated nanocapsules were produced by emulsion-diffusion method, in order to preserve the physico-chemical and biological properties of L. sidoides essential oil. The nanocapsules were evaluated in terms of some physical, chemical, morphological and thermal properties, as well as storage stability. The gas chromatography analysis of the essential oil presented thymol (77.1 %) as the major constituent. Polyvinyl alcohol and Kolliphor P 188® were tested as surfactants. Formulations containing Kolliphor P 188® showed more stable nanoemulsified systems, exhibiting average particle diameters between 187 and 214 nm, low polydispersity (< 0.2) and encapsulation efficiency between 31 and 53 %. Studies on the influence of concentration of each component of the formulation (1-5 %) as well as speed (644 - 1.449 g) and stirring time (5-10 min) in the emulsification process were performed. The formulation containing 1% surfactant stirred at 1.006 g or 5 min showed the best results, taking account average particle diameter (173.6 nm) and encapsulation efficiency (36%), and was further analysed by scanning electron microscopy, thermogravimetry, differential scanning calorimetry, and accelerated stability tests. The micrographs revealed well shaped spherical nanocapsules with no cracks, indicating the formation of a continuous film on the outer wall of the capsule. The thermal analyses of suspensions of freeze-dried nanocapsules indicated a high thermal stability (up to ~ 214 ° C) with melting points in the range of 51-58 ° C. Furthermore, the particle size distributions of the formulations remained physically stable during 60 days of storage