Incorporação de micropartículas carreadas com óleo essencial em holocelulose extraída de rejeito orgânico para o desenvolvimento de um biodenfensivo larvicida

Abstract

Plants containing essential oils usually have chemical constituents with pronounced biological activities, especially those belonging to the Piperaceae family. Many studies have focused on extracting essential oil from plant species, then discarding residual biomass. This work makes full use of the essential oil and biomass of the species Piper hispidum within a methodological process, extracting the holocellulose from the produce organic waste. Then, microparticles were developed using Whey Protein Isolate – WPI with the encapsulated essential oil to be incorporated into the extracted holocellulose, aiming at the development of a controlled release system in the form of tablets with larvicidal properties. As many underdeveloped countries have been suffering too much from the diseases caused by the virus transmitted by the vector Aedes aegypti, this system was evaluated for its larvicidal efficacy, obtaining LD50 = 77.7 µg mL-1 and LD90 = 93.3 µg mL-1 after 24 h of exposition. X-Ray Diffraction (XRD) technique allowed the verification of the efficiency of the holocellulose extraction process. Scanning Electron Microscopy (SEM) technique allowed to assess the impact of the holocellulose extraction methodology through the morphological analysis of the dried leaves and the material resulting from the extraction process. FTIR technique allowed the verification of the partial elimination of lignin by the extraction process, in addition to pointing out stretches characteristic of the molecular structure of cellulose and hemicellulose. Finally, pellets were produced from the mixture of microencapsulated material and holocellulose. The pellets showed total dispersion in up to 2 h and the controlled release indicated an approximate concentration of 300 µg mL-1 in 24 h. These results indicate that only one pellet reached the lethal dosage to act in the control of A. aegypti larvae.