Optimization of inclusion complex’s preparation of Psidium cattleyanum S. essential oil and 2-hydroxypropyl-β-cyclodextrin by central composite design for application as larvicide in Aedes aegypti L

Abstract

The present investigation described the preparation of 2-hydroxypropyl-β-cyclodextrin (HPβCD) inclusion complex (IC) of the essential oil (EO) of Psidium cattleyanum (CAT) and the Aedes aegypti larvicidal evaluation of the EO and IC. The EO was extracted from the leaves of CAT with a 0.79% (m m−1) yield. It is mainly composed of sesquiterpenes, with β-caryophyllene being the major component (34.2%). To achieve optimized conditions for the preparation of the IC, through the physical method of kneading, the parameters molar ratio of EO/HPβCD and the kneading time were evaluated. The best molar ratio of EO:HPβCD was 1:1.14 and the kneading time corresponded to 30 min. The amount of essential oil loaded under optimized conditions was (94.9 ± 1.7)%. The prepared IC was characterized by spectroscopy in the UV-Vis region, FTIR, TGA, DLS, and XRD to prove the interaction of the EO with the HPβCD. The release of EO from the IC was evaluated in aqueous media using 1% DMSO (v v−1) and acetonitrile. The EO slowly released into the aqueous medium, which was used to simulate the aquatic environment in which A. aegypti larvae develop. The larvicidal activity of CAT EO in DMSO was 81.73 and 102.50 µg mL−1 for LC50 and LC90, respectively. The IC's toxicity was 134.44 and 168.69 µg mL−1 for LC50 and LC90, respectively. Although the larvicidal activity of EO is higher as compared to the IC, the latter presents great thermal stability and high water solubility. Taking together, the described in this study points to the fact that IC prepared from CAT EO may represent a good alternative for A. aegypti larvae control.