Nano-encapsulated tarragon (Artemisia dracunculus) essential oil as a sustained release nano-larvicide

Abstract

Objective: In recent years, essential oil-based larvicides have been introduced as alternatives to industrial ones. However, an appreciable formulation of essential oils with prolonged larvicidal activity (LA) has not yet been developed.
 Methods: In this study, tarragon essential oil (TEO) was encapsulated in chitosan nanoparticles using ion gelation technique. Physicochemical properties and duration of LA of the prepared nanoformulation were investigated.
 Results: Encapsulation efficiency of the optimum nanoformulations with a particle size of 168±90 nm was calculated as 39.66% using UV-Vis analysis. Encapsulating TEO in chitosan-TPP nanocapsules was shown to increase its efficiency in LA at SSF test: Perfect LA (100% mortality) was achieved at lower concentration (i.e. 31 μg mL-1 instead of 80 μg mL-1). Also, perfect LA continued for 4 and 3 days, compared with 2 days and 1 day for the non-encapsulated form of TEO in the lab and SFF tests, respectively. Besides, the duration of LA of nanoformulation was significantly longer than its corresponding microformulation with the same concentration of ingredients. Furthermore, the concentration of TEO in the solution tests was also monitored and it was found that the nanoformulations provide a sustained release of TEO. Moreover, there was a logical relationship between LA and concentration of TEO in different hours.
 Conclusion: This prepared nanoformulation could be introduced as an interesting alternative to synthetic larvicides, due to its easy and fast method of preparation and its green constituents.