Development of nanoemulsion from Vitex negundo L. essential oil and their efficacy of antioxidant, antimicrobial and larvicidal activities (Aedes aegypti L.)

It is believed that nanoemulsions were emerged as a promising candidate to improve the qualities of natural essential oil towards antimicrobial and insecticidal applications. In the present study, we have focused on the encapsulation of Vitex negundo L. leaf essential oil using Polysorbate80 for its different biological activities including antioxidant, bactericidal and larvicidal activity against dengue fever vector Aedes aegypti L. Initially, the nanoemulsion was prepared by low energy method and droplet size of the formulated nanoemulsion was characterized by using Dynamic Light Scattering analysis. The freshly prepared V. negundo essential nanoemulsion was observed with the mean droplet size of below 200 nm indicating its excellent stability. Further, the larvicidal activity of essential oil and nanoemulsion with various concentrations (25, 50, 100, 200 and 400 ppm). The larvicidal activities were tested 2nd and 3rd instar larval mortality rate that was observed against the 12 and 24 h exposure period. After a 12 h exposure period, the larvicidal activities of 2nd instar larva were observed as essential oil (73.33 ± 1.88), nanoemulsion (81.00 ± 0.88) and the larvicidal activities of 3rd instar larva were displayed essential oil (70.33 ± 2.60) and nanoemulsion (79.00 ± 3.70). Likewise, after a 24 h exposure period, the larvicidal activities of 2nd instar larva were observed as essential oil (90.30 ± 2.15), nanoemulsion (94.33 ± 1.20) and the larvicidal activities of 3rd instar larva were essential oil (80.66 ± 0.66) and nanoemulsion (93.00 ± 1.25) respectively. We finally concluded that the developed plant-based emulsion essential oil systems were thermodynamically stable. Owing to its improved bioavailability and biocompatibility, formulated nanoemulsion can be used in various biomedical applications including drug delivery as well as disease transmitting mosquito vector control. Graphical abstract ᅟ