Development and Physicochemical Characterization of Ocimum sanctum Essential Oil Nanoemulsion with Preliminary Adulticidal Activity against Aedes aegypti

Abstract

Ocimum sanctum has been widely investigated as a source of bioactive compounds with potential applications in vector control. This study examined the phytochemical profile of O. sanctum essential oil and evaluated the physicochemical characteristics and preliminary adulticidal activity of its nanoemulsion formulation against Aedes aegypti. Essential oil obtained by hydrodistillation was formulated into an oil-in-water nanoemulsion and subsequently characterized through physicochemical and stability testing. Phytochemical screening confirmed the presence of alkaloids, flavonoids, terpenoids, steroids, and other essential oil constituents. The nanoemulsion exhibited a homogeneous appearance, a pH of 6-7, a transmittance of 91-94 %, an adhesion time of 10-14 s, and a spreadability of 9-15 cm. Particle characterization confirmed the formation of nanoscale droplets with acceptable distribution profiles. No signs of skin irritation were observed during the preliminary safety assessment. Adulticidal testing demonstrated transient knockdown effects but limited mortality after 24 h of observation. These findings indicate that O. sanctum essential oil can be formulated into a physically stable nanoemulsion; however, further optimization is required to improve biological performance and residual activity before practical public health applications can be considered.