Utilization and Re-use of Orange Peel Derived Oil by Formulating Nanoemulsion for Efficient Vector Control Application

Tons of orange peel (OP) produced as a mammoth by-product during the extraction of juice is discarded as waste that may contaminate natural resources and will increase environmental pollution. This study utilized the OP-derived aromatic oil, to develop oil/water nanoemulsion (OPOLNE) following the spontaneous emulsification method. The monodispersed micelles with an average size of 16 nm were produced and bear spherical morphology, which was confirmed by TEM. The bio-efficacy of bulk and orange peel oil-loaded nanoemulsion (OPOLNE) was comparatively evaluated using standard WHO protocol against third instar larvae of Anopheles stephensi , which revealed significantly higher toxicity of OPOLNE with an LC 50 value of 6.12 µg/mL. The histological studies showed severe lesions in the midgut tissue of the mosquito larva, post-exposure to OPOLNE. In addition, SEM also substantiated the findings of the histological studies as it showed severe morphological alterations in treated larvae. The fluorescently tagged OPOLNE could penetrate the mosquito midgut. To conclude the safety profile, the cytotoxicity on vertebrate cells was noted; OPOLNE did not exhibit toxicity on the mammalian N2A neuroblastoma cells. The proposed concept of OPOLNE, thus judiciously utilizes the orange peel waste for mitigating the disposal-related problems of orange peel waste and controlling mosquito-borne diseases in an eco-sustainable way.