Green Nanoemulsion Formulation of Citrus hystrix Essential Oil: Characterisation, Biological Potentials, and Eco–Biocompatibility Profiling

ABSTRACT Innovative nanotechnology based on plants and plant‐based resources presents unique opportunities for sustainable science. This study meticulously describes the multi–step fabrication and thorough bioevaluation of a plant–origin nanostructure in the form of a nano–emulsion utilising Citrus hystrix seed essential oil. The process commenced with a dual extraction strategy, integrating ultrasonic activation with hydrodistillation to optimise essential oil yield and purity. Subsequent catastrophic phase inversion transformation enabled the generation of highly stable nanodroplets with a uniform size distribution of 397–400 nm. The biological potential of the formulation was rigorously scrutinised: in vitro assays confirmed its superior antimicrobial efficacy against pathogenic strains. Additional analyses demonstrated impressive radical scavenging and glycemic regulatory properties alongside marked anti–inflammatory activity. The product's biocompatibility was validated through hemocyte integrity assessments, and detailed eco–suitability was established through comprehensive soil microbial profiling and enzyme assays, which revealed no cytotoxic or environmental risks. Collectively, these findings demonstrate that such plant–origin nanostructures offer a compelling, environmentally conscious platform for future biomedical and ecological innovations.