Characterisation of the Functional and Bioactive Properties of Underutilised Indigenous Leafy Vegetables and Their Potential for Functional Food Development in South East Nigeria

Indigenous leafy vegetables constitute an integral component of traditional diets in South East Nigeria and represent an underexplored source of bioactive compounds with functional food potential. Despite their wide consumption, comprehensive characterisation of their phytochemical, nutritional, and functional properties remains limited. This study characterised the functional and bioactive properties of ten underutilised indigenous leafy vegetables harvested across Anambra, Ebonyi, and Abia States, and assessed their potential for functional food product development. A comprehensive analytical design was employed, including proximate analysis, mineral determination by atomic absorption spectrophotometry, phytochemical screening for phenolics, flavonoids, alkaloids, and saponins, and assessment of functional properties including emulsification, gelling, and water holding capacity. In vitro antioxidant activity was measured using DPPH, FRAP, and ORAC assays. In vitro anti-inflammatory and antibacterial assays were also conducted. Structure-activity relationships were explored through correlation analysis. Prototype functional food products were developed using the three highest-scoring vegetables and evaluated for nutritional composition, stability, and sensory acceptability. Results identified four previously underdocumented species with exceptional antioxidant and anti-inflammatory activity. Flavonoid content was the strongest predictor of antioxidant capacity. Prototype soup paste products received high sensory acceptability. The study advances knowledge on the nutritional and functional food value of South East Nigerian indigenous vegetables and provides a scientific basis for their commercialisation. Keywords: indigenous vegetables, functional food, bioactive compounds, antioxidant, South East Nigeria