Biochemical potential of four widely consumed African leafy vegetables

Wild African leafy vegetables (ALVs) hold potential to enhance nutrition and health in resource-limited communities, yet they remain underutilized in local food systems. This study investigated four widely consumed ALVs, Gnetum africanum Welw., Hibiscus cannabinus L., Phaseolus vulgaris L., and Vigna unguiculata (L.) Walp., focusing on their nutritional profiles, chemical composition, and bioactive properties in relation to their traditional dietary use, in boiled and decocted preparations consumed as soups and side dishes. The leaves of P. vulgaris and V. unguiculata had the highest protein contents (25.0 and 22.6 g/100 g dried weight, respectively), while H. cannabinus stood out for its organic acid and polyunsaturated fatty acid content. Considering food-relevant extraction, decoction and hydroethanolic models were used to simulate traditional cooking and solvent-assisted extraction, respectively. Hydroethanolic extraction enhanced the recovery of phenolic compounds and flavonoids across all species, with H. cannabinus and G. africanum exceeding 13 mg/g extract. H. cannabinus showed strong antioxidant activity in the DPPH assay (EC₅₀ = 0.021 mg/mL), while its decocted extract was most effective in lipid peroxidation inhibition (TBARS EC₅₀ = 0.007 mg/mL), highlighting the relevance of traditional boiling practices. Distinct flavonoid profiles, including apigenin derivatives, quercetin, and kaempferol glycosides, were associated with bioactivity. G. africanum showed the strongest antimicrobial activity (MIC values = 2.5 mg/mL against Escherichia coli and Enterobacter cloacae). These findings demonstrate that ALVs consumed in traditional cooked forms are valuable sources of nutrients and bioactive compounds, supporting their integration into diets to improve dietary diversity and food security in African communities.