Phenolic Compound Extraction, Characterisation, and Antioxidant Activity of Nigerian Fermented Locust Beans (Dawadawa)

Dawadawa, produced by fermentation of African locust bean (Parkia biglobosa), is a widely used flavour condiment across West Africa with documented antioxidant properties attributable to its phenolic compound profile. Systematic characterisation of these bioactive compounds and the factors governing their extractability from dawadawa produced in different Nigerian zones has not been adequately reported. This study extracts, characterises, and quantifies phenolic compounds from dawadawa samples obtained from Oyo State (South West), Benue State (North Central), and Kano State (North West), evaluating the effect of extraction solvent on total phenolic content, total flavonoid content, and antioxidant activity. Extraction solvents evaluated include 70 percent ethanol, 80 percent methanol, and aqueous extraction. Phenolic profiling was conducted by high-performance liquid chromatography with diode array detection. Antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays. Results showed that 70 percent ethanol extract from the Oyo State sample had the highest total phenolic content of 48.3 mg GAE per gram dry weight and the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. Gallic acid, epicatechin, and rutin were the dominant phenolic compounds identified across all samples. Regional variation in phenolic content was statistically significant and correlated with differences in fermentation duration and drying method. The study contributes to the bioactive compound characterisation literature for African fermented condiments. Keywords: dawadawa, locust bean, phenolic compounds, antioxidant, fermentation