Abstract:

Single-factor experiments combined with three-factor quadratic rotation orthogonal composite design were
adopted to analyze the effects of ethanol concentration, solid to solvent ratio, extraction temperature, and extraction time
on the yield of flavonoids from yellow maize (Zea mays Jiyuan 1) and the radical scavenging abilities of the extracted
flavonoids against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (·OH) in vitro. The results indicated that the
optimum parameters for extracting flavonoids were found to be extraction at 69 ℃ for 1.85 h with a solid/liquid ratio of
1:35.5 (g/mL). The yield of flavonoids was 85.88 mg/g under the optimized conditions. The scavenging rates of 20 mg/mL
yellow maize flavonoids against DPPH and hydroxyl radicals were 76.47% and 32.62%, respectively, which were equivalent
to 81%–84% and 40%–50% as compared to rutin (0.1 and 0.2 mg/mL, respectively). The yellow maize flavonoids showed
more powerful scavenging activities against DPPH radical than against hydroxyl radical, which increased significantly with
increasing flavonoid concentrations.

Key words: yellow maize (Zea mays L.), flavonoids, extraction conditions, antioxidant activity