Effect of extraction conditions on phenolic compounds and antioxidant properties of koreeb (Dactyloctenium aegyptium) seeds flour

The objective of the present study is to investigate the effect of solvent type (methanol, acetone, ethanol, n-propanol, and water), solvent-to-solid ratio (20–100 mL/g), solvent acidity (0–1.25% HCl), extraction time (60–300 min) and extraction temperature (30–70 °C) on total phenolic content (TPC), total flavonoid content (TFC) and the free radical-scavenging capacity (2,2′-diphenyl-1-picrylhydrazyl (DPPH) and ABTS radical scavenging assay) of koreeb (Dactyloctenium aegyptium) seeds using single-factor experiments. On the basis of TPC and antioxidant activity assays, the best extraction conditions were 80 mL methanol/g, 1.00% HCl, 180 min and 60 °C, as well as the results of TPC, TFC and DPPH were 32.38 mg GAE/g, 20.88 mg QE/g and 82.22%, respectively. The TPC was positively observed to be correlated with TFC, DPPH and ATBS (r = 0.89, 70 and 0.66, respectively) of koreeb seeds flour (KSF) extracts, under influence of solvent type extraction, whereas TPC and TFC were significantly correlated with DPPH (0.97 ≥ r ≥ 0.94) and ABTS (0.95 ≥ r ≥ 0.94) under the effect of extraction temperature. In general, KSF can be applied in functional foods and medicine related products for its health benefits.