2.5. Measurement of anti-oxidative activity
Linoleic acid emulsion (50 mM) was prepared by mixing 0.284 g of linoleic acid, 0.284 g of Tween 20 and 50 mL of 0.1 M sodium phosphate buffer (pH 7.0). For the oxidation test, we prepared a reaction mixture containing 0.5 mL of water, 2.5 mL of the linoleic acid emulsion, 2.0 mL of 0.1 M sodium phosphate buffer (pH 7.0) and 0.5 mL of methanolic test samples in a 10-mL glass vial. The total reaction volume was fixed uniformly to 5.5 mL, and the final concentration of antioxidant was 90 μM. The glass vials containing reaction mixture were capped with rubber septa, and kept at 50 °C