in 0.1 M acetate buffer
for 16 h. After extraction, samples were centrifuged (20 min,
25 C, 3000 rpm) and supernatants were collected. The supernatants
were diluted to appropriate volume with water. The 25 ll
of diluted samples were added to 96-well plate, followed by
125 ll of 10% Folin–Ciocalteau and 100 ll 0.5 M sodium hydroxide to each well and mixed.