Two gram samples with 20 ml of 70% methanol (v/v) were put
into a 50 ml conical tube. The tube was shaken at 250 rpm for an
hour. It was then centrifuged at 160 g (10 min) and filtrated by a
filter paper (110 mm 100 circles, Whatman, UK). Ten-milliliter
filtered solutions were diluted by 20 ml of water. The 10-ml
diluted extracted solution was ran in the immuno-affinity column.
Ten milliliters of water was added for cleaning, and then 1 ml
of methanol was eluted in columns for AFs elution.