Five gram of sample were extracted with 40 mL ethyl acetate/methanol/0.2 M ammonium bicarbonate pH 8.5 (62.5/25/12.5, v/v/v) during 30 min on an Agitelec overhead shaker.The sample extract was centrifuged and a phase separation was induced by adding 5 mL of a 0.2 M ammonium bicarbonate buffer pH 10 and 5 mL of a saturated solution of ammonium sulphate to 15 mL of the extract