Various extraction times affecting to the extraction efficiency were also determined. The ratio of sample to solvent was still fixed at 1:6 (g mL-1). The mixture was shaken for 0, 2, 4 and 8 h then filtered through the Whatman filter paper No.1. The filtrate was centrifuged at 10,000 rpm for 15 min. The obtained volume of supernatant was recorded and kept at 4 °C until used.