Approximately, 5 g of each plant sa

Approximately, 5 g of each plant sample was weighed accurately and macerated with 250 ml of n-hexane at room temperature for 2 days using a laboratory-scale shaker. Then, the n-hexane phases were filtrated and evaporated under vacuum until dryness. The residue was dissolved again in 100 ml of n-hexane and the n-hexane phase was washed in a separatory funnel with 2% NaOH solution to get rid of impurities, which are soluble in NaOH. After discarding the alkali solution present in the lower layer, the upper solutionwaswashed with distilled water several times until it was neutralized. The extract, obtained after distillation under vacuum at 45 ◦C in a rotary evaporator,was dissolved with 95% ethanol and then filtrated in a 250 ml-measuring flask. Then, 10 ml of filter liquor was transferred into a 100 ml-measuring flask. Forty millilitres of 0.2% NaOH solution was added in the flask, and then, left to react at 50 ◦C for 30 min. Finally, 0.08 mol/l acetic acid solution was filled up to the mark (Hao et al., 2002). The same procedure was applied to all samples.