Preparation of the extracts
The parts of P. vera mentioned above were chopped and extraction of the samples was carried out with n-hexane during 8 h continuously for each part using a Soxhlet apparatus in the presence of anhydrous Na2SO4. After filtrating, the n-hexane phases evaporated under vacuum at 40 °C to dryness and the lipophylic extracts were obtained as described in our previous study ( Aslan et al., 2002).