2.2. Preparation of essential oil and extracts
Fifty g of air dried leaves were mixed with 500 ml of distilled
water and the essential oil was isolated by hydrodistillation in a
Clevenger type apparatus over 3 h. The obtained oil was separated
from the water and dried over anhydrous sodium sulphate.
Isolation of essential oils was performed in duplicate and the samples
were stored in a freezer prior to further analysis.
The residues of hydrodistillation were separated into the solid
and liquid fractions. The solid residue was dried at 30C and
extracted with acetone, methanol and ethanol, while the liquid
fraction (water extract) was divided into two parts. One was
spray-dried and the other one freeze-dried. The yields of the
extracts were 5.15 ± 0.10–8.20 ± 0.25% for a liquid fraction (water
extracts) and 11.30 ± 0.10%, 14.61 ± 0.35% and 15.80 ± 0.30% for
acetone, methanol and ethanol extracts of solid fractions, respectively. The extractions were performed in triplicate.