For analysis of essential oils, healthy leaves, flowers and fruits
were collected of ten different individuals of H. oreadica. The
flowers were collected in November and fruits in January. The
leaves were collected monthly for one year. Fresh plant material
was triturated separately and submitted to hydrodistillation
in a Clevenger-type apparatus for two hours. At the end of each
distillation the oils were collected, dried with anhydrous Na2SO4,
measured, and transferred to glass flasks and kept at a temperature
of−18 ◦C for further analysis.