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 as 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.