The impact of morpho- and ontogenetic variation on essential oil profile of Hypericum heterophyllum Vent., an endemic species in Turkey's Flora

The objectives of this research were to determine the variation in the amount and composition of the herbage essential oil according to different harvesting periods, and the amount and composition of the dry capsule essential oil in H. heterophyllum. The samples of herbage in four different growth stages as before flowering, beginning flowering, 50% of flowering, and full flowering and dry capsule in full maturity stage were taken from plants in a natural environment. The highest essential oil rate (0.09%) in aerial parts was recorded before the flowering stage. Also, germacrene-D, δ-cadinene, spathulenol, and α-guaiene in herbage and germacrene-D, caryophyllene oxide, and α-guaiene in the dry capsule were determined as main components. The essential oil content and the components show variation depending on the developmental stages of the plant and the part used.