Effect of phenological stages on chemical compositions of essential oils of Dracocephalum kotschyi Boiss. growing wild in Dizin of Iran

Abstract

The volatile compounds of D. kotschyi, a valuable endemic medicinal and aromatic plant in Iran, were analyzed by GC and GCMS at three different phenological stages. About 98.2%, 97.5% and 99.1% of compounds were identified at vegetative, flowering and fruiting stages, respectively. Average yields of essential oil were 0.67, 0.8 and 0.3% (v/w), for vegetative, flowering and fruiting stages, respectively. The major compounds at the vegetative stage were – (E)βocimene 53.28% and Nerol 36.38%, at the flowering stage were – (E)βocimene 47.24%, Nerol 15.53%, Methyl geranate 8.3%, αpinene 7.98% and Geraniol 5.92. At the fruiting stage – (E)βocimene 33%, αpinene 16.34%, Geraniol 14.77% Geranial 11.4% and Methyl geranate 11% were identified as major compounds. Therefore the vegetative stage is suggested as the best time collection, to obtain highest amounts of – (E)βocimene and Nerol that are two major compounds of essential oil from fragrance materials. Also in order to Geraniol and Geraniol compounds flowering and fruiting stage is as suggestible stages for gathering.