Variation of the main terpenes in dragonhead (Dracocephalum moldavica L.) during growth

The essential oil from dragonhead, Dracocephalum moldavica L., was studied with special attention being paid to the yield of oil and how the amount of the main components changes during the vegetative period. The oil reaches its maximum level during the flowering, as is also the case with geranyl acetate, geranial and geraniol. The content of neral, however, decreases during flowering. These observations indicate that the biosynthesis of geranyl acetate is dominant at the beginning of the vegetative period, but is superseded by biosynthesis of geranial and geraniol, from the early stage of flowering. The optimum harvest time proved to be during the flowering stage, when the oil content is highest and thus also the amount of the main terpenes is highest.