Effects of different harvest time on essential oil content and composition of dragonhead (Dracocephalum moldavica L.)

Dragonhead (Dracocephalum moldavica L.) is an annual plant that belongs to the (Labiate or Lamiaceae) family. The essential oil of dragonhead has natural antibacterial and antimicrobial substances and having wide usage in industries like pharmaceutical, dietary and many others. In this research, effects of different harvest times on content and composition of essential oil were studied in Research field at Khoy Agricultural Research Center in West Azarbaijan province. Dragonhead seeds from both landrace and modern cultivars were planted simultaneously. The aerial parts of plant were harvested in six stages. After drying the plant materials in shade, their essential oils were obtained by hydro-distillation. The oils were analyzed by GC and GC-MS. According to the results, maximum and minimum essential oils percentage for both landrace and modern cultivars were respectively observed in full flowering (0.53) and yellow-maturity stage (0.07). In addition, there were some differences between oil compositions of these dragonhead accessions at different harvest times. The major oil components of dragonhead were the geranial, geraniol and geranyl acetate. The highest and the lowest sum total amount of geranial and geraniol were obtained at the early flowering (65.1%) and yellow-maturity (44.9%) for the landrace cultivar. The largest amount of geranyl acetate (50.7%) was gained for the modern cultivar at the early flowering stage while the least one (28.1%) was recorded for landrace cultivar plants 26 days after flowering when 10 to 30 percent of the flowers remained. The results showed that different harvest times had significant effects on essential oil content and composition.