Intraspecific Variability of the Essential Oil of Ziziphora clinopodioides ssp. rigida from Iran

Hydrodistillated essential oils of Ziziphora clinopodioides ssp. rigida from nine populations of the Lashgardar protected region (Hamedan Province, Iran) were analyzed by using GC and GC/MS techniques to determine the intraspecific chemical variability. Altogether, 39 compounds were identified in the oils, and a relatively high variation in their contents was found. The main constituents of the essential oils were pulegone (0.7-44.5%), 1,8-cineole (2.1-26.0%), neomenthol (2.5-22.5%), 4-terpineol (0.0-9.9%), 1-terpineol (0.0-13.2%), neomenthyl acetate (0.0-7.1%), and piperitenone (0.0-5.4%). For the determination of the chemotypes and the intraspecific chemical variability, the essential oil components were subjected to cluster analysis (CA). The five different chemotypes characterized were Chemotype I (pulegone/neomenthol), Chemotype II (pulegone), Chemotype III (pulegone/1,8-cineole), Chemotype IV (neomenthol), and Chemotype V (1,8-cineole/4-terpineol).