Essential oil variability in Stachys pilifera Benth populations: a narrow endemic species of Iran.

Stachys pilifera Benth is an endemic species of Iran where it is found in the mountainous habitats of Zagros region. The plant is a rich source of secondary metabolites endowed with different medicinal properties. Here, for the first time, the essential oil variability among eleven wild populations of S. pilifera , was investigated. Results indicated that the variation of the chemical profile of essential oils was remarkable. The most abundant components were cis -chrysanthenyl acetate (19.1-48.2%), viridiflorol (1.4-19.1%), trans -caryophyllene (2.3-11.9%), caryophyllene oxide (1.9-11.0%), limonene (2.0- 5.9%) and spathulenol (0.0- 9.5). Based on the cluster analyses (CA), four main chemotypes were recognized: chemotype I ( cis -chrysanthenyl acetate), chemotype II ( cis -chrysanthenyl acetate/viridiflorol), chemotype III ( cis -chrysanthenyl acetate/viridiflorol/spathulenol), chemotype IV ( cis -chrysanthenyl acetate/ trans -caryophyllene/α-pinene). The chemical variation detected can be useful to consider these populations for pharmaceutical industries and industrial applications as well as for domestication and conservation purposes.