The essential oil composition of Iranian oregano (Origanum vulgare L.) populations in field and provenance from Piranshahr district, West Azarbaijan province, Iran

摘要

The aerial parts of Origanum vulgare L. were collected at pre-flowering stage in 5 localities in Piranshahr district, West Azarbaijan province (Iran) in June 2010. The extractions were performed in a Clevenger apparatus for 120 min (3 times) and the essential oils in the field (O.v-F) and 4 provenance oregano plants (0.-Vfl— O.v-W4) were obtained by hydro-distillation at yield of 0.80% and 1.26%, 1.66%, 0.93% and 1.36% (based on v/w), respectively. The essential oils were analyzed by GC/MS. In cultivated plants 22 constituents, representing 94.02% and in the 4 provenance plants (O.v-W,— 0.v-W4) 21,25, 22 and 20 constituents, representing 96.55%, 95.66%, 95.8% and 94.48% of the oils, were identified, respectively. The two major constituents of theessential oils, carvacrol (23.54-67.09%) and y-terpinene (7.71-20.94%) were same in all samples from 5 localities. Five chemotypes of essential oils were identified. The main chemotype was carvacrol-y-terpinene. Essential oils of all the O. vulgare populations from field (O.v-F) and the 4 provenance oregano plants were characterized by high monoterpens and sesquiterpenes proportions. The hydrocarbons and oxygenated monoterpenes constituted the main fraction of the essential oils. The 32 identified components acounted for 94.64-96.55% of the essential oils. Also in the present study, the antioxidant activity of O. vulgare essential oils using the DPPH radical scavenging assay was determined. All of extracts manifested almost the same pattern of antioxidant activity as ascorbic acid (vitamin C).