M. Norani - Department of Horticultural Science, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
A. Crowford - Department of Horticultural Science, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
Y. Tahamtani - Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Islamic Republic of Iran.
M. T. Ebadi - Department of Horticultural Science, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
M. Ayyari - Department of Horticultural Science, Tarbiat Modares University, Tehran, Islamic Republic of Iran.

Dorema ammoniacum D. Don. is a perennial medicinal plant from Apiaceae family. There is some evidence in Iranian traditional medicine about the anticonvulsant and anthelmintic properties of D. ammoniacum gum resin exudating from its root and stem. In this study, D. ammoniacum was collected from southwestern part of Iran and their Essential Oils (EOs) content and compositions were investigated by gas chromatography techniques. The EO yield of D. ammoniacum root, stem, leaves, flower and gum were ۰.۴, ۰.۲, ۰.۲۴, ۰.۴۶, and ۱.۰ v/w%, respectively. Although there were some variations among different organs EOs, some similarities could be easily observed. The major compounds in the gum EO were (۲E, ۶E)-farnesol (۱۲.۲%), cuparene (۱۱.۵%), (۲Z,۶Z)-farnesol (۸.۷%), β-bisabolene (۶.۱%). The root oil had thymol (۱۴.۷%), heptacosane (۱۲.۸%), tridecanol (۱۲.۷%) and ۴-methylene-۵-hexenal (۶.۸ %) as the major compounds. Endo-Fenchyl acetate (۱۳.۱%), elemicin (۱۰.۵%), p-cymen-۸-ol (۶.۸%) and thymol (۵.۶%) were identified in the stem oil. The major constituents of the leaves oil were n-hexadecanol (۹.۱%), cuparene (۸.۲%), Di-n-butyl phthalate (۶.۶%), n-eicosane (۶.۶%), bicyclogermacrene (۵.۴%) and β-bisabolene (۵.۲%). The major compounds in flower oil were tridecanol (۱۳.۲%), δ-elemene (۱۱.۲%), n-eicosane (۸.۲%), and heptadecanoic acid (۷.۸%). According to different applications, nine different extracts were also prepared from all organs and their Antioxidant Activity (AA), Total Phenol Content (TPC) and Total Flavonoid Content (TFC) were evaluated. Analysis of variance showed that there was a significant difference among all extracts of D. ammoniacum in AA, TPC and TFC (P≤ ۰.۰۱). Results showed that the highest radical scavenging activity was observed in M۲F (second Methanolic extract of Flower) and M۲L (second Methanolic extract of Leaves) samples with IC۵۰ of ۴۰.۳ μg mL-۱ and ۴۳.۶ μg mL-۱ compared to BHT (۲۶.۰ μg mL-۱). The highest TPC in M۲F and M۲R (second Methanolic extract of Root) samples were ۳۶.۴ and ۳۵.۷ mg GAE g-۱ DW of extracts, respectively. The highest TFC belonged to M۲L with ۲۶.۴ mg QE g-۱ DW of extract. Results also showed that D. ammoniacum organs extracts contained moderate to high amounts of AA and TPC.

GC/MS, Bisabolene sesquiterpenes, D. ammoniacum, Sequential extraction, Volatile compounds.