Chemical composition of the essential oil of Parthenium argentatum Gray. flowers

Parthenium argentatum Gray. (Guayule) is a perennial shrub and a source of latex. The essential oil of flowers and latex has distinctive odor and honey bees which are effective pollen carriers of this species, are mostly being attracted to its flowers. Therefore, the flowers oil of cultivar UC/100, collected in July 2004 from Research Institute of Forest and Rangelands field, was investigated. The essential oil isolated by hydro-distillation was analyzed by a combination of GC and GC/MS. The mean oil content was 0.8% (w/w). A total of sixteen components were identified representing 97.6% of the oil. The main constitutes of the essential oil were α-pinene (27.2%), b-phellandrene (17.0%), γ-eudesmol (11.3%), β-pinene (10.0%), β-eudesmol (9.0%), bicyclogermacrene (4.0%). Other components present in appreciable amounts were sabinene (7.3%), α-eudesmol (1.9%), bornyl acetate (1.6%), germacrene D (1.4%) and (Ε)-β-ocimene (2.2%).