GC-MS Analysis, Free-Radical-Scavenging and Insecticidal Activities of Essential Oil of Scrophularia oxysepala Boiss.

Background: scrophularia oxysepala boiss. is endemic to western and central regions of iran, and belongs to the genus scrophularia (family: scrophulariaceae), which has long been used in traditional medicines. in the present work, chemical composition of the essential oil of the aerial parts of this species was analyzed. methods: the air-dried ground aerial parts of s. oxysepala were subjected to hydro-distillation. the resulting oil was analyzed, for the first time, by the gas chromatography/mass spectrometry (gc-ms) and gas chromatography/flame ionization detection (gc-fid). free-radical-scavenging activity of the essential oil was determined by the dpph assay. adults of oryzeaphilus mercator were used for contact toxicity insecticidal assay. results: a total yield of 0.1 ml of essential oil per 100 g of plant dry mass was obtained, and 15 compounds were identified, representing 91.2% of total oil. the essential oil was characterized by a high content of aromatic compounds and phytol. the main constituents were phytol (25.3%), methyl benzyl alcohol (9.3%), dehydrodieugenol (6.7%), methyl benzaldehyde (5.3%) and eugenol (1.3%). the low level of free-radical-scavenging activity of the essential oil was demonstrated by the rc50 value of 1.852mg/ml, and the insecticidal activity was also found to be low. conclusion: the insecticidal activity of this essential oil was not remarkable, but was time and concentration-dependent. the low free-radical-scavenging activity was probably due to its low percentage of phenolic compounds.