the seasonal variations of the chemical composition of essential oil obtained from <i>scrophularia frigida</i>

Background]in general, seasonal growing of plants influences chemical composition and biological activities of essential oils.[objectives]therefore, the aerial parts of <i>scrophularia frigida </i>(<i>s. frigida</i>) were used in the current study to find seasonal variations in the content and composition of essential oil.[materials and methods]the oil was extracted by hydrodistillation from two samples collected in different seasons, and analyzed by gcfid and gcms.[results]in total, 18 and 20 components were identified and quantified in the oil of summer and autumn samples representing 97.42% and 94.77% of the oil components, respectively. the essential oil of autumn sample was mainly composed of fatty acid derivatives (42.69%). the major components of the autumn oil were palmitic acid (30.49%), phytol (12.99%), llinalool (11.41%), and hexahydrofarnesyl acetone (6.65%). the essential oil of summer sample was dominated by oxygenated monoterpenes (68.91%), llinalool (38.69%), geraniol (11.20%), αterpineol (9.99%), and palmitic acid (7.32%).[conclusions]based on these observations, wide variation is detected in the chemical composition of the oil obtained from the same plant in different seasons.