Seasonal variation in phytochemicals of essential oil from<i>Juniperus communis</i>needles in western Himalaya

Abstract

Essential oil from Juniperus communis needles were examined in three different seasons (spring, rainy and winter) throughout the year for the analysis of yield and chemical composition. Volatiles of the needles were obtained by hydrodistillation process using clevenger type apparatus. The essential oil yield in all the seasons was not significantly changed and was found 0.29% (rainy), 0.3% (winter) and 0.33% (spring). Chemical compositions of the oils were analyzed by GC and GC-MS techniques on DB-5 capillary column resulted in identification of twenty-eight components. Identified components accounted for 91.1–93.1% of the total oils. The major class of compounds identified in present essential oil was monoterpene hydrocarbons (51.9–63.7%) with sabinene (30.1–37.1%) as the major constituent. Other compounds characterized in all the seasons were limonene (11.3–15.7%), 4-terpineol (9.1–10.5%), α-pinene (3.6–7.9%), δ-cadinene (3.7–4.6%), cis-sabinene hydrate (3.6–4.2%), myrcene (2.5–3.1%), α-terpinene (2.3–2.8%) and manool (1.3–2.2%). In this experiment winter was found to be most suitable time for the isolation of sabinene and limonene.