Chemical Composition of Essential Oil among Seven Populations of Zanthoxylum armatum from Himachal Pradesh: Chemotypic and Seasonal Variation

Abstract

Essential oil from the fresh leaf of Zanthoxylum armatum, collected from the different regions of Himachal Pradesh, India, was obtained by hydrodistillation. The main constituents of essential oil, as well as locational and seasonal change in its composition have been determined by GC-FID and GC-MS techniques. Thirty-five constituents, making up about 93.1-99.4% of the total composition of oil, were characterized. Among all the characterized components, non-terpenic hydrocarbons (2-undecanone and (E)-2-decanal), oxygenated monoterpenes (linalool, 1,8-cineol and β-terpineol) and monoterpene hydrocarbons (β-phellandrene, α-pinene, sabinene and β-myrcene) contribute to major proportion of oil. Further, principal component analysis was carried out to distinguish the variation of essential oil composition among the collected samples in summer and winter season. Based on the cluster separation, five chemotypes were identified, representing β-phellandrene/2-undecanone; linalool/2-undecanone; linalool; 2-undecanone; 2-undecanone /1,8-cineol.