title: Comparison of Eucalyptus cinerea essential oils produced by hydrodistillation and supercritical carbon dioxide extraction.
abstract: The essential oil of Eucalyptus cinerea is reported to possess a higher 1,8-cineole content than other Eucalyptus species. Variations in the quantitative and qualitative characteristics of E. cinerea oil produced by hydrodistillation (HD) and supercritical carbon dioxide extraction (SCE) techniques and a comparison between glycoside-bound and free volatile constituents produced by HD have been studied. It was found that HD produced higher oil (free volatiles) content (3.1%) as compared with SCE (1.1%), whereas bound volatiles constituted only about 0.4%. Gas chromatographic (GC) analysis of the oil samples revealed significant difference in their chemical composition. The essential oil (free volatiles) produced by HD contained 1,8-cineole (85.1%) as the major constituent, followed by a-terpineol (7.2%) and limonene (4.4%). In the bound volatile fraction produced by HD, 1,8 cineole (20.6%), alpha-terpineol (7.6%), p-cymene (6.3%), and limonene (4.5%) were found as major constituents. The extract produced by SCE was dominated by 1,8-cineole (70.4%), a-terpineol (8.6%), globulol (3.1%), aromadendrene (2%), citronellal (1.7%), viridiflorol (1.3%), phytol (1.1%) and terpinen-4-ol (1%). Although HD produced higher oil yields, SCE produced better extract in terms of the number of components detected.
authors.affiliation: Natural Plant Products Division, Institute of Himalayan Bioresource Technology (Council of Scientific and Industrial Research), Post Box 6, Palampur-1 76 061, Himachal Pradesh, India.
authors.forename: Tavleen S
authors.initials: TS
authors.lastname: Mann
authors.forename: Garikapati D
authors.initials: GD
authors.lastname: Kiran Babu
authors.forename: Shailja
authors.initials: S
authors.lastname: Guleria
authors.forename: Bikram
authors.initials: B
authors.lastname: Singh
mesh_terms: D002245:Carbon Dioxide; D000081005:Cyclohexane Monoterpenes; D003511:Cyclohexanols / Q000302:isolation & purification; D053138:Cyclohexenes / Q000302:isolation & purification; D057168:Distillation; D000077591:Eucalyptol; D005052:Eucalyptus / Q000737:chemistry*; D039821:Monoterpenes / Q000302:isolation & purification; D009822:Oils, Volatile / Q000302:isolation & purification*
chemical_list: D000081005:Cyclohexane Monoterpenes; D003511:Cyclohexanols; D053138:Cyclohexenes; D039821:Monoterpenes; D009822:Oils, Volatile; D002245:Carbon Dioxide; C016775:alpha-terpineol; D000077591:Eucalyptol