title: Characterization and antioxidant activity of essential oils from fresh and decaying leaves of Eucalyptus tereticornis.
abstract: The composition of essential oils hydrodistilled from fresh and decaying leaves of Eucalyptus tereticornis was analyzed by means of gas chromatography and mass spectrometry, and a total of 68 constituents were identified. The essential oils were assayed for antioxidant activity in terms of scavenging of 2,2-diphenyl-1-picrylhydrazil (DPPH) and hydroxyl (OH(*)) radical, and superoxide anion (O2(-*)).The major constituents of the fresh leaf oil were alpha-pinene (28.53%) and 1,8-cineole (19.48%), whereas in the decaying leaf oil, beta-citronellal (14.15%), (-)-isopulegol (13.35%), and (+)-beta-citronellol (10.73%) were the major components. Both essential oils exhibited a strong radical scavenging activity against DPPH radical with IC50 values of 110 and 139.8 microg/mL for fresh and decaying leaf oil, respectively (IC50 of BHT = 164.2 microg/mL). Further, the essential oils (at 400 microg/mL) also exhibited OH(*) (56-62%) and O2(-*) (65-69%) scavenging activity parallel to the commercial antioxidant BHT/ascorbic acid. However, unlike the essential oils, the major monoterpene constituents exhibited significantly less scavenging activity (<35% DPPH or OH(*); at 400 microg/mL). The study concluded that fresh and decaying leaves of E. tereticornis are a source of monoterpenoid rich oil exhibiting antioxidant activity.
authors.affiliation: Department of Environment and Vocational Studies, Panjab University, Chandigarh 160 014, India. hpsingh_01@yahoo.com
authors.forename: Harminder P
authors.initials: HP
authors.lastname: Singh
authors.forename: Sunil
authors.initials: S
authors.lastname: Mittal
authors.forename: Shalinder
authors.initials: S
authors.lastname: Kaur
authors.forename: Daizy R
authors.initials: DR
authors.lastname: Batish
authors.forename: Ravinder K
authors.initials: RK
authors.lastname: Kohli
mesh_terms: D005052:Eucalyptus / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D016166:Free Radical Scavengers; D009822:Oils, Volatile; D010938:Plant Oils