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GENETIC VARIABILITY TO ESSENTIAL OIL CONTENTS AND COMPOSITION
IN FIVE SPECIES OF EUCALYPTUS
ZAFAR IQBAL, IMTIAZ HUSSAIN*, A. HUSSAIN AND M.
YASIN ASHRAF
Abstract:
Essential oils from the leaves
of Eucalyptus camaldulensi, Eucalyptus citriodora, Eucalyptus globulus,
Eucalyptus crebra and Eucalyptus tereticornis were extracted by hydro-distillation.
Maximum oil (1.47 %) was found in E. crebra and minimum (0.58 %) in E.
tereticornis. Specific gravity of the oils ranged between 0.86 to 0.91, refractive
index 1.42 to 1.44 and optical rotation -12.3 to 3.63 at 25 oC. Extracted oils
were resolved and identified by GC/FID on Carbowex-20 M packed glass column. Maximum
components (21) were detected in E.crebra and minimum (15) in E. citriodora
and E. globulus oils, whereas in the oils of E. camaldulensis and
E. tereticornis 16 and 19 components were resolved respectively. In E.
camaldulensis, E. globulus and E. tereticornis oils five components
(α -pinene, 3∆carene, ß-phellandrene, 1,8-cineole and p-cymene),
in E. citriodora oil four components (a- pinene, 1,8-cineole, citronellal
and citronellol) and in E.crebra oil three components (a-pinene, limonene
and 1,8-cineole) were identified. The 1,8-cineole, found in the oils of different
species, was 72.17 % in E. crebra, 53.22 % in E. camaldulensis,
26.57 % in E. globulus and 50.51 % in E. tereticornis. Lemon scented compounds
citronellal (74.65 %) and citronellol (6.13 %) were found in E. citriodora
oil which were absent in the other E. species. Chemical composition
of oils from all the species varied significantly which may be due to the differences
in their genetic make up.
Nuclear Institute for Agriculture and Biology (NIAB), P.O.
Box-128, Jhang Road, Faisalabad, Pakistan.
* Department of Chemistry, Govt. College, Sargodha,
Pakistan.
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