[Extraction and determination of volatile constituents in leaves of Eucalyptus citriodora].

The volatile constituents in leaves of Eucalyptus citriodora, including oil fraction and water-soluble fraction, were extracted and determined. Oil fraction of volatile components was obtained through steam distillation. Ether was used as the solvent to extract the water-soluble fraction of volatile compounds from the liquid left after steam distillation in order to know the quantity and constituents of volatile compounds dissolved in the water phase. The oil yield in the oil fraction was 1.36%, and the oil yield in the water-soluble fraction was 0.48% (both on fresh weight basis). Both oil fraction and water-soluble fraction were analyzed by gas chromatography-mass spectrometry (GC-MS) method. The results showed that 37 compounds (97.36%) in the oil fraction and 10 compounds (82.05%) in the water-soluble fraction were identified. There were 12 hydrocarbon compounds and 25 oxygenated compounds identified in oil fraction. The major constituents in oil fraction were citronellal (57.00%), followed by citronellol (15.89%) and citronellyl acetate (15.33%). Alcohols dominated the compounds in water-soluble fraction. cis-p-Menthane-3, 8-diol (53.43%) and trans-p-menthane-3, 8-diol (16. 48%) were found to be the major compounds, which have the activity to repel insects. It is concluded that the comprehensive utilization value of leaves of Eucalyptus citriodora was enhanced owing to the extraction of water-soluble volatile components.