Use of gas chromatograms of the essential leaf oils of the genus Eucalyptus for taxonomic purposes: E. subser. Euglobulares (Blakely)

Abstract

Leaves were harvested from 37 trees of Eucalyptus subser. Euglobulares Blakely, E. globulus Labill., E. bicostata Maiden, Blakely and Simmonds, E. maidenii F. Muell. and E. pseudoglobulus Naudin ex Maiden, selected from six sites around Australia: both native-growing and cultivated taxa were chosen. Volatile leaf oils were isolated by vacuum distillation and analysed by GC (one tree was previously analysed by GC-MS). The conditions of distillation and analysis were maintained throughout this study. Many of the taxa contained α-pinene (1.5-19.6%), limonene (1.0-5.1%), 1,8-cineole (39.3-71.7%), p-cymene (0.2-2.0%), pinocarvone (0.1-4.2%), β-caryophyllene (0-5.5%), aromadendrene (0.9-20.3%), allo-aromadendrene (0.1-4.0%), α-terpineol (0.1-6.4%), globulol (0.1-5.5%), γ-eudesmol (0-1.8%), α-eudesmol (0.1-5.6%) and β-eudesmol (0.1-10.8%) as the main leaf oil components. The principal components analysis (PCA) and linear discriminant analysis (LDA) performed on the gas chromatograms of the 37 single trees studied revealed groupings of the taxa in approximate agreement with the results obtained from comparative morphological studies; LDA yielded four distinct groups, while PCA was not as discriminating. Nevertheless, in both cases the five pseudoglobulus trees formed distinct groups of their own. In addition, the loading factors of the PCA analysis indicated that the pseudoglobulus group was due to the presence in this taxon of large amounts of the three eudesmol oil components.

Eucalyptus oleosa Essential Oils: Chemical Composition and Antimicrobial and Antioxidant Activities of the Oils from Different Plant Parts (Stems, Leaves, Flowers and Fruits)

“…Many investigations have been done on the volatile components of essential oils from different species of Eucalyptus . Moreover, there are many reports which have determined the composition of essential oils from the leaves [13,14], immature flowers [8] and recently from the fruits [5]. Previous studies of the composition of Eucalyptus oleosa leaves essential oil have been reported [9,15,16], but to the best of our knowledge, no previous studies on the chemistry and antioxidant and antimicrobial activities of the essential oils of stem, immature flowers and fruit of E. oleosa have been presented in the literature to date.…”

Variation in Volatile Leaf Oils of 13 Eucalyptus Species Harvested from Souinet Arboreta (Tunisia)

“…were richer in essential oil than those from Australia (oil yields of 0.4, 0.5, 0.6, 0.4, and 2.8%, resp.) [8] [10] [13] [17]. On the other hand, the oil yields of E. gunnii, E. viminalis, and E. bicostata from Tunisia (0.5, 2.1, and 3.0%) were lower than those from Australia (2.1, 3.6, and 3.2%) [7] [17].…”