Chemical composition of 8 eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities
Hydrodistillation of the dried leaves of five species of the genus Eucalyptus L' Hér., viz., E. dundasii Maiden, E. globulus Labill., E. kitsoniana Maiden, E. leucoxylon F. Muell., and E. populifolia Hook., harvested from Jbel Abderrahman arboreta (region of Nabeul, northeast of Tunisia) in April 2006, afforded essential oils in yields varying from 0.9±0.3 to 3.8±0.6%, dependent on the species. E. globulus and E. Kitsoniana provided the highest and the lowest percentage of essential oil amongst the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 127 compounds, representing 93.8 to 98.7% of the total oil composition. The contents of the different samples varied according to the species. The main components were 1,8-cineole (2; 4.7-59.2%), followed by α-pinene (1; 1.9-23.6%), trans-pinocarveol (6; 3.5-21.6%), globulol (8; 4.3-12.8%), p-cymene (3; 0.5-6.7%), α-terpineol (1.5-4.5%), borneol (0.2-4.4%), pinocarvone (1.1-3.8%), aromadendrene (1.4-3.4%), isospathulenol (0.0-1.9%), fenchol (4; 0.1-2.5%), limonene (1.0-2.4%), epiglobulol (0.6-2.1%), viridiflorol (9; 0.8-1.8%), and spathulenol (0.1-1.6%). E. leucoxylon was the richest species in 2. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) separated the five Eucalyptus leaf essential oils into four groups, each constituting a chemotype.