4.1 Eucalyptol (1,8-cineole)
Eucalyptol (fig. 2) is a natural saturated bicyclic monoterpenoid that is extracted from various species of Eucalyptus (e.g., Eucalyptus globulus Labill., Eucalyptus polybractea R.T. Baker andEucalyptus smithii R.T. Baker, Fam. Myrtaceae). The essential oil of eucalyptus contains not less than 70% of eucalyptol as reported in Ph. Eur. 10th ed. Pure eucalyptol is a clear liquid at room temperature, and the melting point is 1.5°C with a flash point of 49°C (Prasanthi et al., 2012).