Investigating Eucalyptus essential oil: classification and prediction of volatile compounds using GC-FID and FT-MIR spectroscopy combined with chemometric techniques

The essential oil (EO) extracted from Eucalyptus leaves is known for its therapeutic effects and is used as an essential component in the formulation of numerous drugs targeting respiratory infections, including colds and flu. However, several factors affect its chemical composition and its extraction yield. The objective of this study was to investigate the effect of geographical origin and botanical variety on the chemical composition and extraction yield by chemometric techniques such as Principal Component Analysis (PCA) and to evaluate the potential of FT-MIR (Fourier Transform mid-InfraRed spectroscopy) in predicting the chemical composition of the extracted EO. The results of PCA showed that the composition of Eucalyptus EO depends mainly on the geographical origin and botanical variety. Additionally, the chemical composition obtained by the gas chromatography with flame ionization detection (GC-FID) technique was accurately predicted by partial least squares regression technique based on FT-MIR spectra, suggesting that combining FT-MIR spectroscopy with chemometrics can replace the GC-FID method, providing a rapid and accurate solution for EOs classification based on their origin and botanical variety and their chemical composition prediction.