Comparison of chemical profiles of Kānuka (Kunzea robusta de Lange & Toelken, Myrtaceae) essential oils

Kānuka/rawirinui (Kunzea robusta de Lange & Toelken) is an endemic plant species in Aotearoa/New Zealand, which is still used today and traditionally by Māori. Chemical profiling of kānuka essential oils has been performed previously, although comprehensive studies are rare, as is the integration of multiple analytical platforms. In this study, we wished to compare the use of GCMS and NMR metabolomic methods for the analysis of eleven kānuka essential oils, and to apply statistical tools to evaluate how well the data sets corresponded. The main compounds detected were α-pinene (35 – 59%), p-cymene (0.1 – 19%), γ-terpinene (not detected – 12%), α-terpinolene (0.1 – 4%), linalool (1 – 5%), limonene (2 – 3%), eucalyptol (0.1 – 7%) and sesquiterpenoid viridiflorol (2 – 9%). Use of Procrustes analysis to compare the analytical data obtained from a pilot study using both GCMS and NMR metabolomic profiling indicated a high level of correlation between the data sets, suggesting either approach is suitable for analysis of kānuka essential oils in an unbiased fashion. In addition, we also report on the absolute configuration of the major component of the essential oil, (+)-D-α-pinene.