Investigation of organic extractives from unifloral chestnut (Castanea sativa L.) and eucalyptus (Eucalyptus globulus Labill.) honeys and flowers to identification of botanical marker compounds

Ultrasound-assisted extraction was employed to investigate the composition of extractable compounds from unifloral chestnut and eucalyptus honeys. 1-phenylethanol and 2′-aminoacetophenone are the most powerful botanical markers of chestnut honey. Additionally, cis-cinnamyl alcohol, and p-hydroxyacetophenone were found exclusively in chestnut honey. Organic extractives from whole chestnut flowers were predominated by 1-phenylethanol, nonanal, benzyl alcohol, and nonanoic acid. Of the 16 compounds found in the flower extract, 13 were present in honey as well. Some of them are transferred directly to honey, while in other cases modification reactions take place. Eucalyptus honey is characterized by 2-hydroxy-5-methyl-3-hexanone and 3-hydroxy-5-methyl-3-hexanone, as well as exo-2-hydroxycineole and an unknown norisoprenoid. Aside from, acetoin, nonanal, methyl nonanoate, and dehydrovomifoliol were present in higher concentrations. In eucalyptus flower extracts, norisoprenoids were the most abundant compounds, all of which were also present in the honey samples. 3-Oxo-α-ionone comprised half of the total amount, followed by eucalyptol.