Valorization of a Waste Product of Edible Flowers: Volatile Characterization of Leaves

(1) Background: The leaves of some plants are reported for their culinary uses, while in edible flowers, they are one of the discarded products in the supply chain. We investigated the volatile profile (VP) and the essential oil (EO) compositions of leaves from 12 Lamiaceae species, of which nine belong to the Mentheae tribe and three to the Ocimeae tribe. (2) Methods: Phytochemical analyses were performed using a GC-MS instrument. (3) Results: More than 53% of the Ocimeae tribe VP was represented by sesquiterpene hydrocarbons (SH), followed by phenylpropanoids, except for O. × citriodorum, where oxygenated monoterpenes (OM) were the second main class. OM prevailed in six species of the Mentheae tribe except for Agastache ‘Arcado Pink’, Salvia discolor, and S. microphylla, where SH dominated. The EO composition of Ocimeae tribe showed a similar behavior to that of VP concerning the predominant classes. O. basilicum ‘Blue Spice’ (Ob-BS) was an exception, since it showed oxygenated sesquiterpenes (OS: 29.6%) as a second principal class. Sesquiterpene compounds were also present in a high amount in two species of the Salviinae subtribe (S. microphylla and S. discolor) and two of the Nepetinae subtribe (Nepeta × faasenii and A. ‘Arcado Pink’). The remaining species of the Mentheae tribe were characterized by OM. (4) Conclusions: Many of the main compounds found were reported for their importance in human health and thus are important as ingredients in several new industrial products.