First total phytochemical analysis on the aerial parts of an endemic Italian species: Ajuga tenorei C. Presl

In this work, we report the first analysis in absolute about an endemic Italian plant, Ajuga tenorei C. Presl and in particular we focused on its phytochemical pattern. A. tenorei C. Presl (A. acaulis Brocchi), better known with the common name of Tenore's Bugle, is a herbaceous perennial plant belonging to the tribe Ajugoideae of the Lamiaceae family. From a botanical standpoint, this species is mainly characterized by the fact that it has no stem or this is very short for which it can be easily distinguished from the other species of the genus. Its height can reach up to 10 cm. Its leaves are all collected in a basal rosette and have an oblanceolate shape and are crenate. The flowers are small and are blue-violet colored blooming from May to June. Its habitat is represented by rocky forests and calcareous soils from 1200 to 2200 m a.s.l. This species is endemic in Italy, typically located in the Central and Southern regions even with many exceptions. Several species of the Ajuga genus own an ancient traditional use in folk medicine in many areas of the world for several disorders and against several diseases but are also noted for other pharmaceutical activities. The studied sample was collected within the “Majella” National Park territory and in particular, in the town of Rivisondoli in the province of L’Aquila (Abruzzo Region, Central Italy) (geographic coordinates: 41°86'13'' N; 13°98'99'' E) during August, 2015 at an altitude of about 1750 m a.s.l. The phytochemical analysis was performed on the ethanolic extract and we used techniques such as classical Column Chromatography for the separation of the polar compounds and NMR spectroscopy and Mass spectrometry for their identification. This procedure evidenced the presence of five compounds namely verbascoside (1), echinacoside (2), ajugoside (3), harpagide (4) and 8-O-acetylharpagide (5), which are important for two different points of view: chemotaxonomy and ethno-pharmacology. For what concerns the first one, all these compounds have already been reported in the genus and in the family but also in other correlated families like Scrophulariaceae or Orobanchaceae confirming the botanical classification of this species and the systematic proximity of all these families. By the way compounds (1) and (2) are very common phenyl-ethanoid glycosides and the iridoid compounds (3), (4) and (5) are considered chemotaxonomic markers respectively of the genus and the family. For what concerns the second point, instead, they all present strong pharmacological activities i.e. anti-inflammatory and anti-bacterial which might suggest the possibility of a future employment of this species in medicine, too.