Secondary metabolites from Scrophularia canina L.

Scrophularia canina L. is a herbaceous perennial plant belonging to Scrophulariaceae and growing abundantly in Italy. In this work we report the composition of the polar fraction of the ethanolic extract of S. canina harvested in the pre-park area of National Park of Abruzzo, Lazio and Molise (Central Italy). This study allowed the isolation and the identification of a total of six compounds: one phenyl-propanoid, verbascoside; one acyclic diterpenic alcohol called phytol; four iridoid glucosides namely aucubin, harpagide, 8-O-acetyl-harpagide and 8-epiloganic acid. Verbascoside is a quite common compound which is often identified as a constituent of species of the Asterideae subclass and has a taxonomic relevance when evidenced together with iridoids. Also phytol is a widespread compound since it’s part of the chlorophyll structure. Aucubin, harpagide and 8-O-acetyl-harpagide have already been evidenced in this species while the other three compounds were recognized for the first time in this study. From a biosynthetic point of view, it’s important to underline the presence of 8-epiloganic acid since it is considered the biogenetic precursor of a wide series of substances owning an iridoidic skeleton which are generally found in Scrophulariaceae and in other families of the Lamiales order and for this reason they are considered of chemotaxonomical relevance.