Preliminary study on the phytochemical evolution of different Lamiaceae species based on iridoids

In this work, an interesting potential application of phytochemistry is reported. In particular, we employed the Sporne diagrams to provide information about the evolution of some different Lamiaceae species in relation to their content in secondary metabolites. In more details, fifteen species belonging to six different genera were studied i.e. Ajuga L., Galeopsis L., Melittis L., Sideritis L., Stachys L. and Teucrium L. The selected secondary metabolites were iridoids because of their wide occurrence and distribution within all the family, thus providing a more accurate and general overview. Nineteen different compounds of this class were identified in the studied species. The aim of this work was to verify if the evolutionary data available in literature for the studied species and based on molecular studies, matched with those obtained from a more phytochemical approach or not. The final objective was to ascertain a correspondence between these two opposite methods. The results of this study clearly showed that, only in some cases, this correspondence was present. This may suggest the possibility to use both methods for drawing phylogenetic trees of plants. Anyway, this study is not general and is quite limited in studied species and in collection areas and does not intend to affirm its absolute accuracy even though it may be a good starting point for future researches in this field.