In continuation of our investigations of the genus Plantago L. (Plantaginaceae), sixteen species were investigated with respect to watersoluble glycosides. The iridoids auroside, strictoloside and globularicisin, as well as poliumoside, 3-[(4-beta-D-glucopyranosyloxy)phenyl]propionic acid and 2-[4-(beta-D-glucopyranosyloxy)phenyl]acetic acid were isolated from Plantago for the ﬁrst time. The latter compound has not previously been isolated as a natural product. Sorbitol was the main carbohydrate in all the species investigated. The distribution of iridoids correlates well with the morphological classiﬁcation of Rahn and also with a recently published molecular phylogenetic study of nuclear ribosomal and plastid DNA sequences. A new chemotaxonomic ﬁnding is an abundance of iridoid glucosides present in one of the two groups within subgenus Coronopus section Coronopus, while the other group lacks iridoids, supporting a subdivision of this section. Moreover, in subgenus Albicans, 10-benzoylcatalpol is a characteristic constituent of section Gnaphaloides, while the corresponding cinnamoyl ester globularin occurs in section Lanceifolia. In biosynthetic experiments, labelled epideoxyloganic acid and deoxygeniposidic acid were incorporated into aucubin and geniposidic acid in Plantago ovata, consistent with earlier ﬁndings, but no incorporation into asperuloside was observed. The evolution of biosynthetic pathways in Plantago is discussed.
|Journal||Plant Systematics and Evolution|
|Publication status||Published - 2003|