Phenolic glucosides in the course of ligulate flower development in diploid and tetraploid Matricaria chamomilla

The main secondary metabolites of Matricaria chamomilla ligulate flowers are apigenin-7-O-glucoside derivatives and (Z)- and (E)-2-β-d-glucopyranosyloxy-4-methoxy cinnamic acids (GMCAs), which are the precursors of herniarin. The quantities of these compounds were determinated in six phases of development of ligulate flowers in diploid and tetraploid cultivar. The content of the apigenin glucoside and its main acylated derivatives in ligulate flowers of diploid plants was found to be significantly higher before the start of flowering in comparison with tetraploid plants. During the flowering and post-flowering phase their content decreased and no difference between diploid and tetraploid plants was observed. The (E)-izomer was the dominant form of 2-β-d-glucopyranosyloxy-4-methoxy cinnamic acid. These secondary stress metabolite precursors were accumulated in higher concentrations in young growing ligulate flowers, but during flowering and post-flowering phases their content decreased. Significantly higher content was found in tetraploid plants in comparison with diploid plants. Aglycones of glycosides were found in low concentrations.