Matricaria chamomilla synthesize (Z)- and (E)-2-ß-D-glucopyranosyloxy-4-methoxy cinnamic
acid (GMCA), the biosynthetic precursors of herniarin. During leaf development the
content of (E)-GMCA decreased and no changes were found in the content of other
compounds evaluating in the experiments. Methyl jasmonate elicits an increase in (E)-
GMCA and herniarin content in young growing leaves as well as mature and senescing
leaves 48 h after treatment. In contrast, attack by the thrips, Echinothrips americanus,
causes increase not only in GMCAs and herniarin content but also in the amount of
coumarin, umbelliferone. The results confirmed that coumarin-like metabolites can be
considered as plant defence compounds in biotic and abiotic stress conditions.