Release and ecological impact of algicidal hydrolysable polyphenols in Myriophyllum spicatum

Aqueous acetone extracts of shoots of Eurasian watermilfoil (Myriophyllum spicatum) exhibit a strong inhibitory action against various coccoid and filamentous cyanobacteria and to a slightly less extent against chlorophytes and diatoms. Bioassay-directed fractionation led to the isolation of a hydrolysable polyphenol, tellimagrandin II, which turned out to be the main inhibitory substance. Myriophyllum spicatum contains large amounts of this compound (1.5 % of dry wt). Part of the inhibitory activity is due to complexation and inactivation of algal extracellular enzymes (e.g. alkaline phosphatase) by hydrolysable polyphenols from M. spicatu