β-Fluoro-coniferyl alcohol does not inhibit lignin biosynthesis in suspension cultures of Picea abies (L.) Karst

A fluorinated analogue of coniferyl alcohol has been reported to be a specific inhibitor of oxidases involved in the biosynthesis of lignin. The Z isomer of β-fluoro-coniferyl alcohol was synthesized and used for the preparation of dehydrogenation polymers (DHPs) and was also tested on lignin producing suspension cultures of spruce ( Picea abies (L.) Karst.). The growth of the cells or the production of lignin by the suspension cultures was not significantly affected by the addition of fluoroconiferyl alcohol. This analogue did not form polymers quite as easily as did coniferyl alcohol in oxidation with hydrogen peroxide and horseradish peroxidase. In both cases the β-fluoroconiferyl alcohol became incorporated in the polymeric product. We were unable to detect any specific inhibition of peroxidase activity, which is at variance with earlier reports of pronounced inhibition of lignin biosynthesis in poplar plantlets by fluoroconiferin, a potential inhibitor of oxidases involved in lignin biosynthesis. A potential inhibitor of oxidases involved in lignin biosynthesis was synthesized and tested on lignin-producing suspension cultures of spruce.