Condensed Tannins as a Source of Novel Biocides

  • Peter E. Laks


The condensed tannins are natural preservatives of lignocellulosic materials. They are commonly found in high concentrations in many external protective plant tissues like seedcoats and bark as well as in the heartwood of some tree species. Condensed tannins have traditionally been used in many areas of the world as preservatives for fishing nets, twines, and fabrics. More modern applications that have been investigated are food and wood preservatives, with especially good results achieved for the latter. Treatment with a procyanidin/copper(II) chelate yielded wood blocks with greater resistance to decay by Coriolus versicolor than pentachlorophenol when evaluated in a standard ASTM soil-block test. Condensed tannins can also be reacted directly with the wood to give it decay resistance and dimensional stability similar to a naturally durable wood. It is also possible to synthesize flavonoids with antimicrobial activity by thiolysis of procyanidins and ketalization of catechin. The structure-activity relations of these semisynthetic flavonoids have provided information on the mode of action of flavonoid phytoalexins.


Condensed Tannin Wood Preservative Decay Resistance Naphthenic Acid Dual Treatment 


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Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • Peter E. Laks
    • 1
  1. 1.Institute of Wood ResearchMichigan Technological UniversityHoughtonUSA

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