Detection and determination of p-coumaroylated units in lignins

J Agric Food Chem. 1999 May;47(5):1988-92. doi: 10.1021/jf981140j.


The derivatization followed by reductive cleavage (DFRC) method cleaves alpha- and beta-ethers in lignins but leaves lignin gamma-esters intact. When applied to grasses, which contain p-coumarate esters on their lignins, esterified monolignol derivatives are released. Saturation of the p-coumarate double bond occurs during DFRC, so the released products are 4-acetoxycinnamyl 4-acetoxyphenylpropionates. Synthesis of the esters allowed determination of response factors for the released products. Maize and bamboo lignins released 221 and 38 micromol/g of p-coumarate-derived esters. The sinapyl ester was much more abundant than the coniferyl one. The bamboo and maize lignin S/G ratios in the conjugates were 12 and 38 times greater than those of the normal monomers released by DFRC, evidence of a strong selectivity for acylation of syringyl units. Of three possible biochemical mechanisms for incorporating p-coumarates into lignin, evidence is mounting that the process involves incorporation of preacylated monolignols into the normal lignification process.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Chemistry, Organic / methods
  • Coumaric Acids / analysis*
  • Esters / analysis*
  • Ethers / analysis*
  • Lignin / chemistry*
  • Oxidation-Reduction
  • Poaceae / chemistry


  • Coumaric Acids
  • Esters
  • Ethers
  • Lignin