Grape skins (Vitis vinifera L.) catalyze the in vitro enzymatic hydroxylation of p-coumaric acid to caffeic acid

Biotechnol Lett. 2009 Dec;31(12):1953-60. doi: 10.1007/s10529-009-0103-5. Epub 2009 Aug 21.

Abstract

The ability of grape skins to catalyze in vitro conversion of p-coumaric acid to the more potent antioxidant caffeic acid was studied. Addition of different concentrations of p-coumaric to red grape skins (Cabernet Sauvignon) resulted in formation of caffeic acid. This caffeic acid formation (Y) correlated positively and linearly to p-coumaric acid consumption (X): Y = 0.5 X + 9.5; R (2) = 0.96, P < 0.0001. The kinetics of caffeic acid formation with time in response to initial p-coumaric acid levels and at different grape skin concentrations, indicated that the grape skins harboured an o-hydroxylation activity, proposedly a monophenol- or a flavonoid 3'-monooxygenase activity (EC 1.14.18.1 or EC 1.14.13.21). The K (m) of this crude o-hydroxylation activity in the red grape skin was 0.5 mM with p-coumaric acid.

MeSH terms

  • Caffeic Acids / metabolism*
  • Coumaric Acids / metabolism*
  • Cytochrome P-450 Enzyme System / metabolism
  • Hydroxylation
  • Kinetics
  • Monophenol Monooxygenase / metabolism
  • Plant Proteins / metabolism
  • Propionates
  • Time Factors
  • Vitis / metabolism*

Substances

  • Caffeic Acids
  • Coumaric Acids
  • Plant Proteins
  • Propionates
  • Cytochrome P-450 Enzyme System
  • flavonoid 3'-hydroxylase
  • Monophenol Monooxygenase
  • p-coumaric acid
  • caffeic acid