Peroxidase-dependent cross-linking reactions of p-hydroxycinnamates in plant cell walls

• Published in: Phytochemistry reviews Vol. 3; no. 1-2; pp. 79 - 96
• Main Authors: Ralph, John, Bunzel, Mirko, Marita, Jane M., Hatfield, Ronald D., Lu, Fachuang, Kim, Hoon, Schatz, Paul F., Grabber, John H., Steinhart, Hans
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01-01-2004
• Subjects: Abbreviations; Acids; Animal nutrition; Cell walls; Chemical reactions; Crosslinking; Dietary fiber; Esters; Food technology; Gas chromatography; Human nutrition; Hydroxycinnamic acid; Lignin; Mass spectrometry; Mass spectroscopy; Monomers; NMR; Nuclear magnetic resonance; Nutrition; Oligomers; Organic chemistry; Peroxidase; Plant physiology; Polysaccharides; Sinapic acid; Trimers
• ISSN: 1568-7767; 1572-980X
• DOI: 10.1023/B:PHYT.0000047811.13837.fb

Peroxidases are heavily implicated in plant cell wall cross-linking reactions, altering the properties of the wall and impacting its utilization. Polysaccharide-polysaccharide cross-linking in grasses is achieved by dehydrodimerization of hydroxycinnamate-polysaccharide esters; a complex array of hydroxycinnamic acid dehydrodimers are released by saponification. Ferulates are the major cross-linking agents, but sinapate-ferulate cross-products have been discovered implicating sinapates in a similar role. New dehydrodimers have been authenticated, expanding our knowledge of the chemistry, role, and extent of cross-linking reactions. Ferulate dehydrotrimers have been discovered; whether these trimers truly cross-link three independent polysaccharide chains or only two remains to be determined. Hydroxycinnamates and their dehydrodimers also undergo radical coupling reactions with lignin monomers and possibly oligomers, resulting in lignin-polysaccharide cross-linking in the wall. Both polysaccharide-polysaccharide and lignin-polysaccharide cross-links inhibit the enzymatic hydrolysis of cell walls. The cross-linking process has particular relevance to plant physiology, human and animal nutrition and health, and food technology.Abbreviations: CW – cell wall; DFA – dehydrodiferulic acid (or dehydrodiferulate in context); DSA – dehydrodisinapic acid; TFA – dehydrotriferulic acid; SA – sinapic acid (1S); TA – thomasidioic acid (5C3SS); IDF – insoluble dietary fiber; SDF – soluble dietary fiber; GC-MS – gas chromatography-mass spectrometry; NMR – nuclear magnetic resonance (spectroscopy).