Substituted truxillic and truxinic acids in cell walls of Cynodon dactylon

Abstract

Twelve substituted truxillic and truxinic acids were separated by GC-MS from the compounds released from the cell walls of Cynodon dactylon by treatment with sodium hydroxide. These acids are probably formed in cell walls from two ester-linked molecules of p-coumaric acid, two ester-linked molecules of ferulic acid, or from one ester-linked molecule of each of the two acids. The three major dimers found were 4, 4′-dihydroxy-α-truxillic acid, 4, 4′-dihydroxy-3,3′-dimethoxy-α-truxillic acid, and 4,4′-dihydroxy-3-methoxy-α-truxillic acid; tentative structures are proposed for the other dimers, some of which have not been described previously. The same three major dimers were obtained by treatment with sodium hydroxide of the water-soluble compounds released from the cell walls with wall degrading carbohydrases suggesting that the dimers are ester-linked to cell wall polysaccharides. Dimer formation within cell walls could involve cross-linking of wall polysaccharides, thus affecting cell wall properties including biodegradability.