The metabolism of gallic acid and hexahydroxydiophenic acid in higher plants part 4; polyphenol interactions part 3. Spectroscopic and physical properties of esters of gallic acid and (S)-hexahydroxydiphenic acid with D-glucopyranose (4C1)
NMR spectroscopic methods, based upon 1H and 13C and two-dimensional long-range heteronuclear shift correlation, have been used accurately to define the positions of esterification to D-glucopyranose of structurally related phenolic acids in natural polyphenols. Quantitative measurements of physical properties i.e. gelling, distribution between octan-1-ol and water, and self-association of natural phenolic esters are described and related in some cases to features of putative biogenetic schemes for these metabolites.