Metabolites of Gallic Acid

Family Genus, species Part Common name 

Anacardiaceae Rhus typhina R. coriaria Leaves Sumac 

Leguminosae Caesalpinia coriaria Fruit pods Divi-divi 

Fagaceae Castanea spp. Wood, bark, leaves Chestnut 

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The Interaction of Proteins with Metabolites of Gallic Acid... 

Polyphenols (syn vegetable tannins - proanthocya-nidins and esters of gallic acid, vide supra) constitute one of the most distinctive groups of higher plant secondary metabolites. Their uniqueness lies not only in their molecular size and polyphenolic character but also in their ability to complex strongly with proteins, carbohydrates, nucleic acids and alkaloids. Studies of these properties are not only of intrinsic scientific interest. a scientist who confesses to an interest in polyphenols is invariably asked one question - why do plants form them ... 

Methylated 20% of metabolites S position also glucuronidated, sulfated 20-30% of metabolites 3 -position also glucuronidated, sulfated 4-Position Not detected 3i or 4iposition 3- or 4-position of gallic acid... 

Many of their characteristic properties (in particular, their complexation with proteins, polysaccharides, and various nitrogenous metabolites) draws attention once again to the distinctive position of gallic acid as a secondary plant product. 

Gallic acid is almost invariably found in plant tissues in ester form. Various simple esters of gallic acid have been described from plant sources (Table 7.2.2, Table 7.2.3) and these metabolites are in many ways analogous to the hydroxycinnamoyl esters occurring in plants. These esters are thus formed by association with sugars. 

The patterns of further metabolism of 15, which have been discerned in the leaves of plants (46), are broadly divisible into at least three groups, labelled A, B, and C (Fig. 7.2.4). Attention is directed in this review to these three major patterns but it should be noted that this scheme probably does not yet represent an all-embracing classification of gallic acid metabolism in higher plants. We previously noted those plant species that provided extracts of commercial importance in history whereas several points of contact between the phenolic metabolites of these particular plants and Fig. 7.2.4 are self-evident (vide infra) others - notably Terminalia chebula, Caesalpinia coriaria, and C. brevifolia - quite clearly produce a range of phenolic metabolites which, on the basis of the available evidence. 

Shahrzad, S. and Bitsch, 1. (1998) Determination of gallic acid and its metabolites in human plasma and urine by high-performance liquid chromatography. /. Chromatogr. B, 705, 87-95. 

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