Chemotaxonomic and Phylogenetic Significance

Proanthocyanidins have been popular taxonomic markers because of their ready detection. Initial observations were often limited to presence/absence, or at the most to reports of the presence of specific proanthocyanidin (oxidation pattern) types (7). More recently the ready ability to isolate and purify tannins has enabled assessment of stereochemistry as an additional classification character (37). 

Bate-Smith was the first to note the correlation of woodiness with proanthocyanidins. In his early surveys of leaf extracts, he found, in a sample of about 800 species that included most major plant families, that 61% of the woody families had proanthocyanidins, whereas only 15% of herbaceous families were shown to contain these constituents (7). Bate-Smith (9) later formalized these observations, and his words are worth quoting here . . but the presence or absence of leuco-anthocyanins (denoted a and 3., respectively) is highly significant taxonomically. Similarly, the presence or absence (denoted b and bo, respectively) of the vie- 

The profisetinidins in the Anacardiaceae are of unusual structure as they consist of flavanoid units with a IS rather than the normal 2R configuration (see Sect. 7.6). This situation is rare in the proanthocyanidins and only a few other instances are known the widespread occurrence of e z epicatechin and ent-epicatechin-4 procyanidins in monocotyledonous plants (29), and the presence of ezz epicatechin in Polygonum multiflorum (93) and Uncaria gambir (95). Ent-catechin has been isolated from Polygonum multiflorum (93) and Rhaphiolepsis umbellata (91) - as the 7-O-glucoside and 3-O-gallate, respectively. 

The occurrence of propelargonidins (1, 4) in woody families is more widespread (see Table 7.7.4). These are normally accompanied by procyanidins and sometimes prodelphinidins. A possible tendency is for them to occur in families in the Rosidae group, the 5-deoxy proanthocyanidins occurring exclusively here. Propelargonidins, on current evidence, are absent from the Magnoliidae (the most primitive group), Caryophyllidae, and Hamamelidae. 

Structure Order (Group) Family Species Organ Reference 

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