Heartwood Flavonoids of the Leguminosae

More chemistry has been carried out on the heartwood flavonoids of the Leguminosae than on those of any other plant family. This is not surprising considering that there are many tree species in what is a very large family and also that these trees are used as timber, for furniture, or as a source of tannin. But it also reflects the fact that there are an enormous variety of chemical structures present, particularly of isoflavonoids. The discovery of interesting and novel structures in one tree inevitably encourages investigation of related species for further novelties. 

In spite of the intensity of chemical investigation, it is still true that a completely representative survey of the family for heartwood flavonoids has still to be carried out. Chemical efforts have been concentrated in certain plant groups, notably on Acacia in the Australian and African floras, on Dalbergia, Machaeri-um and other Brazilian genera, and on some Asian taxa, such as the sandalwoods Pterocarpus. Our knowledge of flavonoid patterns is thus limited. Certain structural features that we assume to be characteristic of the family - e.g. the absence of 5-hydroxylation - may not in fact extend to more than a certain percentage of the family. 

The distribution of these phenolics in Dalbergia and Machaerium woods is indicated in Table 7.5.8. The two genera are close morphologically, and it is therefore interesting that they merge into each other chemically, with no sharp cut-off 

Continent of origin Genus, species Neoflavonoids Isoflavonoids  

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