LIGNANS - DIVERSITY, BIOSYNTHESIS, AND FUNCTION

The Amazonian region contains one of the world's most important repositories of plant biodiversity, whose careful and lasting stewardship is a most pressing issue facing this and future generations. Remarkably, only a tiny fraction of its plant life has been systematically and comprehensively examined for its (bio)chemical constituents and ultimate benefit to humanity. Consequently preservation of this resource is of paramount importance. This chapter addresses the occurrence and distribution of a large class of phenylpropanoid metabolites, collectively known as lignans, and their increasing significance as physiologically and pharmacologically active substances e.g., as antiviral, antitumor, biocidal and other bioactive agents. Based upon emerging chemotaxonomic data and recently discovered biochemical pathways, it appears that a high level of probability can be exercised in predicting lignan structural variants likely to be present in representatives of specific plant family superorders. Using the lignans as an example, it is proposed that further compilation of such data (at the chemical, biochemical, and gene expression levels) will be of great significance in ''cataloging'' plant biodiversity.