Phytochemical variations on a biosynthetic theme

Biosynthetic pathways that may lead to the diverse secondary metabolites occurring in liverwort oil bodies are considered in relation to the apparently disparate products that can be found in closely related taxa. Discussion centres on recent work with Plagiochila bifaria (Sw.) Lindenb., a broadly defined species where different chemotypes are characterized by either 9,10-dihydrophenanthrenes, methyl orsellinates, or 9-arylnon-6-en-2-ones. A scenario is presented to illustrate the possibility that a biosynthetic theme common to all examples of the taxon studied could account for the phytochemical variations observed. A complementary study of members of Plagiochila sect. Rutilantes Carl illustrates that taxa maintained at specific rank may nevertheless contain several secondary metabolites in common.

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