8-8' - and 8-7' - Norlignan Biosynthesis Roadmap

As for natural product classes (e.g. terpenoids, alkaloids) the prefix nor- that is used in lignan phytochemical descriptions depicts loss or removal of a single carbon functionality, potentially regardless of oxidation state. Agatharesinol and sequirin differ from (E)-hinokiresinol by addition of two hydroxyl groups to the pendant olefinic group to afford agatharesinol, and an additional hydroxyl group on one of the phenyl rings for sequirin. Both norlignans constitutively accumulate in Cryptomeria japonica heartwood, with levels of agatharesinol increasing from the sapwood side of the intermediate wood to the heartwood, whereas sequirin levels increased rapidly from intermediate wood tissue to heartwood tissue Norlignan biosynthesis is also inducible. In the absence of experimental proof, a more plausible biochemical explanation is that the acetylenic products are, in fact, diarylpentanoids with no biochemical relationship to norlignan biosynthesis.