Biosynthesis of antioxidant lignans in Sesamum indicum seeds

Sesame lignans, whose biosynthetic pathway is the subject of this study, have well-established antioxidant and health protecting properties. Using a combination of radio-and stable-isotopically labelled precursor administration experiments, it was demonstrated that E-coniferyl alcohol undergoes stereoselective coupling to afford (+)-pinoresinol in Sesamum indicum seeds. Only this enantiomer, and not its (-)-antipode, is metabolized further in maturing seeds to afford (+)-piperitol, (+)-sesamin, and (+)-sesamolin. Introduction of the methylene dioxy bridges occurs sequentially with piperitol first being formed, this being subsequently modified to afford sesamin. Copyright (C) 1997 Elsevier Science Ltd. All rights reserved.