BIOSYNTHESIS OF ANTIOXIDANT LIGNANS IN SESAMUM-INDICUM SEEDS

Sesame lignans, whose biosynthetic pathway is the subject of this stud y, have well-established antioxidant and health protecting properties. Using a combination of radio-and stable-isotopically labelled precurs or administration experiments, it was demonstrated that E-coniferyl al cohol 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 bridg es occurs sequentially with piperitol first being formed, this being s ubsequently modified to afford sesamin. Copyright (C) 1997 Elsevier Sc ience Ltd. All rights reserved.