A new mammalian lignan precursor, asarinin

Enterolactone (ENL) and enterodiol are mammalian lignans. Several plant lignans have been reported as precursors of mammalian lignans. However, asarinin (AS), a furofuran type lignan which occurs in medicinal plants and foods, has not been reported as mammalian lignan precursor to date. After the incubation of AS with human intestinal microflora, AS was converted to not only ENL, but also two more metabolites (mono-demethylenated and ring-cleaved compounds). Under the same conditions, sesamin (SM) was converted to ENL. Furthermore, chiral HPLC analysis showed that ENL produced from AS and SM was (−)-ENL. This is the first report which shows that AS is a mammalian lignan precursor.