Episesamin is an isomer of sesamin, resulting from the refining process of non-roasted sesame seed oil. Episesamin has two methylendioxyphenyl groups on exo and endo faces of the bicyclic skeleton. The side methylendioxyphenyl group was metabolized by cytochrome-P450. Seven metabolites of episesamin were found in rat bile after treatment with glucuronidase/arylsulfatase and were identified using NMR and MS. The seven metabolites were (7α,7′β,8α,8′α)-3,4-dihydroxy-3′,4′-methylenedioxy-7,9′:7′,9-diepoxylignane (EC-1-1), (7α,7′β,8α,8′α)-3,4-methylenedioxy-3′,4′-dihydroxy-7,9′:7′,9-diepoxylignane (EC-1-2) and (7α,7′β,8α,8′α)-3,4:3′,4′-bis(dihydroxy)-7,9′:7′,9-diepoxylignane (EC-2), (7α,7′β,8α,8′α)-3-methoxy-4-hydroxy-3′,4′-methylenedioxy-7,9′:7′,9-diepoxylignane (EC-1m-1), (7α,7′β,8α,8′α)-3,4-methylenedioxy-3′-methoxy-4′-hydroxy-7,9′:7′,9-diepoxylignane (EC-1m-2), (7α,7′β,8α,8′α)-3-methoxy-4-hydroxy-3′,4′-dihydroxy-7,9′:7′,9-diepoxylignane (EC-2m-1) and (7α,7′β,8α,8′α)-3,4-dihydroxy-3′-methoxy-4′-hydroxy-7,9′:7′,9-diepoxylignane (EC-2m-2). EC-1-1, EC-1-2 and EC-2 were also identified as metabolites of episesamin in human liver microsomes. These results suggested that similar metabolic pathways of episesamin could be proposed in rats and humans.
2012 The Pharmaceutical Society of Japan