Sesquiterpenes from Acorus calamus L.

Abstract

Three new sesquiterpenes, acoragermacrone (1), acolamone (2), and isoacolamone (3) were isolated from Acorus calamus L., and their structures were elucidated. In particular, acoragermacrone, a ten-membered ring sesquiterpene, is the most important precursor of the other sesquiterpenes included in the same plant. Acoragermacrone was converted into shyobunone, epi-shyobunone, preisocalamendiol, acolamone, and isoacolamone.