[Extraction of thermolabile compounds with supercritical gases.].

The thermolabile acoragermacrone and other sesquiterpenes could be extracted with supercritical carbon dioxide from beta-asarone free calamus rhizomes ( Acorus calamus L. var. americanus Wulff. A usual steam distillation lets this substance partly decompose into shyobunone. By using high pressure extraction with fractionated separation a higher yield of the bitter principles of calamus, acorone and isoacorone, is obtained.