Relation of Cathartic Activity to Structural Modifications of Ricinoleic Acid of Castor Oil

Castor oil and certain of its derivatives were tested in rats to elucidate the specific structural configuration of castor oil responsible for its cathartic action. The results indicate that the hydroxyl function on carbon-12 and the double bond between carbons 9 and 10 of the ricinoleic acid moiety are essential for the cathartic action, as evidenced by the loss of activity upon either masking of the hydroxyl group or hy-drogenation of the double bond. On the other hand, the naturally occurring cis configuration of the double bond is not essential for this action, as evidenced by the retention of the activity upon elaidinization to the trans configuration.