A novel tetracyclic compound useful as an immuno-suppressant, represented by general formula (I), or a pharmacologically acceptable salt thereof wherein X¹ and X² may be the same or different from each other and each represents hydrogen or lower alkyl, and n represents an integer of 1 to 4.
This invention relates to a novel tetracyclic compound represented by formula (I): ##STR1## or its pharmacologically-acceptable salt. The compound of this invention has strong immunosuppressive activity, and is useful as an immunosuppressive agent and as an agent for treating autoimmune disease.