Abstract: It is intended to find a compound that is structurally simpler than yohimbine, a pentacyclic condensed heterocyclic compound, and has an effect similar to that of yohimbine. The present invention relates to a pharmaceutical or food composition for ?2 receptor blockage comprising a compound represented by the formula (I) or a pharmaceutically acceptable salt thereof: (wherein R1 represents a hydrogen, alkyl group, alkenyl group, alkynyl group, aromatic group, aralkyl group, acyl group, arylsulfonyl group, alkylsulfonyl group, or hydroxyl group; R2 represents a hydrocarbon group; R3, R4, R5, R6, and R7 are the same or different and represent a hydrogen, halogen, alkyl group, or alkoxy group; R8 represents a hydrogen or acyl group; n represents an integer of 1 to 6; and a and b are the same or different and represent 1 or 0).