The present invention provides a compound represented by the following formula (I):wherein: Ring A represents an optionally substituted piperazine ring, an optionally substituted morpholine ring, or an optionally substituted homopiperazine ring； R1and R2are the same or different from each other, and represent a hydrogen atom or optionally substituted lower alkyl； R3and R4are the same or different from each other, and represent a hydrogen atom or halogenated or non-halogenated lower alkyl； R5to R7are the same or different from each other, and represent a hydrogen atom, hydroxy, optionally substituted lower alkyl, optionally substituted lower alkenyl, optionally substituted lower alkoxy, optionally substituted cycloalkyl, optionally substituted aryl, an optionally substituted aromatic heterocyclic ring, optionally substituted amino, or acyl； andrepresents a single bond or double bond, or a salt thereof.本發明提供下式(I)所示之化合物或其鹽：式中：A環代表視需要經取代之哌環、視需要經取代之嗎啉環、或視需要經取代之高哌環；R1與R2彼此相同或不同，係代表氫原子或視需要經取代之低級烷基；R3與R4彼此相同或不同，係代表氫原子或經鹵化或未經鹵化之低級烷基；R5至R7彼此相同或不同，係代表氫原子、羥基、視需要經取代之低級烷基、視需要經取代之低級烯基、視需要經取代之低級烷氧基、視需要經取代之環烷基、視需要經取代之芳基、視需要經取代之芳族雜環、視需要經取代之胺基、或醯基；及代表單鍵或雙鍵。
