A pharmaceutical composition, comprising:a compound represented by formula (I): ##STR9## wherein X is an alkyl group having from 1-4 carbon atoms or an alkoxy group having from 1-4 carbon atoms; Y is a hydrogen atom or an alkoxy group having from 1-4 carbon atoms; Z is an alkyl group having from 1-4 carbon atoms or an alkoxy group having from 1-4 carbon atoms; A is an alkylene group having from 1-