Patent ID: 8119686

Claim:
A spiroquinone compound represented by the following formula (1): wherein R 1a , R 1b , R 1c and R 1d are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent, and R 2a and R 2b are the same or different and each represents a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, an N-substituted carbamoyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, or an aralkyl group which may have a substituent, the groups R 2a and R 2b may bond together to form a hydrocarbon ring with an adjacent carbon atom, and the hydrocarbon ring may have a substituent, provided that compounds in which all of the groups R 1a , R 1b , R 1c and R 1d are t-butyl groups, and both of the groups R 2a and R 2b are hydrogen atoms or both of the groups R 2a and R 2b are methyl groups are excluded; or a pharmacologically acceptable salt thereof.