JNK inhibitor

332 1 A JNK inhibitor containing a compound having an isoquinolinone skeleton or a salt thereof, such as a compound represented by the formula wherein ring A and ring B are each an optionally substituted benzene ring, X is -O-, -N═, -NR- or -CHR-, Ris an acyl group, an optionally esterified or thioesterified carboxyl group, an optionally substituted carbamoyl group or an optionally substituted amino group and the like, a broken line shows a single bond or a double bond, and Ris a hydrogen atom, an optionally substituted hydrocarbon group, an optionally substituted heterocyclic group and the like, and the like.