Substituted pyrrolidine compound and use thereof

A compound represented by the formula (I):

• wherein
• X1, X2, X3 and X4 are each independently a nitrogen atom, or CRa;
• Y is an oxygen atom, NRb, or CRcRd;
• R1 is an optionally substituted C1-6 alkyl group, an optionally substituted hydrocarbon ring group, or an optionally substituted heterocyclic group bonded on the carbon atom;
• R2 is a hydrogen atom, or an optionally substituted C1-6 alkyl group;
• R3 is an optionally substituted C1-6 alkyl group, or an optionally substituted cyclic group;
• Ring A is an optionally further substituted pyrrolidine ring;
• Ra, Rc and Rd are each independently a hydrogen atom, a halogen atom, an optionally substituted C1-6 alkyl group, or an optionally substituted C1-6 alkoxy group;
• and
• Rb is a hydrogen atom, or an optionally substituted C1-6 alkyl group,
• or a salt thereof.