The Attorney General shall represent the State in all suits and pleas in the Supreme Court of the State in which the State may be a party, and shall especially inquire into the charter rights of all private corporations, and from time to time, in the name of the State, take such action in the courts as may be proper and necessary to prevent any private corporation from exercising any power or demanding or collecting any species of taxes, tolls, freight or wharfage not authorized by law. He shall, whenever sufficient cause exists, seek a judicial forfeiture of such charters, unless otherwise expressly directed by law, and give legal advice in writing to the Governor and other executive officers, when requested by them, and perform such other duties as may be required by law.