You should pursue the cheque bounce case. However, it may take time but it may convict your friend for dishonour of cheque and he will pay double the amount mentioned in the cheques. This is the sole option you have to resort to legal remedy. You have not made a written agreement for sharing profit in the business and his business is also lacking legal formalities.
You can file a civil suit for recovery of money
You have the evidence that your friend has borrowed money from you. The bank statement is sufficient to file a civil suit for recovery of money. In absence of business or commercial agreement you cannot sue your friend for the payment of interest upon the money. If you would have contracted for sharing profit in the business then you have the right to claim interest. You have the right to recover the amount you paid and a simple interest under the provisions of Code of Civil Procedure. The court may grant payment of simple interest on the whole amount. But you must file a civil suit simultaneously to the cheque bounce case.