Unsecured loan transferred to partner’s capital A/c
Situation behind this transaction is not clear from your question, But there may be some situation as given below;-

1. There may be a case, when a partner has given unsecured loan to his partnership firm and later on that partner is agreed to convert its loan to its capital. Assuming that partnership deed allow such conversion, then there is no issue in converting unsecured loan of that partner to his capital. A single entry need to be posted by debiting the unsecured loan a/c and by crediting the partner capital account. 
2. There may be case where, a partnership firm has received unsecured loans from different creditors, which are repaid by a partner from his personal account, and this sum is payable to that partner by the firm but partner agreed to convert his dues to his capital…this is accounted by debiting unsecured loan account and by crediting the partner personal account and then debited the partner personal account and by crediting the partner’s capital a/c.  Assuming that partnership deed allow such type transactions if such transactions are not allowed as per partnership deed then partnership deed can be amended to allow such type of transactions. 

Accounting entries of such transactions are explained in above points. Now coming to your question above allowing such transaction (transfer of unsecured loans to partner capital account) in income tax act, the partnership firm and individuals need to ensure compliance of section 269SS & 269T regarding cash transaction. And other actions regarding conversion of loan to capital are governed by partnership deed. no clause in income tax prohibit such conversion. But transactions should be real.