Monohydroxy melphalan is a DNA alkylating agent and a degradation product of melphalan . Monohydroxy melphalan is formed by the hydrolysis of melphalan in aqueous solutions, including cell culture medium and human plasma. It increases the level of DNA adducts in ML-1 myeloblastic leukemia cells in a concentration-dependent manner and induces cytotoxicity with an IC50 value of 28.1 ug/ml.