Melphalan is a phenylalanine derivative of mechlorethamine, belonging to the family of nitrogen mustard alkylating agents that are used for chemotherapy. It attaches an alkyl group to guanine bases in DNA at the 7-nitrogen of the imidazole ring, which leads to DNA interstrand and intrastrand crosslinks, cytotoxicity, and apoptosis. Melphalan can inhibit the growth of PC-3 prostate cancer cells with IC50 values of 0.074 or 0.77 μM for sequential dosing or single dosing, respectively.