Treatment with fisetin alone at the dose of 20 μM or 50 μM slightly inhibited COX-2 or iNOS protein expression (Fig. 5A, 5B), while the combinational treatment with melatonin at the dose of 1.0 mM markedly reduced the expression of COX-2 or iNOS at protein level in melanoma cells (Fig. 5A, 5B). Here, NOS2 is linked to melanoma.