The total curcumin yield was used as an index for optimizing the conditions of the extraction of Curcuma wenyujin dregs with response surface methodology.The antioxidant activity of the extracts was determined by the DPPH and ABTS free radical inhibition methods,and the influence of them on survival rate,melanin synthesis and tyrosinase activity in mouse melanoma B16 cells was also investigated.The results showed that the optimal extraction conditions were:ethanol concentration 82%,ultrasonic time 55 min,liquid/solid ratio 22 mL/g.The average extraction yield of total curcumin was 6.38 mg/g.In addition,the extracts from C. wenyujin dregs could scavenge DPPH and ABTS free radicals with IC₅₀ values of 24.99 μg/mL and 49.72 μg/mL,respectively.Further,it can effectively inhibit melanin synthesis and tyrosinase activity of B16 cells,with significant differences compared with normal control(P < 0.05).This study provided the basis for the secondary development and utilization on the dregs of C. wenyujin after extracting essential oil.