Fig. 1. Inhibitory effect of curcumin on histamine-induced itching.

(A, B) After application of topical curcumin cream, there was a statistically significant decrease in the 0.1 wt.%, 1 wt.%, and 3 wt.% curcumin treatment groups and the IC₅₀ of curcumin was 0.33 wt.%. (C) The effect of systemically administered curcumin or locally applied capsaicin on histamine-induced itching. Intraperitoneal injection of curcumin (50 mg/kg) and local treatment with 0.05 wt.% capsaicin cream decreased histamine-induced itching. Each bar graph shows a comparison of the total number of scratches in each group for a period of 30 min after administration of histamine versus the total number of scratches in the control group. (D) Rota-rod with motor function test after intraperitoneal injection of curcumin. The fall latency of curcumin-treated mice was similar to that of control mice. Results are presented as means±SEM and asterisks indicate p<0.05.