Fig. 4. (A) The synthesis of tetrahydrocurcumin by catalytic hydrogenation of curcumin. (B) Effects of curcumin and tetrahydrocurcumin on dextran sulfate sodium (DSS)-induced colitis. Curcumin and tetrahydrocurcumin were treated to mice by gastric intubation at a dose of 0.25 mmol/kg each. Histology of H&E-stained mouse colon was visualized under a microscope. (a) Control; (b) DSS alone; (c) DSS + curcumin; (d) DSS + tetrahydrocurcumin.