Study on Synthesis and Antioxidant Activities in Vitro of Curcumin Pyrazole Derivative
Objective To construct curcumin pyrazole derivative by the reaction of diketone of curcumin and benzylhydrazine based on the above structure-activity relationship,and to explore its antioxidant activity to provide experimental basis for the development of curcumin antioxidant derivative.Methods Curcumin-N-substituted pyrazole derivative was synthesized from curcumin and benzylhydrazine.The structures of the derivative were confirmed by infrared spectroscopy(IR),nuclear magnetic resonance spectroscopy(1H-NMR,13C-NMR)and LC-MS.The antioxidant activity in vitro of the derivative was evaluated by determination of curcumin and its pyrazole derivative scavenging ability for 2,2-diphenyl-1-picrylhydrazyl(DPPH)free radical and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid(ABTS)free radical.Results Curcumin pyrazole derivative was successfully synthesized.Curcumin and its pyrazole derivative showed good free radical scavenging effects in the range of 4.6-73.6,6.25-100 μg·mL-1,respectively,with a significant dose-effect relationship.The half-maximal inhibition(IC50)values of curcumin and its pyrazole derivatives determined by DPPH method were 14.24,40.37 μg·mL-1,respectively,while the IC50 values of curcumin and its pyrazole derivatives determined by ABTS method were 36.65,19.26 µg·mL-1,respectively.Conclusion The antioxidant activity of β-dione of curcumin was retained through the substitution of the pyrazole ring,and the curcumin pyrazole derivative deserves further investigation as a potential antioxidant.