Synthesis, Characterization, and Pharmacological Activities of Copper(II) Complexes of Curcumin Derivatives

Background: Curcuma longa L. is an herbaceous plant of the Zingiberaceae family. curcumin and its derivatives possess a vast variety of biological activities like antimicrobial, antioxidant, anti-inflammatory, antimalarial, antirheumatic, etc. Looking into the biological significance of curcumin and its derivatives, we have decided to synthesize novel derivatives of curcumin and their coordinated Copper (II) complexes and evaluate their pharmacological activities like antioxidant, antibacterial, etc. Methods: Targeted derivatives of curcumin were prepared in good yield (95%) by the condensation reaction of carbohydrazide (1), and curcumin (2), in the presence of copper salts using classical heating methods in the presence of absolute ethanol. Results: The targeted derivatives of curcumin were evaluated for their collaborative antimicrobial activity against gram-positive and gram-negative bacterial strains. The zone of inhibition was measured by considering the disc diffusion method. In vitro minimum inhibitory concentrations of targeted compounds were measured using the broth micro-dilution method. In addition to this, the in vitro antioxidant activity of target compounds was also evaluated by adopting the DPPH method using ascorbic acid as a standard substance. Most of the compounds showed fascinating antibacterial and antioxidant activities in contrast to pure curcumin. Conclusion: In conclusion, the present work explains the synthesis, characterization, and evaluation of biological activities of novel derivatives of curcumin and their coordinated Copper (II) complexes. All the targeted compounds were screened for their pharmacological activities against selected human pathogenic bacteria. The antioxidant activity of the synthesized compounds was also evaluated against DPPH and ascorbic acid standard substances. Among the designed molecules, most of the compounds showed fascinating antibacterial and antioxidant activities as compared to pure curcumin.