Synthesis and biological evaluation of new curcumin derivatives as antioxidant and antitumor agents

Twenty-four new compounds were prepared, taking curcumin as a lead, in order to explore their antioxidant and antitumor properties. The capacities of these derivatives to scavenge the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS.+), and to protect human red blood cells (RBCs) from oxidative haemolysis were investigated. In addition, the percentage viability of different cell lines (Hep G2, WI38, VERO and MCF-7) was tested. The result of the antitumor testing was generally in accordance with those of the antioxidant assays. Compounds which bear o-methoxy substitution to the 4-hydroxy function in the phenyl ring (7g, 5g and 3g) exhibited significantly higher ABTS.+-scavenging, antihaemolysis, and antitumor activities than other derivatives. In addition, molecular modelling studies were carried out for biologically active and inactive compounds, to study the structure–activity relationship, with the aim to elucidate which portions of the molecules are critical for the antioxidant and antitumor activity.