Anti-tumour and free radical scavenging activity of synthetic curcuminoids

Eight synthetic curcuminoids were investigated for their cytotoxic and tumoricidal activities as well as for their free radical scavenging activity. All the curcuminoids were found to be cytotoxic to cultured L929 cells; concentration needed for 50% inhibition being around 1 mu g/ml (3.9-2.5 mu M). As antitumour agents, veratryl curcuminoid and salicyl curcuminoid increased the life span of animals by 100.6 and 86.9%, respectively. All the curcuminoids inhibited in vitro lipid peroxidation and scavenged superoxides and hydroxyl radicals. Curcuminoids with a free hydroxyl group on the phenyl ring, such as salicyl curcuminoid, were found to be most active. Compounds which did not have free hydroxyl group such as veratryl curcuminoid, had lower activity in vitro but showed comparable activity in vivo. The results indicated that synthetic curcuminoids, like natural curcumin are potent antioxidants.