The Possible role of Reactive Centre’s of Curcumin in deciding its biological activity

Abstract

The aim of the study was to investigate the role of keto-enol centre of curcumin in deciding its ROS quenching efficiency, toxicity and DNA binding ability. Curcumin has three major contributing centers for free radical reaction, namely phenol, enol and conjugated diene. The activity of metal complex of curcumin and curcumin was compared to evaluate the effect of keto-enol reactive center towards the biological and antioxidant activity. The metal complex of curcumin exhibited ROS quenching efficiency comparable to that of curcumin emphasising importance of phenolic centre. Morphological studies with H9c2 cells revealed insignificant levels of alterations in 48 h of treatment with curcumin and its metal complexes. The comparable cytotoxicity value of curcumin and its metal complexes point to the insignificance of keto-enol centre in deciding its activity. The complexes of curcumin showed better binding capability in the order of 105 in comparison to our previously reported curcumin binding of the order 103. The change in the curcumin scaffold at keto-enol center by metal retained its ROS quenching efficiency, exhibiting comparable cytotoxicity to that of curcumin at the same time improving the binding capability to DNA emphasizing the importance of phenolic centre in deciding its activity and complexation with metal has modest effect its antioxidant property