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Antioxidant capacity of curcumin-directed analogues: Structure-activity relationship and influence of microenvironment

Shang, Ya-Jing, Jin, Xiao-Ling, Shang, Xian-Ling, Tang, Jiang-Jiang, Liu, Guo-Yun, Dai, Fang, Qian, Yi-Ping, Fan, Gui-Juan, Liu, Qiang, Zhou, Bo
Food chemistry 2010 v.119 no.4 pp. 1435-1442
curcumin, turmeric, medicinal properties, antioxidant activity, chemical structure, erythrocytes, human cell lines, oxidative stress, hemolysis, protective effect, free radical scavengers, hydrophobicity, in vitro studies, structure-activity relationships
Curcumin is the active ingredient of turmeric powder with a variety of biological activities including antioxidative activity. In order to find more active antioxidants with curcumin as the lead compound we synthesised a series of enone analogues of curcumin. The present work studied and compared the capacity of curcumin-directed analogues to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH ) and protect human red blood cells (RBCs) from oxidative haemolysis. It was found that these compounds which bear o-diphenoxyl and o-dimethoxyphenoxyl groups exhibited significantly higher DPPH -scavenging and anti-haemolysis activities than those which bear no such groups. In contrast to curcumin analogues that retained the 7-carbon spacer, the compounds with a 5-carbon linker had lower activity. In the case of the latter, the introduction of a ring further decreased DPPH -scavenging activity. However, the introduction of a ring did increase anti-haemolysis activity, suggesting that the lipophilicity of these compounds might play an important role in the antioxidant activity.