名称:
Preparation of two sets of 5,6,7-trioxygenated dihydroflavonol derivatives as free radical scavengers and neuronal cell protectors to oxidative damage
摘要:
An unusual class of 5,6,7-trioxygenated dihydroflavonols (3a-e and 4a-j) were designed and prepared. Their antioxidative properties were assessed by examining their capacities in several in vitro models, including superoxide anion and 1,1-diphenyl-2-picrylhydrazyl ( DPPH) radical scavenging, rat liver homogenate lipid peroxidation inhibition, PC12 cells protection from oxidative damage, and xanthine oxidase inhibition. These dihydroflavonols displayed positive quenching abilities towards O-2(center dot-) and DPPH free radicals, in which the majority exhibited superior antioxidant properties to Vitamin C. cis-Configurated compound (+/-)-3e demonstrated remarkable inhibition to LPO with an IC50 value of 1.9 +/- 0.3 mu M, which was apparently stronger than that of quercetin (IC50 = 6.0 +/- 0.4 mu M). trans-Configurated dihydroflavonol (+/-)-4h exhibited significant protective effect on PC12 cells against oxidative damage with an EC50 value of 41.5 +/- 5.3 mu M, more effective compared to that of quercetin (EC50 = 81.8 +/- 8.7 mu M). The 6-OH-5,7-dimethoxy analogue (+/-)-3d showed significant inhibition of xanthine oxidase with an IC50 value of 16.0 +/- 0.8 mu M, which is superior to that of allopurinol (IC50 = 23.5 +/- 2.0 mu M). In addition to the hypothesized action mechanism of the bio-active compounds, 3D modeling was used to analyze the relationship between the minimized-energy structures and antioxidant activities. (C) 2009 Elsevier Ltd. All rights reserved.