为了研究黄酮化合物与金属离子协同作用增加抗氧化活性的构效关系,本文分别以天然黄酮化合物金雀异黄酮和山奈酚为原料,在无水乙醇-水混合溶剂中制备了2个铜(II)配合物。采用元素分析、络合滴定、红外光谱、电子吸收光谱和热重分析对2个目标配合物的组成及结构进行了分析,通过NBT光照还原法和水杨酸法测定了配合物的体外抗氧化活性。结果表明,在配合物的分子结构中,黄酮母核上的羰基氧和羟基氧与中心铜离子双齿配位,摩尔比为2:1,推测分子式为[Cu(Gen)2(H2O)2]·3H2O(Gen=金雀异黄酮)(1)和[Cu(Kae)2(H2O)2]·1.5H2O(Kae=山奈酚)(2)。在本实验条件下,配合物清除O2-·的IC50分别为0.250和0.646 μmol/L,起主要作用的是中心铜离子;清除OH·的IC50分别为158和129 μmol/L,黄酮配体发挥主导作用。配合物具有良好的清除O2-·和OH·的能力,且中心铜离子和黄酮配体显示出协同抗氧化活性。
Two copper complexes containing Genistein and Kaempferol had been prepared according to the previously reported methods for study on the effect of the synergistic interaction between flavonoid compounds and copper ion on their antioxidant activity. The structure of the complexes was characterized by elemental analysis, complexometric titration, IR spectroscopy, Electronic absorption spectroscopy and TG, and then the antioxidant activities for the complexes were determined by the photoreduction of nitroblue tetrazolium (NBT) and salicylic acid method. The results suggested that the hydroxyl and carbonyl O atoms at A-ring and C-ring were coordinated to Cu (II) ion bidentately, the molar ratios between flavonoid compounds and Cu (II) were both 2:1, the possible formulae were as follows:[Cu (Gen) 2 (H2O) 2]·3H2O (1) and[Cu (Kae) 2 (H2O) 2]·1.5H2O (2). The complexes exhibited the excellent scavenging ability for O2-·with IC50 values of 0.250 and 0.646 μmol/L, respectively, in which Cu (II) played a vital role. The IC50 values of complexes 1 and 2 for scavenging OH·were 158 and 129 μmol/L, respectively, in which the flavonoid compounds were crucial. Therefore, the complexes showed the positive synergistic effect between the flavonoid compounds and Cu (II) ion on the scavenging ability of O2-·and OH·.