黄酮类化合物结构特征与抗氧化性关系研究进展

Research review between structure and antioxidation of flavonoids compounds

黄酮类化合物是具有显著抗氧化功能的第二大植物多酚类化合物。黄酮类化合物抗氧化性与其结构特征一一对应,由于这些化合物均以黄烷为母核,因此取代基数量、位置和类型都极大影响它们抗氧化功能;尽管许多结论之间还存在不一致,但仍有一些构效关系在体外已得到确证。例如,多个羟基赋予化合物分子更显著抗氧化性质,甲基基团虽对化合物立体效应不利,但增加分子亲脂性和在细胞膜中分配性能,更有利于分子发挥其抗氧化功能;双键和羰基结构增加化合物活性,则是与其分子上电子共轭和离域有关。

Flavonoids are a class of secondary plant phenolics with significant antioxidation properties. The propensity of a flavonoid to inhibit free-radical mediated events is governed by its chemical structure. Since these compounds are based on the flavan nucleus, the number, positions, and types of sub- stitutions influence radical scavenging and chelating activity. Despite some inconsistent lines of evi- dence, several structure-activity relationships are well established in vitro. For example, multiple hydroxyl groups confer upon the molecule substantial antioxidation activity. Methoxy groups introduce unfavorable steric effects and increase lipophilicity and membrane partitioning. A double bond and carbonyt function of the nuclear structure increases activity by affording a more stable flavonoid radical through conjugation and electron delocalization.