作者:Jun NISHIDA、Jun KAWABATA
DOI:10.1271/bbb.70.193
日期:2006.1
The DPPH radical scavenging activity of 2′,4′,6′-trihydroxy- and 2′-hydroxy-4′,6′-dimethoxychalcones carrying a 2,3- and 3,4-dihydroxylated, and 3,4,5-trihydroxylated B-ring was evaluated in alcoholic and non-alcoholic solvents. All test compounds scavenged more than two equivalent of radicals by a possible conversion to the corresponding B-ring quinones and in most cases subsequently underwent cyclization to aurones and flavanones, these being identified in the reaction solutions by an in situ NMR analysis. Interestingly, the reaction between 2′,3,4-trihydroxy-4′,6′-dimethoxychalcone and the DPPH radical was significantly affected by the solvent used, which might be accounted for by the difference in readiness for cyclization to an aurone.
在酒精和非酒精溶剂中,对带有 2,3- 和 3,4- 二羟基以及 3,4,5- 三羟基 B 环的 2′,4′,6′-三羟基和 2′-羟基-4′,6′-二甲氧基查耳酮的 DPPH 自由基清除活性进行了评估。所有测试化合物都能清除两个当量以上的自由基,并可能转化为相应的 B 环醌,在大多数情况下还会环化为醛酮和黄酮,这些化合物在反应溶液中通过原位核磁共振分析得以确定。有趣的是,2′,3,4-三羟基-4′,6′-二甲氧基查尔酮与 DPPH 自由基的反应受到所用溶剂的显著影响,这可能是由于环化为醛酮的准备程度不同造成的。