Reactions of Antimalarial Peroxides with Each of Leucomethylene Blue and Dihydroflavins: Flavin Reductase and the Cofactor Model Exemplified
作者:Richard K. Haynes、Kwan-Wing Cheu、Maggie Mei-Ki Tang、Min-Jiao Chen、Zu-Feng Guo、Zhi-Hong Guo、Paolo Coghi、Diego Monti
DOI:10.1002/cmdc.201000508
日期:2011.2.7
argon. Under the same conditions, FADH2 in turn cleanly reduces the antimalarial drug methylene blue (MB) to leucomethylene blue. The latter is rapidly re‐oxidized by artemisinins, thus supporting the proposal that MB exerts its antimalarial activity, and synergizes the antimalarial action of artemisinins, by interfering with redox cycling involving NADPH reduction of flavin cofactors in parasite flavin
在氩气中,pH 7.4的水性缓冲液中的NADPH-大肠杆菌黄素还原酶(Fre)将黄素腺嘌呤二核苷酸(FAD)还原为FADH 2。在相同条件下,FADH 2依次将抗疟疾药物亚甲基蓝(MB)还原为无色亚乙基蓝。后者被青蒿素迅速重新氧化,从而支持了MB发挥其抗疟活性,并通过干扰寄生虫黄素二硫键还原酶中黄素辅因子的NADPH还原的氧化还原循环,发挥了青蒿素的抗疟作用的提议。直接处理FADH 2在生理条件下,pH 7.4时,青蒿素和抗疟疾活性四恶烷和三恶烷结构类似物从NADPH-Fre-FAD中产生,导致青蒿素快速还原,过氧化物结构类似物有效转化为酮产物。FADH 2氧化相对速率的比较表明三氧戊环的最佳活性。因此,对于三氧戊环而言,寄生内氧化还原扰动的速率将最大,这与其增强的体外抗疟活性有关可能是重要的。使用BNAH-核黄素(RF)模型系统的1 H NMR光谱研究表明,四恶烷能够同时使用两个过氧化物单元来氧化RFH