Masuda T, Ueno Y
Mutat Res. 1984 Feb;125(2):135-44. doi: 10.1016/0027-5107(84)90065-4.
The activation mechanism of emodin, a fungal anthraquinone and constituent of rhubarb, into a direct mutagen to Salmonella typhimurium TA1537 was investigated by using the S9 and microsomes of rat livers. Upon incubating emodin with the hepatic S9 derived from PCB-pretreated rats, this anthraquinone exhibited mutagenicity in the presence of NADPH or NADH, and this enzymatic activation, maximal at pH 7.0 and occurring in the microsomes, was induced by the pretreatment of rats with PCB, 3-methyl-cholanthrene or phenobarbital and was inhibited by alpha-naphthoflavone, SKF 525A and carbon monoxide. Thin-layer chromatographic analysis revealed that emodin was biotransformed by the microsomal enzymes into at least 5 quinonoid metabolites, among which one pigment, identified as 2-hydroxyemodin (1,2,3,8-tetrahydroxy-6-methyl-anthraquinone), was proved to be a direct mutagen to the test strain, and the remaining 4 quinoniod metabolites were negative or far less active than this active principle.
采用大鼠肝脏的S9和微粒体，研究了大黄的真菌蒽醌成分大黄素激活为鼠伤寒沙门氏菌TA1537直接诱变剂的机制。大黄素与多氯联苯预处理大鼠的肝脏S9一起孵育后，在存在烟酰胺腺嘌呤二核苷酸磷酸（NADPH）或烟酰胺腺嘌呤二核苷酸（NADH）的情况下，这种蒽醌表现出致突变性。这种酶促激活在pH 7.0时最大，发生在微粒体中，可由多氯联苯、3-甲基胆蒽或苯巴比妥预处理大鼠诱导产生，并被α-萘黄酮、SKF 525A和一氧化碳抑制。薄层色谱分析表明，大黄素被微粒体酶生物转化为至少5种醌类代谢物，其中一种色素被鉴定为2-羟基大黄素（1,2,3,8-四羟基-6-甲基蒽醌），被证明是测试菌株的直接诱变剂，其余4种醌类代谢物为阴性或活性远低于这种活性成分。
