Meng Bin, Gao Weina, Wei Jingyu, Pu Lingling, Tang Zhenchuang, Guo Changjiang
Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, China ; Tianjin Key Laboratory for Prevention and Control of Occupational and Environmental Hazard, Tianjin 300309, China.
Tianjin Institute of Health and Environmental Medicine, Tianjin 300050, China.
Biomed Res Int. 2015;2015:815210. doi: 10.1155/2015/815210. Epub 2015 Oct 19.
This study was aimed at investigating the effects of quercetin on mRNA expression and activity of critical enzymes in homocysteine metabolism in rats fed a methionine-enriched diet. Rats were fed for 6 weeks the following diets, that is, control, 0.5% quercetin, 1.0% methionine, and 1.0% methionine plus 0.5% quercetin diets. Serum homocysteine was significantly increased after methionine treatment and decreased after the addition of quercetin. The mRNA expression of methionine synthase was significantly increased after methionine or methionine plus quercetin supplementation, while its enzymatic activity was significantly increased after methionine plus quercetin supplementation. The mRNA expression and enzymatic activity of cystathionine β-synthase and cystathionine γ-lyase were upregulated after quercetin, methionine, or quercetin plus methionine treatment and a more significant increase was observed for hepatic cystathionine β-synthase in the methionine plus quercetin treated rats, suggesting an interaction between methionine and quercetin. Meanwhile, hepatic ratio of S-adenosylmethionine to S-adenosylhomocysteine was significantly decreased in response to methionine supplementation and normalized after the addition of quercetin. It is concluded that quercetin reduces serum homocysteine by increasing remethylation and transsulfuration of homocysteine in rats exposed to a methionine-enriched diet.
本研究旨在探讨槲皮素对喂食高蛋氨酸饮食的大鼠同型半胱氨酸代谢关键酶的mRNA表达及活性的影响。将大鼠分为以下几组喂食6周，即对照组、0.5%槲皮素组、1.0%蛋氨酸组以及1.0%蛋氨酸加0.5%槲皮素组。蛋氨酸处理后血清同型半胱氨酸显著升高，添加槲皮素后降低。补充蛋氨酸或蛋氨酸加槲皮素后，蛋氨酸合成酶的mRNA表达显著增加，而在补充蛋氨酸加槲皮素后其酶活性显著增加。槲皮素、蛋氨酸或槲皮素加蛋氨酸处理后，胱硫醚β-合成酶和胱硫醚γ-裂解酶的mRNA表达及酶活性上调，在蛋氨酸加槲皮素处理的大鼠肝脏中观察到胱硫醚β-合成酶有更显著的增加，提示蛋氨酸与槲皮素之间存在相互作用。同时，补充蛋氨酸后肝脏中S-腺苷甲硫氨酸与S-腺苷同型半胱氨酸的比例显著降低，添加槲皮素后恢复正常。得出结论，在喂食高蛋氨酸饮食的大鼠中，槲皮素通过增加同型半胱氨酸的再甲基化和转硫作用降低血清同型半胱氨酸水平。
