Department of Food Science, Graduate School of Nutrition and Bioscience, Institute for Health Biosciences, University of Tokushima, Tokushima, Japan.
Nutrition. 2011 Jul-Aug;27(7-8):847-52. doi: 10.1016/j.nut.2010.09.002. Epub 2011 Mar 3.
Quercetin is a flavonoid found in plant foods and herbal medicines. It possesses antidepressant-like effects in forced swimming test-loaded rodents. We wanted to clarify the mechanism of action of dietary quercetin for exerting antidepressant-like effects. The effect of quercetin and its antioxidative metabolite quercetin 3-glucuronide (Q3GA) on the activity of mouse brain mitochondrial monoamine oxidase-A (MAO-A) was evaluated by measuring the deamination product of serotonin, 5-hydroxyindole acetaldehyde (5-HIAL).
An ultraviolet high-performance liquid chromatographic analysis was applied to measure the 5-HIAL generated by the reaction of MAO-A with serotonin. The inhibitory effect of quercetin and Q3GA on mitochondrial MAO-A activity was estimated by the content of 5-HIAL and hydrogen peroxide accompanied by the MAO-A reaction.
Quercetin (but not Q3GA) decreased the production of 5-HIAL by MAO-A activity. Q3GA inhibited the generation of hydrogen peroxide from the MAO-A reaction with serotonin. A periodic forced swimming test in mice increased brain mitochondrial MAO-A activity. Brain mitochondrial MAO-A activity was decreased in mice administered quercetin for 7 d, but its effect was much weaker than that of the selective MAO-A inhibitor clorgyline.
Quercetin is effective in the modulation of serotonergic activity by attenuating mitochondrial MAO-A activity in the brain. Its antioxidative metabolite Q3GA attenuates oxidative stress by interrupting the generation of hydrogen peroxide accompanying the MAO-A reaction.
槲皮素是一种存在于植物性食物和草药中的类黄酮。它在强迫游泳试验负荷的啮齿动物中具有抗抑郁样作用。我们想阐明饮食槲皮素发挥抗抑郁样作用的作用机制。通过测量血清素的脱氨产物 5-羟吲哚乙醛（5-HIAL），评估了槲皮素及其抗氧化代谢物槲皮素 3-葡糖苷酸（Q3GA）对小鼠脑线粒体单胺氧化酶-A（MAO-A）活性的影响。
采用紫外高效液相色谱分析法测量 MAO-A 与血清素反应生成的 5-HIAL。通过 MAO-A 反应伴随的 5-HIAL 和过氧化氢的含量来估计槲皮素和 Q3GA 对线粒体 MAO-A 活性的抑制作用。
槲皮素（而非 Q3GA）降低了 MAO-A 活性产生的 5-HIAL。Q3GA 抑制了 MAO-A 与血清素反应生成的过氧化氢。周期性强迫游泳试验会增加小鼠大脑线粒体 MAO-A 活性。在给予槲皮素 7 天的小鼠中，大脑线粒体 MAO-A 活性降低，但效果远弱于选择性 MAO-A 抑制剂氯丙嗪。
槲皮素通过减轻大脑中线粒体 MAO-A 活性有效调节 5-羟色胺能活性。其抗氧化代谢物 Q3GA 通过中断 MAO-A 反应伴随的过氧化氢生成来减轻氧化应激。
