Department of Food Sciences, University of Tokushima Graduate School, Tokushima, Japan.
J Agric Food Chem. 2012 Oct 17;60(41):10270-7. doi: 10.1021/jf303055b. Epub 2012 Oct 8.
Quercetin, a typical dietary flavonoid, is thought to exert antidepressant effects by inhibiting the monoamine oxidase-A (MAO-A) reaction, which is responsible for regulation of the metabolism of the neurotransmitter 5-hydroxytryptamine (5-HT) in the brain. This study compared the MAO-A inhibitory activity of quercetin with those of O-methylated quercetin (isorhamnetin, tamarixetin), luteolin, and green tea catechins ((-)-epicatechin, (-)-epicatechin gallate, (-)-epigallocatechin, and (-)-epigallocatechin gallate) by measuring the formation of the oxidative deamination product of 5-HT, 5-hydroxyindole aldehyde (5-HIAL), in mouse brain mitochondria. Quercetin was inferior to luteolin in the inhibition of MAO-A activity, whereas isorhamnetin, tamarixetin, and tea catechins scarcely exerted inhibitory activity. Quercetin did not affect MAO-A activity in mouse intestinal mitochondria, indicating that it does not evoke side effects on the metabolism of dietary monoamines in the gut. These data suggest that quercetin is a weak (but safe) MAO-A inhibitor in the modulation of 5-HT levels in the brain.
槲皮素是一种典型的膳食类黄酮，被认为通过抑制单胺氧化酶-A（MAO-A）反应发挥抗抑郁作用，该反应负责调节大脑中神经递质 5-羟色胺（5-HT）的代谢。本研究通过测量小鼠脑线粒体中 5-HT 的氧化脱氨产物 5-羟吲哚醛（5-HIAL）的形成，比较了槲皮素与 O-甲基化槲皮素（异鼠李素、杨梅素）、木樨草素和绿茶儿茶素（（-）-表儿茶素、（-）-表儿茶素没食子酸酯、（-）-表没食子儿茶素和（-）-表没食子儿茶素没食子酸酯）对 MAO-A 活性的抑制作用。槲皮素在抑制 MAO-A 活性方面逊于木樨草素，而异鼠李素、杨梅素和儿茶素几乎没有抑制活性。槲皮素不影响小鼠肠线粒体中的 MAO-A 活性，表明它不会对肠道中单胺类物质的代谢产生副作用。这些数据表明，槲皮素在调节大脑中 5-HT 水平方面是一种较弱（但安全）的 MAO-A 抑制剂。
