Tokuyama-Nakai Shota, Kimura Hideto, Hirabayashi Yu, Ishihara Tomoe, Jisaka Mitsuo, Yokota Kazushige
Department of Research and Development, Kotobuki Seika Co., Ltd., 2028 Hatagasaki, Yonago, Tottori 683-0845, Japan.
The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-minami, Tottori-shi, Tottori 680-8553, Japan.
Heliyon. 2019 Mar 8;5(3):e01317. doi: 10.1016/j.heliyon.2019.e01317. eCollection 2019 Mar.
Lour. (family Polygonaceae), known as indigo plant, has been useful as a medicinal or edible plant abundant in polyphenolic compounds. We have recently shown that flavonol -glycosides with 3,5,4'-trihydroxy-6,7-methylenedioxyflavone (TMF) are predominant flavonoids in indigo leaves. However, no study has been performed regarding changes in the levels of flavonoid species during the germination and growth of indigo plant. Here, we attempted to determine the individual constituents of flavonol -glycosides and the changes in their contents of the seeds, sprouts, and aerial parts. These results revealed that only the seeds predominantly contained flavonol -(acetyl)-rhamnosides with quercetin or kaempferol as an aglycone. During the development of the sprouts and aerial parts, flavonol -glycosides with TMF as an aglycone became mainly detectable and accounted for 79.4% and 74.9% of total flavonol -glycosides from the extracts of aerial parts harvested in 2016 and 2017, respectively. Of the plant organs tested, the aerial parts exhibited the highest antioxidant activities concomitant with greatly increased levels of total polyphenols. Thus, we were able to conduct the identification and quantification of flavonol -glycosides from the seeds, sprouts, and aerial parts of indigo plant and to evaluate antioxidant activities of their extracts. Taken together, our findings clearly provide the evidence that the aerial parts of indigo plant are a rich source of flavonol -glycosides with TMF and exhibit much higher antioxidant activities, indicating the usefulness for the application to food and nutraceutical purposes.
蓼蓝（蓼科），又称靛蓝植物，作为一种富含多酚化合物的药用或食用植物一直很有用。我们最近发现，以3,5,4'-三羟基-6,7-亚甲二氧基黄酮（TMF）为苷元的黄酮醇糖苷是靛蓝叶中的主要黄酮类化合物。然而，关于靛蓝植物发芽和生长过程中黄酮类化合物种类水平的变化尚未有研究。在此，我们试图确定黄酮醇糖苷的具体成分及其在种子、芽和地上部分的含量变化。这些结果表明，只有种子中主要含有以槲皮素或山奈酚为苷元的黄酮醇-（乙酰基）-鼠李糖苷。在芽和地上部分的发育过程中，以TMF为苷元的黄酮醇糖苷开始主要被检测到，分别占2016年和2017年收获的地上部分提取物中总黄酮醇糖苷的79.4%和74.9%。在所测试的植物器官中，地上部分表现出最高的抗氧化活性，同时总多酚水平大幅增加。因此，我们能够对靛蓝植物种子、芽和地上部分的黄酮醇糖苷进行鉴定和定量，并评估其提取物的抗氧化活性。综上所述，我们的研究结果清楚地证明，靛蓝植物的地上部分是富含TMF的黄酮醇糖苷的丰富来源，并表现出更高的抗氧化活性，表明其在食品和营养保健品方面的应用价值。
