Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang 330045, China.
J Pharm Biomed Anal. 2018 Jun 5;155:202-209. doi: 10.1016/j.jpba.2018.04.005. Epub 2018 Apr 6.
Astilbin is the most predominant flavonoid in Rhizoma Smilacis Glabrae (RSG) with many bioactivities. The interconversion of the astilbin and its three stereoisomers was found with incubation of RSG extract at different temperatures, and the equilibrium ratios were calculated. Under certain conditions, neoastilbin would replace astilbin and become the predominant flavonoid in RSG extract. The effects of ascorbic acid, sucrose, sodium benzoate, β-cyclodextrin (β-CD) and common metal ions on the isomerization and decomposition of astilbin were studied. Ascorbic acid showed the best protective effect on the decomposition of astilbin and its isomers, which may be attributed to its reducing and radical scavenging ability. Besides, ascorbic acid also accelerated the isomerization of astilbin. β-CD suppressed both isomerization and decomposition of astilbin through complexation between them. Most metal ions had inhibition effects on the isomerization of astilbin. Al could almost completely inhibit the isomerization. The presence of Fe caused the rapid decomposition of astilbin, and Cu also showed weak effects. Based on the isomerization study, a novel and simple method for preparative separation of astilbin and neoastilbin from RSG sample was developed. Astilbin and neoastilbin with purity of 93% and yield of 0.86% and 0.48% were obtained, respectively, which represent 46.8% of total flavonoids in RSG sample. By controlling the isomerization conditions, astilbin and neoastilbin could be used as the initial reactants to produce neoisoastilbin and isoastilbin, respectively.
梓醇是菝葜中含量最高的黄酮类化合物，具有多种生物活性。在不同温度下孵育菝葜提取物时发现梓醇及其三种立体异构体之间的相互转化，并计算出平衡比。在某些条件下，新梓醇会取代梓醇并成为菝葜提取物中的主要黄酮类化合物。研究了抗坏血酸、蔗糖、苯甲酸钠、β-环糊精（β-CD）和常见金属离子对梓醇及其异构体异构化和分解的影响。抗坏血酸对梓醇及其异构体的分解表现出最好的保护作用，这可能归因于其还原和自由基清除能力。此外，抗坏血酸还加速了梓醇的异构化。β-CD 通过与梓醇形成复合物来抑制其异构化和分解。大多数金属离子对梓醇的异构化有抑制作用。Al 几乎可以完全抑制异构化。Fe 的存在导致梓醇迅速分解，Cu 也表现出较弱的作用。基于异构化研究，开发了一种从菝葜样品中制备分离梓醇和新梓醇的新颖而简单的方法。分别获得纯度为 93%和收率为 0.86%和 0.48%的梓醇和新梓醇，分别占菝葜样品总黄酮的 46.8%。通过控制异构化条件，可以将梓醇和新梓醇分别用作初始反应物来生产新异梓醇和异梓醇。
