二氢杨梅素异构体手性分析及其在线抗氧化活性研究

Chiral Analysis and On-line Antioxidant Activity Study of Dihydromyricetin Isomers

二氢杨梅素是药食两用植物藤茶的主要活性成分,然而其在提取过程中容易受其他因素的影响而发生消旋化。本研究利用高效液相色谱法,使用chiralpak IG色谱柱(250 mm×4.6 mm,5μm),以0.1%乙酸水溶液和乙腈为流动相,采用梯度洗脱的方式,对二氢杨梅素手性异构体进行拆分,进而建立藤茶中(2R,3R)-二氢杨梅素含量的测定方法,并进行方法学考察;同时以2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)配制自由基溶液,使用柱后反应系统对二氢杨梅素手性异构体的抗氧化活性进行在线研究。结果表明(2S,3S)-二氢杨梅素和(2R,3R)-二氢杨梅素在该条件下分离度良好;(2R,3R)-二氢杨梅素在0.01~0.6 mg/mL范围内,其质量浓度和峰面积具有良好的线性关系(r=0.9998),目标物的平均加标回收率为104.2%;在线抗氧化研究结果显示,(2R,3R)-二氢杨梅素和(2S,3S)-二氢杨梅素具有相似的自由基清除活性。该方法适用性强,为手性化合物的活性比较提供了新思路。

Dihydromyricetin(DMC)is the main active component in vine tea.However,DMC is easy to be racemized due to many factors in the extraction process.In order to separate the enantiomers and assay the content of(2R,3R)-dihydromyricetin in vine tea,an HPLC method was performed on a chiralpak IG(4.6×250 mm,5μm)column by using 0.1%acetic acid aqueous solution and acetonitrile as mobile phase.At the same time,the antioxidant activity of dihydromyricetin enantiomers were studied on a post column reaction system by using ABTS as free radical.Results showed that(2S,3S)-dihydromyricetin and(2R,3R)-dihydromyricetin had a good separation under the above conditions.The concentration of(2R,3R)-dihydromyricetin had a good linear relationship with the peak area in the range of 0.01-0.6 mg/mL(r=0.9998),and the average recovery was 104.2%.The results of on-line antioxidant study showed that(2R,3R)-dihydromyricetin and(2S,3S)-dihydromyricetin had similar free radical scavenging activities.The method established in this study was of great significance for analyzing the racemates of DMC,as well as controlling the extraction process of vine tea and ensuring the quality of related products,and it also provided a new idea for the activity comparison of chiral compounds.