Key Laboratory of Oil and Gas Fine Chemicals, Ministry of Education & Xinjiang Uyghur Autonomous Region, College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, P.R. China.
Rapid Commun Mass Spectrom. 2013 Feb 15;27(3):451-60. doi: 10.1002/rcm.6476.
Flavonoids exhibit a wide range of biological activities. The differentiation and structural characterization of the flavonol O-rhamnosides and their isomers are important research topics. Electrospray ionization tandem mass spectrometry (ESI-MS(n) ) is an indispensable tool and has become an efficient method for the identification of bioactive natural products.
Negative ion ESI-MS(n) was used to characterize and differentiate flavonol O-rhamnosides and their isomeric compounds. The collision energies in collision-induced dissociation were varied to optimize the structural information.
Flavonol 7-O-rhamnosides containing either a hydroxyl or a methoxyl group at the C-8 position clearly differed from their isomeric compounds, such as the flavonol 3-O-rhamnosides, in the product ion spectra of the M-H ions. The differences in the locations of the glycosyl group and OCH(3) group resulted in a significant change in the relative abundances of the Y(0)(-) and Y(0) -H ions, and the formation of some characteristic ions, such as (1,3)A(0)(-) and (1,3)A(0)-CH(3).
An efficient ESI-MS(n) method for the structural identification and isomeric differentiation of flavonol O-rhamnosides was developed. The differences in the glycosyl type, and the glycosylation and methoxylation positions in the structures of isomeric flavonoids, can be determined using (-)ESI-MS(n) spectra. The formation and relative abundances of Y(0)-H and Y(0) (-) ions, as well as the comparison of some diagnostic ions, are vital in the differentiation of isomeric flavonoids. These results have practical applications in the rapid identification of flavonol O-rhamnosides present in crude bioactive extracts.
类黄酮表现出广泛的生物活性。黄酮醇 O-鼠李糖苷及其异构体的分化和结构特征是重要的研究课题。电喷雾串联质谱（ESI-MS(n)）是一种不可或缺的工具，已成为鉴定生物活性天然产物的有效方法。
采用负离子 ESI-MS(n)对黄酮醇 O-鼠李糖苷及其异构体化合物进行特征分析和区分。通过改变碰撞诱导解离中的碰撞能来优化结构信息。
在M-H离子的产物离子谱中，在 C-8 位含有羟基或甲氧基的黄酮醇 7-O-鼠李糖苷与 3-O-鼠李糖苷等异构体化合物明显不同。糖基和 OCH(3) 基团位置的差异导致 Y(0)(-)和Y(0)-H离子的相对丰度发生显著变化，并形成一些特征离子，如(1,3)A(0)(-)和(1,3)A(0)-CH(3)。
建立了一种用于黄酮醇 O-鼠李糖苷结构鉴定和异构体区分的高效 ESI-MS(n)方法。利用（-）ESI-MS(n)谱可以确定异构体黄酮类化合物的糖苷类型以及结构中糖苷化和甲氧基化位置的差异。Y(0)-H和 Y(0)(-)离子的形成和相对丰度，以及一些诊断离子的比较，对于异构体黄酮类化合物的区分至关重要。这些结果在快速鉴定粗生物活性提取物中存在的黄酮醇 O-鼠李糖苷方面具有实际应用价值。
