利用HPLC-ESI-MS/MS区分黄芩中黄酮C-苷异构体的研究

Differentiation of the Flavonoid C-glycoside Isomers in Scutellaria baicalensis Georgi Using HPLC-ESI-MS/MS

采用 HPLC-ESI-MS/MS联用技术区分了黄芩中两种互为同分异构体的黄酮 C-苷类化合物 5 ,7-OH-6-C-阿拉伯糖 -8-C-葡萄糖黄酮和 5 ,7-OH-6-C-葡萄糖 -8-C-阿拉伯糖黄酮 .阐述了黄酮 C-苷类化合物同分异构体的电喷雾串联质谱 (ESI-MSn)的特征碎裂规律 ,证明了 [M-H-60 ]- ,[M-H-90 ]- 及 [M-H-1 2 0 ]-离子是其特征离子 .实验结果表明 ,对于 C-6位五碳糖取代和 C-8位六碳糖取代的黄酮 C-苷二级串联质谱产生的 [M-H-60 ]- 离子 (0 ,3 5X) ,其丰度一般大于 5 0 % ;而对于 C-6位六碳糖取代和 C-8位五碳糖取代的黄酮 C-苷二级串联质谱产生的 [M-H-60 ]-离子 (0 ,35X) ,其丰度一般小于 5 0 % .据此可区分两种互为同分异构体的黄酮 C-苷类化合物 .

HPLC-ESI-MS/MS is becoming one of the most important tools for the on-line identification of natural products in crude plant extracts. In this paper, a combined HPLC-ESI-MS/MS method was developed to character two flavonoid C-glycoside isomers in Scutellaria baicalensis Georgi. Using tandem mass spectrometry, useful fragments of the two flavonoid C-glycoside isomers were obtained. The experimental results demonstrate that cross-ring ions of [M-H-60]-, [M-H-90]-, [M-H-120]- are characteristic ions of flavonoid C-glycoside. By analyzing the differences of the retention time and the relative abundance of ions [M-H-60]-, the two isomers can be distinguished conveniently.