LC-MS法鉴定桑叶中生物碱类成分

目的：建立LC-MS法对桑叶中生物碱类成分进行结构鉴定。方法：对桑叶中生物碱类成分分别采用9-芴甲氧羰酰氯（FMOC-Cl）衍生化后ODS柱分离或Hypersil SCX色谱柱直接分离，电喷雾正离子化高分辨TOF/MS检测，结合MS/MS法和对照品对照法进行鉴定。结果：在所建立的条件下，共检测并鉴定4个生物碱成分（2-氧-α-D-半乳吡喃糖苷-1-脱氧野尻霉素、1-脱氧野尻霉素、荞麦碱和1，4-二脱氧-l，4-亚胺基-D-阿拉伯糖醇），衍生化法和直接测定法2种分离分析方法的鉴定结果相互验证。此外，9-芴甲氧羰酰氯（FMOC-Cl）柱前衍生化法亦适用于桑叶生物碱成分的准确定量，方法准确可靠。结论：桑叶中生物碱类成分鉴定为相关中药的物质基础研究和质量控制提供依据。

Objective: To develop a hyphenated LC-MS method for the separation and characterization of alkaloids in mulberry leaf. Methods: The alkaloids were separated on a reversed-phase ODS column after 9-fluorenylmethyl chloroformate pre-column derivatization or Hypersil SCX column by direct cation exchange, respectively. The determination was performed with positive ESI high-resolution TOF-MS of their protonated adduct ions and then the corresponding product mass spectra by tandem mass spectroscopy. The structures of the alkaloids were elucidated afterwards and verified further through reference substances. Results: Four alkaloids(2-O-α-D-galactopyranosyl-1-deoxynojirimycin,1-deoxynojirimycin,fagomine and 1,4-dideoxy-1,4-imino-D-arabinitol)were detected and identified. The results of the two different methods:pre-column derivatization and direct cation exchange were in good agreement. In addition,the method of 9-fluorenylmethyl chloroformate pre-column derivatization,which is accurate and reliable,can also be applied to the quantitation of alkaloids in mulberry leaf. Conclusion: The identification and characterization of the alkaloids in mulberry leaf would provide reference for the quality control and clinical rational of the related traditional Chinese medicines.