Glycosylated platycosides: Identification by enzymatic hydrolysis and structural determination by LC–MS/MS. Issue 1 (11th December 2013)

• Record Type: Journal Article
• Authors: Jeong, Eun‐Kyung; Ha, In Jin; Kim, Yeong Shik; Na, Yun‐Cheol
• Is Part Of: Journal of separation science. Volume 37:Issue 1/2(2014)
• Page Start: 61
• Page End: 68
• Publication Date: 2013-12-11
• Subjects: Separation (Technology) -- Periodicals; Chromatographic analysis -- Periodicals; 543.089
• DOI: 10.1002/jssc.201300918
• Languages: English
• ISSNs: 1615-9306

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>In this study, enzymatic hydrolysis and chemometric methods were utilized to discriminate glycosylated platycosides in the extract of Platycodi Radix by LC–MS. Laminarinase, whose enzymatic activity was evaluated using gentiobiose and laminaritriose, was a suitable enzyme to identify the glycosylated platycosides. The laminarinase produced deapi‐platycodin D and platycodin D from the isolated deapi‐platycoside E and platycoside E through the loss of two glucose units by enzymatic reaction, respectively. After hydrolyzing a crude extract by laminarinase, the reconstructed total ion chromatogram generated by a chemometric technique sorted peaks of deglycosylated platycosides easily. Structural information of the glycosylated isomers was revealed through fragment ions generated by the sodiated C_0β ion corresponding to reduced disaccharides in the positive MS⁴ spectra. Characteristic fragment ions of Glc‐(1→6)‐Glc moieties were observed through ring cleavages of ^{0, 2}A_0β, ^{0, 3}A_0β, and ^{0, 4}A_0β, whereas Glc‐(1→3)‐Glc moieties produced only ^{0, 3}A_0β ions. Lithium‐adducted platycosides allowed more detailed structural analysis of glycosidic bond cleavage corresponding to Y_1β and B_1β in addition to ring cleavage.</p> </abstract>