Integrating targeted glycomics and untargeted metabolomics to investigate the processing chemistry of herbal medicines, a case study on Rehmanniae Radix

UPLC-QTOF-MS/MS-guided isolation and purification of sulfur-containing derivatives from sulfur-fumigated edible herbs, a case study on ginseng

In this study, a novel ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-QTOF-MS/MS)-guidance strategy was proposed for preparation of sulfur-containing derivatives in sulfur-fumigated edible herbs. Being versatile in both chromatographic separation and mass spectrometric detection, UPLC-QTOF-MS/MS was inducted into each experimental step for multifaceted purposes including finding, tracking, purity determination and structural elucidation of targeted compounds as well as UPLC-HPLC chromatographic conditions transplantation, whereby the isolation and purification procedures were greatly facilitated. Using this strategy, a new sulfur-containing ginsenoside Rg₁ derivative (named compound I) was obtained from sulfur-fumigated ginseng. The chemical structure of compound I was elucidated to be (3β, 6α, 12β)-3, 12-dihydroxydammar-25-ene-6, 20-diylbis-β-d-glucopyranoside, 24-sulfonic acid by QTOF-MS/MS, ¹H-NMR and ¹³C-NMR analysis, and its generation mechanisms by sulfur-fumigation were accordingly discussed. The research deliverable suggests that the UPLC-QTOF-MS/MS-guidance strategy is promising for targeted preparation of sulfur-containing derivatives from sulfur-fumigated edible herbs.

Laser microdissection hyphenated with high performance gel permeation chromatography-charged aerosol detector and ultra performance liquid chromatography-triple quadrupole mass spectrometry for histochemical analysis of polysaccharides in herbal medicine: Ginseng, a case study

This study establishes a new combinatorial approach for histochemical analysis of polysaccharides in herbal medicines using laser microdissection followed by high performance gel permeation chromatography coupled with charged aerosol detector and ultra-performance liquid chromatography hyphenated with triple quadrupole mass spectrometry. Ginseng was employed as a study model. Tissue-specific qualitative and quantitative characterization of ginseng polysaccharides was performed by determining their molar masses and monosaccharide compositions in three macro-dissected parts (rhizome, main and branched roots) and five micro-dissected tissues (cork, cortex, xylem, phloem and resin canal). The results showed that ginseng "flesh" (xylem, phloem and resin canal) contained more polysaccharides with larger molecular weights and higher ratios of glucose residue, whereas ginseng "skin" (cork and cortex) had fewer polysaccharides with smaller molecular weights and higher ratios of non-glucose constituents (e.g. galacturonic acid, galactose, arabinose and rhamnose). These findings suggested that the polysaccharides of the "flesh" were predominantly starch-like glucans, while those of the "skin" were of a higher proportion of acidic pectins. The revealed histologic distribution and accumulation pattern of ginseng polysaccharides contributes to the scientific understanding of ginseng regarding the biosynthesis and transportation of polysaccharides, medicinal quality evaluation as well as empirical clinical application.