Analysis of phenolic compounds in rhubarbs using liquid chromatography coupled with electrospray ionization mass spectrometry

Abstract

Rhubarb is an important herbal medicine for the treatment of constipation, inflammation, and cancer. In this study, a facile method based on liquid chromatography coupled with electrospray ionization tandem mass spectrometry has been established for the analysis of bioactive phenolic compounds in rhubarbs. From six rhubarb species, official (Rheum officinale, R. palmatum, and R. tanguticum) and unofficial (R. franzenbachii, R. hotaoense, and R. emodi), a total of 107 phenolic compounds were identified or tentatively characterized based on their mass spectra. These compounds include sennosides, anthraquinones, stilbenes, glucose gallates, naphthalenes, and catechins. Ion chromatograms for the identified compounds of different rhubarbs were then compared. Consistent with previous reports, sennosides and rhein were only detected in official rhubarbs. Unexpectedly, we found that R. officinale contained very different phenolic compounds from the other two official species. Sennoside A, which has been considered as the major purgative component of rhubarb, was only detected in R. officinale, while its close isomers were observed in R. palmatum and R. tanguticum. In addition, the predominant anthraquinone glycosides in R. officinale were found to be rhein 8-O-glucoside and emodin 1-O-glucoside, whereas those in R. palmatum and R. tanguticum were rhein 1-O-glucoside and emodin 8-O-glucoside. Stilbenes, which are the major constituents of unofficial rhubarbs, were also different among the species. Our results clarify the chemical composition of rhubarbs comprehensively for the first time. Due to the significant differences in chemical components of rhubarbs, we suggest that different Rheum species be used separately in clinical practice. (J Am Soc Mass Spectrom 2007, 18, 82-91)

Extraction, Isolation And Characterization Of Bioactive Compounds From Plants’ Extracts

“…It provides abundant information for structural elucidation of the compounds when tandem mass spectrometry (MS n ) is applied. Therefore, the combination of HPLC and MS facilitates rapid and accurate identification of chemical compounds in medicinal herbs, especially when a pure standard is unavailable (Ye et al, 2007).…”

Karyotype analysis of Rheum palmatum

“…Our research group has investigated the distribution and genetic variation of the section Palmata (Wang et al, 2010(Wang et al, , 2012a, and many previous studies on this section have focused on components analysis (Zheng and Zhang, 1993;Zhang and Liu, 2004;Ye et al, 2007) and pharmacological properties (Xiao et al, 1984;Yu et al, 2005;Tseng et al, 2006). However, the chromosome number and karyotype of this section are not yet known.…”

Polyphenolic composition of roots and petioles of Rheum rhaponticum L.

“…On the other hand, a number of hydroxystilbenes and their derivatives have been identified in the rhizome of Korean rhubarb R. undulatum L. (Kashiwada et al, 1984;Ko, 2000;Matsuda et al, 2000a,b;Kageura et al, 2001), in the roots of R. maximowiczii Loinsk (Shikishima et al, 2001) and in the rhizome of R. emodi (Babu et al, 2004). More than 100 different phenolic compounds have either been identified or tentatively characterised in six rhubarb species (R. officinale, R. palmatum, R. tanguticum, R. franzenbachii, R. hotaoense and R. emodi) by their parent ion fragmentation spectra by Ye and co-authors (Ye et al, 2007).…”