A new liquid chromatography-high resolution Orbitrap mass spectrometry-based strategy to characterize Glucuronide Oleanane-type Triterpenoid Carboxylic Acid 3, 28-O-Bidesmosides (GOTCAB) saponins.A case study of Gypsophila glomerata Pall ex M. B. (Caryophyllaceae)

Abstract

Glucuronide Oleanane-type Triterpenoid Carboxylic Acid 3, 28-Bidesmosides (GOTCAB) saponins are bioactive natural compounds spread in Caryophyllidae. The high complexity of GOTCAB occurring as closely related isobaric and positional isomers is a challenge in their separation and identification. A new liquid chromatography - high resolution Orbitrap mass spectrometry acquisition strategy would be important for the structural elucidation of GOTCAB in plant extracts. In this study, the fragmentation behaviors of GOTCAB from methanol-aqueous root extract of Gypsophila glomerata Pall ex M. B. (Caryophyllaceae) were investigated using ultra high-performance liquid chromatography (UHPLC) coupled with hybrid quadrupole-Orbitrap high resolution mass spectrometry (HRMS). A new saponin was isolated and its structure was established by 1D and 2D-NMR spectroscopic experiments as 3-O-β-D-galactopyranosyl-(1→2)-[α-L-arabinopyranosyl-(1→3)]-β-D-glucuronopyranosyl gypsogenin 28-O-α-L-arabinopyranosyl-(1→3)-[β-D-xylopyranosyl-(1→4)]-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranosyl ester. On the basis of the accurate mass measurements, fragmentation patterns in MS/MS analyses and comparison with previously isolated authentic references, a total of 41 GOTCAB saponins were identified or tentatively elucidated in G. glomerata roots, including 14 pairs of isobars. Possible fragmentation pathways for three groups of GOTCAB are suggested. The group I appeared to be GOTCAB of gypsogenin with two carbohydrate chains: a branched trisaccharide at C-3 and tri- to hexa-saccharide attached to C-28 of the aglycone through a deoxyhexose residue. Saponins with monoacetylated (group II) or sulphated (group III) C-28 chain were evidenced, as well as quillaic and oleanolic acid GOTCAB. Sixteen GOTCAB were previously not described. The content of Gypsophila prosaponins, gypsogenin 3-O-glucuronide (7.4079 ± 0.0723 mg/g dry weight, dw) and quillaic acid 3-O-glucuronide (4.4593 ± 0.1207 mg/g dw), was determined by solid phase extraction - high-performance liquid chromatography (SPE-HPLC). In this study is presented the first systematic investigation on the fragmentation patterns and diagnostic fingerprints of the fragment ions in the MS/MS spectra of the gypsogenin -, quillaic acid - and oleanolic acid - bidesmosides. A LC-HRMS Orbitrap acquisition strategy could give an insight in the GOTCAB containing taxa.

Flavonoids of the Caryophyllaceae

“…1), 16a-hydroxygypsogenic acid or their derivatives, constitutes the main group of saponins in these plants (Hegnauer 1989;Vincken et al 2007;Böttger et al 2011;Cheikh-Ali et al 2019). For example, this class of compounds is synthesized in Gypsophila altissima (Chen et al 2010a, b), Gypsophila glomerata (Gevrenova et al 2018), Gypsophila capillaris (Elgamal et al 1995), Saponaria officinalis (Koike et al 1999), Silene vulgaris (Kim et al 2015), Vaccaria segetalis (Koike et al 1998), Dianthus versicolor (Ma et al 2009), Silene cucubalus (Larhsini et al 2003), Paronychia chionaea (Avunduk et al 2007) and many other species (Hegnauer 1964;Böttger and Melzig 2011). Moreover, among triterpene saponins from Caryophyllaceae, ursane-type, hopane-type, and lupane-type saponins have also been reported (Vincken et al 2007).…”

Molecular networking-assisted flavonoid profile of Gypsophila glomerata extract in relation to its protective effects on carbon tetrachloride-induced hepatorenal damage in rats

“…1). They are tentatively ascribed to 2"-O-pentosyl-6-C-hexosyl-luteolin (20) and its mono- (21) and diacetylated ( 22 SI). Consequently, the cluster was assessed as 2"-O-pentosyl-6-C-hexosyl-luteolin structural type.…”

“…However, there is no information about the possible protective effect of the commonly found species, G. glomerata. Recently, a large number of triterpenoid saponins in G. glomerata roots was characterized (21). Eleven C-glycosyl flavones and 4 O-glycosyl flavonoids, including 2"-O--pentosyl-6-C-hexosyl-apigenin/methylluteolin together with the common saponarin, homoorientin, orientin, isovitexin and vitexin were already reported in the aerial parts of G. glomerata (18).…”

Gypsophila saponins enhance the cytotoxicity of etoposide in HD-MY-Z lymphoma cells

“…The mass spectrometer was operated in negative ionization mode at a resolution 35000 FWHM (MS) and 17500 FWHM (MS/MS). Data were acquired over the mass range of m/z 400-2500 in Full МS-ddMS 2 /Top 5 scan type, 80 msec maximal trap filling time, 4 m/z quadrupole isolation window of precursor ions, loop count 5, MSX count 1 (Gevrenova et al, 2018b). In stepped higher energy collision-induced dissociation (hcd), two steps fragmentation on the precursor ions was proceed: 25 -(25 × 40%) and 25 + (25 × 40%).…”

“…The non-targeted methabolic profiling of G. trichotoma methanol-aqueous extract was carried out by previously developed UHPLC-ESI/HRMS platform (Gevrenova et al, 2018b). The total ion chromatogram (TIC) and Full scan MS spectrum are depicted in Fig.…”