Characterization and Screening of Cycloartane and Flavonoid Glycosides from Stem-Leaves of Sutherlandia frutescens by Using HPLC-UV-ESI-MS and MS-MS Fingerprint Analysis

Sutherlandia frutescens (L.) R. BR. (Family Fabaceae) is a widely used medicinal plant from South Africa. It is traditionally used for stomach problems, internal cancers, diabetes, inflammatory conditions and recently to improve the overall health in cancer and HIV/AIDS patients [1,2]. LC-ESI-MSD-TOF and ESI-MS-MS analysis were performed on cycloartane and flavonoid glycosides employing two mass spectrometers equipped with ion-trap and TOF analyzers. The data illustrates the ability of the ESI techniques in the identification of cycloartane and flavonoid glycosides, including the nature of parent compound, the number of sugar residues and the type of saccharide moiety. The preliminary analytical results showed that numerous compounds have not been investigated yet. Additionally, screening and structural characterization offered more information about the chemical constitutions of Sutherlandia frutescens. About 55 compounds were screened using the ESI-TOF method, the major base peak ions generated by cycloartane glycosides are m/z 435, 437, and 439 [M+H-sugar-3 H₂O]⁺ and flavonoid glycosides at m/z 287, and 303, respectively. Sutherlandioside B was found to be the major compound among the analyzed glycosides. Fragments detected in the LC-ESI-TOF spectra of plant sample of S. frutescens and the dietary supplement are m/z 653.42 [M+H]⁺, 491.37 [M+H-sugar]⁺, 473.36 [M+H-sugar-H₂O]⁺, 455.35 [M+H-sugar-2 H₂O]⁺, 437.34 [M+H-sugar-3 H₂O]⁺. In the MS-MS spectra, fragmentation reactions of the [M+Na]⁺ were recorded to provide structural information about the glycosyl and aglycone moieties.

Acknowledgements: This research is funded in part by “Science Based Authentication of Dietary Supplements” Funded by the Food and Drug Administration grant number 2 U01 FD 002071-07 and “The International Center for Indigenous Phytotherapy Studies” funded by NCCAM, grant number 5 U19 AT 003264. References: [1] Stander BA, et al., (2007), Journal of Ethnopharmacology, 112(2): 312–318. [2] Mils E, et al. (2005), Nutrition Journal, 4: 19.

Fig. 1 TIC of cycloartane and flavonoid glycosides from stem-leaves of Sutherlandia frutescens by using HPLC-ESI-MSD-TOF.

Fig. 2 MS spectrum of Sutherlandioside B (peak 31 in Fig. 1). Inset is the structure and its MS fragment pathway.