Quantitative Determination of Cycloartane and Flavonoid Glycosides from Sutherlandia frutescens by UPLC-UV, UPLC-ELSD Methods and Confirmation by UPLC-MS

Sutherlandia frutescens (L.) R. BR., Family Fabaceae, is a well-known and widely used medicinal plant from the Western Cape, South Africa [1,2]. Traditionally it has been used as a remedy for stomach problems, internal cancers, diabetes and various inflammatory conditions. Recently, it has been used for the management of HIV/AIDS in patients [1]. This paper describes the analytical method suitable for the determination of four flavonoid glycosides (Sutherlandin A, B, C, D) and four cycloartane glycosides (Sutherlandioside A, B, C, D) from stem-leaves of Sutherlandia frutescens (L.) R. BR. A separation by UPLC was achieved by using Acquity shield RP18 column, PDA with ELS detection, and a water/acetonitrile gradient as the mobile phase. The major cycloartane glycoside compound (sutherlandioside B) was detected at a concentration as low as 1.0 µg/mL. The analysis of plant material and products showed considerable variation of 0.6–2.7% for the major compound. This method involved the use of the [M+H]⁺ and [M+Na]⁺ ions in the positive ion mode with extractive ion monitoring (EIM). The eight compounds were further confirmed by UPLC-MS method in plant sample and products. In the positive ion mode, the protonated species [M+H]⁺ at m/z 741.2, 741.2, 725.2, 725.2, 653.4, 651.4, 635.4 and 653.4 and sodiated species [M+Na]⁺ at m/z 763.2, 763.2, 747.2, 747.2, 675.4, 673.4, 657.4 and 675.4 for compounds 1–8 were observed. 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 UPLC chromatograms of a mixture of standard [Sutherlandin A (1), Sutherlandin B (2), Sutherlandin C (3), Sutherlandin D (4), Sutherlandioside B (5) Sutherlandioside C (6), Sutherlandioside D (7), Sutherlandioside A (8)] (A, C), leaves of Sutherlandia frutescens (B, D) by ELSD and UV detection at 260 nm.