Chemical Profiling and Characterization of Anthraquinones from Two Bulbine Species and Dietary Supplements Using Liquid Chromatography–High Resolution Mass Spectrometry

Abstract

Abstract Background Bulbine natalensis Baker and Bulbine frutescens (L.) Willd., belonging to the family Asphodelaceae, are widely distributed in South Africa and traditionally used as an aphrodisiac and skin remedies. Objective The aim of this study is to develop an analytical method for chemical profiling and identification of components in Bulbine species, which would be useful for herbal identification and understanding of the biological activity of B. natalensis in terms of safety and benefits to human health. Method The anthraquinone-type compounds were structurally characterized from the extracts of dried stem and roots of Bulbine species and dietary supplements using liquid chromatography–quadrupole time-of-flight mass spectrometry (LC-QToF) with negative and positive ion electrospray. The calculated accurate masses of the protonated and deprotonated molecules and fragment ions were used for identification of the components from two Bulbine species. Results A total of 55 anthraquinone-type compounds, including 11 standard compounds, were identified in the crude extracts of two Bulbine species. Two Bulbine species and dietary supplements were clustered into different groups and possible chemical markers were identified. Conclusions The developed analytical method provided a fast and economic method for quality assessment of Bulbine species in dietary supplements based on anthraquinone-type compounds. Highlights This study reports holistic chemical profiling of Bulbine species using LC-QToF. The developed analytical method enabled non-targeted analysis of components in B. natalensis and B. frutescens, and is recommended for commercial and regulatory purposes.