Xanthone- and benzophenone-enriched nutraceutical: Development of a scalable fractionation process and effect of batch-to-batch variation of the raw material (Cyclopia genistoides)

Abstract

Extracts of honeybush (Cyclopia genistoides) containing glucosylated xanthones and benzophenones inhibit α-glucosidases, a group of key glycolytic enzymes and drug targets in the treatment of type 2 diabetes mellitus. Ultrafiltered C. genistoides extract was used as the starting material for the development of an optimized protocol to produce xanthone- and benzophenone-enriched fractions (XEFs and BEFs, respectively) by macroporous adsorbent resin chromatography. Static sorption experiments were performed to determine resin loading capacity. Adsorption isotherm data were fitted to the Langmuir and Freundlich models. A fractionation protocol using step-wise gradient elution with 0–30% EtOH-water mixtures was developed, based on the results of dynamic sorption experiments. All XEFs contained 3-β-D-glucopyranosyliriflophenone due to co-elution with the xanthones, mangiferin and isomangiferin, whereas BEFs contained zero or trace amounts of xanthones. Phenolic variation between different batches of the raw material (n = 10) manifested as variation in the composition and degree of enrichment of BEFs and XEFs. This scalable, eco-friendly enrichment strategy should find application for the preparation of enriched fractions from other herbal plants containing the target compound.