Cyclopia genistoides (Honeybush) – A rich source of bio-active xanthones and benzophenones

T Beelders; D De Beer; DJ Brand; E Joubert

doi:10.1055/s-0034-1394549

Planta Medica, Table of Contents

Cyclopia genistoides (Honeybush) – A rich source of bio-active xanthones and benzophenones

T Beelders ¹^,², D De Beer ², DJ Brand ³, E Joubert ¹^,²

¹Department of Food Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
²Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa
³Central Analytical Facility, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa

Abstract

Cyclopia genistoides Vent is a commercially important species of the genus Cyclopia, endemic to the Cape Floristic region of South Africa. In recent years, the utilization of Cyclopia spp. has progressed from their traditional use as herbal tea (honeybush) to the production of hot water extracts destined for the food and nutraceutical industries. The functional ingredient status of Cyclopia extracts is supported by their biological properties [1], which may partially be attributed to their phenolic composition [2]. Comprehensive data regarding the nature of these phenolic constituents, as well as their individual content values, are therefore required. High-performance liquid chromatographic (HPLC) methods currently employed in the quantitative analysis of C. genistoides extracts are, however, hampered in terms of limited resolution and the number of quantifiable analytes [3 – 4]. In light of the above, a validated HPLC method was developed to quantify the major polyphenols present in hot water extracts of C. genistoides. The phenolic constituents were identified with electrospray-ionisation mass spectrometry (ESI-MS) and characterized on the basis of their unique fragmentation pattern (ESI-MS/MS). The optimized method enabled accurate quantification of twenty compounds, with the xanthones (mangiferin, isomangiferin) and benzophenones (iriflophenone-3-C-β-D-glucoside, iriflophenone-3-C-β-D-glucoside-4-O-β-D-glucoside) representing the major phenolic constituents. This is the first report of the presence of iriflophenone-3-C-β-D-glucoside-4-O-β-D-glucoside in C. genistoides extracts, unambiguously identified by appropriate procedures including nuclear magnetic resonance after isolation. C. genistoides was ultimately shown to be a rich source of bio-active xanthones and benzophenones and is, to our knowledge, the only known natural source of iriflophenone-3-C-β-D-glucoside-4-O-β-D-glucoside.

Keywords: HPLC, ESI-MS, mangiferin, isomangiferin, iriflophenone-3-C-β-D-glucoside, iriflophenone-3-C-β-D-glucoside-4-O-β-D-glucoside, quantification, isolation

References:

[1] Joubert E, Joubert ME, Bester C, de Beer D, De Lange JH. Honeybush (Cyclopia spp.): From local cottage industry to global markets – The catalytic and supporting role of research. S Afr J Bot 2011; 77: 887 – 907.

[2] Joubert E, Gelderblom WCA, Louw A, de Beer D. South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides – A review. J Ethnopharmacol 2008; 119: 376 – 412.

[3] Joubert E, Otto F, Grüner S, Weinreich B. Reversed-phase HPLC determination of mangiferin, isomangiferin and hesperidin in Cyclopia and the effect of harvesting date on the phenolic composition of C. genistoides. Eur Food Res Technol 2003; 216: 270 – 273.

[4] de Beer D, Joubert E. Development of HPLC method for Cyclopia subternata phenolic compound analysis and application to other Cyclopia spp. J Food Compos Anal 2010; 23: 289 – 297.