Planta Med 2010; 76 - P539
DOI: 10.1055/s-0030-1264837

Improved separation of green tea catechins and xanthines with calixarene bonded silica packings in narrow-bore HPLC systems

G Bazylak 1, T Pan 2
  • 1Nicolaus Copernicus University, Collegium Medicum, Faculty of Pharmacy, Department of Pharmaco-Bromatology & Molecular Nutrition, Jagiellonska 13, 85067 Bydgoszcz, Poland
  • 2School of Traditional Chinese Medicine, Chang Gung University, 259 Wen-Hwa 1st Road, 333 Kweishan, Taoyuan, Taiwan

Epigallocatechin gallate (EGCg), the predominant green tea catechin, is recommended as the health-promoting and complementary agent in the current management of variety infectious diseases with approved antivirals and antibiotics [1]. However, in commonly applied isocratic HPLC assays with octadecylsilica-C18 packed columns the baseline separation of critical pairs as catechine/epigallocatechine and caffeine/EGCg was often failed. In presented isocratic narrow-bore HPLC procedure, the three different calixarene bonded stationary phases were successfully applied with AcN-2.65 mM H3PO4 (10:90, v/v), pH 3.0, as mobile phase to enable a complete separation of six catechins and six xanthines present in aqueous-AcN extracts of green tea. Compared to the retention with C18 columns, the trans isomer (catechine) was eluted before the cis isomer (epicatechine) on each calixarene-based packing studied. However, when the dihydroxyphenyl substituents in catechine moiety were replaced by trihydroxyphenyl fragment, as was also in case of its gallate esters, the cis isomers were eluted first. These phenomena showed that selectivity of catechins separation with calixarene stationary phases was closely related with stability of their inclusion (1:1) host-guest complexes formed between analyte molecules and calixarene cavities [2]. In case of xanthines the increased size of substituents attached to the N1 nitrogen atom of the pyrimidine ring, caused enhanced retention of these compounds in proposed HPLC systems. The distribution profiles of catechins and xanthines in series of commercially available green teas and catechins-based nutraceuticals were determined with the developed HPLC procedure to offer more detailed data for standardization of such health-promoting products.

Acknowledgements: Nicolaus University, Torun, Poland (Internal Grant No. 407/2010).

References: 1. Song, J.M., Seong, B.L. (2007) Expert Rev. Anti Infect. Ther. 5(3): 497–506.

2. Bazylak, G. et. al. (2008) Curr. Drug Discov. Technol. 5(2): 177–189.