Original

Simultaneous determination of catechins and procyanidins in bottled tea drinks by LC/MS

Isao Murakami, Takumi Nakamura, Yukiko Ishibashi, Ryo Shibuya, Eri Ayano, Yuko Morita-Murase, Yoshiko Nagata and Hideko Kanazawa*

Department of Physical Pharmaceutical Chemistry, Kyoritsu University of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo 105-8512, Japan

Abstract:

Catechins, major polyphenol constituents of green tea, are well known because of their antioxidative activity and chemopreventive effects against cancers. Bottled tea drinks contain not only green tea epicatechins, namely (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC), but also four tea catechin epimers, namely (-)-gallocatechin gallate (GCG), (-)-catechin gallate (CG), (-)-gallocatechin (GC) and (+)-catechin (C). These catechin epimers in bottled tea drinks are produced during the sterilization step in their manufacture. In the present study, we determined the amounts of the eight tea catechins and two procyanidins, including heat-epimerized catechins in bottled oolong tea drinks by liquid chromatography/mass spectrometry (LC/MS). Oolong tea is a traditional Chinese tea that has long been believed to be beneficial to health, such as by decreasing body fat. We investigated the antioxidative activity of heat-epimerized catechins compared with their corresponding precursors. The antioxidative activity of the heat-epimerized catechins were greater than the parent tea catechins and procyanidins.

Keywords: LC/MS; catechins; procyanidins; bottled tea drinks; heat-epimerized catechin; oolong tea; epigallocatechin gallate (EGCG); gallocatechin gallate (GCG); antioxidative activity.

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