HPLC-DAD-ESI-MS/MS analysis of polyphenols and purine alkaloids in leaves of 22 tea cultivars in China

• Published in: Journal of food composition and analysis 2008-08, Vol.21 (5), p.361-369
• Main Authors: Wang, Dongmei, Lu, Jiali, Miao, Aiqing, Xie, Zhiyong, Yang, Depo
• Format: Article
• Language: English
• Subjects: alkaloids; Biological and medical sciences; black tea; catechin; Catechins; chemical analysis; Coffee, tea and other stimulative beverage industries; cultivars; epicatechin; epigallocatechin; extraction; Food industries; Fujian and Taiwan cultivars; Fundamental and applied biological sciences. Psychology; gallic acid; General aspects; green tea; Guangdong cultivars; HPLC-DAD-ESI-MS/MS; leaves; Methods of analysis, processing and quality control, regulation, standards; Oolong tea; People's Republic of China; plant extracts; Polyphenols; Purine alkaloids; purines; quantitative analysis; reversed-phase high performance liquid chromatography; tea (beverage); Tea cultivars; Young leaves
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2008.01.002

Using the HPLC-DAD-ESI-MS/MS method, polyphenols and purine alkaloids were analyzed in young leaves of 22 tea cultivars mainly for making oolong tea in China. Ultrasonic extraction in acetonitrile–water (1:1, v/v) was chosen for the preparation of samples for HPLC analysis. Separations were performed on an ODS column with linear gradient elution by the mobile phase consisting of acetonitrile and 1% formic acid aqueous solution. Compared with the standards and data in the literature, 11 catechins, two purine alkaloids, and three non-catechin type of polyphenols were identified, including (−)-epigallocatechin-3-(3″- O-methyl) gallate, (−)-epigallocatechin-3,5-digallate, (−)-epicatechin-3-(3″- O-methyl) gallate, and (−)-epicatechin-3,5-digallate, which are not common catechins in all tea leaves. The contents of the major components, nine catechins and two purine alkaloids were quantified by the HPLC method which were fully validated. The composition of catechins in the leaves of Fujian and Taiwan cultivars group was similar, while the contents of gallated catechins were higher in Guangdong cultivars group than in Fujian and Taiwan cultivars group.