Food Sci. Biotechnol. 20(2): 327-333 (2011) DOI 10.1007/s10068-011-0046-1 Optimal Extraction Conditions for Simultaneous Determination of Catechins and Caffeine in Green Tea Leaves Myoung-Gun Choung and Min-Seuk Lee Received: 4 August 2010 / Revised: 24 November 2010 / Accepted: 25 November 2010 / Published Online: 30 April 2011 © KoSFoST and Springer 2011 Abstract The amount of catechins and caffeine in green tea are considered a standard of quality evaluation for green tea. The objectives of this study were to investigate the optimal conditions for simultaneous extraction of catechins and caffeine and to compare their quantity and composition within the exotic tea varieties. Moreover, 8 tea varieties of exotic origin were tested with the optimal extraction conditions found in this study. Regarding the caffeine and catechins contents, a 2 h room temperature extraction using a 2% phosphoric acid-40% EtOH solution was the most suitable simultaneous extraction method. The total catechins and caffeine contents of the tea leaves ranged 44.25-64.80 and 9.26-13.11 mg/g, respectively. The optimal extraction method of catechins and caffeine in tea leaves may be used for further studies and breeding of high quality tea plants. Keywords: caffeine, catechin, green tea, high performance liquid chromatography, simultaneous extraction Introduction Tea (Camellia sinensis L.) is the most consumed beverage in the world after water, and the average consumption in the world is more than 120 mL/day/person (1). It has become a popular caffeinated non-alcoholic drink along with coffee and cocoa (2). Tea has grown to be such an important drink because it has a popular appeal to a number of nations and has recently been given attention because of its medicinal value. Tea is known to activate the body including controlling the biorhythm, enhancing immunity, preventing or treating diseases, and slowing the aging process (3). Tea, compared with other beverages, contains large quantities of nitrogenous compounds, polyphenols, sugars, organic acids, vitamins, and minerals (2) and, especially, polyphenols, which are abundant in tea. The polyphenols contained in tea are mostly flavonols, known as catechin compounds. The main catechin compounds of green tea are (+)-catechin (C), (-)- gallocatechin (GC), (-)-epigallocatechin (EGC), (-)- epigallocatechin gallate (ECGC), (-)-epicatechin (EC), (-)- gallocatechin gallate (GCG), and (-)-epicatechin gallate (ECG). The catechin compounds of green tea have beneficial effects as they are known to reduce blood cholesterol levels (4,5), act as an antioxidant (6-8), act as anticancer compounds (9,10), aid in detoxication (11), have antibacterial activities (12), and prevent whiten skin (13). There was also a report on the antiviral effect of green tea catechins against the influenza virus (14). Because of these bioactive and medical qualities, the polyphenols in green tea, i.e., catechin compounds, have been studied extensively. Research on tea has focused on the possibility of using it as food or functional materials, but not much comprehensive research has been conducted on the methods of analysis and extraction of catechin compounds, despite such a high probability of application. Nwuha et al. (15) has reviewed the solubility and stability of caffeine and catechins in green tea. Caffeine and catechins were shown to be more soluble in ethanol than in pure water. The solubility of caffeine and catechins in 95% ethanol at 40 o C was 25.73 and 214.70 mg/mL, respectively, and the solubility of caffeine and catechins in pure water at 62 o C was 4.60 and 29.77 mg/mL, respectively. Previous studies on the extraction Min-Seuk Lee ( ) Sulloc Cha R&D Center, Jangwon Co., Ltd., Seogwipo, Jeju 699-920, Korea Tel: +82-64-794-6491; Fax: +82-64-794-6493 E-mail: leems@jwgreent.co.kr Myoung-Gun Choung Department of Herbal Medicine Resource, Kangwon National University, Samcheok, Gangwon 245-711, Korea RESEARCH ARTICLE