Antioxidative activities of Korean and tea materials by a simple and fast method.

2 3 Shin-Kyo Chung, Young-Chan Kim 1, Sang-Lyong Oh , Kunihisa Iwai and Hajime Matsue

1 : Kyungpook National University, Taegu, 702-701, 2: Sangju National University, Sang-ju, 742-711, KOREA 3 : Aomori Advanced Industrial Technology Center, Aomori, 030-01, JAPAN

Summary Antioxidative activity is one. of important quality factors of tea because it could become a criteria for the prevention of several disease mediated by free radical. XYZ dish method developed by us was a simple and fast method for antioxidative activity of tea in normal drinking conditions. Thirty kinds of commercial tea products and 54 kinds of tea materials were examined. Tea products containing showed much stronger activities than other . Activities by XYZ dish method" exhibited a high correlation between by HPLC and DPPH radical scavenging activities. These results suggest that XYZ dish method was reliable for antioxidative evaluation of various tea products in normal drinking conditions.

Keywords Antioxidative activity, Korean health tea, XYZ-dish method, Catechin

Introduction Recently various kinds of health teas have become popular in Korea. , rhizome, grain and ofherbs and medicinal plants were processed into tea products in small regional factory. Due to this health-benefit effect should be evaluated. A number of researchers have reported on the free radical generation in our body and its mediation to several diseases and cancer, for example, diabetes melitalis, arteriosclerosis and cardiovascular heart diseases. Antioxidative activity is considered to be an important quality factor of food and tea for the prevention of free radical mediated diseases. Methods for testing antioxidative activity vary in the substrate, oxidation inducer. and reactants using spectrophotometer, HPLC, GC and ESR. However simpler, faster and more reproducible method is urgently needed for the evaluation of the varied forms of foods and agricultural plants. Yoshiki et al.( 1) reported chemiluminescent photon generation of some polyphenols, and suggested the possibility of the chemiluminescent photon detection method to test antioxidative activity. XYZ-dish method has been developed by chemiluminescent photon detection that is simpler, faster and also applicable to the varied forms of sample. Moreover, the antioxidative activities of 27 kinds of Korean health tea and some potent tea materials have been evaluated by this method and thus verified its application.

Materials and Methods Sample teas and tea materials Fourteen kinds of type teas, 9 kinds of soild extract type teas and 4 kinds of powder type tea was used. Sample tea was infusioned or solubilized at 70°C water for three minutes. 0.1 mL of them were subjected to XYZ-dish test. 54 kinds of dried plant parts were extracted by water, and lyophilized and diluted to 500 ppm for XYZ-dish test.

-53- Session ill XYZ-dish method

Ch P = K[X][Y][Z]

here [X] = H202 , OH

[V] = Tea solution dish

[Z] = CH3CHO Cooler Photon detector Photon counter Fig. 1. Chemiluminescence analyzer system and sample dish The number of chemilumnescence photon was expressed as in above equation (2). A sample solution adjusted to 1 mL with distilled water was put into a stainless steel dish (50 X 9 mm) and inserted into the detector. When OH was used, FeCh had been previously added. Two mililiters of reactant solution containing 50% CH30H diluted with 50 mM phosphate buffer (pH 7.0), 441 mM H202 as X and 1136 mM as Z was inserted to the detector by syringe. Photon generation was detected and integrated by Chemiluminescence Analyzer system (CLD 110, Tohoku Electronic Industrial Co. Ltd., Japan).

DPPH test DPPH test was executed by the method of Blois (3).

Catechin analysis Seven kinds of of infusion type teas were analyzed by HPLC (LC lOA, Shimatzu Co. Japan) (4). Authentic catechins were purchased from Sigma Chemical Co. U.S.A.

Results and Discussion Antioxidative activities of Korean health teas by XYZ-dish method The antioxidative activities of 14 kinds of infusion health teas were examined by the XYZ­ method. The antioxidative activities of the samples were proportioned to the number of photons. Activities were exhibited as gallic acid units. Green tea (KITll, KIT?) and its mixed products (KIT2, KIT!2) exhibited stronger activities. While KIT8 (pine needle) and KIT! 0 (ginko leaf) showed fairly strong antioxidative activities.

4 .H202 DOH " 60 r .H20' DOH o gaI 40 iii ..9 'c -:I l: 20 :~u < o o ~"'l" ~":> ~.. ~., ~fb ~" ~'t> ~",~...<:>~...... ~..."v~...":>~..... ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ ~~ Fig. 2. Antioxidative activities of Korean Fig. 3. Antioxidative activities of Korean solid infusion type teas extract and powder type teas

Session ill -54- The antioxidative activities of nine kinds of solid extract tea and four kinds of powder teas showed much weaker activities than infusion teas. But KSTlO exhibited particularly strong antioxidative activity especially. Comparing with two kinds of different herb extract teas, it was supposed that synergistic effect of combination of different materials should have a positive role to strong activity.

Correlation of antioxidative activities by XYZ-dish and DPPH method and catechin contents To verify the antioxidative value by XYZ-dish method, the antioxidative activities of health teas were examined by well-known DPPH method. Fig. 4 shows the scattergram of antioxidative values of infusion teas by XYZ-dish method 80 ,.....------.---~--~~, and DPPH method. Antioxidative • H202(r=0.8967) values against H202 (r=0.8957) and • OH(r-0.9494) • OH (r=0.9494) by XYZ-dish method • were well correlated with the values • by DPPH method. The antioxidative 20 values of solid extract and powder type teas by XYZ-dish method were also well correlated with the values by 123 4 DPPH method Gallic acid unit by DPPH metho( Fig. 4. Scattergram of antioxidative values by XYZ- Seven kinds ofcatechins (EC, C, EGC, dish and DPPH methods EGCG, CG, ECG, GCG) in korean infusion teas were analyzed by HPLC (data was not shown). As with the result of antioxidative activities, KITlI and KIT7 contained higher catechins, particularly EGCG. The correlation coefficient of the each catechin contents and antioxidative activity showed varying values according to the kinds ofcatechins.

Antioxidative activities of Korean plant tea materials In order to search for new potent antioxidative tea material, the antioxidative activity of 54 kinds of Korean plant extracts have been examined. The leaves, stems, , fruits and of these plants were dried, extracted by water, and lyophilized to serve to XYZ-dish test. The Leaves of Sageretia theezans and stems of Elaeagnus umbellata showed strong antioxidative activities in the XYZ-dish method.

References I. Y. Yoshiki, K. Okubo, M. Onuma and K. Igrashi, Chemiluminescence of benzoic acids, and cinnamic acids, and flavonoids in the presence of aldehyde and hydrogen peroxide or hydroxyl radical by Fenton reaction. Phytochemistry, 39 (I), pp. 225-229 (1995). 2. K. lwai, K .Abe, H. Matsue. Estabilishment of XYZ-dish method for a new antioxidative activity assay using photon detection. Nippon Shokuhin Kagaku Kaishi. 47 (3). pp. 181-190 (2000). 3. Blois, M. S. Antioxidant determination by the use of a stable free radical, Nature 181, pp. 1199­ 1204(1958) 4. W. E. Bronner, G. R. Beecher, Method for determining the content of catechins in tea by high-performance liquid chromatofraphy, Journal of Chromatography A, 805, pp. 137-142 (1998).

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