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[SANET-MG] Tea Compounds against Human Cancer Cells



If tea is like strawberries then organic tea should be even better
J. Agric. Food Chem., ASAP Article 10.1021/jf062276h S0021-8561(06)02276-X
Web Release Date: December 16, 2006 Structure-Activity Relationships of Tea Compounds against Human Cancer Cells

Mendel Friedman,* Bruce E. Mackey, Hyun-Jeong Kim, In-Seon Lee, Kap-Rang Lee, Seung-Un Lee,# Etsuko Kozukue,# and Nobuyuki Kozukue#

Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710; The Center for Traditional Microorganism Resources, Keimyung University, 704-701 Daegu, South Korea; College of Human Ecology and Kinesiology, Yeungnam University, 712-149 Gyeongsan, South Korea; and Department of Food Service Industry, Uiduk University, 780-713 Gangdong, Gyeongju, Gyongbuk, South Korea

Received for review August 7, 2006. Revised manuscript received October 11, 2006. Accepted November 2, 2006.

Abstract:

The content of the biologically active amino acid theanine in 15 commercial black, green, specialty, and herbal tea leaves was determined as the 2,4-dinitrophenyltheanine derivative (DNP-theanine) by a validated HPLC method. To define relative anticarcinogenic potencies of tea compounds and teas, nine green tea catechins, three black tea theaflavins, and theanine as well as aqueous and 80% ethanol/water extracts of the same tea leaves were evaluated for their ability to induce cell death in human cancer and normal cells using a tetrazolium microculture (MTT) assay. Compared to untreated controls, most catechins, theaflavins, theanine, and all tea extracts reduced the numbers of the following human cancer cell lines: breast (MCF-7), colon (HT-29), hepatoma (liver) (HepG2), and prostate (PC-3) as well as normal human liver cells (Chang). The growth of normal human lung (HEL299) cells was not inhibited. The destruction of cancer cells was also observed visually by reverse phase microscopy. Statistical analysis of the data showed that (a) the anticarcinogenic effects of tea compounds and of tea leaf extracts varied widely and were concentration dependent over the ranges from 50 to 400 g/mL of tea compound and from 50 to 400 g/g of tea solids; (b) the different cancer cells varied in their susceptibilities to destruction; (c) 80% ethanol/water extracts with higher levels of flavonoids determined by HPLC were in most cases more active than the corresponding water extracts; and (d) flavonoid levels of the teas did not directly correlate with anticarcinogenic activities. The findings extend related observations on the anticarcinogenic potential of tea ingredients and suggest that consumers may benefit more by drinking both green and black teas.

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