Abstract
Tea(Camellia sinensis) contains numerous polyphenolic flavonoid-derived compounds known as catechins, which have shown interesting protective activity against cancer and cardiovascular disease. Numerous products based on tea are commercially available, many of which claim to contain specific amounts of the bioactive catechins. The catechin content of seven commercial green tea products (encapsulated extracts or tea bags) was quantified by HPLC and, where possible, compared to that claimed on the label. Wide variability was observed in the catechin content between green tea products, even those that appear outwardly similar to consumers. Measured catechin content ranged from 9% to 48% of label claims; all values were significantly lower than those claims (P < 0.05). These results continue to demonstrate the problems that exist with quality control in the dietary supplement and herbal medicine industry and, there, for consumers of nutraceuticals.
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Notes on contributors
Jeanette C. Roberts
F. U. Alakbarov is Head Scientific Officer, expert in the Oriental and Folk Medicine, Institute of Manuscripts of the Azerbaijan Academy of Sciences, 8 Istiglaliyat str., Baku, 370001, Azerbaijan.
At the time of writing Liya Davydov was PharmD candidate, College of Pharmacy and Allied Health Professions, St. John's University. Currently, she is Pharmacy Practice Resident, Mount Sinai Medical Center, New York, NY.
Ila Mehra Harris is Assistant Professor, Department of Pharmaceutical Care & Health Systems, College of Pharmacy, and Clinical Assistant Professor, Department of Family Practice & Community Health, Medical School, University of Minnesota, Minneapolis, MN.
Colin J. Briggs is Professor of Pharmacy, Faculty of Pharmacy, University of Manitoba. Recently he completed a secondment to Health Canada, as Senior Science Advisor in the Therapeutics Products Programme with special responsibility for complementary medicines.
Gemma Briggs is Research Assistant, IMPACT, The Injury Prevention Centre of Children's Hospital, 501G-715 John Buhler Research Centre, Winnipeg, MB, Canada.
Mary Chavezis Professor of Pharmacy Practice, Director of Complementary Medicine Education and Research, The Center for the Advancement of Pharmacy Practice, Midwestern University, College of Pharmacy Glendale, Glendale, AZ 85308.