Catechin and Caffeine Content of Green Tea Dietary Supplements and Correlation with Antioxidant Capacity

• DOI: 10.1021/jf052857r
• Publication Date: 2006-03-01T12:39:49Z
• Authors: Navindra P. Seeram; Susanne M. Henning; Yantao Niu; Rupo Lee; H. Samuel Scheuller; David Heber
• Keywords: Trolox; Epicatechin gallate; Phytochemical

The health benefits associated with tea consumption have resulted in the wide inclusion of green extracts botanical dietary supplements, which are widely consumed as adjuvants for complementary and alternative medicines. Tea contains polyphenols such catechins or flavan-3-ols including epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate (EGCG), well alkaloid, caffeine. Polyphenols antioxidants, EGCG, due to its high levels, is accepted major antioxidant tea. Therefore, commercial supplements (GTDS) may be chemically standardized EGCG levels and/or biologically capacity. However, label claims on GTDS not correlate actual phytochemical content capacity nor provide information about presence In current study, 19 commonly available were evaluated catechin caffeine (using high-performance liquid chromatography) antioxidative activity [using trolox equivalent (TEAC) oxygen radical (ORAC) assays]. Product labels varied provided inconsistent contents. Only seven studied made content, 11 five specified total polyphenol content. Caffeine, contents from 28 183, 12−143, 14−36% tablet capsule weight, respectively. TEAC ORAC values ranged 187 15340 166 13690 μmol Trolox/g capsule, activities determined by well-correlated each other Reliable labeling manufacturing practices, based both chemical standardization biological assays, recommended quality control supplements. Keywords: Green tea; polyphenols; catechins; flavan-3-ols; caffeine; TEAC;