Goitrogenic and Antithyroid Potential of Green Tea of Indian Origin

  • Amar K Chandra Professor, Endocrinology and Reproductive Physiology Laboratory, Department of Physiology, University College of Science & Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700009
  • Neela De Post-Doc Fellow, Department of Physiology, University College of Science & Technology, University of Calcutta, Kolkata
Keywords: Green tea, Catechin, Thyroid peroxidase, Na , K -ATPase, 5’ Deiodinase I, Thyroid, Goiter, Antithyroidal activity, Goitrogens

Abstract

Polyphenolic flavonoids, specially catechins are major constituents of tea. Antithyroidal and goitrogenic effect of flavonoids have been reported however such effects of green tea on thyroid physiology has not been explored earlier. Green tea is derived from the tea leaves of Camellia sinensis and widely consumed globally. The green tea extracts(GTE) at different concentrations (1.25g% a 5 cups of tea/ day; 2.5g% a 10 cups of tea/ day and 5.0g% a 20 cups of tea/ day) were orally fed to male rats for 30 days. Similarly, pure catechin was administered orally to male albino rats for 30 days at doses of 25, 50 and 100 mg/kg body weight that are equivalent to above doses of green tea extract in terms of its total catechin content and the morphological and functional changes of the thyroid have been investigated. The overall results reveal that oral administration of green tea extract at 2.5g% and 5.0g% concentrations for 30 days changed the morphology and histology resembling hypertrophy of thyroid follicles with differential colloid sizes as found in hypothyroid due to environment influences associated with significant inhibited activities of thyroid peroxidase(TPO) and 5 monodeiodinase (5 DI1) with elevated Na+,K+ ATPase and concomitant decrease in serum thyroxine (T4), triiodothyronine (T3) and increase in serum thyrotropin (TSH) levels developing a state of absolute biochemical hypothyroidism. All these suggest that catechin present in green tea has the antithyroidal as well as goitrogenic potential and its regular consumption at relatively high doses pose a threat to the functioning of thyroid.

DOI: http://dx.doi.org/10.3329/jbsp.v9i2.22807

Bangladesh Soc Physiol. 2014, December; 9(2): 105-116

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Abstract
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Published
2015-03-30
How to Cite
Chandra, A., & De, N. (2015). Goitrogenic and Antithyroid Potential of Green Tea of Indian Origin. Journal of Bangladesh Society of Physiologist, 9(2), 105-116. https://doi.org/10.3329/jbsp.v9i2.22807
Section
Review