Green tea and thermogenesis: interactions between catechin-polyphenols, caffeine and sympathetic activity

The thermogenic effect of tea is generally attributed to its caffeine conte nt. We report here that a green tea extract stimulates brown adipose tissue thermogenesis to an extent which is much greater than can be attributed to its caffeine content per se, and that its thermogenic properties could res ide primarily in an interaction between its high content in catechin-polyph enols and caffeine with sympathetically released noradrenaline (NA), Since catechin-polyphenols are known to be capable of inhibiting catechol-O-methy l-transferase (the enzyme that degrades NA), and caffeine to inhibit trance llular phosphodiesterases (enzymes that break down NA-induced cAMP), it is proposed that the green tea extract, via its catechin-polyphenols and caffe ine, is effective in stimulating thermogenesis by relieving inhibition at d ifferent control points along the NA-cAMP axis, Such a synergistic interact ion between catechin-polyphenols and caffeine to augment and prolong sympat hetic stimulation of thermogenesis could be of value in assisting the manag ement of obesity.