Teaghrelins, unique acylated flavonoid tetraglycosides in Chin-shin oolong tea, are putative oral agonists of the ghrelin receptor.
Chin-shin oolong tea, a popular tea in Taiwan, was empirically perceived to induce hunger and accelerate gastric emptying in a manner similar to the physiological effects of ghrelin, an endogenous acylated peptide known as the hunger hormone. Two unique acylated flavonoid tetraglycosides previously identified in Chin-shin oolong tea were demonstrated to induce hunger of rats in a food intake assay and, thus, named teaghrelin-1 and teaghrelin-2. Similar to GHRP-6, a synthetic analogue of ghrelin, teaghrelin-1 stimulated growth hormone secretion of rat primary anterior pituitary cells in a dose-dependent manner, and the stimulation was inhibited by [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]-substance P, an antagonist of the ghrelin receptor. While teaghrelin-2 remained unmodified, a meta-O-methylated metabolite of teaghrelin-1 was detected in bile of rats after intravenous injection. Presumably, teaghrelins are promising oral agonists of the ghrelin receptor.
Graduate Institute of Biotechnology, National Chung Hsing University , Taichung 402, Taiwan.
Yuan-Hao
YH
Lo
Ying-Jie
YJ
Chen
Chi-I
CI
Chang
Yi-Wen
YW
Lin
Chung-Yu
CY
Chen
Maw-Rong
MR
Lee
Viola S Y
VS
Lee
Jason T C
JT
Tzen
D000215:Acylation; D000818:Animals; D028241:Camellia sinensis / Q000737:chemistry*; D004435:Eating / Q000187:drug effects; D005419:Flavonoids / Q000737:chemistry / Q000494:pharmacology*; D054439:Ghrelin / Q000378:metabolism; D006027:Glycosides / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054440:Receptors, Ghrelin / Q000819:agonists* / Q000378:metabolism
D005419:Flavonoids; D054439:Ghrelin; D006027:Glycosides; D010936:Plant Extracts; D054440:Receptors, Ghrelin