Structural Determination of Acylated Flavonol Glycosides in Seven Taiwan Tea Cultivars

• Main Authors: Ruo-Hsuan Wo, 吳若玄
• Other Authors: Jason T.C. Tzen
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/30371511658411200191

碩士 === 國立中興大學 === 生物科技學研究所 === 105 === Taiwan has been well known as one of the regions to produce tea. Due to unique terrain and salubrious climate, Taiwan has a suitable environment for various cultivars. There are several tea cultivars in Taiwan, including Chin Shin Oolong, Shy Jih Chuen, Taiwan Tea Experiment Station (TTES) No.12, etc. According to previous study from our lab, we discovered unique acylated flavonol tetraglycosides in Chin Shin Oolong, which could improve gastrointestinal emptying and induce hunger. These compounds could bind to the ghrelin receptor and trigger physiological responses via the same molecular mechanism as ghrelin. Due to these similar responses, these compounds were named Teaghrelins. Teaghrelins show high potential in developing treatment of growth hormone deficiency. My research goal is to find out Teaghrelin-similar compounds in seven Taiwan tea cultivars. In this study, tea samples were analyzed through liquid chromatography tandem mass spectrometer (LC-MS/MS). From total ion chromatogram (TIC) and MS/MS fingerprint, many analogous have been discovered. Molecule weights at 1064, 1048, 1050 and 1034 Da were identified. These ions were further dissociate through collision (MS/MS). Ions contained 146 Da (rhamnosyl and coumaroyl group) fragment with aglycones, quercetin (302 Da) and kaempferol (286 Da) were identified. According to the results mentioned above, these compounds were presumed as Teaghrelin-similar compounds. In order to prepare pure samples for structural derermination by NMR, a purification platform was constructed. By water extraction, styrene-divinylbenzene (ST-DVB) and Sephadex LH-20 column, fractions contained Teaghrelin-similiar compounds (TSCs) were acquired. The fractions were separated and collected by High-performance liquid chromatography (HPLC) system and Thin layer chromatography (TLC). Finally, used Sephadex LH-20 column remove the residue acid and recover the pure compound.