Quantitation of Chafurosides A and B in Tea Leaves and Isolation of Prechafurosides A and B from Oolong Tea Leaves
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- 作者：Hitoshi Ishida ; Toshiyuki Wakimoto ; Yukiko Kitao ; Shimako Tanaka ; Toshio Miyase ; Haruo Nukaya
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2009
- 出版时间：August 12, 2009
- 年：2009
- 卷：57
- 期：15
- 页码：6779-6786
- 全文大小：880K
- 年卷期：v.57,no.15(August 12, 2009)
- ISSN：1520-5118
文摘
A procedure was developed for the quantitative determination of chafuroside A, a flavone C-glycoside with potent anti-inflammatory activity, and its regioisomer chafuroside B, as well as isovitexin and vitexin, by selected reaction monitoring liquid chromatography−tandem mass spectrometry (SRM LC-MS/MS) analysis. This method was successfully applied to commercial leaves of green tea, houji tea, oolong tea, and black tea. High levels of chafurosides A and B were found in oolong tea leaves that had been heated at >140 °C. Next, their precursors, prechafurosides A and B, were isolated from methanol extract of oolong tea leaves prepared from Shizu 7132, Camellia sinensis (L.) O. Kuntze, by partition with n-butanol and H2O and chromatography on Diaion SP-825, Sephadex LH-20, and ODS C-18, guided by assay of chafuroside formation. Prechafurosides A and B gave chafurosides A and B, respectively, in good yields when heated at 160 °C for 0.5 h. Solvolysis of prechafurosides A and B with pyridine and dioxane quantitatively afforded isovitexin and vitexin, respectively. On the basis of these results and physicochemical data (MS, UV, and NMR), prechafurosides A and B were concluded to be new flavone C-glycoside sulfates, isovitexin-2′′-sulfate and vitexin-2′′-sulfate, respectively.