P-18 ウーロン茶中の強力な抗炎症作用成分Chafuroside Aの生成機構(ポスター発表の部)

抄録

A procedure was developed for quantitative determination of chafuroside A1, a flavone C-glycoside with potent anti-inflammatory activity, and its regioisomer chafuroside B2, as well as isovitexin and vitexin, by selected reaction monitoring liquid chromatography-tandem mass spectrometry analysis. This method was successfully applied to commercial leaves of green tea, houji tea, oolong tea and black tea. High levels of chafuroside A and chafutoside B were found in oolong tea leaves that had been heated at over 140℃. Next, their precursors, prechafuroside A and prechafuroside B, were isolated frommethanol extract of oolong tea leaves prepared from Shizu 7132, Camellia sinensis (L.) O. Kuntze, by partiton with n-butanol and H_2O and chromatography on Diaion SP-825, Sephadex LH-20, and ODS C-18, guided by assay of chafuroside formation. Prechafuroside A and prechafutoside B gave chafuroside A and Chafuroside B, respectively, in good yields when heated at 160℃ for 0.5h. Hydrolysis of prechafuroside A and prechafuroside B with pyridine and dioxane quantitatively afforded isovitexin and vitexin, respectively. Based on these results and physicochemical data (MS, UV and NMR), prechafuroside A and prechafuroside B were concluded to be new flavone C-glycoside sulfates, isovitexin-2"-sulfate 5 and vitexin-2"-sulfate 6, respectively.