Abstract: The study proposed a standard analyzing method based on high performance liquid chromatography combined with ultraviolet (UV) to quantify extracting characteristics of flavone glycosides in Xihulongjing tea under different brewing conditions, and their contributions to taste was estimated by Dot factor (Dose-over-Threshold). Results indicated that: (1) This method can be used to separate and quantify eleven flavone and flavonol glycosides in tea; (2) In traditional brewing conditions, Myr-gala and Que-rut were the principal flavonol glycosides in Xihulongjing tea. With brewing temperature and time rising, eleven flavone and flavonol glycosides except Kae-rut increased variably with the raising of brewing temperature and the prolonging of brewing time, Que-rut and Que-gala leached fastly, while Myr-rha and Vit-rha leached slowly among 11 flavone and flavonol glycosides; (3)All of the Dot factors of Que-rut、Que-gala and Myr-gala were higher than 10. According to the definition of Dot factor, they may be showed a significant contributor to tea taste.

Key words: brew condition, Xihulongjing tea, flavone and flavonol glycosides, extracting characteristic, taste contribution