Identification of triterpenoid saponins in flowers of four Camellia Sinensis cultivars from Zhejiang province: Differences between cultivars, developmental stages, and tissues

•A total of 21 triterpenoid saponins were identified and characterized for the first time from tea flower extracts from selected cultivars from Zhejiang province.•A very high accumulation of saponins was observed in early flower stages of all tea cultivars.•The significance of different saponin profiles in tea flower cultivars is discussed.

Triterpenoid saponins are important bioactive compounds in tea flowers. Using ultra-high performance chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry, a total of 21 triterpenoid saponins were identified and characterized from tea flower extracts of selected cultivars from Zhejiang province. A comparison of the seven main saponins was performed in the four main Zhejiang tea flower samples at different developmental stages. High accumulation of saponins at the early stages was observed in all tea flower cultivars. This may be explained, at least partly, by the high levels of saponins in petals at the green bud stage, when petals constitute over 50% of the whole flower weight. Floratheasaponin A and floratheasaponin D were the most abundant saponins in the flowers of Longjing NO.43, Baiye NO.1, and Jiaming NO.1, which is similar to results with tea flowers from Anhui province. Considerable amounts of chakasaponins I and II were found in Yingshuang flowers, as in the parent cultivar, Fudingdabai, and tea flowers from Fujian province. The quantified saponins profiles were analyzed by principal component analysis (PCA) and hierarchical clustering analysis (HCA) and successfully discriminated between all tea flower samples.