Identification And Variation Of Triterpenoid Saponins In Flowers Of Camellia Sinensis

Triterpenoid saponins are a group of important bioactive compounds in tea resources.Recently,more and more attentions were paid on the researches of tea triterpenoid saponins.The research work on the separation,structure identification and health function of triterpenoid saponins has been done.There is little literature on saponin composition of tea flowers from Zhejiang province.In this work,optimized ultra-high performance chromatography(UHPLC)method was used to efficiently analysis triterpenoid saponins in tea flower samples,and coupled with electrospray ionization quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS),the structures of triterpenoid saponins were identified;a comparison of main saponins between cultivars,developmental stages and tissues was performed.The main contributions of this work were as follows:1.A Welch Ultimate LP-C18(250 mm � 4.6 mm,i.d.,3 ?m)was used for separating triterpenoid saponins from tea flower samples.The optimized UHPLC method was as following:the mobile phase consisted of 0.1%phosphoric acid(A)and acetonitrile(B)at a flow rate of 1 mL/min.A gradient elution was applied for chromatographic separation:0 min:15%B;15 min:38%B;60 min:43%B;63 min:70%B;64 min:15%B;72 min:15%B.The column temperature was set at 25?,the injection volume was 10 ?L and the detection wavelength was 210 nm.A total of 21 triterpenoid saponins were tentatively identified and characterized by UPLC-Q-TOF/MS.Based on the published fragmentation data and nominal masses calculated from known structures,the tentatively identified saponins Peak 1-21 were summarized as:Peak 1 was Theasaponin A6,Peak 2 was Floraassamsaponin III,Peak 3 was Chakasaponin ?,Peak 4 was Theasaponin As,Peak 5 was Teaseedsaponin F,Peak 6 was Theasaponin A2,Peak 7 was Chakasaponin IV,Peak 8 was a new compound,Peak 9 was Floratheasaponin D,Peak 10 was Chakasaponin I,Peak 11 was Floratheasaponin A,Peak 12 was Floratheasaponin H,Peak 13 was Foliatheasaponin ?/?,Peak 14 was Teaseedsaponin D,Peak 16 was Chakasaponin ?,Peak 18 was Floratheasaponin J,Peak 19 was Floratheasaponin C,Peak 21 was Floratheasaponin B,Peak 15,Peak 17 and Peak 20 were Chakasaponin V/Floratheasaponins E/isomers.2.Five cultivars of Jiaming No.1,Yingshuang,Longjing No.43,Baiye No.1 and Fudingdabai were chosen in this work.And the variations of contents and compositions of main saponins from different tea flower cultivars and different developmental stages were analyzed.Floratheasaponins were the most abundant saponins in the flowers of Jiaming No.1,Longjing No.43 and Baiye No.1.While Chakasaponins were major saponins in the flowers of Yingshuang and Fudingdabai.The tendencies of the contents of main saponins were similar for all cultivars:high accumulation of saponins was observed at the early stages and then there was a decline.3.Tea flower samples of Yingshuang were divided into three parts:P1:petals;P2:stamens,pistils and ovaries;P3:calyces and receptacles.The tendencies of the contents of main saponins at different tissues were similar to whole flowers.However,the contents and compositions of main saponins were different in three diverse parts of tea flower samples.The contents of main saponins were observed as P1>P2>P3.As the weight proportions of these parts were P2>P1>P3,the accumulation of main saponins was observed in P1 and P2.