Analysis Of Seasonal Changes On Flavonoid Metabolome Of Tetrastigma Hemsleyanum

Tetrastigma hemsleyanum belongs to the grape family of Vitaceae,which is a unique and rare medicinal plant in China.It has anti-tumor,anti-inflammatory,analgesic and anti-pyretic properties,and is used for the treatment of high fever,pneumonia,asthma,hepatitis,rheumatism and sore throat.Flavonoids are the most typical and important active components of Tetrastigma hemsleyanum,and play an important role in anti-tumor,anti-inflammation and anti-oxidation.In order to explore the rule of flavonoids in response to seasonal changes,this study took the tubers of Tetrastigma hemsleyanum grown in Siming Mountain(Ningbo,China)as the research object,established the UV determination method of flavonoids,the UPLC-MS/MS qualitative and quantitative method of flavonoids monomer components,and the UV determination method of antioxidant activities of ABTS,DPPH and·OH radical.To find out the specific metabolites response to season changes,PCA and OPLS-DA model were used to evaluate the samples,and the different accumulated metabolites were screened out according to FC algorithm and VIP value.We selected 11 representative standard products to calculate the absolute contents of flavonoids,and their accumulation and change rules were compared.In addition,according to network pharmacology,we used Swiss Target Preditcion database to screen active ingredients and analyze metabolite targets as well as associated diseases.The main research results are as follows:1.Using targeted metabolomics,a total of 170 flavonoids were identified in 24 samples,including 109 known compounds with CAS number and 61 unknown compounds without CAS number.All these flavonoids can be divided into 8 different subclasses,including chalcone(10),dihyroflavanonol(10),aurone(1),flavanol(9)and isoflavone(1),flavanone(12),flavone(58),and flavonol(69).2.The total content of flavonoids was highest in summer,followed by autumn and winter.11 standard products of naringin chalcone,naringin,formononetin,vitexin,luteolin,wheat flavone,citipine,catechin,kaigol,rutin and myricetin were selected to quantify the metabolome of flavonoids.The contents of chalcone and dihydroflavone were the highest in autumn,which were 2.50μg/g and 25.38 μg/g,respectively.The contents of flavonoids,flavonols and dihydroflavones were the highest in summer,which were 14.79 μg/g,433.92 μg/g,98.55 μg/g,while the maximum content of flavanols was in winter with 135.59 μg/g.These results indicated that seasonal change had a specific selective effect on the metabolism of flavonoids.3.Using VIP and FC dual conditions to screen differential substances,a total of 12 kinds of key different accumulated metabolites responding to seasonal changes were screened,which are phreoside,dihydrochalcone-4’-o-glucoside,ductibaicalein,5,6,7,4’-tetramethoxyl flavonoid,5,7,3’,4’-tetramethoxyl flavonoid,sweet orange,hesperidin,neohesperidin,dihydroxydimethoxyl flavonoid,6-hydroxykaempfer-7-oglucoside,3,5,3’,4’-pentamethoxyl flavonoid,3,5,3’,4’-pentamethoxyl flavonoid,3,5,3’,4’-pentamethoxyl flavonoid,6,7,8,3’,4’-heptamethoxy flavonoid.4.The scavenging rates of three kinds of free radicals in summer were higher than those in other seasons,indicating that the antioxidant activity in summer was better than that in other seasons.108 flavonoid metabolome groups were screened into active components,305 targets and 34 core components,which were mainly concentrated in antioxidant,cell necrosis,apoptosis and other pathways,providing new clues for further pharmacological research of Tetrastigma hemsleyanum.