Analysis of Flavonoid Metabolites in Buckwheat Leaves Using UPLC-ESI-MS/MS

Abstract

Flavonoids from plants are particularly important in our diet. Buckwheat is a special crop that is rich in flavonoids. In this study, four important buckwheat varieties, including one tartary buckwheat and three common buckwheat varieties, were selected as experimental materials. The total flavonoid content of leaves from red-flowered common buckwheat was the highest, followed by tartary buckwheat leaves. A total of 182 flavonoid metabolites (including 53 flavone, 37 flavonol, 32 flavone C-glycosides, 24 flavanone, 18 anthocyanins, 7 isoflavone, 6 flavonolignan, and 5 proanthocyanidins) were identified based on Ultra Performance Liquid Chromatography–Electrospray Ionization–Tandem Mass Spectrometry (UPLC-ESI-MS/MS) system. Through clustering analysis, principal component analysis (PCA), and orthogonal signal correction and partial least squares-discriminant analysis (OPLS-DA), different samples were clearly separated. Considerable differences were observed in the flavonoid metabolites between tartary buckwheat leaves and common buckwheat leaves, and both displayed unique metabolites with important biological functions. This study provides new insights into the differences of flavonoid metabolites between tartary buckwheat and common buckwheat leaves and provides theoretical basis for the sufficient utilization of buckwheat.

Treasure from garden: Bioactive compounds of buckwheat

“…Extremely high rutin content and activity of rutinoside makes very strong bitterness, which prevents animals to graze the common buckwheat particularly Tartary buckwheat ( Kreft et al, 2020 , Joshi et al, 2020 ). Recently, thirty seven flavonols i.e., syringetin 3- O -hexoside, dihydromyricetin, kaempferol 3- O -robinobioside, kaempferol 3- O -rutinoside, methyl quercetin O -hexoside, quercetin 4′- O -glucoside, kaempferol 3- O -galactoside, quercetin 3-alpha- l -arabinofuranoside, kaempferide, isorhamnetin 5- O -hexoside, dihydroquercetin, isorhamnetin O -hexoside, myricetin, quercetin, kaempferol, kumatakenin, 3-Hydroxyflavone, myricetin 3- O -galactoside, rutin, isorhamnetin 3- O -neohesperidoside, fustin, kaempferol 3,7-dirhamnoside, quercetin 3- O -glucoside, quercetin 7- O -β- d -Glucuronide, quercetin O -acetylhexoside, kaempferol 3- O -glucoside, kaempferol 3- O -rhamnoside, aromadedrin, kaempferol 7- O -rhamnoside, kaempferol 3,7- O -diglucoside 8-prenyl derivative, laricitrin, morin, syringetin, isorhamnetin, di- O -methylquercetin, 7- O -methxyl quercetin, and 3,7-di- O -methylquercetin were identified from leaves of three varieties of common buckwheat and one variety of Tartary buckwheat ( Li et al, 2019a ). Moreover, kaempferol, quercitrin (quercetin-3- O -rhamnoside) and quercetin-3- O -rutinoside-3′- O -β-glucopyranoside have been identified from various organs ( i.e., leaf, root, stem, flower, and seed) of F. tataricum and F. cymosum , while quercetin-3- O -β- d -galactoside found in F. esculentum and F. tataricum .…”

“… Li et al (2019a) have isolated a total of twenty four flavanones from leaves of three varieties of common buckwheat and one variety of Tartary buckwheat and those are afzelechin (3,5,7,4 ′ -Tetrahydroxyflavan), eriodictyol O -malonylhexoside, hesperetin 7-rutinoside (hesperidin), hesperetin 7- O -neohesperidoside, naringenin 7- O -glucoside, naringenin O -malonylhexoside, naringenin, isoliquiritigenin, xanthohumol, hesperetin O -hexosyl- O -hexoside, hesperetin 5- O -glucoside, naringenin 7- O -neohesperidoside, hesperetin O -malonylhexoside, eriodictyol, isosakuranetin-7-neohesperidoside, naringenin chalcone, butein, phloretin, homoeriodictyol, hesperetin, 7- O -Methyleriodictyol, 4′-Hydroxy-5,7-dimethoxyflavanone, isosakuranetin, and pinocembrin. Besides, flavanone, (−)-liquiritigenin has been detected from Tartary buckwheat roots ( Lv et al, 2017 ).…”

Dynamic transcriptome and metabolome analyses of two types of rice during the seed germination and young seedling growth stages

“…A specific set of MRM transitions was monitored for each period according to the metabolites eluted within this period. Qualitative and quantitative determination of metabolites followed the methods of Li et al [60]. The significant differences in the relative metabolite content was tested by orthogonal partial least squares discriminant analysis (OPLS-DA).…”

Analysis of Flavonoid Metabolites in Chaenomeles Petals Using UPLC-ESI-MS/MS

“…Declustering potential (DP) and collision energy (CE) for individual MRM transitions were done with further DP and CE optimization. A specific set of MRM transitions was monitored for each period according to the metabolites eluted within this period [ 50 , 51 ]. Moreover, the MS/MS diagrams of some metabolites are shown in Supplementary Figure S4 .…”