Study of C- and O-glycosylflavones in sugarcane extracts using liquid chromatography: exact mass measurement mass spectrometry

Abstract

Os flavonóides presentes nos extratos de cana-de-açúcar (Saccharum officinarum) foram analisados por cromatografia líquida acoplada à espectrometria de massas (LC-MS), e o estudo da rota de fragmentação dos flavonóides selecionados foi realizado utilizando a espectrometria de massas com aceleração ortogonal por tempo de vôo e ionização eletrospray (ESI-oa-ToF MS). Sete flavonas C-e O-glicosiladas foram identificadas nos extratos: schaftosídeo, isoschaftosídeo, luteolina-8-C-(ramnosilglicosídeo), vitexina, orientina, tricina-7-O-neohesperidosídeo e tricina-7-O-glicosídeo. Destas, cinco foram identificadas sem comparação direta com seus respectivos padrões. O método descrito também permitiu a diferenciação das 6-C e 8-C flavonas isoméricas, schaftosídeo e isoschaftosídeo. A combinação dos dados de fragmentação e a medida de massa exata mostraram ser complementares às técnicas de HPLC-UV-MS previamente utilizadas para discriminação de isômeros nos estudos da cana-de-açúcar.The flavonoids present in sugarcane (Saccharum officinarum) extracts were analyzed by liquid chromatography -mass spectrometry (LC-MS), and a study of the fragmentation patterns of selected flavonoids was conducted using orthogonal acceleration time-of-flight electrospray ionization mass spectrometry (ESI-oa-ToF MS). Seven C-and O-glycosylflavones were identified in the extracts, namely, schaftoside, isoschaftoside, luteolin-8-C-(rhamnosylglucoside), vitexin, orientin, tricin-7-O-neohesperidoside and tricin-7-O-glucoside. Of these, five were identified in the absence of direct comparison with their respective standards. The described method also permitted the differentiation of the 6-C and 8-C isomeric flavones, schaftoside and isoschaftoside. The combination of fragmentation data and exact mass measurement showed to be complimentary to the HPLC-UV-MS techniques previously utilized for isomers discrimination in sugarcane studies.

On-line identification of minor flavones from sugarcane juice by LC/UV/MS and post-column derivatization

“…These fragments have already been described for tricin 7-O-neohesperidoside (compound 11) 11 and were also studied by exact mass measurement. 13 The fragment at m/z 639 [M+H-146] + indicated loss of a rhamnose moiety. 14,17 The UV data obtained with sodium acetate showed positions 7, 3' and 4' blocked, while the 5-OH group was free.…”

The Occurrence, Fate and Biological Activities ofC-glycosyl Flavonoids in the Human Diet

“…During processing, a surprising array of flavonoids is found in the extracted juice and bagasse (the lignin-based material left after juice extraction), many of which are Cglycosylated. These include the dimethylated flavone 4 ,5 -dimethyl luteolin-8-C--Dglucoside, luteolin-8-C-rutinoside, vitexin, orientin, schaftoside, isoschaftoside, and diosmetin-8-C--D-glucoside (Colombo et al, 2008;Colombo et al, 2006). Whilst these compounds are easily detectable during processing, no data is currently available detailing flavonoid survival through further refinement to consumed products such as molasses or refined sucrose.…”

Tricin—a potential multifunctional nutraceutical

“…Mabry et al 1984;Lin et al 2009;Park et al 2007;Wang et al 2004;Zhang et al 2008a, b), and less often as the 5-glucoside (Wallace 1974;AdjeiAfriyie et al 2000a, b), although tricin 5-glucoside and tricin 5-diglucoside and tricin 5,7-glucoside were also reported to occur in M. flacata (Polyakova 1992); 4 0 -glucoside (Hasegawa et al 2008) and 4 0 -apioside (Syrchina et al 1992); 7-glucuronide (Harborne and Hall 1964;Markham and Porter 1973); 7-diglucuronide (Timoteo et al 2008); 7-glucuronide sulphate (Williams et al 1983) as well as several tricin glycosides conjugated with sulphate (Harborne and Williams 1976), 7-(2 00 -rhamnosyl)-a-galacturonide (Mabry et al 1984); 7-glucuronide-4 0 -glucoside (Stochmal et al 2001;Kowalska et al 2007); 7-diglucuronide (Timoteo et al 2008) and 7-neohesperidoside (Colombo et al 2006(Colombo et al , 2008 derivatives, to mention only a few. Other recently reported conjugated forms of tricin include the flavonolignan derivatives: 7-b-(6 00 -methoxycinnamic)-glucoside (Duarte-Almeida et al 2007); 4 0 -b-guaiacylglyceryl (Bouaziz et al 2002;Lei et al 2007); 4 0 -(b-guaiacylglyceryl)-7-b-glucoside (Yang et al 2006); six new guaiacylglyceryl derivatives, considered as three pairs of stereoisomers (Nakajima et al 2003); 7-[2 0 -pcoumaroyl]-b-triglucuronide and the feruloyl diglucuronide derivative (Kowalska et al 2007); as well as two other related conjugates, one with a coniferyl moiety linked to tricin by an ether bond and the other linked by a C-C bond (Wenzig et al 2005).…”