Phytochemical Analysis of the methanolic extract of tigernut, tuber of Cyperus esculentus, by ultra-high performance liquid chromatography coupled with electrospray ionization-quadrupole-time of flight-mass spectrometry (UHPLC/ESI-Q-TOF-MS)

Abstract

In the present work a Spanish local variety of Cyperus esculentus (chufa Appellation of origin Spanish province of Valencia) was studied. The main phenolic compound profile of chufas was obtained using ultra high performance liquid chromatography coupled to a quadrupole-timeof-flight mass spectrometry (UHPLC/ESI-Q-TOF-MS). The assayed chromatographic method enables a rapid and extraordinary efficient separation, allowing easy identification of the three main phenolic compound groups present in the methanolic extracts: phenylethanoids, phenylpropanoids and flavonoids. We also investigated, for the characterization of some other compounds, the possibility of using of in-source fragmentation (ISF) with electrospray ionization (ESI) followed by product ion scan in the QTOF mass spectrometer system. This approach is based on the elucidation of the various fragmentation pathways by further dissociation of each fragment ion in the ion spectrum. This can be achieved predominately, by combining fragmentor voltage induced dissociation (in-source fragmentation IS-CID) with subsequent collision-induced dissociation (CID). 37 compounds (3 amino acids and derivatives, 6 phenolic acids and derivatives, 16 flavonoids, and 8 fatty acids) were either unambiguously indentified or tentatively characterized. One, N-malonyl-Ltryptophan, identified for the first time in tigernut.