[Screening for limonoid glucosides in Citrus grandis L. Osbeck by high performance liquid chromatography-electrospray...

A screening method for limonoid glucosides in the peel of Citrus grandis L. Osbeck, utilizing high performance liquid chromatography (HPLC) with diode-array detection (DAD), interfaced to electrospray ionization-mass spectrometry (ESI-MS), has been developed. The methanol extract of citrus peel was preseparated with conventional polymer adsorption column and weak base anion ion-exchange column and then the eluate from the column was analysed by LC-ESI/MS. In this paper, the UV-Vis spectra and the mass spectra provide structural information without the necessity of isolating the individual compounds. Two major limonoid glucosides-obacunone glucoside (OG) and nomilin glucoside (NG) were identified in the methanol extract of the peel of Citrus grandis L. Osbeck. Then the two limonoid glucosides were taken as the target and isolated by means of preparative HPLC on a C18 reversed-phase column with an acidic acetonitrile-water mobile phase. The structures of OG and NG were further confirmed by NMR spectrometry. The results show that this method is rapid, convenient, sensitive and very useful for screening bioactive natural products.