Screening for limonoid glucosides in Citrus tangerina (Tanaka) Tseng by high-performance liquid chromatography-electrospray ionization mass spectrometry.

A screening method for limonoid glucosides in the peel of Citrus tangerina (Tanaka) Tseng, which utilizes high-performance liquid chromatography (HPLC) with diode-array detection and interfaced to electrospray ionization mass spectrometry, has been developed. In this way, the UV-Vis spectra and the mass spectra indicate the presence of limonoid glucosides 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. 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 nuclear magnetic resonance spectrometry.