Identification and quantification of two biologically active polyisoprenylated benzophenones xanthochymol and isoxanthochymol in Garcinia species using liquid chromatography-tandem mass spectrometry.

A sensitive liquid chromatography/electrospray ionization tandem mass spectrometrical (LC/ESI-MS/MS) method was developed for the identification and quantification of two polyisoprenylated benzophenones xanthochymol and isoxanthochymol in the extracts of the fruit rinds, stem bark, seed pericarps and leaves of Garcinia indica and in the fruit rinds of Garcinia cambogia. The separation of xanthochymol and isoxanthochymol was achieved on a RP-18 column using the solvent system consisting of a mixture of acetonitrile-water (9:1) and methanol-acetic acid (99.5:0.5) as a mobile phase at a flow rate of 0.4ml/min. A multiple reaction monitoring (MRM) method was developed for quantification of xanthochymol and isoxanthochymol in the above extracts of Garcinia species. On the basis of signal to noise ratio of 3, the limits of detection in MRM mode for xanthochymol and isoxanthochymol were 1.0ng/ml and 0.5ng/ml, respectively. The method was validated in terms of linearity, accuracy and precision for 6 days. The method developed was found to be useful for identification and quantification of xanthochymol and isoxanthochymol in the extracts of the fruit rinds, stem bark, seed pericarps and leaves of G. indica and in the fruit rinds of G. cambogia.