Following investigation of Garcinia genus, a sensitive, rapid and simple reversed-phase high performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the identification and quantification of three polyisoprenylated benzophenones, garcinol (1), isogarcinol (2) and 7-epi-clusianone (3), in the extracts of five Garcinia species from Cameroon. The separation of those compounds was achieved on a RP-18 column using a solvent system consisting of a mixture of acetonitrile-water-formic acid as a mobile phase in a gradient elution mode. The identification of the three compounds was determined on a triple quadripole mass spectrometer with ESI interface operating in the negative mode. A multiple reaction monitoring (MRM) method was developed for the quantification of these polyisoprenylated benzophenones in the extracts of the Garcinia species. The method was validated through intra-and inter-day precision, with the relative standard deviation (RSD) less than 6%, limits of detection (LOD) and limits of quantification (LOQ) <1 ng. Overall recoveries ranged from 94% to 104%, with RSDs ranging from 0.8% to 4.5%. The results indicated that the fruits of G. preussii and the roots of G. brevipedicellata are good source of garcinol (1) and isogarcinol (2) respectively.