Identification of antibacterial component from extract of Garcinia indica fruit rinds using LC/MS/MS

Ionization of the sample for mass spectrometric analysis was carried out using DUIS mode available in LCMS-8040 system. Here, both Electro-Spray Ionization (ESI) and Atmospheric Pressure Chemical Ionization (APCI) techniques are used simultaneously and hence polar to slightly mid-polar molecules can be analyzed in the same run.
LCMS-8040 has a feature of ‘optimisation of method’ in which the mass spectrometer selects the best product ion(s) and optimises voltages and collision energies for the precursor to product transition.
For Garcinol, MRM was optimized for the precursor ion of m/z 603 using the above mentioned feature. During this optimisation, the precursor ion was subjected to a series of collision energies with a step width of 5 V to obtain product ions ranging from lower m/z to higher m/z.
At High CE (-50 V) major fragments of 95, 137, 177 were observed. Similarly, characteristic fragments were formed at low CE of -10 V (585, 535, 467) and at mid CE of -35 V (233, 287, 343, 411). This information helped in fragmentation studies and thereby characterization of the Garcinol molecule.