Flash chromatographic isolation of garcinol and isogarcinol from Garcinia indica Choisy (kokum) fruit and evaluation of their potential antibiofilm activity

The present study describes the isolation and separation of isogarcinol and garcinol from kokum fruit by flash chromatography using water (containing 0.1 % formic acid) and methanol mixed with acetonitrile (1:1) with UV detection at 254 nm and was characterised by HR-MS and NMR studies. These were further subjected to antimicrobial studies on Staphylococcus aureus FR1722 and Listeria monocytogenes Scott A by agar diffusion assay and broth microdilution method wherein the MIC (Minimum Inhibitory Concentration) of garcinol and isogarcinol were, 20 mu g/mL and 50 mu g/mL for S. aureus FR1722 and 50 mu g/mL and 100 mu g/mL for L. monocytogenes Scott A respectively. Further, studies on the control of biofilm growth were tested using MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide) assay followed by Crystal Violet (CV) assay, which showed up to 80 % inhibition. In addition, the biofilm eradication as evaluated by bright field microscopy and the metabolic activity were also carried out against these bacterial strains and the experimental details are presented.