Prenylated benzoylphloroglucinols and biphenyl derivatives from the leaves of Garcinia multiflora Champ

Garcimultiflorones H-J (1-3), three new polyprenylated benzoylphloroglucinols, multiflorabiphenyls B-D (4-6), three new biphenyl derivatives, and six known compounds, were isolated from an acetone extract of the leaves of Garcinia multiflora by bioassay-guided fractionation. The structures of the new compounds were elucidated by extensive 1D and 2D NMR spectroscopic analyses and mass spectrometry, and the absolute configurations of compounds 1-3 were determined by the comparison of experimental and calculated electronic circular dichroism (ECD) spectra. All of the isolates were evaluated for cytotoxic activities against several human cancer cell lines. Garcimultiflorone I (2) exhibited significant inhibitory activity against the SGC7901 and HCT116 cell lines, with IC₅₀ values of 4.20 and 5.96 μM, respectively. A cell cycle analysis using flow cytometry showed that the compound arrests the cell cycle at the G1 phase and induces cell death. Moreover, Bcl-2, caspase-3, caspase-9, and PARP western blotting suggested that compound 2 can induce apoptosis. Taken together, these results suggest that compound 2 has anticancer activity that targets the cell cycle through apoptosis signalling pathways.