3.1.1. Anti-cell proliferation
Each extract from the Riceberry bran exhibited anti-cell proliferation effect on the three cancer cells by decreasing percentage of
cell viability in a time–dose dependent fashion (Fig. 1). As revealed
from the 50% inhibitory concentration (IC50) at 48 h after treatment, the IC50 values of DCM extract treatments for HL-60, MCF7 and Caco-2 cells were 0.28, 0.32 and 1.54 mg/ml, respectively,
whereas the IC50 of MeOH-extract treatments for HL-60, MCF-7
and Caco-2 cells were 1.86, 2.69 and 3.54 mg/ml, respectively.
Therefore, the DCM extract showed more potent effect than the
MeOH extract and HL-60 cell was more sensitive than MCF-7 cell
or Caco-2 cell.
3.1.2. Inhibition of DNA synthesis
Treatment of the cancer cells with DCM and MeOH extracts significantly decreased BrdU incorporation in survival cells in a time–
concentration dependent manner, suggesting a decrease in DNA
synthesis. Comparing the DCM and MeOH-extract treatment, the
DCM extract exhibited stronger inhibition efficiency in HL-60 cell
than the other cell lines, whereas the MeOH extract showed higher
efficiency in Caco-2 cell. Both extracts acted almost equally on
inhibition of DNA synthesis in MCF-7 cell (Fig. 2).