Table 3. Quinone reductase (QR) activities of black glutinous rice bran extracts (MS, SK, PY, PC and KK; for sample abbreviations see Materials and Methods).
| Rice bran | CD/(µg/mL) | IC50/(µg/mL) | CI |
|---|---|---|---|
| MS | (3.9±0.1)b | N/A | N/A |
| SK | (0.9±0.1)c | (5.1±0.2)b | 5.7 |
| PY | (0.8±0.1)c | (5.5±0.0)b | 7.2 |
| PC | (0.7±0.1)c | (5.9±0.1)b | 8.3 |
| KK | (5.6±0.2)a | (32.0±1.6)a | 5.5 |
CD=the concentration of anthocyanins required to double the QR activity, IC50=the concentration that causes 50% cell death, CI=chemopreventive index (calculated as IC50/CD), N/A=data not applicable due to the very low toxicity of the extract. Different letters in the same column indicate statistically different values (p≤0.05)