Table 3.
Induction of his+ revertants in S. typhimurium strains by Origanum majorana essential oil with and without metabolic activation (S9 mix).
| Substance | Concentration | S. typhimurium strains | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| TA98 | TA97a | TA100 | TA1535 | TA102 | |||||||
| Rev/platea | MIb | Rev/platea | MIb | Rev/platea | MIb | Rev/platea | MIb | Rev/platea | MIb | ||
| Without metabolic activation (−S9) | |||||||||||
| NCc | — | 19.7 ± 8.2 | — | 69.7 ± 3.1 | — | 103.7 ± 6.1 | — | 4.3 ± 2.5 | — | 291.7 ± 10.5 | — |
| Essential oil (µL/plate) |
0.0025 | 24.7 ± 6.4 | 1.03 | 91.7 ± 7.5 | 1.32 | 102.3 ± 9.3 | 0.99 | 4.7 ± 2.1 | 1.09 | 268 ± 12.5 | 0.92 |
| 0.005 | 14.5 ± 3.4 | 0.74 | 84.7 ± 18.9 | 1.22 | 110.7 ± 10.5 | 1.07 | 6.3 ± 4 | 1.45 | 255.3 ± 26.5 | 0.88 | |
| 0.01 | 15.2 ± 6.2 | 0.77 | 89.3 ± 23 | 1.28 | 95.7 ± 15.6 | 0.92 | 2 ± 0 | 0.46 | 253 ± 46.5 | 0.87 | |
| 0.02 | 10.5 ± 2.3 | 0.53 | 71.7 ± 15.5 | 1.03 | 75.5 ± 30.4 | 0.73 | 4 ± 1.7 | 0.92 | 174.7 ± 15.6 | 0.60 | |
| 0.04 | 9.2 ± 2.5 | 0.47 | 72 ± 13.1 | 1.03 | 41.7 ± 4 | 0.40 | 1.3 ± 1.2 | 0.31 | 111.3 ± 9.1 | 0.38 | |
| PCd (µg/plate) | 0.5 (4NQO) | 332 ± 22.6∗∗∗ | 20.68 | 464.3 ± 91.8∗∗∗ | 6.66 | — | — | — | — | 1031 ± 93.5∗∗∗ | 3.54 |
| 1 (NaN3) | — | — | — | — | 427.3 ± 31.2∗∗∗ | 4.12 | 312.3 ± 9∗∗∗ | 72.13 | — | — | |
|
| |||||||||||
| With metabolic activation (+S9) | |||||||||||
| NCc | — | 15.3 ± 1.5 | — | 100.7 ± 9.9 | — | 179.7 ± 11.1 | — | 9.3 ± 2.9 | — | 325.7 ± 15.5 | — |
| Essential oil (µL/plate) |
0.005 | 19 ± 3.6 | 1.24 | 109.3 ± 8.5 | 1.09 | 155.7 ± 10 | 0.87 | 10.3 ± 4.5 | 1.1 | 310 ± 3.6 | 0.95 |
| 0.01 | 23.3 ± 1.5 | 1.52 | 112 ± 20.1 | 1.11 | 141.3 ± 12.6 | 0.79 | 8 ± 3 | 0.86 | 338 ± 12.7 | 1.04 | |
| 0.02 | 15.7 ± 1.5 | 1.01 | 115 ± 10.5 | 1.14 | 135.3 ± 6.7 | 0.75 | 7.7 ± 1.5 | 0.83 | 332.7 ± 29 | 1.02 | |
| 0.04 | 21 ± 9.5 | 1.37 | 113.7 ± 8.7 | 1.13 | 112 ± 14.9 | 0.62 | 8.3 ± 3.5 | 0.89 | 301.7 ± 26 | 0.93 | |
| 0.08 | 18.7 ± 1.2 | 1.22 | 131.7 ± 10.6 | 1.31 | 99.3 ± 14 | 0.55 | 7.7 ± 2.3 | 0.83 | 295.7 ± 31.1 | 0.91 | |
| PCe (µg/plate) | 1 (AFB1) | 1587 ± 91.1∗∗∗ | 103.5 | 587 ± 88.5∗∗ | 5.83 | 660.7 ± 59.9∗∗ | 3.68 | — | — | — | — |
| 10 (2-AF) | — | — | — | — | — | — | 104.3 ± 12.1∗∗ | 11.18 | 767.3 ± 53.6∗∗∗ | 2.36 | |
aNumber of revertants/plate: mean of three independent experiments ± SD; bMI: mutagenic index (number of his+ induced in the sample/number of spontaneous his+ in the negative control). cNegative control: DMSO (10 µL) used as solvent for the extract. dPositive control (−S9): NaN3 (sodium azide) to TA100 and TA1535 and 4-NQO to TA97a, TA98, and TA102. ePositive control (+S9): AFB1 (aflatoxin B1) for TA97a, TA98, and TA100 and 2-aminofluorene for TA102 and TA1535; ∗∗ p < 0.01; ∗∗∗ p < 0.001, in relation to the negative control.