Table 1.
Antioxidant properties of isothiocyanates (ITCs).
| Compound name | DPPH |
ORAC (mM TE)b | BR (s)c | Rancimat (PF)c | |
|---|---|---|---|---|---|
| IC50 (mM) | Inhibition (%)a | ||||
| Phenyl ITC (1) | 1.08 ± 0.01 | 88.4 ± 1.8 | 26.3 ± 0.1 | n.d. | 2.5 |
| Benzyl ITC (2) | – | 9.9 ± 0.4 | 4.0 ± 1.6 | n.d. | 1.5 |
| 2-Phenylethyl ITC (3) | – | n.d. | 4.8 ± 0.5 | n.d. | 1.3 |
| 4-Methylsulfanylphenyl ITC (4) | – | 9.9 ± 0.6 | 32.3 ± 3.6 | 65 ± 2 | 1.1 |
| 4-Methylphenyl ITC (5) | 1.45 ± 0.02 | 80.6 ± 0.6 | 16.3 ± 5.0 | n.d. | 1.0 |
| 4-Methoxyphenyl ITC (6) | 1.25 ± 0.02 | 80.4 ± 0.9 | 11.7 ± 0.5 | >1 hd | 1.0 |
| 2-Methoxyphenyl ITC (7) | 3.90 ± 0.03 | 60.9 ± 0.4 | 1.6 ± 0.1 | n.d. | 1.7 |
| 3-Methoxyphenyl ITC (8) | 1.16 ± 0.03 | 84.8 ± 0.5 | 20.9 ± 0.9 | 10 ± 1 | 1.7 |
| Allyl ITC (9) | – | 10.1 ± 0.3 | 9.5 ± 1.6 | 430 ± 8 | 1.7 |
| Isopropyl ITC (10) | – | 4.2 ± 0.6 | 1.4 ± 0.5 | n.d. | 1.1 |
| 3-(Methylsulfanyl)propyl ITC (11) | – | 12.6 ± 1.3 | 20.3 ± 3.8 | 23 ± 3 | 1.6 |
TE: trolox equivalents; PF: protection factor (control PF = 1.00); –, not determined; n.d.: not detected.
All compounds were tested at a concentration of: a4.76 mM, except for 4 which was at 1.19 mM due to turbidity; b1.56 μM; and c3.23 mM.
dFor 3.23, 1.61, 1.29 and 0.81 mM did not start to oscillate after 1 h. For 0.65 and 0.48 mM of added compound oscillation lasted 470 ± 11 and 38 ± 5 s, respectively. Measurement was effected visually for 0.81 mM and the reaction started to oscillate after 9180 ± 15 s.