Table 1.
Radical scavenging and antioxidant activities of phenols, enols and anilines
| Entry | Compound | % DPPH inh. | Peroxyl inh. | % OH inh. | ksa | % AOb activity | % AOc activity |
|---|---|---|---|---|---|---|---|
| 1 |
Phenol |
2.3 |
0.0 |
0.4 |
0.83 |
0.0 |
0.0 |
| 2 |
Catechol |
98.0 |
1.8 |
70.0 |
402.59 |
54.0 |
49.0 |
| 3 |
Resorcinol |
2.5 |
0.8 |
5.1 |
9.40 |
4.0 |
5.0 |
| 4 |
Hydroquinone |
97.0 |
2.1 |
67.0 |
360.50 |
54.0 |
47.0 |
| 5 |
2- Aminophenol |
92.0 |
1.49 |
63.1 |
307.42 |
46.0 |
40.0 |
| 6 |
3-Aminophenol |
20.2 |
0.7 |
7.3 |
13.82 |
7.0 |
2.0 |
| 7 |
4- Aminophenol |
97.0 |
1.4 |
65.0 |
333.41 |
44.0 |
40.0 |
| 8 |
3- Nitrophenol |
1.3 |
0.89 |
2.9 |
5.36 |
5.0 |
4.0 |
| 9 |
4- Nitrophenol |
1.1 |
0.0 |
5.6 |
10.51 |
5.0 |
6.0 |
| 10 |
3-Chlorophenol |
3.1 |
1.1 |
|
|
|
|
| 11 |
4- Chlorophenol |
3.6 |
0.81 |
1.7 |
3.04 |
0.0 |
0.0 |
| 12 |
4-Hydroxybenzaldehyde |
1.1 |
0.3 |
4.6 |
8.29 |
2.0 |
3.0 |
| 13 |
2-Hydroxyacetophenone |
0.0 |
|
|
|
|
|
| 14 |
Phenol-4-sulfonic acid |
0.3 |
0.9 |
3.4 |
6.08 |
1.0 |
1.0 |
| 15 |
Salicylic acid |
1.3 |
0.9 |
8.9 |
17.14 |
1.0 |
2.0 |
| 16 |
3-Hydroxybenzoic acid |
2.5 |
0.0 |
6.9 |
12.72 |
4.0 |
3.0 |
| 17 |
4-Hydroxybenzoic acid |
1.8 |
0.56 |
2.5 |
4.48 |
3.0 |
1.0 |
| 18 |
Ethyl salicylate |
1.2 |
0.81 |
|
|
|
|
| 19 |
Methyl salicylate |
1.6 |
0.77 |
|
|
|
|
| 20 |
Ethyl 4-hydroxybenzoate |
1.9 |
0.47 |
|
|
|
|
| 21 |
3,5-Dinitrosalicylic acid |
0.8 |
0.0 |
4.3 |
7.19 |
0.0 |
1.0 |
| 22 |
3,4-Dihydroxybenzoic |
89.6 |
2.41 |
35.4 |
93.44 |
57.0 |
51.0 |
| 23 |
2,5-Dihydroxybenzoic |
95.0 |
2.62 |
49.0 |
88.47 |
63.0 |
60.0 |
| 24 |
Ethyl 2,5-dihydroxybenzoate |
96.1 |
2.5 |
|
|
|
|
| 25 |
o-cresol |
12.2 |
0.62 |
|
|
|
|
| 26 |
p- Cresol |
15.5 |
0.52 |
|
|
|
|
| 27 |
Thymol |
35.0 |
|
|
|
|
|
| 28 |
Carvacrol |
33.9 |
|
|
|
|
|
| 29 |
Butylatedhydroxytoluene (BHT) |
96.0 |
2.98 |
95.0 |
361.61 |
66.0 |
59.0 |
| 30 |
α-Tocopherol |
96.2 |
|
68.8 |
373.77 |
47.0 |
45.0 |
| 31 |
Eugenol |
98.1 |
|
97.0 |
389.81 |
63.0 |
60.0 |
| 32 |
Guaiacol(o-methoxyphenol) |
28.3 |
|
|
|
|
|
| 33 |
Vanillic acid |
25.1 |
0.8 |
2.7 |
5.03 |
2.1 |
2.3 |
| 34 |
Syringic acid |
90.4 |
2.9 |
62.2 |
283.09 |
58.0 |
52.0 |
| 35 |
Gallic acid |
92.0 |
3.09 |
65.0 |
331.20 |
61.0 |
59.0 |
| 36 |
Caffeic acid |
91.2 |
2.78 |
53.5 |
196.29 |
62.0 |
57.0 |
| 37 |
Ascorbic acid |
99.1 |
2.94 |
81.0 |
361.61 |
46.0 |
49.0 |
| 38 |
4- hydroxycoumarin |
1.5 |
|
2.4 |
3.59 |
0.0 |
0.0 |
| 39 |
1-Naphthol |
35.0 |
1.23 |
|
|
|
|
| 40 |
Aniline |
8.7 |
|
8.6 |
16.59 |
2.0 |
6.0 |
| 41 |
p-Tuluidine |
18.4 |
|
|
|
|
|
| 42 |
p-Anisidine |
31.1 |
|
4.9 |
8.85 |
6.0 |
3.0 |
| 43 |
p-Phenylenediamine |
90.1 |
|
66.0 |
347.78 |
43.0 |
49.0 |
| 44 |
o-Phenylenediamine |
5.1 |
|
2.8 |
5.032 |
3.0 |
1.0 |
| 45 |
2,3-Diaminophethaline |
2.9 |
|
5.5 |
9.95 |
5.0 |
4.0 |
| 46 |
Anthranillic acid |
5.7 |
|
|
|
|
|
| 47 |
p-Aminobenzoic acid |
4.6 |
|
|
|
|
|
| 48 |
m-Bromoaniline |
0.0 |
|
|
|
|
|
| 49 |
p-Chloroaniline |
0.0 |
|
|
|
|
|
| 50 |
o-Nitroaniline |
0.0 |
|
|
|
|
|
| 51 | p-Nitroaniline | 0.0 |
a Bimolecular rate constant, ks × 10-7(M-1s-1).
b % Antioxidant activity in sunflower system.
c % Antioxidant activity in liver homogenate system.