Table 2.

Experimental values of the toxicity of phenols to Tetrahymena pyriformis (pIG ₅₀) and the values calculated by the GA-MLR and GA-ANN global models

No.	Compound	pIG 50 (exp)	MLR	ANN
Training
1	4-Hydroxyphenylacetic acid	−1.50	0.10	−1.43
3	3-Hydroxybenzyl alcohol	−1.04	−0.51	−0.97
5	3-Hydroxy-4-methoxybenzyl alcohol	−0.99	0.07	−0.50
6	4-Hydroxy-3-methoxybenzylamine HCl	−0.97	−0.41	−0.83
8	4-Hydroxyphenethylalcohol	−0.83	−0.69	−0.86
10	3-Hydroxybenzoic acid (3-carboxylphenol)	−0.81	0.45	−0.27
11	4-Hydroxybenzamide	−0.78	−0.33	−0.76
13	Resorcinol	−0.65	−0.14	−0.05
15	2,4,6-Tris(dimethylaminomethyl)phenol	−0.52	−0.52	−0.54
16	3-Aminophenol (3-hydroxyaniline)	−0.52	−0.40	−0.82
18	2-Methoxyphenol (guaiacol)	−0.51	−0.24	−0.17
20	5-Methylresorcinol	−0.39	0.09	−0.20
21	4-Hydroxybenzylcyanide (4-cyanomethylphenol)	−0.38	0.01	−0.64
23	2-Ethoxyphenol	−0.36	−0.28	−0.28
25	4-Hydroxyacetophenone (4-acetylphenol)	−0.30	−0.30	−0.30
26	3-Ethoxy-4-methoxyphenol	−0.30	−0.06	−0.28
28	Salicylamide (2-hydroxybenzamide)	−0.24	0.04	−0.33
30	Phenol	−0.21	−0.22	−0.22
31	p-Cresol (4-methylphenol)	−0.18	−0.33	−0.19
33	3-Acetamidophenol (3-hydroxyacetanilide)	−0.16	0.10	−0.08
35	4-Methoxyphenol	−0.14	−0.47	−0.17
36	Isovanillin (3-hydroxy-4-methoxybenzaldehyde)	−0.14	0.38	0.02
38	3,5-Dimethoxyphenol	−0.09	0.31	−0.09
40	4-Aminophenol (4-hydroxyaniline)	−0.08	−0.56	−0.15
41	3-Cyanophenol	−0.06	0.27	0.29
43	Methyl 3-hydroxybenzoate	−0.05	−0.04	−0.51
45	4-Hydroxy-3-methoxybenzonitrile	−0.03	0.33	0.09
46	4-Ethoxyphenol	0.01	−0.41	−0.16
48	4-Fluorophenol	0.02	0.30	0.08
50	5′-Fluoro-2′-hydroxyacetophenone	0.04	0.02	0.15
51	4′-Hydroxypropiophenone	0.05	−0.21	0.08
53	2-Hydroxyacetophenone	0.08	−0.25	−0.18
55	Methyl 4-hydroxybenzoate	0.08	0.16	0.05
56	3-Hydroxybenzaldehyde	0.09	0.18	−0.05
58	4′-Hydroxypropiophenone	0.12	−0.21	0.08
60	3,4-Dimethylphenol	0.12	0.36	0.07
61	4-Chlororesorcinol	0.13	0.65	−0.27
63	2-Ethylphenol	0.16	0.10	0.12
65	Salicylhydrazide	0.18	0.30	0.33
66	2-Chlorophenol	0.18	0.76	0.09
68	4′-Hydroxy-2′-methylacetophenone	0.19	0.04	0.38
70	3-Ethylphenol	0.23	0.17	0.20
71	Salicylaldoxime	0.25	0.13	0.22
73	3,4-Dinitrophenol	0.27	0.84	0.34
75	2,3,6-Trimethylphenol	0.28	0.64	0.28
76	2,4,6-Trimethylphenol	0.28	0.84	0.27
78	2′-Hydroxy-5′-methylacetophenone	0.31	0.19	0.20
80	5-Hydroxy-2-nitrobenzaldehyde	0.33	0.73	0.63
81	2-Allylphenol	0.33	0.22	0.33
83	2,3,5-Trimethylphenol	0.36	0.73	0.38
85	4-Methylcatechol	0.37	0.34	0.32
86	o-Vanillin (3-methoxysalicylaldehyde)	0.38	0.26	0.03
88	3-Fluorophenol	0.38	0.40	0.36
90	4-Allyl-2-methoxyphenol (eugenol)	0.42	0.53	0.42
91	Salicylaldehyde (2-hydroxybenzaldehyde)	0.42	0.34	0.68
93	5-Amino-2-methoxyphenol	0.45	−0.12	−0.49
95	2,6-Difluorophenol	0.47	0.99	0.39
96	Hydroquinone	0.47	−0.12	0.13
98	Ethyl 3-hydroxybenzoate	0.48	0.33	0.34
100	3-Nitrophenol	0.51	0.61	0.80
101	4-Cyanophenol	0.52	0.05	0.52
103	2,6-Dinitrophenol	0.54	0.82	0.54
105	2′-Hydroxy-4′-methoxyacetophenone	0.55	0.31	0.54
106	Ethyl 4-hydroxybenzoate	0.57	0.14	0.41
108	5-Methyl-2-nitrophenol	0.59	0.95	1.05
110	2,4-Difluorophenol	0.60	0.81	0.73
111	3-Isopropylphenol	0.61	0.70	0.62
113	3-Methyl-2-nitrophenol	0.61	0.77	0.35
115	α,α,α-Trifluoro-p-cresol	0.62	1.01	0.62
116	Methyl 4-methoxysalicylate	0.62	0.31	0.90
118	4-Propylphenol	0.64	0.40	0.54
120	2-Nitroresorcinol	0.66	0.94	1.35
121	2-Nitrophenol	0.67	0.86	0.54
123	2-Chloro-4,5-dimethylphenol	0.69	1.14	1.12
125	4-Chloro-2-methylphenol	0.70	0.82	0.63
126	2′-Hydroxy-4′,5′-dimethylacetophenone	0.71	0.25	0.96
128	2,6-Dichlorophenol	0.74	1.38	0.97
130	2-Methoxy-4-propenylphenol	0.75	0.55	0.75
131	Catechol	0.75	0.17	0.80
133	3-Chloro-5-methoxyphenol	0.76	0.53	0.76
135	5-Chloro-2-hydroxyaniline (2-amino-4-chlorophenol)	0.78	0.55	0.67
136	4-Chloro-3-methylphenol	0.80	0.75	0.86
138	2,6-Dichloro-4-fluorophenol	0.80	1.56	0.91
140	1,2,3-Trihydroxybenzene	0.85	0.49	0.87
141	3-Chlorophenol	0.87	0.60	0.31
143	4-Amino-2-nitrophenol	0.88	0.71	0.84
145	6-Amino-2,4-dimethylphenol	0.89	0.59	0.94
146	4-tert-Butylphenol	0.91	1.18	0.94
148	3-Fluoro-4-nitrophenol	0.94	0.72	0.93
150	2,5-Dinitrophenol	0.95	1.40	0.61
151	2,2′,4,4′-Tetrahydroxybenzophenone	0.96	1.08	1.04
153	4-sec. Butylphenol	0.98	0.86	0.85
155	3-Hydroxydiphenylamine	1.01	1.19	0.97
156	4-Hydroxybenzophenone	1.02	1.27	1.13
158	2,4-Dichlorophenol	1.04	1.11	1.48
160	4-Chlorocatechol	1.06	0.72	0.97
161	Benzyl 4-hydroxyphenyl ketone	1.07	1.30	1.01
163	4-Chloro-3-ethylphenol	1.08	0.98	1.03
165	2-Phenylphenol	1.09	1.27	1.30
166	3-Iodophenol	1.12	0.90	1.12
168	3-Chloro-4-fluorophenol	1.13	1.02	1.09
170	3-Bromophenol	1.15	0.79	1.15
171	6-tert-Butyl-2,4-dimethylphenol	1.16	1.31	1.20
173	2,3,5,6-Tetrafluorophenol	1.17	1.73	1.42
175	2-Amino-4-chloro-5-nitrophenol	1.17	1.03	1.04
176	4-Chloro-3,5-dimethylphenol	1.20	1.15	1.21
178	4-tert-Pentylphenol	1.23	1.23	1.38
180	Chlorohydroquinone	1.26	0.75	0.78
181	4-Bromo-3,5-dimethylphenol	1.27	1.50	0.99
183	4-Bromo-6-chloro-o-cresol	1.28	1.64	1.32
185	p-Cyclopentylphenol	1.29	1.20	1.58
186	2-tert-Butylphenol	1.30	1.00	0.92
187	2-tert-Butyl-4-methylphenol	1.30	1.40	1.30
190	2-Hydroxydiphenylmethane	1.31	1.09	1.29
191	Butyl 4-hydroxybenzoate	1.33	0.92	1.35
193	3-Phenylphenol	1.35	1.32	1.42
195	n-Pentyloxyphenol	1.36	0.95	1.33
196	4-Fluoro-2-nitrophenol	1.38	1.11	1.06
198	2,4-Dibromophenol	1.40	1.46	1.49
200	2,3-Dimethylhydroquinone	1.41	0.82	1.31
201	2-Hydroxy-4-methoxybenzophenone	1.42	1.06	1.42
203	4-Amino-2,3-dimethylphenol HCl	1.44	0.65	1.21
205	Benzyl 4-hydroxybenzoate	1.55	1.43	1.57
206	3,5-Dichlorosalicylaldehyde	1.55	1.44	1.55
208	3,5-Dichlorophenol	1.57	1.24	1.69
210	4-Bromo-2-fluoro-6-nitrophenol	1.62	1.56	1.92
211	4-Hexyloxyphenol	1.64	1.42	1.76
213	3,5-Dibromosalicylaldehyde	1.64	1.72	1.39
215	4-Chloro-6-nitro-m-cresol	1.64	1.42	1.46
216	4-Nitro-3-(trifluoromethyl)-phenol	1.65	1.53	1.69
218	Tetrachlorocatechol	1.70	2.30	1.88
220	4,6-Dinitro-o-cresol (4,6-dinitro-2-methylphenol)	1.72	1.51	1.58
221	3-Methyl-4-nitrophenol	1.73	0.83	1.27
223	2,4-Dichloro-6-nitrophenol	1.75	1.52	1.87
225	4-Hexylresorcinol	1.80	1.74	1.72
226	2,6-di-tert-Butyl-4-methylphenol (BTH)	1.80	1.98	1.72
228	4-Chloro-2-isopropyl-5-methylphenol	1.85	1.55	1.81
230	4-Bromo-2-nitrophenol	1.87	1.47	1.84
231	Phenylhydroquinone	2.01	1.38	1.74
233	4-Heptyloxyphenol	2.03	2.01	2.03
235	4-Chloro-2-nitrophenol	2.05	1.25	1.64
236	2,4,5-Trichlorophenol	2.10	1.55	2.08
238	3,5-di-tert-Butylcatechol	2.11	2.25	1.70
240	Methoxyhydroquinone	2.20	0.31	1.66
241	2,3,5,6-Tetrachlorophenol	2.22	1.95	2.20
243	3,5-Diiodosalicylaldehyde	2.34	1.96	2.29
245	4-Nonylphenol	2.47	2.98	2.55
246	2-Ethylhexyl 4′-hydroxybenzoate	2.51	2.14	2.51
248	Nonyl 4-hydroxybenzoate	2.63	2.65	2.51
250	2,3,4,5-Tetrachlorophenol	2.71	2.11	2.37
Validation
2	1,3,5-Trihydroxybenzene	−1.26	0.08	−0.92
7	2-Hydroxybenzylalcohol (salicylalcohol)	−0.95	−0.01	−0.93
12	4-Hydroxy-3-methoxybenzyl alcohol	−0.70	−0.27	−0.40
17	Salicylic acid	−0.51	0.42	−0.23
22	3-Hydroxyacetophenone	−0.38	−0.11	−0.48
27	o-Cresol (2-methylphenol)	−0.30	0.14	−0.34
32	4-Hydroxy-3-methoxyphenethylalcohol	−0.18	−0.31	−0.19
37	4-Hydroxy-3-methoxyacetophenone (acetovanillone)	−0.12	−0.08	−0.05
42	m-Cresol(3-methylphenol)	−0.06	−0.16	−0.06
47	3-Ethoxy-4-hydroxybenzaldehyde	0.02	−0.17	−0.02
52	2,4-Dimethylphenol	0.07	0.44	0.13
57	3,5-Dimethylphenol	0.11	0.47	0.24
62	2,4-Diaminophenol 2HCl	0.13	−0.16	0.11
67	2-Fluorophenol	0.19	0.51	0.32
72	4-Hydroxybenzaldehyde	0.27	−0.02	0.35
77	3-Methylcatechol	0.28	0.14	0.58
82	5-Bromo-2-hydroxybenzylalcohol	0.34	0.86	0.31
87	Salicylhydroxamic acid	0.38	0.23	0.15
92	1,2,4-Trihydroxybenzene	0.44	0.46	0.48
97	4-Isopropylphenol	0.47	0.65	0.69
102	4-Propyloxyphenol	0.52	0.46	0.54
107	4-Methyl-2-nitrophenol	0.57	0.96	0.98
112	4-Hydroxy-3-nitrobenzaldehyde	0.61	1.00	0.73
117	2,6-Dichloro-4-nitrophenol	0.63	1.75	1.21
122	4-Bromophenol	0.68	0.62	0.71
127	3-tert-Butylphenol	0.73	1.00	0.98
132	2-Chloromethyl-4-nitrophenol	0.75	1.06	0.64
137	2-Isopropylphenol	0.80	0.57	0.60
142	2-Bromo-2′-hydroxy-5′-nitroacetanilide	0.87	0.91	0.89
147	3,4,5-Trimethylphenol	0.93	0.84	0.93
152	4,6-Dichlororesorcinol	0.97	1.20	0.60
157	4-Benzyloxyphenol	1.04	1.66	0.99
162	2-Fluoro-4-nitrophenol	1.07	1.06	0.93
167	2,5-Dichlorophenol	1.13	1.13	1.44
172	4-Bromo-2,6-dimethylphenol	1.17	1.49	1.04
177	2-Hydroxybenzophenone	1.23	1.06	1.14
182	2,3-Dichlorophenol	1.28	1.29	1.10
188	5-Pentylresorcinol	1.31	1.70	1.37
192	Trimethylhydroquinone	1.34	0.97	1.11
197	4-Phenylphenol	1.39	1.06	1.54
202	4-Nitrophenol	1.42	0.51	0.95
207	4-Cyclohexylphenol	1.56	1.81	1.56
212	3,5-di-tert-Butylphenol	1.64	2.44	1.70
217	Bromohydroquinone	1.68	1.11	1.47
222	3,4-Dichlorophenol	1.75	1.08	1.54
227	Tetrafluorohydroquinone	1.84	1.81	1.55
232	2,4,6-Tribromophenol	2.03	1.88	1.81
237	4-tert-Octylphenol	2.10	2.10	2.18
242	4-(4-Bromophenyl)phenol	2.31	1.74	2.20
247	3,4,5,6-Tetrabromo-o-cresol	2.57	2.59	2.57
Prediction
4	4-Hydroxybenzoic acid (4-carboxylphenol)	−1.02	0.08	−0.70
9	4-Acetamidophenol (4-hydroxyacetanilide)	−0.82	−0.07	−0.63
14	2,6-Dimethoxyphenol	−0.60	0.02	−0.60
19	4-(4-Hydroxyphenyl)-2-butanone	−0.50	0.47	−0.35
24	3-Methoxyphenol	−0.33	−0.07	−0.33
29	Ethyl 4-hydroxy-3-methoxyphenylacetate	−0.23	0.47	−0.13
34	2,4,6-Trinitrophenol	−0.16	1.61	0.06
39	2-Hydroxyethyl salicylate	−0.08	0.20	−0.17
44	Vanillin (3-methoxy-4-hydroxybenzaldehyde)	−0.03	0.20	−0.01
49	2-Cyanophenol	0.03	0.43	0.39
54	2,5-Dimethylphenol	0.08	0.22	−0.09
59	2,3-Dimethylphenol	0.12	0.32	0.12
64	Syringaldehyde	0.17	0.82	0.19
69	4-Ethylphenol	0.21	−0.01	0.18
74	3-Hydroxy-4-nitrobenzaldehyde	0.27	1.03	0.41
79	2-Bromophenol	0.33	0.95	0.65
84	2-Amino-4-tert-butylphenol	0.37	1.21	0.26
89	2-Chloro-5-methylphenol	0.39	0.66	0.69
94	2,3-Dinitrophenol	0.46	1.23	0.52
99	2-Amino-4-nitrophenol	0.48	0.81	0.73
104	4-Chlorophenol	0.55	0.42	0.55
109	2-Bromo-4-methylphenol	0.60	1.11	0.65
114	5-Bromovanillin	0.62	1.16	0.29
119	4-Nitrosophenol	0.65	0.36	0.28
124	4-Butoxyphenol	0.70	0.66	0.69
129	4-Methyl-3-nitrophenol	0.74	0.89	1.11
134	2-Methyl-3-nitrophenol	0.78	0.75	0.43
139	4-Iodophenol	0.85	0.70	0.87
144	2,2′-Biphenol	0.88	1.14	0.82
149	2-Aminophenol (2-hydroxyaniline)	0.94	−0.13	0.99
154	Tetrabromocatechol	0.98	2.45	1.05
159	2,4,6-Tribromoresorcinol	1.06	2.00	1.72
164	2,4-Dinitrophenol	1.08	1.24	0.98
169	5-Fluoro-2-nitrophenol	1.13	1.00	0.72
174	4-Nitrocatechol	1.17	0.98	0.89
179	2,6-Dinitro-p-cresol	1.23	1.47	1.09
184	Tetramethylhydroquinone	1.28	1.35	1.52
189	4-Amino-2-cresol	1.31	0.18	1.31
194	2,6-Dibromo-4-nitrophenol	1.36	1.99	1.46
199	2,4,6-Trichlorophenol	1.41	1.57	2.00
204	Isoamyl 4-hydroxybenzoate	1.48	1.22	1.54
209	2-Chloro-4-nitrophenol	1.59	1.30	1.54
214	Pentafluorophenol	1.64	2.15	1.71
219	2,6-Diiodo-4-nitrophenol	1.71	2.09	1.52
224	4-Bromo-2,6-dichlorophenol	1.78	1.66	1.51
229	Methylhydroquinone	1.86	0.51	1.75
234	Pentachlorophenol	2.05	2.46	1.99
239	Tetrachlorohydroquinone	2.11	2.24	1.93
244	2,3,5-Trichlorophenol	2.37	1.53	2.20
249	Pentabromophenol	2.66	2.69	2.66