2,4-Di-tert-butylphenol

2,4-ジ-tert-ブチルフェノール


[CAS No. 96-76-4]

2,4-Bis(1,1-dimethylethyl)phenol

2,4-ビス(1,1-ジメチルエチル)フェノール

Molecular formula: C14H22O Molecular weight: 206.32

ABSTRACT

2,4-Di-tert-butylphenol was studied for oral toxicity in rats in a single dose toxicity test at doses of 0, 819, 1024, 1280, 1600 and 2000 mg/kg for both sexes. The single dose oral toxicity test revealed approximate LD50 values of ca. 2000 mg/kg for males and 1762.4 mg/kg for females.

2,4-Di-tert-butylphenol was studied for oral toxicity in Crj:CD(SD)IGS rats in a 28-day repeat dose toxicity test at doses of 0, 5, 20, 75 and 300 mg/kg.

No deaths occurred of either males or females. Salivation was observed in the males and females of the 300 mg/kg group. No effects related to the test substance were observed in terms of body weight or food consumption. Urinalysis showed increase in urine volume, decreases in osmotic pressure and specific gravity, and a pale yellow color in the males and females of the 300 mg/kg group. Hematological examination showed decreases in hemoglobin and hematocrit, and increase in the proportion of segmented neutrophils in the females of the 300 mg/kg group. Further, prolongation of prothrombin time and activated partial thromboplastin time in the males of the 300 mg/kg group was detected. Blood chemical examination showed increases in total cholesterol and phospholipid in the females of the 75 and 300 mg/kg groups. Macroscopically, enlargement of the kidneys was observed in males of the 300 mg/kg group. Light gray spots on the kidneys were observed in females of the 300 mg/kg group. Liver weights were increased in females of the 75 mg/kg group and in males and females of the 300 mg/kg group. Histopathologically, centrilobular hypertrophy of hepatocytes, basophilic change of renal tubules, and granular and proteinaceous casts in the kidneys were observed in the males and females of the 300 mg/kg group. Cellular infiltration (neutrophils), dilatation of the distal tubules and/or hypertrophy of the proximal tubules were also observed in the animals with lesions in the kidney at necropsy. In the recovery test, these changes observed during the administration period demonstrated recovery. The NOELs are considered to be 75 mg/kg/day for males and 20 mg/kg/day for females.

Genotoxicity of 2,4-di-tert-butylphenol was studied by reverse mutation test in bacteria and by chromosomal aberration test in cultured Chinese hamster lung (CHL/IU) cells.

2,4-Di-tert-butylphenol was not mutagenic in Salmonella typhimurium TA100, TA1535, TA98, TA1537 and Escherichia coli WP2 uvrA, with or without an exogenous metabolic activation system.

2,4-Di-tert-butylphenol induced structural chromosomal aberrations in CHL/IU cells after short-term treatment with an exogenous metabolic activation system.

SUMMARIZED DATA FROM THE STUDIES

1. Single Dose Oral Toxicity 1)

Purity:99.67 %
Test species/strains:Rat/Crj:CD(SD)IGS
Test method:OECD Test Guideline 401
　Route:Oral (gavage)
　Doses:0(vehicle), 819, 1024, 1280, 1600, 2000 mg/kg
　Number of animals/group:Males, 5; females, 5
　Vehicle:Corn oil
GLP:Yes

　Test results:

Deaths occurred in the males of the 1600 mg/kg or more groups and in females of the 1280 mg/kg or more groups. Treatment-related clinical signs were noted as follows: loose stool, soiled periproctal areas, hypoactivity, bradypnea, hypothermia, a soiled lower abdomen and soiled perinaris. Decrease of body weight and/or depression of body weight gain were observed in all the treated groups. In the dead animals, white spots in the forestomach mucosa were noted at necropsy. In addition, dark red maculae in the lung, dark red spots and small-size of the thymus, dark red coloration in the cecum and dark red maculae in the adrenals were observed at necropsy. Histopathological examination showed ulceration in the forestomach. In addition, edema in the alveoli of the lung, atrophy of the thymus, hemorrhage in the thymus, hemorrhage from lamina propria to submucosa in the cecum and hemorrhage in the cortex of the adrenal were observed. In the surviving animals, light gray spots and enlargement of the kidneys were noted at necropsy. Histopathological examination showed basophilic change and dilatation of the renal tubules, granular casts in the renal tubules, cellular infiltration of neutrophils in the kidney, exudation of neutrophil into renal tubules and mineralization in the cortex of the kidney.
Estimated LD50: Males, ca. 2000 mg/kg; females, 1762.4 mg/kg

2. Repeat Dose Toxicity 1)

Purity:99.67 %
Test species/strain:Rat/Crj:CD(SD)IGS
Test method:Guideline for 28-Day Repeated Dose Toxicity Test in Mammalian Species (Chemical Substances Control Law of Japan)
　Route:Oral(gavage)
　Dosage:0(vehicle), 5, 20, 75, 300 mg/kg/day
　Number of animals/group:Males, 6 or 12(0, 300 mg/kg)
　Vehicle:Corn oil
　Administration period:Males and females, 28 days
　Terminal kill:Males and females, on days 29 and 43(0, 300 mg/kg)
GLP:Yes

　Test results:

No deaths occurred of either males or females. Salivation was observed in the males and females of the 300 mg/kg group. No effects related to the test substance were observed in body weight or food consumption. Urinalysis showed increase in urine volume, decreases in osmotic pressure and specific gravity, and pale yellow coloration in the males and females of the 300 mg/kg group. Hematological examination showed decreases in hemoglobin and hematocrit, and increase in the segmented neutrophil ratio in the females of the 300 mg/kg group. Further, prolongation of prothrombin time and activated partial thromboplastin time in the males of the 300 mg/kg group was detected. Blood chemical examination showed increases in total cholesterol and phospholipid in the females of the 75 and 300 mg/kg groups. Macroscopically, enlargement of the kidneys was observed in males of the 300 mg/kg group. Light gray spots in the kidney were observed in females of the 300 mg/kg group. Liver weights were increased in females of the 75 mg/kg group and in males and females of the 300 mg/kg group. Histopathologically, centrilobular hypertrophy of hepatocytes, basophilic change of renal tubules, and granular and proteinaceous casts in the kidney were observed in the males and females of the 300 mg/kg group. Cellular infiltration (neutrophils), dilatation of the distal tubules and/or hypertrophy of the proximal tubules were also observed in the animals with lesions in the kidneys at necropsy. In the recovery test, these changes observed during the administration period demonstrated recovery.
The NOELs are considered to be 75 mg/kg/day for males and 20 mg/kg/day for females.

3. Genetic Toxicity

3-1. Bacterial test 2)

Purity:99.67%
Test species/strains:Salmonella typhimurium TA100, TA1535, TA98, TA1537, Escherichia coli WP2 uvrA
Test method:Guidelines for Screening Mutagenicity Testing of Chemicals(Chemical Substances Control Law of Japan) and OECD Test Guideline 471
　Procedures:Pre-incubation method
　Solvent:DMSO
　Positive controls:-S9 mix; 2-(2-Furyl)-3-(5-nitro-2-furyl)acrylamide (TA100, TA98, WP2 uvrA), Sodium azide (TA1535) and 9-Aminoacridine (TA1537)
+S9 mix; 2-Aminoanthracene (all strains)
　Doses:-S9 mix; 0, 0.781, 1.56, 3.13, 6.25, 12.5, 25 μg/plate(TA100, TA1535, TA1537)
-S9 mix; 0, 1.56, 3.13, 6.25, 12.5, 25, 50 μg/plate(TA98)
-S9 mix; 0, 3.13, 6.25, 12.5, 25, 50, 100 μg/plate(WP2 uvrA)
+S9 mix; 0, 3.91, 7.81, 15.6, 31.3, 62.5, 125 μg/plate(WP2 uvrA)
+S9 mix; 0, 7.81, 15.6, 31.3, 62.5, 125, 250 μg/plate(TA1535, TA1537)
+S9 mix; 0, 15.6, 31.3, 62.5, 125, 250, 500 μg/plate(TA100, TA98)
　S9:Rat liver, induced with phenobarbital and 5,6-benzoflavone
　Plates/test:3
　Number of replicates:2
GLP:Yes

　Test results:

This chemical did not induce gene mutations in the S. typhimurium and E. coli strains. Toxicity was observed at more than 12.5 μg/plate (TA100, TA1535, TA1537), 25 μg/plate (TA98) and 50 μg/plate (WP2 uvrA) without S9 mix, and at more than 62.5 μg/plate (WP2 uvrA), 125 μg/plate (TA1535, TA1537) and 250 μg/plate (TA100, TA98) with S9 mix.

Genetic effects:
Salmonella typhimurium TA100, TA1535, TA98, TA1537
+?-
　Without metabolic activation:[ ][ ][*]
　With metabolic activation:[ ][ ][*]

Escherichia coli WP2 uvrA
+?-
　Without metabolic activation:[ ][ ][*]
　With metabolic activation:[ ][ ][*]

3-2. Non-bacterial in vitro test (chromosomal aberration test)2)

Purity:99.67 %
Type of cell used:Chinese hamster lung (CHL/IU) cells
Test method:Guidelines for Screening Mutagenicity Testing of Chemicals(Chemical Substances Control Law of Japan) and OECD Test Guideline 473
　Solvent:DMSO
　Positive controls:-S9 mix; 1-Methyl-3-nitro-1-nitrosoguanidine
+S9 mix; 3,4-Benzo[a]pyrene
　Doses:-S9 mix(6 hr short-term treatment); 0, 10, 20, 30, 40, 50, 60 μg/mL
+S9 mix(6 hr short-term treatment); 0, 1.25, 2.5, 5, 7.5, 10 μg/mL
　S9:Rat liver, induced with phenobarbital and 5,6-benzoflavone
　Plates/test:2
GLP:Yes

　Test results:

With 6 hr short-term treatment, structural chromosomal aberrations were induced at 7.5 and 10 μg/mL (12.5 and 22.0 %), respectively, with S9 mix. Polyploidy was not induced in any treatment group.
Cytotoxicity was observed at 50 and 60 μg/mL with 6 hr short-term treatment without S9 mix.

Lowest concentration producing cytogenetic effects in vitro:
　With metabolic activation (6 hr short-term treatment):7.5 μg/mL(clastogenicity)

Genetic effects:
clastogenicitypolyploidy
+?-+?-
　Without metabolic activation:[ ][ ][*][ ][ ][*]
　With metabolic activation:[*][ ][ ][ ][ ][*]

1)The tests were performed by the Safety Assessment Laboratory, Panapharm Laboratories Co., Ltd., 1285 Kurisaki-machi, Uto-shi, Kumamoto, 869-0425, Japan Tel +81-964-23-5111 Fax +81-964-23-2282
2)The tests were performed by the Research Institute for Animal Science in Biochemistry and Toxicology, 3-7-11 Hashimotodai, Sagamihara-shi, Kanagawa 229-1132, Japan. Tel +81-42-762-2775 Fax +81-42-762-7979