2,3,6-Trimethylphenol

2,3,6-トリメチルフェノール


[CAS No. 2416-94-6]

Molecular formula: C9H12O　Molecular weight: 136.19

ABSTRACT

A single oral dose LD50 value of 2,3,6-trimethylphenol was between 1400 and 2000 mg/kg in both sexes.

2,3,6-Trimethylphenol was studied for oral toxicity in rats in a 28-day repeat dose toxicity test at doses of 0, 100, 300 and 1000 mg/kg. In the 1000 mg/kg group of both sexes, body weight gain and food consumption were suppressed. Similar changes were sporadically found in the 300 mg/kg treated animals. Yellowish urine was observed in both sexes of the 1000 mg/kg group. In female animals given 1000 mg/kg, proteinuria with increased excretion of bilirubin and urobilinogen was observed. The RBC count, hemoglobin content and hematocrit were decreased in the 1000 mg/kg females. Plasma levels of inorganic phosphorus were increased and that of albumin decreased in males of the 300 mg/kg and 1000 mg/kg groups. Weight of the adrenal glands were decreased in the males. Weights of the spleen and the liver were increased in 1000 mg/kg females. Hypertrophy with ground glass appearance of centrilobular hepatocytes, and hemosiderin deposition, dilatation of sinus in the spleen, and diffuse squamous cell hyperplasia of the forestomach were observed in both sexes of the 1000 mg/kg group. Most of the changes disappeared after withdrawal. Therefore, the NOEL for the 28-day repeat dose oral toxicity test of 2,3,6-trimethylphenol is considered to be 100 mg/kg/day for male and female rats.

2,3,6-Trimethylphenol was not mutagenic in Salmonella typhimurium TA100, TA1535, TA98, TA1537 and Escherichia coli WP2 uvrA, with or without an exogenous metabolic activation system.

2,3,6-Trimethylphenol induced structural chromosomal aberrations in CHL/IU cells with 6 hr short-term treatment with and without an S9 mix and on continuous treatment for 48 hr. Polyploidy was not induced in any treatment group.

SUMMARIZED DATA FROM THE STUDIES

1. Single Dose Oral Toxicity 1)

Purity:99.67 %
Test species/strain:Rat/Crj:CD(SD)
Test method:OECD Test Guideline 401
　Route:Oral (gavage)
　Doses:0 (vehicle), 1000, 1400, 2000mg/kg
　Number of animals/group:Males, 5; females, 5
　Vehicle:Corn oil
GLP:Yes

　Test results:

Deaths occurred in males given 1400 mg/kg and more and in females given 2000 mg/kg. Adoption of a lateral or prone position and passivity were apparent in all groups administered 2,3,6-trimethylphenol in both sexes. Clinical signs became more severe and persisted longer dose-dependently, females being more evident than males. Body weight gain was depressed dose-dependently in both sexes. At autopsy, pericardiac fluid accumulation, pleural effusion, reddish discoloration of the lung and the liver, pale and thickened area of the mucosa of the glandular stomach and dilatation of the stomach were observed in dead animals. The LD50 value was between 1400 and 2000 mg/kg in both sexes.

2. Repeat Dose Toxicity 1)

Purity:99.67 wt%
Test species/strain:Rats/Crj:CD(SD)
Test method:Guidelines for 28-Day Repeat Dose Toxicity Testing of Chemicals (Japan)
　Route:Oral (gavage)
　Doses:0 (vehicle), 100, 300, 1000 mg/kg/day
　Number of animals/group:Males, 10; females, 10 (0, 1000 mg/kg)
:Males, 5; females, 5 (100, 300 mg/kg)
　Vehicle:Corn oil
　Administration period:Males and females, 28 days
　Terminal kill:Males and females, on day 29 or 43
GLP:Yes

　Test results:

Two females given 1000 mg/kg died due to an inappropriate procedure for administration. In both sexes, an ataxic gait or adoption of a prone position and salivation were observed transiently but frequently after dosing. However, the salivation were considered to be toxicologically insignificant. During the administration period, inhibition of body weight gain and decrease of food consumption were noted. Yellowish urine in both sexes, increased urine volume with low specific gravity in males, and increased total protein, bilirubin and urobilinogen contents in females were revealed. Decreases in RBC, hemoglobin content and hematocrit value were noted in females. Elevated inorganic phosphorus level and decreased albumin contents were noted in males. Furthermore, absolute weights of the adrenal glands in males were decreased, and absolute and relative weights of the spleen and liver, were increased in females. Histopathologically, both sexes showed hypertrophy and ground glass appearance of centrilobular hepatocytes, deposits of hemosiderin and dilatation of sinus as in the spleen and diffuse squamous hyperplasia of the forestomach. Females showed marked hematopoiesis in the spleen. Most of the above-mentioned changes with in 1000 mg/kg disappeared on withdrawal. Nevertheless, males showed lower MCV and MCH and females showed a higher relative weight of spleen than control group. In addition, deposits of hemosiderin in the spleen in both sexes continued to be marked as compared with control group. In the 300 mg/kg group, transient salivation in both sexes, inhibition of body weight gain and decrease of food consumption in females and lower urinary specific gravity, higher inorganic phosphorus level in plasma and higher absolute weights of adrenal glands were observed. Neither sex given 100 mg/kg showed any symptoms. Thus, the NOEL for the 28-day repeat dose toxicity is considered to be 100 mg/kg/day for males and females.

3. Genetic Toxicity

3-1. Bacterial test 2)

Purity:99.67 %
Test species/strain:Salmonella typhimurium TA100, TA1535, TA98, TA1537, Escherichia coli WP2 uvrA
Test method:Guidelines for Screening Mutagenicity Testing of Chemicals (Japan) and OECD Test Guidelines 471 and 472
　Procedures:Pre-incubation method
　Solvent:DMSO
　Positive controls:-S9 mix; AF-2 (TA100, TA98), Sodium azide (TA1535), ENNG (WP2 uvrA) and 9-Aminoacridine (TA1537)
+S9 mix; 2-Aminoanthracene (all strains)
　Doses:-S9 mix; 39.1, 78.1, 156, 313, 625 and 1250 μg/plate
+S9 mix; 39.1, 78.1, 156, 313, 625 and 1250 μg/plate
　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 a concentration of 625 μg/plate or more (TA100 and TA1535) and at 1250 μg/plate (WP2 uvrA, TA98 and TA1537), with and without metabolic activation.

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 CHL/IU cells
Test method:Guidelines for Screening Mutagenicity Testing of Chemicals (Japan) and OECD Test Guideline 473
　Solvent:Acetone
　Positive controls:-S9 mix, Mitomycin C
+S9 mix, Benzo[a]pyrene
　Doses:-S9 mix (24 and 48 hr continuous treatment);
0, 25, 50, 100, 200 μg/mL (main test)
0, 12.5, 25, 50, 100, 200 μg/mL (confirmation test)
-S9 mix (6 hr short-term treatment); 0, 25, 50, 100, 200 μg/mL
+S9 mix (6 hr short-term treatment); 0, 25, 50, 100, 200 μg/mL
　S9:Rat liver, induced with phenobarbital and 5,6-benzoflavone
　Plates/test:2
GLP:Yes

　Test results:

Structural chromosomal aberrations, including gaps, were induced at 200 μg/mL on 6 hr short-term treatment with an S9 mix (11.5 %) and without an S9 mix (11.0 %), and at 50, 100 and 200 μg/mL on 48 hr treatment (9.5, 13.5 and 8.5 %, respectively) in the confirmation test. Polyploidy was not induced in any treatment group.

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

1)The tests were performed by the Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano-shi, Kanagawa, 257-8523, Japan. Tel +81-463-82-4751 Fax +81-463-82-9627
2)The tests were performed by the Mitsubishi Chemical Safety Institute Ltd., 14 Sunayama, Hasaki-machi, Kashima-gun, Ibaraki, 314-0255, Japan. Tel +81-479-46-2871 Fax +81-479-46-2874