Reaction mass of 2,4,6-tris(1-phenylethyl)phenol and bis(1-phenylethyl)phenol and o-(1-phenylethyl)phenol

Biotransformation and kinetics

Administrative data

Endpoint:

biotransformation and kinetics

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study according to a sound study design.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The potential for biotransformation of TSP by hepatic enzymes was investigated in rainbow trout liver S9 fractions. Rainbow trout liver S9 fractions were incubated with TSP for 120 min. In addition, buffer-only, heat deactivated and No NADPH controls were assayed alongside the S9 reaction mix fractions. Over the 120 min, time course samples were taken and analyzed by GC-MS to determine the loss of TSP relative to the control samples.

GLP compliance:

yes

Type of medium:

animal

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tris(1-phenylethyl)phenol

EC Number:

242-128-1

EC Name:

2,4,6-tris(1-phenylethyl)phenol

Cas Number:

18254-13-2

Molecular formula:

C30H30O

IUPAC Name:

2,4,6-tris(1-phenylethyl)phenol

Test material form:

liquid: viscous

Details on test material:

The test material is one of the main constituents of the reaction mass of 2,4,6-tris(1-phenylethyl)phenol and Bis(1-phenylethyl) phenol.

Results and discussion

Transformation products:

no

Any other information on results incl. tables

The liver S9 assay was conducted with the assays being stopped using 1:1 ACN:THF.  The results of the biotransformation assay of 5 µM TSPafter 120 min of incubation in the rainbow trout S9 fractionare compiled in the below table.

 

At 120 minutes, no loss of TSP wasobserved relative to Time 0 min. Likewise, the results indicated that there was no loss wit the heat-inactivated liver S9 fraction and No-NADPH negative controls. The positive controldisappeared to levels below analytical detection before 120 mins of incubation exhibited. Overall, the data indicates there is no metabolic degradation of TSP using the in vitro liver S9 metabolism assay.

It should be noted that higher levels of TSP and fluroxypyr were detected in this S9 study, as opposed tothe subsequent hepatocyte experiments, even though both studies utilized the same concentration . While adefinitive reason cannot be given, it is likely due to differences in binding within the cell suspension and ultimate bioavailability. It is likely that these compounds had a greater affinity for the hepatocytes compared to the S9 suspension, thus lowering the overall bioavailable free measurable fraction.

		TSP S9 Reaction Mix	No NADPH Control	Heat Inactivated Control	Positive Control
Run	Time point	TSP Conc. (ppm)	TSP Conc. (ppm)	TSP Conc. (ppm)	TSP Conc. (ppm)
1	0 min	27.6	#	20.78	17.03
2	0 min	21.0	22.50	20.24	17.50
3	0 min	23.6	21.50	21.07	17.73
Avg.	0 min	24.1	21.82	20.70	17.38
1	15 min	21.4
2	15 min	33.8
3	15 min	27.1
Avg.	15 min	27.4
1	30 min	33.8
2	30 min	29.7
3	30 min	26.7
Avg.	30 min	30.0
1	60 min	21.8	#	20.36	BD
2	60 min	29.5	22.48	19.72	BD
3	60 min	26.4	25.19	20.28	BD
Avg.	60 min	25.9	23.66	20.12	-0.42
1	120 min	21.7	#	17.61	BD
2	120 min	23.3	22.27	22.56	BD
3	120 min	30.7	21.29	20.55	BD
Avg.	120 min	25.2	21.69	20.24	-0.42

# Vial broken, could not be analyzed.

Applicant's summary and conclusion

Conclusions:

There was not significant loss of parent materials over time due to the active biotransformation of liver S9 from rainbow trout.

Executive summary:

The potential for biotransformation of TSP by hepatic enzymes was investigated in rainbow trout liver S9 fractions. Rainbow trout liver S9 fractions were incubated with TSP for 120 min. In addition, buffer-only, heat deactivated and No NADPH controls were assayed alongside the S9 reaction mix fractions. Over the 120 min, time course samples were taken and analyzed by GC-MS to determine the loss of TSP relative to the control samples.

5 µM of TSP was incubated with rainbow trout liver S9 fractions (1 mg/ml protein) for 120 min. One-way ANOVA followed by Dunnett's post hoc testing showed no significant loss of TSP relative to time 0 minutes for the liver S9 assays (p > 0.05). No significant differences were observed for loss of TSP in the Heat Deactivated Controls for the liver S9 assay.

In conclusion there was not significant loss of parent materials over time due to the active biotransformation of liver S9 from rainbow trout.