5-nitrofurfurylidene di(acetate)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Weight of evidence: Bacterial reverse mutation assay (Wang 1976):

The nitrofuran 5 -nitrofurfurylidene diacetate (up to 20 µg/plate) and the urine of rats fed with this compound (0.5% nitrofuran diet for 4 days, urine collected during the first 10h at 5th day) were assayed for mutagenic activity in Salmonella typhimurium strains TA100 and TA100FR1. 5 -nitrofurfurylidene diacetate was determined to be mutagenic in both strains. Nevertheless, strains which lack the ability to reduce nitro groups under aerobic condition (TA100FR1) was much less sensitive to mutagenesis than strains which have the ability to reduce the nitrofuran under aerobic conditions (TA100). Thus, the mutagenic activity seems to be due to the reduced metabolites of these compounds. The urine of rats fed with 5 -nitrofurfurylidine diacetate was found to be non-mutagenic. In fact, no test item was detected in the urine. Moreover, the mutagenic activity of urine of rats fed with the nitrofuran could not be enhanced by the addition ofβ-glucuronidase, suggesting that the rats do not excrete glucuronide conjugated active metabolites of the nitrofuran in the urine. Based on the results, the authors suggested that the noncarcinogenic properties of the substance may be due to its rapid metabilization. They also point out that the failure of the nitrofuran to induce tumors may also be due to their weak mutagenic activity or weak ability to induce DNA damage.

Weight of evidence: Bacterial reverse mutation assay (Goodman 1977):

The mutagenicity of 5 -nitrofurfurylidene diacetate was tested in the Salmonella typhimurium tester strain TA100.The substance appeared to be a weak mutagen in TA100 strain without metabolic activation.

Weight of evidence: Bacterial reverse mutation assay (Ni 1987):

The test item 5 -nitrofurfurylidenen diacetate was assayed for mutagenicity in Salmonella typhimurium strains TA98, TA98NR, which is deficient in the major component of nitroreductase activity and TA98/1,8-DNP6, which is deficient in transesterificase activity. The pattern of mutagenicity in these 3 tester strains indicates whether or not bacterial nitroreduction and/or esterification are potential pathways for the activation of a 2-substituted 5-nitrofurans to a mutagen or carcinogen. The test item was determined to be mutagenic in the 3 tester strains with and without metabolic activation. The addition of S9 had little effect on the mutagenicities. According to the authors, this latter finding suggests that the tested nitrofuran and its S9-mediated oxidative metabolites have similar mutagenic potencies in this tester strain. The mutagenicities observed in TA98NR, both with and without S9, were less than those in TA98. The study point out that these results suggest that both nitroreduction and possibly oxidative S9 metabolism followed by nitroreduction are major routes of mutagenic activation for these compounds. A significant portion of the mutagenicity elicited by the test item in TA98 appeared to be independent of the classical nitroreductase. It is possible that this mutagenicity was due to metabolism by minor components of the bacterial nitroreductase system (i.e. nitroreductases other than the 'classical' nitroreductase missing in TA98NR). Evidence for the involvement of transesterification, as indicated by lowered mutagenicity in TA98/I,8-DNP6, was also seen. The significant mutagenic responses in TA98/1,8-DNP6 suggests that both esterified and unesterified N-hydroxy derivatives of the nitrofuran may be ultimate mutagenic species.

Weight of evidence: Bacterial reverse mutation assay (McCalla 1974):

The test item 5 -nitrofurfurylidene diacetate was tested for ability to induce revertants of Escherichia coli WP2 uvrA- derivative from tryp- to tryp+. The test item produced a significant number of revertants in spot tests (without metabolic activation).

Weight of evidence: In-vitro Sister Chromatid Exchange (Shirai 1980):

The test item 5 -nitrofurfurylidene diacetate was assayed for the enhancement of sister-chromatid exchange (SCE) in Chinese hamster ovary (CHO). The test item significantly increased the frequency of SCE (p<0.01) at all doses without metabolic activation.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

(only one strain TA100 tested, without metabolic activation, no positive control included).

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Chemical name: 5-Nitro-2-furanmethandiol diacetate
Source: Aldrich.

Target gene:

Histidine requiring strain

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

without

Test concentrations with justification for top dose:

0.1, 0.5, 1.0, 5.0, 10.0, and 25.0 µg/plate.

Vehicle / solvent:

Dimethyl sulfoxide (Aldrich).

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

positive

Remarks:

weak mutagen

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(probably at 25 µg/plate)

Vehicle controls validity:

valid

Dose µg/plate	TA100
0	74	76
0.1	74
0.5	55
1.0	61
5.0	64
10.0	120
25.0	0

The substance appears to be a weak mutagen.

Conclusions:

The substance appeared to be a weak mutagen in TA100 strain without metabolic activation.

Executive summary:

The mutagenicity of 5 -nitrofurfurylidene diacetate was tested in the Salmonella typhimurium tester strain TA100. The nitrofuran was dissolved in dimethyl sulfoxide (DMSO) and incorporated uniformly in the top agar overlay. Revertant his+ colonies were counted after incubation at 37°C for 48 h. The nitrofuran compound was tested at 0.1, 0.5, 1.0, 5.0, 10.0, and 25.0 µg/plate. The substance appeared to be a weak mutagen in TA100 strain without metabolic activation.

Reference 2

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

(only strains TA98, TA98NR and TA98/1,8-DNP6 tested, no positive control included)

Principles of method if other than guideline:

Salmonella typhimurium tester strains TA98, TA98NR, which are deficient in the major component of nitroreductase activity and TA98/1,8-DNP6, which is deficient in transesterificase activity, have been extensively employed to assay nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) and to study the metabolic activation routes of these compounds. The pattern of mutagenicity in these 3 tester strains indicates whether or not bacterial nitroreduction and/or esterification are potential pathways for the activation of a 2-substituted 5-nitrofurans to a mutagen or carcinogen.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Chemical name: 5-nitro-2-furaldehyde diacetate
Source: Aldrich, Milwaukee, WI (USA)
Purity: >99 % (HPLC)

Target gene:

Histidine requiring strain

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium, other: TA98NR

Additional strain / cell type characteristics:

other: deficient in the major component of nitroreductase activity

Species / strain / cell type:

S. typhimurium, other: TA98/1,8-DNP6

Additional strain / cell type characteristics:

other: deficient in transesterificase activity

Metabolic activation:

with and without

Metabolic activation system:

S9 fractions were prepared from the livers of 250-350 g male Sprague-Dawley rats pretreated with 3-methylcholanthrene.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Details on test system and experimental conditions:

The cells were grown at 37°C for 12 h in Oxoid Nutrient Broth No. 2 in an incubator shaker. Mutagenicity assays were performed by the plate-incorporation method in the presence and absence of 1.2 mg of S9 protein per plate. All assays were performed in triplicate. Colonies were counted with a Bactronic colony counter. All compounds were tested on at least two separate occasions with similar results.

Evaluation criteria:

A treatment which resulted in at least twice the number of revertants per plate above that obtained in the solvent control was considered to produce a positive response.

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(100 µg/plate, -S9 mix)

Vehicle controls validity:

valid

Key result

Species / strain:

S. typhimurium, other: TA98NR

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(100 µg/plate, ±S9 mix)

Vehicle controls validity:

valid

Key result

Species / strain:

S. typhimurium, other: TA98/1,8-DNP6

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(>= 20 µg/plate, -S9 mix)

Vehicle controls validity:

valid

Dose µg/plate	TA98		TA98NR		TA98/1,8-DNP6
	-S9 mix	+S9 mix	-S9 mix	+S9 mix	-S9 mix	+S9 mix
1.0	26 ± 2	30 ± 2	21 ± 2	27 ± 3	11 ± 2	13 ± 2
5.0	77 ± 2	74 ± 3	26 ± 2	35 ± 4	14 ± 3	18 ± 4
10.0	88 ± 3	86 ± 2	48 ± 2	40 ± 1	37 ± 2	44 ± 4
20.0	210 ± 6	195 ± 9	71 ± 3	91 ± 7	BK	53 ± 2
100.0	BK	433 ± 25	BK	BK	BK	107 ± 3

BK: Bacteria killing.

Each value expressed as mean ± S.D. of revertants/plate normalized from 2 repeat experiments. The mean numbers of revertants/plate produced in DMSO control using TA98, TA98NR and TA98/1,8-DNP6, respectively, with no S9 were 30 ± 1, 25 ± 3 and 10 ± 1;and with S9 were 34 + 2, 31 ± 1 and 14 ± 2.

TA98		TA98NR		TA98/1,8-DNP6
-S9 mix	+S9 mix	-S9 mix	+S9 mix	-S9 mix	+S9 mix
2.6	2.4	1.2	1.1	0.9	1.1

Results expressed as revertants per nanomole and the values were calculated from the slopes of linear regression lines fit to the increasing portions of the dose-response relationships.

The addition of S9 had little effect on the mutagenicities. According to the authors, this latter finding suggests that the tested nitrofuran and its S9-mediated oxidative metabolites have similar mutagenic potencies in this tester strain. The mutagenicities observed in TA98NR, both with and without S9, were less than those in TA98. The study point out that these results suggest that both nitroreduction and possibly oxidative S9 metabolism followed by nitroreduction are major routes of mutagenic activation for these compounds. A significant portion of the mutagenicity elicited by the test item in TA98 appeared to be independent of the classical nitroreductase. It is possible that this mutagenicity was due to metabolism by minor components of the bacterial nitroreductase system (i.e. nitroreductases other than the 'classical' nitroreductase missing in TA98NR). Evidence for the involvement of transesterification, as indicated by lowered mutagenicity in TA98/I,8-DNP6, was also seen. The significant mutagenic responses in TA98/1,8-DNP6 suggests that both esterified and unesterified N-hydroxy derivatives of the nitrofuran may be ultimate mutagenic species.

Conclusions:

5 -nitrofurfurylidenen diacetate was determined to be mutagenic in Salmonella typhimurium strains TA98, TA98NR and TA98/1,8-DNP6 with and without metabolic activation.

Executive summary:

The test item 5 -nitrofurfurylidenen diacetate was assayed for mutagenicity in Salmonella typhimurium strains TA98, TA98NR, which is deficient in the major component of nitroreductase activity and TA98/1,8-DNP6, which is deficient in transesterificase activity. The pattern of mutagenicity in these 3 tester strains indicates whether or not bacterial nitroreduction and/or esterification are potential pathways for the activation of a 2-substituted 5-nitrofurans to a mutagen or carcinogen. The cells were grown at 37°C for 12 h in Oxoid Nutrient Broth No. 2 in an incubator shaker. The assay was performed by the plate-incorporation method in the presence and absence of 1.2 mg of S9 protein per plate in triplicate. Colonies were counted with a Bactronic colony counter. The compound was tested on at least two separate occasions with similar results. A treatment which resulted in at least twice the number of revertants per plate above that obtained in the solvent control was considered to produce a positive response. Based on the results, the test item was determined to be mutagenic in the 3 tester strains with and without metabolic activation. The addition of S9 had little effect on the mutagenicities. According to the authors, this latter finding suggests that the tested nitrofuran and its S9-mediated oxidative metabolites have similar mutagenic potencies in this tester strain. The mutagenicities observed in TA98NR, both with and without S9, were less than those in TA98. The study point out that these results suggest that both nitroreduction and possibly oxidative S9 metabolism followed by nitroreduction are major routes of mutagenic activation for these compounds. A significant portion of the mutagenicity elicited by the test item in TA98 appeared to be independent of the classical nitroreductase. It is possible that this mutagenicity was due to metabolism by minor components of the bacterial nitroreductase system (i.e. nitroreductases other than the 'classical' nitroreductase missing in TA98NR). Evidence for the involvement of transesterification, as indicated by lowered mutagenicity in TA98/I,8-DNP6, was also seen. The significant mutagenic responses in TA98/1,8-DNP6 suggests that both esterified and unesterified N-hydroxy derivatives of the nitrofuran may be ultimate mutagenic species.

Reference 3

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

(only strains TA100 and TA100FR1 tested, only 3 concentrations tested, without metabolic activation, no positive control included).

Principles of method if other than guideline:

The mutagenic activity in Salmonella typhimurium strains TA100 and TA100FR1 was evaluted for 5-nitrofurfurylidene diacetate and the urine of rats fed with this compound.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Source: Aldrich Chemical Co., Milwaukee, Wis. (USA)

Target gene:

Histidine requiring strain

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium, other: TA100FR1

Additional strain / cell type characteristics:

other: lack of the ability to reduce nitro groups under aerobic conditions

Metabolic activation:

without

Test concentrations with justification for top dose:

Test item: 0.1, 1 and 10 µg/plate
Urine: 0.2, 2, 10 µl/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Dimethyl sulfoxide

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

10 µg/plate (severe growth inhibition was observed)

Vehicle controls validity:

valid

Key result

Species / strain:

S. typhimurium, other: TA100FR1

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Remarks:

(urine)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Key result

Species / strain:

S. typhimurium, other: TA100FR1

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Mutagenicity of the nitrofuran:

Nitrofuran	µg/plate	Number of revertant colonies/plate(a)
		TA100	TA100FR1
Control		78	18
5-Nitrofurfurylidene diacetate	0.1	78
	1	72	27
	10	168(b)	117

(a) Average of duplicate determinations.

(b) Severe growth inhibition was observed.

Strains which lack the ability to reduce nitro groups under aerobic conditions (TA100FR1) are much less sensitive to mutagenesis by nitrofurans than strains which have the ability to reduce nitrofurans under aerobic conditions (TA100). Thus, the mutagenic activity seems to be due to the reduced metabolites of these compounds.

Mutagenicity of the urine of rats fed with nitrofurans:

Nitrofuran	µl/plate	Number of revertant colonies/plate(a)
		TA100	TA100FR1
Control		78	12
Control	20	91	10
	2	68	7
	0.2	60	11
5-Nitrofurfurylidene diacetate	20	105	9
	2	83	8
	0.2	82	11

(a) Average of duplicate determinations.

The urine of rats fed with 5 -nitrofurfurylidine diacetate was found to be non-mutagenic.

Effect of β-glucuronidase on the mutagenic activity of urine of rats fed nitrofuran:

Nitrofuran	µl/plate(a)	Number of revertant colonies/plate(b)
		TA100	TA100FR1
Control		96	82
5-Nitrofurfurylidene diacetate	20	95	139

(a) Urine was diluted in saline and 0.2 mL was added in each plate.

(b) Average of duplicate determinations.

The mutagenic activity of urine of rats fed nitrofurans could not be enhanced by the addition of β-glucuronidase, suggesting that the rats do not excrete glucuronide conjugated active metabolites of nitrofurans in the urine.

Detection of nitrofurans in the urine of rats:

Nitrofuran	Rf value on cellulose TLC(a)	Color		Detected in urine
		Visible light	UV light
5-Nitrofurfurylidine diacetate	0.45(c)	None	D(b)	No

(a) Ascending chromatography with 2% formic acid solvent system

(b) D: Dark

(c) Severe tailing on TLC

The results demonstrated that 5-nitrofurfurylidene diacetate was metabolized to such an extent that this compound could not be

detected in the urine.

Conclusions:

5 -nitrofurfurylidene diacetate (up to 20 µg/plate, without metabolic activation) was determined to be mutagenic in both strains TA100 and TA100FR1. The urine of rats fed with this compound (0.5% nitrofuran diet for 4 days, urine collected during the first 10h at 5th day) was determined to be non-mutagenic since 5-nitrofurfurylidene diacetate was metabolized to such an extent that the compound could not be detected in the urine.

Executive summary:

The nitrofuran 5 -nitrofurfurylidene diacetate (up to 20 µg/plate) and the urine of rats fed with this compound (0.5% nitrofuran diet for 4 days, urine collected during the first 10h at 5th day) were assayed for mutagenic activity in Salmonella typhimurium strains TA100 and TA100FR1. The inoculates were grown in Bactonutrient broth at 37°C overnight in the dark. 25 µl of nitrofuran in dimethyl sulfoxide or saline (09% NaCl) diluted urine (0.2 mL) was added to 2 ml of top agar along with 0.3 ml of the bacterial suspension and plated. The his+ revertant colonies were enumerated after incubation in the dark for 3 days at 37°C. Duplicate determinations were performed. The nitrofuran was detected in urine by thin-layer chromatography (TLC). The effect of B-glucuronidase on the mutagenicity or urine of rats fed was also evaluated. 5 -nitrofurfurylidene diacetate was determined to be mutagenic in both strains TA100 and TA100FR1. Nevertheless, strains which lack the ability to reduce nitro groups under aerobic condition (TA100FR1) was much less sensitive to mutagenesis than strains which have the ability to reduce the nitrofuran under aerobic conditions (TA100). Thus, the mutagenic activity seems to be due to the reduced metabolites of these compounds. The urine of rats fed with 5 -nitrofurfurylidine diacetate was found to be non-mutagenic. In fact, no test item was detected in the urine. Moreover, the mutagenic activity of urine of rats fed with the nitrofuran could not be enhanced by the addition of β-glucuronidase, suggesting that the rats do not excrete glucuronide conjugated active metabolites of the nitrofuran in the urine. Based on the results, the authors suggested that the noncarcinogenic properties of the substance may be due to its rapid metabilization. They also point out that the failure of the nitrofuran to induce tumors may also be due to their weak mutagenic activity or weak ability to induce DNA damage.

Reference 4

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

Deviations:

yes

Remarks:

(without metabolic activation, only 2 concentrations tested)

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Chemical name: 5-nitro-2-furanmethandiol diacetate
Source: Eastman, Rochester, NY (USA)

Target gene:

Tryptophan requiring strains

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

without

Test concentrations with justification for top dose:

10, 50 µg/plate

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Production of revertants on spot tests
Strains	Amount (µg)	Induces mutants per plate
uvrA-	10	24
	50	61

Conclusions:

5-nitrofurfurylidenen diacetate produced a significant number of revertants of E. coli WP2 uvrA- in spot tests (up to 50 µg/plate, without metabolic activation).

Executive summary:

The test item 5 -nitrofurfurylidene diacetate was tested for ability to induce revertants of Escherichia coli WP2 uvrA- derivative from tryp- to tryp+. The compound (10 and 50 µg/plate) was then applied to the centre of the plate as an impregnated sector of filter paper. The plates were incubated for 48 h at 37ºC, the colonies counted and the width of the zone of inhibition between the thin lawn of tryp- cells and the straight edge of the paper sector was measured. The test item produced a significant number of revertants in spot tests (without metabolic activation).

Reference 5

Endpoint:

in vitro DNA damage and/or repair study

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 479 (Genetic Toxicology: In Vitro Sister Chromatid Exchange Assay in Mammalian Cells)

Deviations:

yes

Remarks:

(without metabolic activation)

GLP compliance:

no

Type of assay:

sister chromatid exchange assay in mammalian cells

Specific details on test material used for the study:

Chemical name: 5-nitro-2-furfurylidene diacetate
Source: Aldrich Chemical, Milwaukee, WI (USA)

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Remarks:

(CHO-K1-BH4)

Metabolic activation:

without

Test concentrations with justification for top dose:

5, 20 and 100 µM

Vehicle / solvent:

DMSO- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-Hydroxy-AAF

Details on test system and experimental conditions:

Positive control: N-Hydroxy-AAF enhanced the frequency of SCE in this study.

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(100 µM)

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Concentration (µM)	SCE per cell
100	-
20	9.4 ± 3.0
5	7.8 ± 2.7
Control	5.7 ± 1.7

Exporure time was 1h.

Mean ± SD for 50 cells.

-: Killing.

The test item significantly increased the frequency of SCE (p<0.01) at all doses.

Conclusions:

The test item significantly increased the frequency of SCE (p<0.01) at all doses in the sister chromatid exchange assay in CHO cells (without metabolic activation).

Executive summary:

The test item 5 -nitrofurfurylidene diacetate was assayed for the enhancement of sister-chromatid exchange (SCE) in Chinese hamster ovary (CHO). CHO cells were incubated at 37 ºC for 16h. The media was replaced by a serum free Eagle's MEM containing the test item (5, 20 and 50 µM in DMSO, 10 µl) and the culture was further incubated for 1h. The culture was incubated to allow the cells to undergo 2 cell cycles. Colchicine was added to the media to a final concentration of 1E-05 M for the last 3 h of incubation. The cells were then fixed and stained. SCE frequency of 50 cells which had 20 well spread chromosomes were scored. The test item significantly increased the frequency of SCE in CHO cells.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

According to the OECD QSAR Toolbox v.4.3. software profilers, the substance 5-nitrofurfurylidene diacetate is predicted to bind to DNA. Moreover, there are several structural alerts for mutagenicity.

Although the metabolism of nitrofurans is not well documented, a suggested mechanism is through cleavage of the nitrofuran ring, leaving the specific tail group covalently bound to tissue (Leitner et al. 2001). A characteristic of nitrofurans is the short half-life of the parent compounds due to extensive metabolism, primarily a reduction of the nitro-group. This nitroreduction results in the formation of reactive metabolites able to bind covalently to tissue macromolecules, including proteins (EFSA 2015).

Considering all this information and based on the precautionary principle, it is proposed to classify the substance 5-nitrofurfurylidene diacetate as Germ Cell Mutagen Category 2, H341.

Leitner A et al. (2001). Determination of the metabolites of nitrofuran antibiotics in animal tissue by high-performance liquid chromatography-tandem mass spectrometry. Journal of Chromatogra-phy A, 939: 49-58.

EFSA (2015). Scientific opinion on nitrofurans and their metabolites in food. EFSA Panel on Contaminants in the food chain (CONTAM). European Food Safety Authority (EFSA), Parma, Italy.

Justification for classification or non-classification

Considering all this information and based on the precautionary principle, it is proposed to classify the substance 5-nitrofurfurylidene diacetate as Germ Cell Mutagen Category 2, H341 according to the CLP Regulation 1272/2008.