4-[[4-(dimethylamino)phenyl][4-(methylimino)cyclohexa-2,5-dien-1-ylidene]methyl]-N,N-dimethylaniline monohydrochloride

Carcinogenicity

Administrative data

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Final report on the safety assessment of Basic Violet 1, Basic Violet 3, and Basic Violet 4

Author:

C. Diamante et al.

Year:

2009

Bibliographic source:

International Journal of Toxicology, 28(Suppl 3) 193s-204s

Reference 2

Reference Type:

publication

Title:

Gentian Violet: A 19th Century Drug Re-Emerges in the 21st Century

Author:

Alexander M. Maley et al

Year:

2013

Bibliographic source:

Exp Dermatol. 2013 December ; 22(12): 775–780

Reference 3

Reference Type:

other: abstract

Title:

Chronic toxicity and carcinogenicity studies of gentian violet in mice.

Author:

Littlefield et al

Year:

1985

Bibliographic source:

Fundam Appl Toxicol. 1985 Oct;5(5):902-12.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

4-[[4-(dimethylamino)phenyl][4-(methylimino)cyclohexa-2,5-dien-1-ylidene]methyl]-N,N-dimethylaniline monohydrochloride

EC Number:

210-042-3

EC Name:

4-[[4-(dimethylamino)phenyl][4-(methylimino)cyclohexa-2,5-dien-1-ylidene]methyl]-N,N-dimethylaniline monohydrochloride

Cas Number:

603-47-4

Molecular formula:

C24H27N3.ClH

IUPAC Name:

4-[[4-(dimethylamino)phenyl][4-(methylimino)cyclohexa-2,5-dien-1-ylidene]methyl]-N,N-dimethylaniline monohydrochloride

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

720 male and 720 female mice

Administration / exposure

Route of administration:

oral: feed

Vehicle:

ethanol

Details on exposure:

Gentian violet was dissolved in ethyl alcohol and sprayed directly into the feed at dose levels of 0, 100, 300 and 600 ppm. The ethyl alcohol was subsequently removed during a 30-minute blending process under vacuum.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

12 months (120 mice/sex), 18 months (120 mice/sex) and 24 months (480 mice/sex)

Frequency of treatment:

Daily consumption of food containing gentian violet

Post exposure period:

not specified

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 ppm

Remarks:

The dose represents approximately 100 mg of gentian violet/kg bw/week (females) and 75 to 100 mg of gentian violet/kg bw/week (males)

Doses / concentrations 2

Dose / conc.:

300 ppm

Remarks:

The dose represents approximately 250-275 mg of gentian violet/kg bw/week (females) and 225 to 250 mg of gentian violet/kg bw/week (males)

Doses / concentrations 3

Dose / conc.:

600 ppm

Remarks:

The dose represents approximately 500 mg of gentian violet/kg bw/week (females) and 450 to 475 mg of gentian violet/kg bw/week (males)

No. of animals per sex per dose:

Both sexes of mice received all 4 doses (120 males, 120 females)

Control animals:

yes

Positive control:

not specified

Examinations

Observations and examinations performed and frequency:

not specified

Sacrifice and pathology:

not specified

Statistics:

Yes but the method is not specified

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

mortality observed, treatment-related

Description (incidence):

A dose effect was noted for mortality rates. For controls, mortality of both sexes was less than 15% at 24 months but was approximately 28%, 27% and 64% in females in the 100, 300 and 600 ppm dose groups, respectively. For males, mortality was 14%, 20% and 23% in the 100, 300 and 600 ppm dose levels, respectively. Females appeared to be more susceptible than males.

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

In males at 24 months and in females at 18 and 24 months at the 300 and 600 ppm dose levels, respectively, liver neoplasms were observed.
In female mice, erythropoiesis in the spleen, atrophy of the ovaries, adenoma of the Harderian gland, and the presence of type A reticulum cell sarcomas in the urinary bladder, uterus ovaries and vagina were seen.

Relevance of carcinogenic effects / potential:

A positive dose response for hepatocellular carcinoma was noted in males at 24 months and in females at 18 and 24 months at the 300 to 600 ppm doses. There were statistically significant positive trends with respect to dose and (1) mortality due to liver neoplasms, (2) prevalence of liver neoplasms, and (3) time to onset of liver neoplasms in both males and females.
The estimation of risk of 10(-6) over background for malignant liver neoplasms using linear extrapolations showed a lower bound on the virtually safe dose (VSD) to be 2 ppb for the female mice and 1 ppb for the male mice. For benign and malignant liver tumors together, the lower bound on the VSD was essentially the same as for malignant liver neoplasm alone.
The authors concluded that gentian violet appeared to be a carcinogen in mice at several different sites.

Effect levels

Dose descriptor:

LOAEL

Effect level:

ca. 100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

mortality

Target system / organ toxicity

1

Critical effects observed:

yes

Lowest effective dose / conc.:

300 ppm

System:

hepatobiliary

Organ:

liver

spleen

Treatment related:

yes

Dose response relationship:

not specified

2

Critical effects observed:

yes

Lowest effective dose / conc.:

300 ppm

System:

female reproductive system

Organ:

ovary

uterus

vagina

Treatment related:

yes

Dose response relationship:

not specified

3

Critical effects observed:

yes

Lowest effective dose / conc.:

300 ppm

System:

eye

Organ:

other: Harderian gland

Treatment related:

yes

Dose response relationship:

not specified

4

Critical effects observed:

yes

Lowest effective dose / conc.:

300 ppm

System:

urinary

Organ:

bladder

Treatment related:

yes

Dose response relationship:

not specified

Applicant's summary and conclusion

Conclusions:

Based on the different effects observed when gentian violet was administered to mice at doses up to 600 ppm, the authors concluded that the substance appeared to be a carcinogen in mice at several different sites, especially the liver.
(Littlefield et al, 1985)