International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 2B)

For definition of Groups, see Preamble Evaluation.

VOL.: 56 (1993) (p. 115)
CAS No.: 331-39-5
Chem. Abstr. Name: 3-(3,4-Dihydroxyphenyl)-2-propenoic acid

5. Summary of Data Reported and Evaluation

5.1 Exposure data

Caffeic acid is found in many fruits, vegetables, seasonings and beverages consumed by humans, principally in conjugated forms such as chlorogenic acid.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

Caffeic acid was tested for carcinogenicity by oral administration in the diet in one study in mice and one study in rats. In mice, it produced renal-cell adenomas in females and a high incidence of renal tubular-cell hyperplasia in animals of each sex. An increase in the combined incidence of squamous-cell papillomas and carcinomas of the forestomach was seen in male mice, and a high incidence of hyperplasia of the forestomach was seen in both males and females. In rats, it produced squamous-cell papillomas and carcinomas of the forestomach in animals of each sex and a few renal-cell adenomas in males.

Oral administration of caffeic acid in combination with known carcinogens resulted in enhancing or inhibiting effects depending upon the carcinogen and the time of administration.

5.4 Other relevant data

Humans and experimental animals metabolize caffeic acid to the same metabolites and hydrolyse chlorogenic acid to caffeic acid.

Caffeic acid did not induce micronuclei in mice treated in vivo. It produced gene mutation and chromosomal aberrations in cultured rodent cells. It did not induce gene mutation in bacteria.

5.5 Evaluation

No data were available on the carcinogenicity of caffeic acid to humans.

There is sufficient evidence in experimental animals for the carcinogenicity of caffeic acid.

Overall evaluation

Caffeic acid is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.


Last updated 08/21/97

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