Gardenia blue is not carcinogenic in the rasH2 mouse

Abstract

Gardenia blue is currently being considered as a naturally derived food colorant for use in the global marketplace. To assess its carcinogenic potential, 100 female and 100 male CByB6F1-Tg (HRAS)2Jic (rasH2) mice were allocated to four dose groups and exposed to gardenia blue in the diet for 26 weeks at dose levels of 0.0% (control), 0.5%, 2.5%, or 5.0% (corresponding to 0.0, 664.8, 3341.0, and 6623.2 mg/kg/day in male mice and 0.0, 1182.7, 5561.1, and 10,440.3 mg/kg/day in female mice, respectively). An additional group of 10 males and 10 females was administered intraperitoneal N-methyl-N-nitrosourea (MNU) as a positive control. Clinical observations, body and organ weights, clinical chemistry, hematology, and hormone analyses were performed in addition to urinalysis and histopathology. The positive control elicited expected responses specific to rasH2 mice. There were sporadic background non-dose-related findings in clinical pathology parameters and anatomic pathology common to rasH2 mice in the absence of any gardenia blue induced dose-related changes. Under these study conditions, the no-observed-adverse-effect level was 5% gardenia blue (6623.2 mg/kg/day in male mice and 10,440.3 mg/kg/day in female mice). Based on this study a high dietary level of gardenia blue was negative for carcinogenicity in the rasH2 mouse test system.