Prenatal developmental toxicity of gardenia blue, a natural food colorant, in rats and rabbits

Gardenia blue is a colorant widely used in Asia in food and beverages. The objectives of the present studies were to evaluate the maternal and prenatal embryo-fetal developmental toxicity of gardenia blue in rats and rabbits. Sprague Dawley rats and New Zealand White rabbits were administered gardenia blue daily by oral gavage at doses of 0 (deionized water vehicle), 500, 1000 or 2000 mg/kg/day on Gestation Days 6 through 20 (rats) and 7 through 28 (rabbits). Endpoints evaluated included clinical observations, body weight, food consumption, thyroid hormones (rats), thyroid weights and histopathology (rats), gross pathologic changes, ovarian and uterine observations, fetal weight and anogenital distance (rats) and fetal morphology (external, visceral and skeletal). Treatment related maternal findings attributed to the blue/dark color of the test substance included body surface staining, and dark/blue discoloration of the kidneys, gastrointestinal track and mesenteric lymph nodes at all or most doses in the rat and/or rabbit. Slight reductions in food consumption without effects on body weight were also observed in rats at all doses and in rabbits at 2000 mg/kg/day. There were no treatment related effects on maintenance of pregnancy, postimplantation loss, litter size, fetal weight and anogenital distance, or fetal external, visceral, or skeletal malformations and variations. Based on these results, the maternal and developmental no-observed-adverse-effect level for gardenia blue in rats and rabbits was ≥2000 mg/kg/day.