Limited uptake of [14C]Gardenia Blue administered orally in male and female rats and mice.

Gardenia blue (GB), a widely used plant-derived food color is prepared by reaction of genipin, the aglycone of geniposide, with protein hydrolysate. Recent animal studies investigating GB toxicity have indicated blue coloration in the gastrointestinal tract, kidneys and mesenteric lymph nodes in rodents following dietary administration. This study investigated the uptake and disposition of [¹⁴C]GB in male and female rats and mice administered 100 or 1000 mg/kg by gavage. [¹⁴C]GB was prepared by reaction of [2-¹⁴C]genipin with soy protein hydrolysate. Following administration in rats, ¹⁴C was eliminated primarily in feces (89-97% of administered dose), exhaled volatile organic chemical (VOC) and CO₂ traps contained no radioactivity, and urine contained 0.2-0.4 %. In bile-duct-cannulated rats (100 mg/kg [¹⁴C]GB), 0.25% of dose was recovered in bile, and in urine, 0.5%. The percent of the dose absorbed was 0.9%, based on radioactivity in urine, bile, and carcass minus digestive tract contents. The highest level of radioactivity in tissues was in kidney; however renal recovery was low, with only 0.02-0.04% of the dose recovered in kidney. Repeated dosing indicated that ¹⁴C accumulated in kidney, and was slowly removed following cessation of dosing, consistent with previous studies, in the absence of any functional or histopathological changes.