Quercetagetin (QG) is a naturally occurring flavonoid found in marigold ( Tagetes erecta ). It has garnered attention for its potential to support immune health, regulate blood sugar levels, and enhance metabolism. Yet, unlike the closely related compound quercetin (QC), QG has an extra hydroxyl (-OH) group at the C-6 position of the flavonoid A-ring, whereas quercetin has only a hydrogen atom at that position, which has raised safety concerns. QG has not been thoroughly studied for long-term safety. To fill this gap, we conducted a 90-day study in rats to assess the response to repeated oral doses of QG. The QG-administered group of animals received 500, 1000, or 3000 mg/kg bw per day, and we monitored a wide range of health indicators, from body weight and food intake to blood chemistry, hormone levels, and indicators of organ health. The results were reassuring as there were no changes in the urine parameters, deaths, clinical signs, or changes in growth or eye health. Changes were non-adverse and/or of no significant toxicological concern in blood, and organ weight differences were minor and not associated with any tissue damage. Based on these findings, the No Observed Adverse Effect Level (NOAEL) was established at 3000 mg/kg bw/day, the highest dose tested. We also tested QG for mutagenicity/clastogenicity using standard genotoxic assays, including bacterial mutation tests and micronucleus assays in CHO-k1 cells (in vitro) and Swiss albino mice (in vivo). Across all systems, QG showed no evidence of mutagenicity and/or clastogenicity.
Subrahmanya et al. (Mon,) studied this question.