Acute and subchronic toxicity studies of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™) in rats

The potential use of pyrroloquinoline quinone disodium salt (BioPQQ™), as a supplemental food ingredient, was evaluated in a range of oral toxicity studies in rats including an acute study, a 14-day preliminary and a 28-day repeated-dose study, and a 13-week subchronic study. The median lethal dose of BioPQQ™ was shown to be 1000-2000 mg/kg body weight (bw) in male and 500-1000 mg/kg bw in female rats. In the 14-day study, high doses of BioPQQ™ resulted in increases in relative kidney weights with associated histopathology in female rats only, while a follow-up 28-day study in female animals resulted in increases in urinary protein and crystals. These findings were reversible, and resolved during the recovery period. In the 13-week study, a number of clinical chemistry findings and histopathological changes were noted, which were deemed to be of no toxicological significance, as the levels were within the historical control range, were not dose-dependent, occurred at a similar frequency in control groups, or only occurred in the control group. Based on these findings, a no-observed-adverse-effect level of 100 mg/kg bw/day was determined for BioPQQ™ in rats, the highest dose tested in the 13-week study.