Dietary Quercetin Reduces Plasma and Tissue Methylglyoxal and Advanced Glycation End Products in Healthy Mice Treated with Methylglyoxal

Background: Methylglyoxal (MGO), a precursor of advanced glycation end products (AGEs), has been linked to AGEs-associated diseases. Objectives: This study investigated the efficacy and mechanisms of dietary quercetin in decreasing plasma and tissue concentrations of MGO and AGEs in MGO-administered mice. Methods: Male, 6-wk-old CD-1 mice were administered AIN-93G diet and water (Con) or 0.12% MGO in water (MGO) or MGO plus 0.2% (0.20) dietary quercetin for 1 wk (n = 5) (experiment 1), and water (Con), 0.12% MGO (MGO), or MGO plus 0.1% (0.1Q), 0.2% (0.20), or 0.4% (0.4Q) dietary quercetin for 6 wk (n = 10) (experiment 2). The plasma, kidney, and liver concentrations of MGO, quercetin, and isorhamnetin and their trapping adducts with MGO were determined by LC-MS, and AGE concentrations were measured by the fluorescent method. Furthermore, the expressions of glyoxalase I/II (GLO I/II) and aldose reductase (AR), MGO detoxification enzymes, were determined by Western blot. One-factor ANOVA and post hoc Dunnett's or Tukey's test were used to analyze the data. Results: After 1 wk of treatment, the MGO concentrations in plasma (20.2%) and kidney (29.9%) in 0.20 mice were significantly lower than those in MGO mice. After 6 wk of treatment, the concentrations of MGO in the plasma (14.7-18.6%), kidney (20-20.8%), liver (15.4-18.6%), and tissue AGEs (28-36.8%) in 0.10, 0.20, and 0.40 mice were significantly lower than those in MGO mice. The plasma concentrations of quercetin, isorhamnetin, and their MGO adducts were dose-dependently increased after quercetin administration. In addition, after 6 wk of quercetin administration, the expressions of GLO I/II and AR in the liver and kidney were significantly upregulated to promote MGO detoxification compared with MGO-treated mice. Conclusions: Quercetin reduced plasma and tissue MGO concentrations and inhibited AGE formation by trapping MGO and regulating the MGO detoxification systems in MGO-administered healthy mice.

Automated summary

The study found that dietary quercetin significantly reduced MGO and AGEs concentrations in the plasma and tissues of mice, inhibiting AGE formation by trapping MGO and regulating the MGO detoxification systems.