Effect of a Nutraceutical Combination on Oxidative Stress Biomarkers in Healthy Subjects and Patients with Alzheimer's Disease.

LC-MS screening of twelve candidate compounds identified genistein, quercetin, and rutin as the most consistent inhibitors of glucose-driven BSA glycation.

• Twelve candidate compounds were screened using a BSA-glucose model with LC-MS peptide mapping to quantify lysine glycation and rank inhibitory activity.
• The screening method measured glucose-driven glycation at lysine residues on bovine serum albumin (BSA).
• The top three candidates were combined into a three-compound anti-AGE blend consisting of quercetin, rutin, and genistein.

In older healthy adults, serum MDA decreased significantly after anti-AGE blend supplementation and differed significantly from placebo.

• Serum MDA decreased after anti-AGE supplementation in older healthy adults (p < 0.001).
• Post-intervention MDA differed between the anti-AGE and placebo arms (p < 0.01).
• No significant change in MDA was observed within the placebo group (ns).
• The trial was 3 months in duration with n = 15 in the anti-AGE arm and n = 15 in the placebo arm among older healthy adults.

In the Alzheimer's disease cohort, post-intervention serum MDA was significantly lower in the anti-AGE arm than in the placebo arm, though within-arm change from baseline was not significant.

• MDA did not change significantly from baseline within either arm in the AD cohort (ns for both arms).
• Post-intervention MDA was lower in the anti-AGE group than in the placebo group (p < 0.05).
• The AD cohort consisted of n = 15 in the anti-AGE arm and n = 15 in the placebo arm.

Urinary CML (Nε-(carboxymethyl)lysine) was unchanged in older healthy adults but decreased significantly after anti-AGE supplementation in the Alzheimer's disease cohort.

• Urinary CML was unchanged in older healthy adults in both arms (ns in both arms).
• In the AD cohort, urinary CML decreased after anti-AGE supplementation (p < 0.01).
• Post-intervention urinary CML differed between the anti-AGE and placebo arms in the AD cohort (p < 0.05).
• Serum MDA and urinary CML were prespecified co-primary biomarker endpoints.

The study was a randomized, double-blind, placebo-controlled 3-month trial with a feasibility-based sample size and no formal a priori sample size calculation.

• Total participants: 60 subjects divided into older healthy adults (n = 30) and individuals with AD (n = 30).
• Within each population, participants were randomized to anti-AGE blend (n = 15) or placebo (n = 15).
• Trial duration was 3 months.
• No formal a priori sample size calculation was performed; the study size was feasibility-based.
• Statistical analysis used REML ANOVA with Tukey post hoc tests for pre/post and between-arm comparisons.

Advanced glycation end products (AGEs) and oxidative stress are implicated in Alzheimer's disease and increase with aging.

• AGEs and oxidative stress were identified as key pathological factors in aging and AD that motivated the study.
• Serum malondialdehyde (MDA) was used as a biomarker of oxidative stress.
• Urinary Nε-(carboxymethyl)lysine (CML) was used as a biomarker of glycation.

The authors conclude that larger trials with extended biomarker panels and LC-MS/MS confirmation are warranted following these findings.

• The current study was feasibility-based with no formal a priori sample size calculation.
• The authors noted that LC-MS/MS confirmation of biomarker findings in future studies is needed.
• Extended biomarker panels beyond MDA and urinary CML were recommended for future trials.