Effects of Quercetin on Blood Sugar and Blood Vessel Function in Type 2 Diabetes.
Condition: Diabetes Mellitus, Type 2
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Interventional
Phase: Phase 2

Summary: 
      The purpose of this study is to measure the effect of quercetin on glucose tolerance and
      postprandial endothelial function in comparison to placebo and Acarbose in participants with
      Type 2 Diabetes.

      Primary Hypothesis: We hypothesize that administration of quercetin (2g oral) prior to a 100g
      maltose tolerance test (MTT) will result in a decrease in postprandial blood glucose at 60
      minutes compared to placebo. Acarbose (100mg oral), a pharmaceutical alpha-glucosidase
      inhibitor, will serve as a positive control.

      Secondary Hypothesis: We hypothesize that administration of quercetin (2g oral) will reduce
      the Area Under the Glucose Curve (AUC) for the 2 hours following a 100g MTT compared to
      placebo. AUC is hypothesized to be comparable between quercetin and Acarbose.

      Tertiary hypothesis: We hypothesize that administration of quercetin (2g oral) prior to a
      100g MTT will result in a smaller reduction in flow mediated dilation (FMD) measured as an
      increase in Reactive Hyperemia Index (RHI) at 90 minutes compared to placebo.
    

Detailed description: 
      This is a phase II, crossover, double-blinded, controlled trial in 20 participants with type
      2 diabetes designed to measure the effect of quercetin on glucose tolerance and postprandial
      endothelial function in comparison to placebo and Acarbose. Glucose tolerance and insulin
      excursion will be measured at 0, 30, 60, and 120 minutes following a 100g maltose tolerance
      test (MTT). Each participant will blindly rotate between three single individual doses of
      placebo, quercetin (2g oral), and Acarbose (100mg oral) prior to the MTT on 3 separate
      occasions. Each participant will serve as their own control and comparison for each of the
      interventions.

      Fasting and post-MTT endothelial function will be measured by peripheral tonometry (Itamar
      EndoPAT (Peripheral Arterial Tone) 2000) and reported as reactive hyperemia index (RHI).
      EndoPAT testing will be performed prior to the fasting blood collection and then again at 90
      minutes following the MTT, during each clinical research visit.

      Exploratory data will also be collected on post-MTT increases in gamma-glutamyltransferase
      (GGT).
    

Intervention name(s): Quercetin; Acarbose; placebo
Intervention type(s): Dietary Supplement; Drug; Drug
Intervention description(s): Quercetin 250 mg capsules; oral single dose of 2000 mg; Acarbose 100 mg tablet; oral single dose of 100 mg; An oral single dose of a solid, colored empty capsule.
Other intervention name(s): Precose
Intervention MeSH terms: Acarbose; Quercetin
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: hyperglycemia; Diabetes Mellitus, Type 2; endothelial dysfunction; quercetin; Acarbose; glucose tolerance; maltose