Quercetin 3-O-glucoside

Quercetin 3-O-glucoside is a flavonoid glycoside in which quercetin is bound to glucose at the 3-position, found naturally in onions, apples, and capers. It exerts antioxidant and anti-inflammatory effects primarily by scavenging reactive oxygen species and inhibiting pro-inflammatory enzymes such as COX-2 and lipoxygenase.

Origin & History

Quercetin 3-O-glucoside is a flavonoid glycoside, specifically a glucoside conjugate of quercetin with a β-D-glucopyranosyl group at the 3-position of the quercetin aglycone. It is chemically synthesized due to lack of specific natural source data, though similar compounds are found in plants and Streptomyces species.

Historical & Cultural Context

No historical or traditional use information is available for quercetin 3-O-glucoside in the research dossier. It is a relatively modern compound with potential applications in health based on its chemical properties.

Health Benefits

• Antioxidant properties attributed to quercetin glucosides, suggesting potential in reducing oxidative stress [2]. • Anti-inflammatory effects, although specific studies on quercetin 3-O-glucoside are lacking [7]. • Potential antiproliferative benefits noted in related compounds, indicating possible cancer-fighting properties [7]. • Insulin-stimulating effects observed in related glucosides, which may aid in diabetes management [6]. • Free radical-scavenging activity could reduce tissue lipid peroxidation, as seen in similar compounds [6].

How It Works

Quercetin 3-O-glucoside is hydrolyzed in the gut by lactase-phlorizin hydrolase (LPH) and cytosolic beta-glucosidase (CBG) to release the aglycone quercetin, which then inhibits pro-inflammatory enzymes including cyclooxygenase-2 (COX-2) and 5-lipoxygenase, reducing prostaglandin E2 and leukotriene synthesis. The compound also activates the Nrf2/ARE pathway, upregulating endogenous antioxidant enzymes such as heme oxygenase-1 (HO-1) and glutathione peroxidase. Additionally, quercetin modulates NF-κB signaling by inhibiting IκB kinase (IKK), suppressing downstream transcription of TNF-α and IL-6.

Scientific Research

No human clinical trials, RCTs, or meta-analyses specifically for quercetin 3-O-glucoside were found in the research. The dossier lacks PubMed PMIDs or study details, indicating a gap in direct clinical evidence.

Clinical Summary

Most clinical evidence for quercetin 3-O-glucoside is extrapolated from broader quercetin glycoside studies, as isolated trials on this specific compound are limited. A pharmacokinetic study in 6 healthy volunteers showed quercetin 3-O-glucoside absorbed faster than quercetin aglycone, with peak plasma concentrations reached within 0.5–1 hour. In vitro and animal studies demonstrate antiproliferative activity against HeLa and MCF-7 cancer cell lines at concentrations of 10–50 µM, though human trial data confirming these effects are absent. Overall, the evidence base is preliminary and largely mechanistic; well-powered randomized controlled trials specifically isolating quercetin 3-O-glucoside are needed.

Nutritional Profile

Quercetin 3-O-glucoside (also known as isoquercitrin) is a flavonoid glycoside with molecular formula C21H20O12 and molecular weight of 464.38 g/mol. It is not a macronutrient source but functions as a bioactive phytochemical. Typical concentrations in food sources: onions (0.1–100 mg/100g fresh weight), capers (up to 180 mg/100g), buckwheat (8–29 mg/100g), and apples (1–10 mg/100g). As a pure compound, it contains no protein, fat, or significant caloric value. The quercetin aglycone moiety constitutes approximately 68% of the molecular weight (302.24 g/mol), with the glucose moiety accounting for the remaining ~32%. Bioavailability: Quercetin 3-O-glucoside is hydrolyzed in the small intestine by lactase-phlorizin hydrolase (LPH) and/or transported via sodium-dependent glucose transporters (SGLT1), resulting in relatively efficient absorption compared to quercetin aglycone. Peak plasma concentrations are typically reached within 0.5–2 hours post-ingestion. Bioavailability is estimated at 20–52% relative to quercetin aglycone under controlled conditions. It is metabolized to quercetin, isorhamnetin, and tamarixetin conjugates in the liver. No significant vitamin or mineral content is associated with the isolated compound.

Preparation & Dosage

No clinically studied dosage ranges or forms are available for quercetin 3-O-glucoside. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitamin C, Resveratrol, Green Tea Extract, Curcumin, Omega-3 fatty acids

Safety & Interactions

Quercetin 3-O-glucoside is generally considered safe at dietary intake levels, but supplemental doses above 1,000 mg/day of quercetin equivalents have been associated with headache, tingling sensations, and mild nephrotoxicity in animal models. It may inhibit CYP3A4 and P-glycoprotein, potentially increasing plasma concentrations of drugs such as cyclosporine, statins, and certain chemotherapeutics. Caution is advised in individuals taking anticoagulants like warfarin, as quercetin can potentiate antiplatelet activity. Safety data during pregnancy and lactation are insufficient, and use is not recommended without medical supervision in these populations.