Quercetin 98%

What is Quercetin?

Quercetin is a naturally occurring flavonol — a subclass of flavonoids — widely distributed throughout the plant kingdom. It is one of the most abundant dietary antioxidants found in nature, present in a broad range of fruits, vegetables, grains, and botanical extracts. As a polyphenolic compound, quercetin has been the subject of extensive scientific research, with thousands of peer-reviewed studies documenting its biological activity and potential health benefits.

Our Quercetin 98% is a highly purified, standardized extract delivering a minimum of 98% quercetin content, making it an ideal active ingredient for premium dietary supplement and nutraceutical formulations.

Plant-Derived Sources

Quercetin is biosynthesized by a wide variety of plants as part of their natural defense mechanisms. Key dietary and botanical sources include:

• Sophora japonica (Japanese Pagoda Tree) — flower buds are among the richest commercial sources, used as the primary raw material for high-purity quercetin extraction
• Capers (Capparis spinosa) — among the highest quercetin concentrations of any food source
• Onions (Allium cepa) — particularly red and yellow varieties
• Apples — especially in the skin
• Berries — including blueberries, cranberries, and elderberries
• Kale, broccoli, and leafy greens
• Green tea (Camellia sinensis)
• Buckwheat (Fagopyrum esculentum)

For commercial supplement-grade production, quercetin is most commonly extracted and purified from Sophora japonica flower buds, yielding the high-purity standardized material suitable for B2B ingredient supply.

Key Benefits & Biological Activity

Antioxidant Activity

Quercetin is a potent free-radical scavenger with well-characterized antioxidant properties. Its polyphenolic structure — featuring multiple hydroxyl groups — enables it to neutralize reactive oxygen species (ROS) and chelate metal ions that catalyze oxidative reactions. Studies consistently demonstrate quercetin's ability to:

• Scavenge superoxide, hydroxyl, and peroxyl radicals
• Inhibit lipid peroxidation
• Upregulate endogenous antioxidant enzymes (e.g., superoxide dismutase, catalase)
• Protect cellular membranes and DNA from oxidative damage

Anti-Inflammatory Effects

Quercetin modulates multiple inflammatory signaling pathways, making it a widely studied ingredient for inflammation management. Its mechanisms include:

• Inhibition of pro-inflammatory enzymes, including cyclooxygenase (COX) and lipoxygenase (LOX)
• Downregulation of NF-κB signaling, a master regulator of inflammatory gene expression
• Reduction of pro-inflammatory cytokine production (TNF-α, IL-1β, IL-6)
• Suppression of inducible nitric oxide synthase (iNOS) activity

Antihistamine & Allergy Support

Quercetin has demonstrated natural antihistamine properties, positioning it as a functional ingredient for allergy and respiratory support formulations. Key mechanisms include:

• Inhibition of histamine release from mast cells and basophils
• Stabilization of mast cell membranes, reducing degranulation in response to allergens
• Modulation of IgE-mediated immune responses
• Reduction of pro-allergic cytokines and leukotrienes

These properties make quercetin a popular ingredient in seasonal allergy, sinus, and respiratory health supplement categories.

Cardiovascular Support

A substantial body of research supports quercetin's role in cardiovascular health. Relevant activities include:

• Inhibition of LDL oxidation, a key step in atherosclerotic plaque formation
• Improvement of endothelial function and nitric oxide bioavailability
• Mild antihypertensive effects, supported by multiple clinical trials
• Antiplatelet and antithrombotic activity
• Modulation of lipid metabolism

Immune Support

Quercetin plays a multifaceted role in immune system modulation:

• Enhances innate immune responses by activating macrophages and natural killer (NK) cells
• Exhibits broad-spectrum antiviral activity, including inhibition of viral replication and entry
• Supports zinc ionophore activity, facilitating intracellular zinc transport — relevant to antiviral defense
• Balances immune responses by modulating both pro- and anti-inflammatory pathways

Applications in Dietary Supplements & Nutraceuticals

Quercetin 98% is a versatile, high-demand ingredient across multiple nutraceutical categories. Its broad biological activity profile supports use in:

• Antioxidant & longevity formulas — standalone quercetin capsules and combination antioxidant blends
• Allergy & respiratory health products — often combined with bromelain to enhance bioavailability and synergistic effect
• Cardiovascular health supplements — heart health blends targeting blood pressure, lipid profiles, and endothelial function
• Immune support formulas — particularly in combination with vitamin C and zinc
• Sports nutrition & recovery — for its anti-inflammatory and cellular protection properties
• Healthy aging & senolytic formulations — emerging research supports quercetin's role in senescent cell clearance

The high purity (≥98%) of this grade ensures consistent potency, minimal excipient load, and suitability for clean-label formulations. It is compatible with capsule, tablet, powder sachet, and softgel delivery formats.

Why Source Quercetin 98% from Us?

As a dedicated B2B ingredient supplier, we provide quercetin that meets the rigorous quality standards demanded by supplement manufacturers and contract formulators:

• Standardized to ≥98% quercetin by HPLC
• Manufactured under GMP-certified conditions
• Full documentation available — COA, MSDS, and specification sheets on request
• Consistent batch-to-batch quality with full traceability
• Flexible packaging and order quantities to suit R&D through commercial-scale production

Quercetin 98% represents a scientifically validated, commercially proven ingredient for formulators seeking to deliver measurable health benefits to end consumers.