TCS Industries Limited (China-sourced API supplier) supplies Quercetin — Plant Extract CAS 6151-25-3 for pharmaceutical B2B procurement — COA, MSDS, and technical documentation available on request.
> Overview
| Product Name | Quercetin |
|---|---|
| Structural Formula |  |
| CAS Number | 6151-25-3 |
| Molecular Formula | C15H14O9 |
| Molecular Weight | 338.27 g/mol |
| InChIKey | GMGIWEZSKCNYSW-UHFFFAOYSA-N |
| SMILES | Available on request where applicable |
| Appearance | Yellow to greenish-yellow crystalline powder |
| Purity / Grade | By agreed specification and batch COA |
| Storage | Keep tightly closed in a cool, dry, well-ventilated place |
Quercetin (CAS 6151-25-3 for the dihydrate; 117-39-5 for anhydrous) is a flavonoid polyphenol with the formula C₁₅H₁₀O₇ (anhydrous MW 302.24). It is an abundant dietary flavonoid, found in onions, apples, berries, tea, red wine, and capers. Quercetin is used in dietary supplements for antioxidant and immune support, and as a reference standard in flavonoid research.
TCS Industries Limited, a Hong Kong-based trading and sourcing company, supplies Quercetin in nutraceutical, food and analytical grades for global procurement programs.
> Applications
Dietary supplement for antioxidant and immune support
Quercetin has been studied extensively in nutritional research with over 5,000 published papers. Supplement formulations typically provide 500–1000 mg/day in capsule or tablet form. Quercetin is often combined with vitamin C or bromelain to enhance bioavailability. Li et al. (Nutrients, 2016, 8:167) conducted a meta-analysis of randomized controlled trials evaluating quercetin effects on blood pressure and cardiovascular risk markers.
Natural pigment and food ingredient
Quercetin and its glycosides (rutin, isoquercitrin) contribute to the yellow colour and astringent taste of foods. Enzymatically modified isoquercitrin (EMIQ) is a water-soluble quercetin derivative used in food and beverage applications. Quercetin dihydrate is the standard commercial form for supplement manufacturing. Analytical-grade anhydrous quercetin is used as a reference standard in HPLC flavonoid analysis.
> Sourcing & Supply
TCS Industries Limited supports development, qualification and commercial purchasing discussions for Quercetin with buyers in Germany, France, Italy, Spain, the United Kingdom, the United States, Canada and Australia.
- Evaluation and commercial quantities: 1 kg samples for qualification; 5 kg to 25 kg drums for production. Dihydrate and anhydrous forms, supplement and analytical grades available.
- Pallet quantities and production campaigns: repeat supply is coordinated against packaging, lead time, annual demand and destination-market import requirements.
> Quality & Documentation
Key specification parameters include assay (≥95.0% quercetin by HPLC for supplement grade, ≥98.0% for analytical grade), water content (appropriate to the form — dihydrate contains ~10.6% water), related substances (kaempferol, isorhamnetin), heavy metals (Pb, As, Cd, Hg), pesticide residues (for plant-derived material), residual solvents, and microbial limits. Identity confirmed by HPLC, UV absorption (λmax ~370 nm), and melting point. COA and MSDS are standard.
> Packaging
Quercetin is a yellow crystalline powder, stable under normal storage conditions but sensitive to strong oxidizing agents. Standard packaging includes 25 kg fibre drums with PE liner or aluminum foil bags in cartons. Store at controlled room temperature (15–25 °C) protected from light and moisture. Shelf life is typically 24 months. Labels and documents are checked before dispatch.
> Pricing & MOQ
Pricing is quoted by specification, packaging and destination. Common commercial discussions use 25 kg bag/drum formats, pallet quantities and production-campaign planning; smaller samples may be reviewed for qualified formulation teams.
> Regulatory & Compounding Context
Quercetin dihydrate is widely used in dietary supplements globally. GRAS in the US for food supplement use. In the EU, quercetin-based food supplements are on the market, though it is not explicitly listed as an authorized Novel Food ingredient — buyers should verify regulatory status for their target EU member state. Listed in the European Pharmacopoeia reference standards catalogue. Not classified as dangerous goods for transport.
> Alias Index
- IUPAC: 2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one
- CAS Number: 117-39-5 (anhydrous); 6151-25-3 (dihydrate)
- Formula: C₁₅H₁₀O₇ (anhydrous, MW 302.24); C₁₅H₁₀O₇·2H₂O (dihydrate, MW 338.27)
- Common names: Quercetin, Sophoretin, Meletin
- Related compounds: Rutin (quercetin-3-O-rutinoside, CAS 153-18-4), Isoquercitrin (quercetin-3-O-glucoside)
- InChIKey: REFJWTPEDVJJIY-UHFFFAOYSA-N
- Commercial request terms: quercetin dihydrate, flavonoid supplement, quercetin 95%, HPLC reference standard, TCS Industries Limited
> FAQ
What is the difference between quercetin anhydrous and dihydrate?
Quercetin anhydrous (CAS 117-39-5, MW 302.24) and quercetin dihydrate (CAS 6151-25-3, MW 338.27) are the same active compound in different crystal forms. Dihydrate contains 10.6% crystal water and is the standard commercial supplement form. Anhydrous is used as an analytical reference standard. Specify which form is required.
What documents are available for Quercetin orders?
COA and MSDS are standard for commercial discussions. COO, packing list, invoice and other import-support documents can be arranged according to order scope.
Do you supply Quercetin to Germany, France and Spain?
Yes. We support B2B buyers in Germany, France, Italy, Spain, the United Kingdom, the Netherlands, Poland and Switzerland, subject to route and document review.
Do you supply the United States, Canada and Australia?
Yes. We review the United States, Canada, Australia and New Zealand for project supply, import documents, packaging and logistics planning before quotation.
What is the relationship between Quercetin and Rutin?
Rutin (CAS 153-18-4) is quercetin-3-O-rutinoside — quercetin bound to the disaccharide rutinose. Rutin has lower bioavailability but higher water solubility than free quercetin. They are related but different compounds with different CAS numbers, specifications, and bioavailability profiles.
What purity grades does TCS supply?
TCS sources quercetin at ≥95.0% (supplement grade) and ≥98.0% (analytical/reference standard grade) by HPLC. Both dihydrate and anhydrous forms are available. Specify the target purity, hydration form, and application at inquiry.
Can you arrange samples before commercial purchasing?
Samples or evaluation quantities may be reviewed for qualified buyers after target specification, application and destination-market requirements are clarified.
How is Quercetin packaged for export?
Packaging is confirmed by quantity and material properties. Typical options include foil bags, HDPE containers, fibre drums, 25 kg bags or palletized export packaging.
Can buyer-defined specifications be reviewed?
Yes. Send the specification, methods, impurity limits and required documents. TCS can review feasibility before confirming quotation and lead time.
What payment terms are normally used?
Standard payment is 100% T/T before dispatch unless a different arrangement has been approved for an established commercial account.
What lead time should buyers expect?
Lead time depends on stock, batch size, document scope and destination. Available stock can move faster; made-to-order or pallet programs require longer planning.
Is Quercetin bioavailable?
Free quercetin has limited oral bioavailability due to poor water solubility and extensive first-pass metabolism. Formulation strategies to improve bioavailability include co-administration with vitamin C or bromelain, phytosome complexes, and use of enzymatically modified isoquercitrin (EMIQ). Specify formulation requirements at inquiry.
Last reviewed: June 2026
Evaluation and research orders (≤10 kg) are shipped with COA, MSDS, and certificate of origin. Bulk commercial orders (>10 kg) qualify for volume pricing with a full technical documentation package available on request.
> Request a Quote
If your team already has a target application, estimated quantity, destination market, or documentation requirements, send those details so the commercial response can be prepared more efficiently.