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Product Name:Quercetin
CAS NO.:117-39-5
Molecular formula:C15H10O7
Molecular weight:302.236
Appearance:Yellow needle-like crystalline powder
EINECS NO.: 204-187-1

Quercetin Natural distribution

Quercetin is widely found in the stem bark, flowers, leaves, buds, seeds and fruits of many plants, mostly in the form of glycosides, such as rutin, quercetin, hypericin, etc. Quercetin can be obtained by acid hydrolysis. Among them, the content is higher in buckwheat stems and leaves, seabuckthorn, hawthorn and onion. Quercetin is also found in many foods, such as onions, shallots, asparagus, cabbage, mustard, green pepper, chicory, grapefruit, lettuce, hawthorn, apple, mango, plum, radish, blackcurrant, potato and spinach. In addition, it is contained in more than 100 kinds of medicinal plants (such as sophora japonica, platycladus orientalis leaves, alpinia officinalis, fandong flowers, mulberry parasites, panax notoginseng, ginkgo, elderberry, etc.).

Quercetin Preparation method

The preparation methods of quercetin include extraction and separation, acid hydrolysis, enzymatic conversion, among which enzymatic conversion is the most practical.

1. Quercetin Natural extraction and separation

Because the content of quercetin in plants is only a few thousandths to ten thousandths, and it is difficult to extract and separate, and the cost is high, it is not practical to extract quercetin directly from plants. However, when analyzing and identifying flavonoids or preparing analytical pure samples, quercetin extraction and separation technology should be used.

2. Quercetin Acid hydrolysis

Rutin (rutin) of quercetin is widely distributed in nature, and its content is high. For example, the content in Sophora japonica is more than 20%. It is feasible to extract rutin from Sophora japonica and then produce quercetin after acid hydrolysis.

The extraction methods of rutin mainly include alkali extraction and acid precipitation, organic solvent extraction and immersion, among which alkali extraction and acid precipitation are the most practical. Select 0.05% NaOH solution to boil for 20min, filter it while hot, extract it four times in the same way, and obtain the alkaline aqueous solution of rutin. Add acid to separate it out. After filtering, add acid to hydrolyze it to obtain quercetin that is insoluble in water. Filter, wash and dry it to obtain quercetin solid.

3. Quercetin Enzymatic transformation

Enzymatic hydrolysis of rutin is used to prepare quercetin monomer with less content in plants. The operation is simple and safe, the whole process is economical and applicable, the output is large, and it is suitable for industrial production. The purity of the product is more than 90%, which can meet the needs of food and clinical application. Therefore, enzymatic transformation is undoubtedly a promising preparation method.


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