Hello Rohan.

Rutin is under the classification of polar substance. It is a type of phenolic compound. It is best dissolved in the ethanol. When you are performing the standard rutin calibration curve, use  ethanol alone as a blank.

Patented Aug. 29, 1950 UNITED STATES PATENT OFFICE METHOD OF PURIFYI NG RUTIN James E. Couch, Glenside, and J'oseph Naghski and William L. Porter, Philadelphia, Pa., assigncrs to the United States of America asr'epresented by the Secretary of Agriculture- No Drawing; Application October 31, 19437,. Serial No. 783,427

5 Claims.

This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described, if patented, may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.

This invention relates to the separation of rutin from mixtures of it and impurities, in particular where the impurity is quercetin, and has among its objects the provision of a method for separating rutin from the impurity with a high yield of substantially pure rutin.

Rutin, a glucoside of the flavonol group, which possesses valuable therapeutic properties, occurs in a wide variety of plants and can be isolated from the plant material by solvent extraction according to known processes. Rutin is readily degraded on hydrolysis to the corresponding aglucon, quercetin, and the preparation of rutin according to the usual processes sometimes yields products containing a relatively large amount of quercetin. Such products cannot be offered for sale as medicinal grade rutin, and heretofore no suitable method has been available for separating rutin from the quercetin.

In general, according to the present invention, rutin is separated from a mixture of it with quercetin by dissolving the mixture in a lower substantially anhydrous aliphatic alcohol to produce a rutin alcoholate, and immediately filtering the solution, if necessary to remove any alcohol insolubles. Upon standing, the rutin alcoholate, that is, rutin containing alcohol combined in molecular form, precipitates in the filtrate,

When the mixture was dissolved, the solution was I filtered and allowed to cool. After standing 24 hours, the resulting precipitate was filtered off, washed with a small amount of cold absolute alcohol, and dried at 110 C. The product so obtained, weighing 9.03 g., was found to consist of 98 percent rutin containing no trace of quercetin, and 2 percent alcohol of crystallization.

Three grams of this product was mixed with 100 ml. of cold water in which it readily dissolved. After 2 l hours, the solution was filtered from the rutin trihydrate which had separated and the precipitate was washed and dried at 110 C. The dry precipitate weighed 2.81 g. and consisted of quercetin-free rutin.

Example II 110.8 g. of rutin containing 6 percent by weight of quercetin was dissolved in 550 ml. of boiling absolute ethanol and the solution filtered. The precipitate which separated on cooling and standing was recovered by filtration.

This product was dissolved in 500 ml. of cold distilled water. The rutin hydrate precipitate formed on standing was filtered oil and dried at 110 C. to constant weight. The yield was 63.8 g. anhydrous rutin containing no trace of quercetin.

Example III 670 g. of rutin containing 1 percent quercetin was dissolved in 3500 m1. of boiling absolute ethanol and the solution was filtered and allowed to stand until no further separation of a precipitate tool: place, fter which the precipitate was filtered off.

This product was dissolved in 2 liters of distilled water. After standing overnight, the rutin hydrate was filtered off and dried at 110 C., yielding 527 g. of rutin free of quercetin.

Similar results were obtained in the procedure described in the foregoing examples using other anhydrous alcohols such as methanol, propanol or butanol in place of anhydrous ethanol. Although it is advantageous to form a concentrated alcoholic solution by dissolving the mixture of rutin and quercetin at temperatures near the boiling temperature of the solvent, solution can also be made at lower temperatures, and if necessary the alcoholic solution concentrated by evaporation to cause separation of the rutin alcoholate. The rutin alcoholate can be converted 3 to rutin trihydrate by treatment with water at any temperature up to 100 C. It is not absolutely necessary to dissolve the alcoholate in water in order to convert it to the hydrate. This may also be eflected on prolonged contact with water.

Having thus described the invention, what is claimed is:

1. In the method of separating rutin from mixtures of it and impurities, dissolving the mixture in a lower substantially anhydrous aliphatic alcohol to produce a. rutin alcoholate, and separating the formed rutin alcoholate.

2. The method of claim 1, wherein the alcohol is ethanol.

3. A method of separation of rutin from a mixture of it and quercetin comprising dissolving the mixture in a lower substantially anhydrous aliphatic alcohol to produce a rutin alcoholate, separating the rutin alcoholate and converting the rutin alcoholate to rutin hydrate by interaction with water.

4. The method of claim 3, wherein the alcohol is ethanol.

5. The method of claim 3, wherein rutin alcoholate is converted to rutin hydrate by dissolving the rutin alcoholate in cold water and allowing the rutin trihydrate to separate from the solution.

JAMES F. COUCH. JOSEPH NAGHSKI. WILLIAM L. PORTER.

' REFERENCES CITED The following references are of record in the file of this patent:

Chemical Abstracts vol. 19 (1925), pages 92-93, 2 pages.

maybe you can try 70% methanol with heating (not boiling）

Please check Chemical Book where you can find all such relevant information for solubility of most compounds that are commercially available. For example: http://www.chemicalbook.com/ChemicalProductProperty_EN_CB8153566.htm. Thus Rutin would also be soluble in water upto 125 mg/ ml and 50 g/ 100 ml in pyridine. This should help. best wishes.

Thanks to all

Hello Rohan.

Rutin is under the classification of polar substance. It is a type of phenolic compound. It is best dissolved in the ethanol. When you are performing the standard rutin calibration curve, use  ethanol alone as a blank.

Hello!

I have a similar problem. Unfortunately, I have already mixed the last available substance of rutin with 3D water, in order to be dissolved for a calibration curve. I tried to heat it at 60C. What can I do in order to dissolve the  rutin trihydrate in this water?

a) to increase the volume of water?  I saw somewhere that rutin trihydrated solubility in water is 1g/8L  and I already  have  0,0151g/30.2ml.

b)to increase the temperature, but I am afraid that the composition will be altered.

c) to follow the freeze-drying techiche in order to get the rutin in powder, but I am afraid of losing enought quantity of rutin compound, as the water which is inside of it will be evaporated too.

If there is something else to suggest please tell me.

Thank you, 

Christiana

I tried to use DMSO to dissolve rutin but the solubility issue is still there. My research involves cell work so i cannot use higher concentration of DMSO. Can anyone help me with this issue? I tried to use methanol as well.I will be doing some in vitro assays and try to work with DMSO and then dilute it with the tris buffer. 

Thank You,

Pari

You can use ethanol to dissolve rutin.

I too encountered same issue when i am trying to dissolve Rutin in methanol as well ethanol , poor solubility occurs , may be degraded on hydrolysis to the corresponding aglucon, quercetin....but i purchased from well reputed supplier from Mumbai.( Analytical grade for analysis) ...with safe pack.... but the pack has been repeated opened and used for some other experiments time and now it is more than 6 months period old ====due to this flavanoid estimation on green tea products test sample showing almost double the value when compared any published articles.....

is there any way to justify the report by addition of analytical support..... i mean by purity test comparison with another std and by cross correlation...

please provide me any suggestions....almost many brands of commercial green tea we estimated and worked more than one month behind this work.... when ever i communicate this work for publication reviewer comments is % of flavonoids content is more - justification ...

according to this paper Solubilities of rutin in eight solvents at T = 283.15, 298.15, 313.15, 323.15, and 333.15 K Junqing Zi b, Bin Peng a, Weidong Yan a,∗

Rutin is freely soluable in ethanol and this is expected from the structure of rutine as a Quercetin rutinoside .

Thank you very much Biswapriya Biswavas Misra. The site is really helpful.

it dissolved in the ethanol