Purification of cinnamoyl-C-glycoside chromone

Abstract

The present invention provides a process for purifying the cinnamoyl-C-glycoside, 8-C-β-D-[2-O-(E)-cinnamoyl]glycopyranosyl-2- [(R)-2-hydroxy]propyl-7-methoxy-5-methyl-chromone. 8- C - β - D -[ 2′ - O - ( E )- cinnamoyl]glycopyranosyl - 2 -[( S ) - 2 - hydroxy]propyl - 7 - methoxy - 5 - methylchromone, referred to herein as the “540 compound.” In one embodiment of the present invention the 540 compound is purified by extraction from a decolorizing agent with an organic solvent. The extracted product can be purified by high pressure liquid chromatography. In a second embodiment crude 540 compound, which has not been treated with a decolorizing agent, is purified by passage over neutral alumina or sephadex.

What is claimed is:  
     
       1. A method for purifying 8-C-β-D-[2-O-(E)-cinnamoyl]glycopyranosyl-2-[(R)-2-hydroxy]propyl-7-methoxy-5-methyl-chromone   8 - C - β - D -[   2 ′ - O -( E )- cinnamoyl]glycopyranosyl -   2   -[( S )-   2   - hydroxy]propyl -   7   - methoxy -   5   - methylchromone  (the “540 compound”), comprising the steps of: 
       (a) contacting a decolorizing agent, which has been obtained from the processing of a slurry of an aloe leaf extract, with an organic solvent to extract the absorbed 540 compound from the decolorizing agent into the organic solvent, thereby forming a mixture of decolorizing agent and organic solvent containing the 540 compound; and  
       (b) separating the decolorizing agent from the organic solvent to yield a solution highly enriched in compound 540.  
     
     
       2. The method of  claim 1 , further comprising the step of: 
       (c) purifying the solution obtained in step (b) by high pressure liquid chromatography (HPLC).  
     
     
       3. The method of  claim 1  wherein the aloe leaf exact is obtained from the Aloe barbadensis plant. 
     
     
       4. The method of  claim 1  wherein the aloe leaf extract is obtained from the whole leaf of the aloe plant. 
     
     
       5. The method of  claim 1  wherein the aloe leaf extract is obtained from the leaf rind of the aloe plant. 
     
     
       6. The method of  claim 1  wherein the decolorizing agent is selected from the group consisting of activated carbon or a synthetic resin. 
     
     
       7. The method of  claim 6  wherein the synthetic resin is an AMBERLITE® resin. 
     
     
       8. The method of  claim 7  wherein said AMBERLITE® resin is XAD-2. 
     
     
       9. The method of  claim 1  wherein the organic solvent is an alkyl alcohol, selected from the group consisting of methanol, ethanol or mixtures derived from ethanol or methanol. 
     
     
       10. The method of  claim 1  wherein the decolorizing agent is contacted with the organic solvent between ambient temperature and the boiling point of the organic solvent. 
     
     
       11. The method of  claim 10  wherein the decolorizing agent is contacted with the organic solvent within a temperature range of 40° C.-60° C. 
     
     
       12. The method of  claim 1  further comprising the steps of: 
       (c) concentrating the solution obtained in step (b);  
       (d) adding water to the concentrated residue to form an aqueous solution; and  
       (e) extracting the aqueous solution with an organic solvent.  
     
     
       13. The method of  claim 12  wherein the organic solvent is selected from the group consisting of butanol, ethyl acetate or methylene chloride. 
     
     
       14. A method for purifying compound 540 isolated from the aloe plant comprising the steps of: 
       (a) applying a solution of crude aloe extract to a pad of neutral alumina; and  
       (b) eluting the extract with an organic solvent.  
     
     
       15. The method of  claim 14  wherein the crude aloe extract is isolated from the leaf rind of the Aloe barbadensis plant. 
     
     
       16. The method of  claim 14  wherein the organic solvent is selected from the group consisting of methanol and ethanol. 
     
     
       17. A method for purifying compound 540 isolated from the aloe plant comprising the steps of: 
       (a) applying a solution of crude aloe extract to a Sephadex, column; and  
       (b) eluting the extract with an organic solvent.  
     
     
       18. The method of  claim 17  wherein the crude aloe extract is isolated from the leaf rind of the Aloe barbadensis plant. 
     
     
       19. The method of  claim 17  wherein the organic solvent is selected from the group consisting of methanol or ethanol.