Supercritical extraction of taxanes

Abstract

A method for extracting taxanes such as taxol, comprising the use of supercritical fluids.

What is claimed is:  
     
         1 . A method for extracting a taxane from a mixture containing said taxane, comprising the step of contacting the mixture with a supercritical fluid capable of solubilizing at least part of the taxane contained therein.  
     
     
         2 . The method of  claim 1 , wherein one or more taxanes selected from taxol, cephalomannine, baccatin III, 10-deacetylbaccatin III, or 10-deacetylcephalomannine are extracted.  
     
     
         3 . The method of  claim 2 , wherein taxol is extracted.  
     
     
         4 . The method of  claim 1 , wherein said mixture is a plant or plant-derived material.  
     
     
         5 . The method of  claim 4 , wherein said plant material is selected from a plant of the genus Amentotaxus, Austrotaxus, Cephalotaxus, Pseudotaxus, Taxus, or Torreya.  
     
     
         6 . The method of  claim 5 , wherein said plant material is from a tree of the Taxus genus.  
     
     
         7 . The method of  claim 6 , wherein said tree is selected from  T. brevifolia, T. baccata, T. media, T. wallichiana, T. canadensis  or  T. cuspidata.    
     
     
         8 . The method of  claim 5 , wherein said plant material includes one or more parts of the plant selected from the bark, roots, leaves or needles, branches, twigs, wood, seeds or whole seedlings.  
     
     
         9 . The method of  claim 1 , wherein said supercritical fluid includes, either alone or in admixture with each other or a modifier, nitrous oxide, ammonia, an alkane, sulfur hexafluoride, an inert gas, a haloalkane, or carbon dioxide.  
     
     
         10 . The method of  claim 9 , wherein said supercritical fluid is carbon dioxide admixed with a modifier.  
     
     
         11 . The method of  claim 10 , wherein said modifier is an organic solvent for the taxane to be extracted.  
     
     
         12 . The method of  claim 11 , wherein said modifier is an alkanol, an aromatic hydrocarbon, an ester, a chloroalkane, a ketone, propylene carbonate or acetonitrile.  
     
     
         13 . The method of  claim 12 , wherein said modifier is acetone or acetonitrile.  
     
     
         14 . The method of  claim 10 , wherein said modifier is pre-contacted with a plant or plant-derived material in liquid form and then, subsequently, the mixture so formed is contacted with supercritical carbon dioxide.  
     
     
         15 . The method of  claim 10 , wherein the pressure of the carbon dioxide employed is greater than about 72.9 atm.  
     
     
         16 . The method of  claim 15 , wherein the pressure of the carbon dioxide employed is from about 400 to about 500 atm.  
     
     
         17 . The method of  claim 10 , wherein the temperature of the carbon dioxide employed is greater than about 31.3° C.  
     
     
         18 . The method of  claim 17 , wherein the temperature of the carbon dioxide employed is from about 35° C. to about 45° C.  
     
     
         19 . The method of  claim 1 , wherein, subsequent to contact with said mixture, the supercritical fluid containing taxane is separated therefrom.  
     
     
         20 . The method of  claim 19 , wherein the supercritical fluid containing taxane is depressurized into an open chamber or into a liquid solvent for said taxane.