Application of protoberberine alkaloid, berberine, an immunosuppressive agent

A process for preparing an oral formulation of berberine comprising:

• a) mixing phosphatidylglycerol, phosphatidylcholine and cholesterol in a molar ratio of 1:4:5 in chloroform;
• b) drying the mixture under reduced pressure;
• c) redissolving in chloroform/diethylether at a concentration of 20-80 .mu.M lipid/ml;
• d) adding 10-1000 .mu.g of berberine to the solution of step c);
• e) removing organic phase by evaporation under reduced pressure to form lipid vesicles containing berberine;
• f) soaking the lipid vesicles containing berberine;
• and
• g) removing free berberine and residual organic solvent.

In a method for isolating berberine wherein:

• dried ground stems and/or roots of Berberis aristata or Coccinia fenestratum are soaked in water or a dilute aqueous solution of an acid for 24-72 hours at room temperature;
• the soaked ground stems and/or roots are then filtered and extracted at least two times with an organic solvent at a ratio in the range of 1:5 to 1:100 of filtrate to organic solvent;
• the organic solvent phase is separated, dried and washed with diethylether for a minimum of 30 minutes at least two times to obtain berberine;
• the improvement comprising using dichloromethane as the organic solvent.