that of the first eluent but higher than that of chloroform so that a first eluate resulting from elution of the first eluent and a second eluate resulting from elution of the second eluent are obtained removing the first eluent and the second eluent from the first eluate and the second eluate by evaporation respectively so that a first concentrated eluate and a second concentrated eluate are obtained as the potent extract the details disclosed in gb 2366565 are incorporated herein by reference the invention is further described by means of example but not in any limitative sense percentages and other amounts referred to in this specification are by weight unless indicated otherwise percentages are selected from any ranges used to total 100 sliced shade dried rhizomes of ginger were pulverized and screened with a sieve of mesh no 10 one part by weight of the resulting powder was mixed with 8 parts by weigh of 95 ethanol and the resulting mixture was boiled under refluxing for one hour and filtered to obtain a filtrate a and a residue the residue was mixed with 95 ethanol in a weight ratio of 1 8 and the resulting mixture was boiled under refluxing for one hour and filtered to obtain a filtrate b the filtrate a and filtrate b were combined and it was concentrated in a water bath of 70 u00b0 c and in vacuo rotavapor r 220 b u00fcchi switzerland by evaporating the solvent therefrom the resulting concentrate was introduced to a reverse phase chromatography column 7 1 cm u00d7 90 cm packed with diaion u00ae hp 20 resin mitsubishi japan in an amount of 20 times by.