Study On Isolation Of The Phenolic Compounds From Rhizomes Of Ginger

Gingerol and shogaol are the main active constituents in ginger, and have been proved to possess antitumor, antiviral, antioxidative and anti-inflammatory activities in many researches.6-gingerol and 6-shogaol have the strongest activities among the compounds. It is very interest to establish a good process to isolate and purify these compounds from ginger because of the lack of a good method.In this study, D4020 macroporous resin, high-speed countercurrent chromatography (HSCCC) and preparative HPLC were successfully used together for the separation and preparation of the main phenolic compounds in ginger. The details of the process are as follows:the ginger rhizomes extract with 95% ethanol solution was partitioned with ethyl acetate after degreasing by petroleum ether. The fraction from ethyl acetate was loaded into a D4020 macroporous resin column, and then was eluted with 25%,50% and 75% ethanol aqueous solution to get fraction A (FrA) and fraction (FrB). FrA was separated by HSCCC-D1200 using a solvent system composed of n-hexane-ethyl acetate-methanol-water (10:16:10:10, v/v/v/v) and yield two sub-fraction FrA1 and 6-gingerol (FrA2). FrA1 was further purified by preparative HPLC to yield 4-gingerol. FrB was separated by HSCCC-D1200 using a solvent system composed of n-hexane-ethyl acetate-methanol- water (12:10:15:10, v/v/v/v) and yield three sub-fraction FrB1,6- shogaol (FrB2) and FrB3. FrB1 and FrB3 were purified by preparative HPLC to yield 8-gingerol and 10-gingerol, respectively.Moreover, one-step flash high-speed countercurrent chromatography (FHSCCC) method for the preparation of 6-gingerol and 6-shogaol from ginger was successfully established. Two-phase solvent system was n-hexane-ethyl acetate-methanol-water. The upper phase of the mixture (12:10:10:16, v/v/v/v) was used as solid phase. The lower phase of the mixtures (12:10:10:16 and 12:10:15:10, v/v/v/v) were used as mobile phase in a gradient elution. The separation was scaled-up gradually using four different type of HSCCC instrument including HSCCC-D400, HSCCC-D1200, HSCCC-DL1200 and HSCCC-D9000. The amount of loaded sample was scaled up from mg to 10 g. The purity of each compound is over 95% and the time for separation is short enough.