Oligosaccharide Preparation Of Rehmannia Glutinosa And Their Bioactive Assay

Radix Rehmanniae is derived from the root of Rehmannia glutinosa Libosch. (family Scrophulariaceae). As a traditional medicine, it has been used in China for more than thousand years. So far, more than 100 constituents have been reported, with oligosaccharides as the main constituents. Recent pharmacological researches revealed that oligosaccharides of R. glutinosa (RGOS) have various bioactivities, such as hypoglycemic, hematopoietic, antitumor, and immuno-enhancing, etc. RGOS used in the previous researches was a mixture of 60% tetrasaccharide, 20%~30% trisaccharide, and some unknown substances. It is, however, unclear that which ingredient is effective in the mixture. With the processing of the root, stachyose, the highest oligosaccharide, decreases, while manninotriose increases and becomes the main component of Radix Rehmanniae Preparata. Whether the degradation of stachyose into manninotriose is related with the pharmacological conversion of the root is unknown. Therefore, it is necessary to make further investigations on RGOS. In the present thesis some researches on the preparation of purified oligosaccharides and their bioactive assays have been carried out. The results are as follows:1. The fresh roots of R. glutinosa were homogenized, and then extracted with 75% ethanol. The concentrated extracts were portioned between water and ethyl acetate. The water solution was concentrated and fractioned by macroporous resin and charcoal column chromatography. The elutes containing stachyose were further fractioned by gel chromatography and purified stachyose was obtained. Manninotriose was obtained by acidolysis and enzymolysis of stachyose. Moreover,...