酸水解制备海参皂苷Echinoside A的次级苷及苷元的方法研究

In this research we selected a classical triterpene glycoside from sea cucumber - echinoside A to investigate the hydrolysis characters of holothone triterpene glycoside by acid. Also, we investigated the preparation of rare secondary glycosides and aglycones in this paper. 2 M of trifluoroacetic acid (TFA) and 0.2 M of sulfuric acid were employed as the hydrolysis solvent. The hydrolysis products were isolated and purified by column chromatograpy, high performance liquid chromatograpy (HPLC), etc. Three aglycones and eight secondary glycosides were obtained. Their chemical structures were determined by NMR and ESIMS. Depending on their structures the hydrolysis characters were illuminated. Hydrolysis products by TFA only contained an aglycone with two -OH groups. The structure of aglycone indicated that dehydration was occurred on aglycone, and the positions of double bonds were changed. Hydrolysis products by 0.2 M of sulfated acid contained a series of secondary glycosides with 1-4 monosaccharide and aglycones with two or three -OH groups. All products did not have sulfate ester which presented in the sugar chain of original echinoside A. Half products were dehydrated on aglycone part. However, the positions of double bonds were not changed. The result will supply methods to prepare some certain secondary glycosides and aglycones. It will also support future studies on hydrolysis, digestion, metabolism and bioactivities of triterpene glycosides from sea cucumber.