RÉSUMÉ
Objective To report a method for preparation of saturated oligosaccharides from al- ginate. Methods The alginate was degraded by acid hydrolysis, followed by fractionation at pH 2.85 resulting in the homopolyguluronic acids (PG) and homopolymannuronic acids (PM). The alginate-derived homopolymers were further degraded by acid hydrolysis at pH 3.8, 120 ℃ for 3 h, and at pH 4, 120 ℃ for 4 h, respectively. The resulted acidic hydrolysates were separated by gel permeation chromatography to get oligosaccharide fractions, and the oligosaccharides were obtaind by repeated purification on gel chromatography. The structures of the oligosaccharides were characterized by analyses of infra-red spectroscopy (IR), nuclear magnetic resonance spectrometry (NMR), and mass spectrometry (MS). Results It was showed that the derived oligosaccharides were in saturated structures with the same structure characteristics as the original alginate macromolecule. Conclusion The method des cribed in this paper is a effective and convenient approach for the preparation of low-molecular-weight oligosaccharides from alginate.
RÉSUMÉ
Objective To investigate the chemical constituents of gorgonian Muriceides collaris. Methods The compounds were isolated and purified by silica gel column,Sephadex LH-20 column chromatography and HPLC. Their chemical structures were identified by physicochemical analysis,spectroscopic analysis,and comparison with the data of literatures. Results From the CH3OH soluble extract of Muriceides collaris,nine compounds were isolated,and their structures were determined as cholesterol (1),batyl alcohol (2),benzoic acid (3),uracil (4),thymine (5),2'-deoxyuridine (6),2'-deoxythymidine (7),thymidine (8) and 2'-deoxyadenosine (9),respectively. Conclusion All compounds were obtained from the species Muriceides collaris for the first time.