Studies On Structure And Biological Activities Of Glycoconjugates From Spirulina Platensis

Spirulina Platensis is a blue-green alga growing in some African and South American lakes rich in salt. It not only is a good food source, but also contains various bio-active components, recent studies have shown that Spirulina Platensis possesses antitumor and radio-protective activities. In this dissertation, the author conducted a series of studies on Spirulina platensis polysaccharide (SPP), the following results were achieved.1 Three glycoconjugates SPPA-1, SPPB-1 and SPPC-1 were isolated from Spirulin platensis by acetone precipitation, protein removal by trichloroacetic acid (TCA), purification of the crude glycoconjugates by gel filtration and ion exchange chromatography. The homogeneity of the glycoconjugates was prved by HPLC and CE. Their physico-chemistry properties were studied.2 Gas chromatography analysis showed that SPPA-1 contained only glucose. Methylation of by Hakomori method and hydrolysis of SPPA-1 followed by NaBH₄-reduction and acetylation afforded to the sample for GC-MS analysis. Comparison of the GC-MS spectra of SPPA-1 with the standard spectra indicated that the sugar chain of SPPA-1 is composed of 1,4-linked, 1, 4, 6-linked and terminal -glucose in a ratio of 10:1:1. NMR techniques and infra-red spectra were also used to elucidate the structure of sugar chain of SPPA-1, the result showed that the three residues are all α - pyranose, the main chain is composed of 1,4-linkage with 1,6-branch on every 11 residues, the repeating- unit structure was as following:→4)-α-D-Glc_p-(1→[4)-α-D-Glc_p-(1]₉→4)-α-D- Glc_p-(1→∩ 6↑ 1∪α -D-GlC_p3 Studies on hydrolysis of SPPC-1 showed that 1.0M Sulfuric acid for 6 hours at...