Study On Structure Characteristics And Antitumor Activity Of Polysaccharides From Gracilaria Lemaneiformis

Gracilaria lemaneiformis were collected on the seaside of Qingdao. The extraction technology of polysaccharides from Gracilaria lemaneiformis was optimized. Then two polysaccharides from wild tetrasporophytic and female gametic thalli of Gracilaria lemaneiformis (denoted as TP and FGP respectively) were extracted and their chemical compositions, molecular weight and structure characteristics were studied. Degraded products with different molecular weight were prepared and their in vitro ant-tumor activities were studied.The orthogonal test was employed to test the effects of four factors including folds of water, temperature of extraction, time of extraction and times of extraction on the yield and total carbohydrate contents of polysaccharides from Gracilaria lemaneiformis. The results show that temperature of extraction and times of extraction have significant effects on the extraction yield of polysaccharides, four factors have no effect on total carbohydrate contents of polysaccharides. The optimum extraction technology of water-soluble polysaccharides were determined as follows: polysaccharides were extracted twice at 120℃with 30 folds of water for 1 h.TP and FGP were extracted with hot water. Their chemical compositions were determined by colorimetric methods and Gas chromatography; the viscosity average molecular weights were calculated from the intrinsic viscosity using the Mark-Houwink equation for agarose; their structure characteristics were determined by means of infrared spectrum analysis and 13C-NMR spectroscopy. The results show that the main monosaccharides of TP and FGP were galactose and 3,6-anhydrogalactose, the sulfate content of FGP was higher than TP and the 3,6-anhydrogalactose content of FGP was lower then TP. The viscosity average molecular weight of TP and FGP was 83400 and 130575 respectively. The structure analysis showed that their structures were similar. Both had the main repeating disaccharide units of (1→3)-linkedβ-D-galactose and (1→4)-linked...