| In this paper the chemical composition and physiological activity of polysaccharide from Gracilaria lemaneiformis, collected from the sea area around Nan'ao Island, Shantou city, Guangdong province, were analyzed. The saccharide content of Gracilaria lemaneiformis was studied. The result showed that the contents of carbohydrate, polysaccharide and crude fiber in dry sample were 43.76%, 31.05% and 4.8%. It reveals that the deepgoing research on polysaccharide has great exploitative potential and practical siginificance.The hot water extraction of the polysaccharide was studied. The effects of processing factors such as the temperature of extraction, the time of extraction and the ratio of material-water were respectively investigated as guiding by the extraction rate of polysaccharide. The optimum conditions of extraction were obtained as follows: adding 100 times water as much as the dry alage in 90℃ for 4 hours.The polysaccharide was isolated by alcohol-precipitating and protein-depositing with trichloroacetic acid (TCA) , and further puried by DEAE-celluose column chromatography. The chemical composition of polysaccharide was analyzed. The result showed that the polysaccharide was separated into three fractions by DEAE. The average molecular weight of each fraction were estimated at 5.1kD , 52kD and 67kD. D-galactose and 3,6-anhydro-L-galactose were the basic units of polysaccharide.The scavenging activities on ·OH of Fenton reaction and ·O2- produced by pyrogallic acid were studied. The result indicated that the polysaccharide had a rather strong activitiy of scavenging free radical with the maximal scavenging activity on ·OH as 72.1 %, and 71.4% on ·O2-. The scavenging ratio of the crude polysaccharide could be as high as 82.7% on ·OH.The inhibitory effect was studied on mouse bone marrow micronucleus and abnormal sperm induced by cyclophosphamide (CP). It showed that at the dose of 4 g·kg-1, the inhibitory ratio of micronucleus was 89.8%, and the polysaccharide could significantly inhibit the aberrance of sperm.The antitumor experiments indicated that the polysaccharide could significantly inhibit the... |
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