The Chemical Degradation Of Defective Gracilaria Lemaneifromis Polysaccharide And The Protective Effect On Diabetic Mice

Gracilaria lemaneiformis is the main economic seaweeds in the eastern Guangdong , rich in resources. Defective Gracilaria lemaneiformis is caused due to improper handling when the asparagus harvest, has not yet been abandoned, resulting in waste of resources and environmental pollution.In this paper, defective Gracilaria lemaneiformis polysaccharide(DGLP)was degraded by free radical from ascorbic acid and hydrogen peroxide in combination to discuss the effect of polysaccharide molecular weigh t on the hypoglycemic,then the hypoglycemic activity of DGLP and its degraded products was examined.Extraction conditions of DGLP were obtained by the orthogonal design,while dry alage to water ratio of 1:80, temperature of 90℃, time of 5 hours was the optimum,the ratio of polysaccharide to dry alage was 25.9% in this condition.DGLP was degraded by free radical from ascorbic acid and hydrogen peroxide.The reaction is mainly affected by the time and concentrations of the two reagents,The results showed that degradation reaction basically completed in 2 hours.When the concentration of ascorbic acid and hydrogen peroxide was 3,5,7 and 9mmol/l,the molecular weight of degradation products were 57016,46238,18836and 14289Da.The sulfate contents of products basic had no changed. with reduce of molecular weight. The contents of 3,6-anhydro-galactose decreased a little with reduce of molecular weight. The infrared spectrum(IR) analysis showed that the mainly units composing were not changed in the degradation.The antioxidant activities of degradation products in vitro were investigated by chemical spectrometric methods.The results showed that the degradation products all have antioxidant activity,the medium molecular weigh products are more effective on antioxidant activities.The hypoglycemic effects of the degradation products and DGLP in alloxan-induced diabetic mice were examined. The results of hypoglycemic experiment showed the administration of the polysaccharide and its degraded products caused a significant decrease in blood glucose levels.in diabetic mice.Simultaneously,the polysaccharide and its degraded products caused a significant increase in activities of enzymic antioxidants and a decrease of maleic dialdehyde(MDA) in diabetic mice.The tissues were stained with hematoxylin / eosin,the results showed the tissues were repaired.