Inhibitory Effect Of Degraded Algal Polysaccharide On Growth Of Calcium Oxalate Crystal

Eucheuma striatum sulfated polysaccharide(ESPS) and Laminaria Japonica sulfatedpolysaccharide(LPS) were degraded by H₂O₂. Compared with other methods, H₂O₂ method hadgreater advantage. Considering the experimental conditions, H₂O₂ method was chosen finally.The sulfation degree of degrading product by H₂O₂ was higher and the cost was also moderate.Viscosity-average molecular weight of polysaccharide before and after degradation and thecontents of sulfate were determined by Ubbleholde viscometry and BaCl₂-gelatin respectively.Average molecular weights of ESPS and LPS before degradation were 147, 0000 and 17, 0000respectively, the contents of sulfate were 16.5% and 5.1% respectively. Average molecularweight of degraded ESPS were 5248 and 9940 respectively under two kinds of differentdegrading conditions, and their corresponding sulfate contents were 15.0% and 14.2%respectively. Average molecular weight of degraded LPS was 9550 and its sulfate content was4.9%. Physico-chemical properties of degraded polysaccharide changed, whose viscosity greatlydecreased and water-solubility also increased due to the decrease of its molecular weight.The effects of ESPS and LPS before and after degradation on the growth of calcium oxalatecrystals were investigated using SEM, FT-IR, XRD, UV and AAS in aqueous solution. Degradedpolysaccharide showed better inhibitory efficiency of urolithiasis. Compared to undegradedESPS, the number and size of calcium oxalate monohydrate(COM) crystals induced by degradedESPS were less, and the edges and angles were much rounder and blunter. And the relativediffraction peak's intensity(I_{((?)01)/I(020)} was enhanced gradually with the increase ofpolysaccharide concentration, resulting that COM crystals were much thinner. Compared to LPS,degraded LPS could induce calcium oxalate dihydrate(COD) only at lower concentration, andthe number and size of COD decreased with the increase of the concentration of degraded LPS.In the growth process of 10 mM CaOxa crystals, the effect of LPS before and afterdegradation on the crystal phase of CaOxa had remarkable difference, the concentration ofundegraded and degraded LPS were 1.0 and 0.1 mg/mL respectively when inducing 100% CODcrystals.The purpose of this article is to prepare a kind of low molecular weight algal polysaccharidein use of rich ocean resourse including Eucheuma striatum and Laminaria Japonica etc. If thecontents of active functional groups(SO₄^2- etc.) were basically kept contant, low molecularweight algal polysaccharide showed much better inhibitory efficiency of urolithiasis than natural high molecular weight polysaccharide. Therefore, it is an important direction of selecting drug ofpreventing urolithiasis to develop low molecular weight sulfuted polysaccharide.