Preparation And Antioxidant Activity In Vitro Of Chondroitin Sulfate Oligosaccharides

Chondroitin Sulfate (CS), a kind of glycosaminoglycans, has been used in clinical and medicine because of the high biological activities. But its bioavailability is relatively lower due to its high molecular weight, high apparent viscosity, complex structure and selective permeability of cell membrance. The different degradation methods of CS, preliminary separation, purification methods and antioxidant activities in vitro of CS degradations were studied in this paper. It can provide a theoretical to screen and apply for carbohydrate drugs.In this paper, different degradation methods of CS were studied. It showed that the sulfate removal rate of acid degradation products reached 3.97%, and some 4, 5-unsaturated uronic acids were generated. The color of products was orange-red. While the enzyme hydrolysis condition was mild, the sulfate of enzymatic degradation products was well-preserved, and the color was milky. The vitro antioxidant experiment showed that DPPH? free radical scavenging capacity and reducing power of acid degradations were superior to the enzyme degradations. In order to effective control the degradation, enzymatic method was used in the following paper.The antioxidant activities in vitro of different molecular weight CS by preliminary separation were also studied. After dialysis (molecular weight 5000) and Sephadex G25 gel column, two low molecular weight CS were gained, which weight-average molecular weight were 4875 Da and 1326 Da, respectively. The antioxidant experiment in vitro showed that the lower molecular weight was, the stronger the activity was. At 10 mg/mL, the low molecular weight CS (1326 Da) could remove 56.22% of hydroxyl radical, higher than CS (21.54%), and the superoxide anion radical scavenging could reach 52.33%. Reducing power of low molecular weight CS (4875 Da) at 10 mg/mL was similar with that of low molecular weight CS (1326 Da) at 2 mg/mL.The purification methods of CS oligosaccharides were established. It's the first time to combine DEAE-52 cellulose chromatography with preparative electrophoresis to separate the CS oligosaccharides. Three chondroitin sulfate oligosaccharides were obtained, which have been confirmed single band by AKTA superdex peptide column and fluorescent assisted carbohydrate electrophoresis. Through HPGFC measured, the molecular weights of these three components were 521 Da, 1024 Da and 1527 Da, corresponding to the disaccharide, tetrasaccharide and hexasaccharide, respectively.Finally, the antioxidant activities in vitro of three CS oligosaccharides (the molecular weights were 521 Da, 1024 Da and 1527 Da) we got were compared. For superoxide anion radical scavenging capacity and reducing power, these three oligosaccharides all showed a definite dose relationship. As the concentration increased, the activities were greater. The activities in the both detecting methods had no significant difference. When the concentration was 4 mg/mL, the superoxide anion radical scavenging abilities of these three oligosaccharides reached the maximum, about 35%. It required higher concentration to achieve the maximal reducing power (> 10 mg/mL).