Research On The Degradation Of Several Marine Polysaccharides With Low-temperature Plasma Induced By Dielectric Barrier Discharge Technology

Compared with polysaccharides,oligosaccharides are better in the aspect of clear structure and excellent bioactivity.Considering the difficulties of obtaining oligosaccharides in nature,it is a key technology to efficiently degrade polysaccharides into oligosaccharides,which have clear structure,convenience for quality control and high recovery rate.In this study,the polysaccharides such as heparin,abalone polysaccharides and Stichopus japonicas polysaccharides were degraded by low-temperature plasma induced by dielectric barrier discharge technology,the rssults showed that different voltage,degradation time,initial concentration,electrode gap,solvent type had effect on the degradation rate of polysaccharides.Low-temperature plasma consumed only power energy but not chemical additives.Water was safely used as medium during polysaccharide degradation.It has the advantage of non-polluting,low-carbon and low-cost with market competitiveness and also solved the disadvantages of quality control and unstable activity,it can lay a foundation for the degradation of polysaccharides and have broad prospects for development.The crude polysaccharides were extracted from abalone and Stichopus japonicas by protease enzymolysis and alkali,then fractionated by a column of Sepharose CL-6B,yielding different molecular weight fractions.The influence factors of voltage,degradation time,initial concentration,electrode gap,solvent type were optimized.The degradation rate,sulfate group content of degradated polysaccharides,molecular weight,pH,structure,anticoagulant activity,anti-tumor activity had been determined.The degradation results of heparin found that,when the voltage increased from 60 to 90 V,the degradation rate gradually increased,the molecular weight of degradation products decreased,pH changed from neutral to acidic,the content of sulfate group decreased to 100?g/mg.With degradation time prolonging,the degradation rate increased,the content of sulfate group decreased.With the initial concentration increasing from 1 to 7 mg/mL,the degradation rate decreased first and then increased.With the distance of electrode gap becoming larger,the degradation rate decreased.To conclude,the optimal degradation condition of heparin was voltage of 70 V,degradation time of 7 minutes,distance of electrode gap 12 mm,initial concentration of 7 mg/mL.IR spectra of the degradation products showed that low-temperature plasma did not change the main structure of heparin but released the sulfate group,as long as controlling the degradation condition,the content was also controlled.The degradation products were derivatived by PMP,then one monosaccharide and six types of oligosaccharides had been detected by HPLC-MSn.The degradation products were ultrafiltrated into different molecular weigh.According to the result of APTT?TT?PT,we characterized the anticoagulant activity,the anticoagulant activity of same molecular weight increased with concentration increasing.The APTT,PT and TT was extended in a dosage-dependent manner.Compared with the fraction of 1?3 kDa and?10 kDa,the anticoagulant activity of molecular weight higher than 10 kDa was much better,which indicated that the higher content of sulfate group the better anticoagulant activity.The crude polysaccharides of abalone and Stichopus japonicas were fractionated by a column of Sepharose CL-6B,yielding different molecular weight fractions named AP-1?AP-2?AP-3?SP-1?SP-2.The content of total polysaccharides were 68.32%±0.84%?88.66%±1.75%?84.80%±0.63%?18.22%±0.84%?38.22%±0.56%respectively,the sulfate polysaccharides content were 14.93%±0.18%?11.18%±0.18%?11.80%±0.35%?53.68%±10.18%?24.43%±0.88%respectively.The voltage and degradation time of AP-2 and SP-2 were tested in this experiment.As for AP-2,with voltage increasing from 60 to 90 V,the degradation rate increased;When the degradation time prolonged from 1 to 7 min,the degradation rate also increased,the result showed that the degradation time also promoted the degradation.As for SP-2,with the voltage increasing from 60 to 90 and the degradation time prolonging from 3 to 9 min,the degradation rate promoted from 60%to 80%,It may be due to the reason of the macromolecular substances reducing leading to the lower voltage and shorter time.The anti-tumor activity of polysaccharides and oligosaccharides was measured by MTT at a concentration range of 10-500?g/mL,the results showed that the degradation products of AP-2 inhibited the growth of cancer cells at the concentration of 50?g/mL,with concentration increasing,it shows no anti-tumor activity.SP-2 and its degradation products did not have obvious anti-tumor activity.This experiment optimized the conditions:voltage,degradation time,initial concentration,electrode gap.The results showed that the degradation rate increased with the increasing of voltage,time and electrode gap,but decreased with initial concentration increasing.The results indicated that the low-temperature plasma induced by dielectric barrier discharge technology can be applied to the degradation of polysaccharides,which lays the foundation for the degradation of polysaccharides,and has some potential in practical application.