Extraction, Purification And Antioxidant Activity Of Three Kind Of Polysaccharides From Apostichopus Japonicus

Sea cucumber is a kind of traditional effective tonic. Polysaccharides extracted from perisome, alimentary tract and ovum of Apostichopus japonicus were studied in this paper as well as the optimum extraction conditions. Apostichopus japonicus perisome polysaccharide (SPP), Apostichopus japonicus alimentary tract polysaccharide (SAP), Apostichopus japonicus ovum polysaccharide (SOP) were gained after purification which was followed by the reach of their physical-chemical properties, molecular structure, chemical modification and antioxidant activity.1. Extraction of polysaccharidesPapain was used to get crude polysaccharide with the consideration of time, temperature and concentration, and phenol-sulphuric acid method was used to evaluate the yield. The optimal conditions for hydrolysis of enzyme: SPP: concentration 16000U/g, temperature 70℃, time 9h, yield 8.91‰; SAP: concentration 10⁴00U/g, temperature 55℃, time 6h, yield 8.11‰; SOP: concentration 14000U/g, temperature 55℃, time 10h, yield 11.13‰.2. Purification and analysis of polysaccharidesIn order to remove free protein and binding protein, the rude polysaccharides were purified by TCA- salting-out method which was proved by UV scanning. Single component which was detected by phenol-sulphuric acid method were obtained by molecular sieve Sephacryl S-400HR. Molecular weight of SPP, SAP and SOP were 5.5×10⁴D, 2.5×10⁴D, 21×10⁴D separately. It was indicated preliminary by IR that acidic glycosaminoglycans structure was exist in the three kind of polysaccharide.3. Sulfation modification of polysaccharidesBarium chloride - gelatin turbidimetry was used to measure polysaccharide sulfate content which was 19.28%, 9.29%, 9.23% of SPP, SAP and SOP separately. Chlorosulfonic acid-pyridine method was used to esterify SAP and SOP. The esterification was proved by infrared absorption spectra and the sulfate content reached 42.43% and 24.57% separately measure by chemical method. 4. Antioxidant property research of PolysaccharidesThe scavenging·OH and O_2· ability of polysaccharides and sulfated polysaccharides were measured by spectrophotometry. It was indicated that all kinds of polysaccharides show antioxidant capacity of which has concentration dependence. Besides, SOP show very weak O_2·-scavenging capacity. The order of·OH-scavenging capacity was SSAP(SAP) = SSOP>SPP>SOP; and the order of O_2·-scavenging was SSOP>SSAP(SAP)>SPP>SOP.