Studies On The Extraction, Purification And Antioxidant Activity Of Chondroitin Sulfate From Shark

Chondroitin sulfate (ChS), a kind of acid glycosaminoglycan with ease arthritis, hypolipidemic, anti-oxidation and anti-angiogenesis functions, is extensively present in the connective tissue of animals and used in food, medicine, cosmetics and other areas, and has broad development prospects."Sea King"---Shark is the universal fish, which is widely distributed in the Indian Ocean, Pacific and Atlantic Ocean, but the byproduct of shark cartilage from shark fin processing has not been fully utilized. Some studies has shown that shark cartilage is rich in chondroitin sulfate, although many manufacturers has began to produce shark chondroitin sulfate, but the complex extraction process, time-consuming, high-cost, unstable product quality and low yield problems also remain. Therefore, it's urgent to optimize extraction process of shark chondroitin sulfate to improve product yield and purity, in order to improve the added value of shark industry. In this study, chondroitin sulfate was isolated and purified from shark cartilage, and its properties and anti-oxidation function were studied. The research contents include following aspects:1. The extracting process of chondroitin sulfate from shark cartilage was optimized.ChS was extracted from shark cartilage with dilute alkali-enzymatic solution. Single-factor experiments and response surface analysis were used to optimize the alkali extraction process. The factor of alkali extraction temperature on the yeild of ChS was significant, followed by alkali concentration. The optimal conditions of alkali extraction were as follows: alkali concentration 4%, extraction temperature 35℃, extraction time 3h. Under this optimal conditions, the extraction rate and purity of ChS were up to 14.50% and 86.01%, respectively.2. The chondroitin sulfate from shark cartilage was purified, analyzed and identified.Crude ChS from shark cartilage were purified by Q-Sepharose FF ion-exchange column, then analyzed by UV spectra, IR spectroscopy and nuclear magnetic resonance.The results showed that Q-Sepharose FF ion-exchange column could effectivly purify the crude ChS from shark cartilage. After purified by ion-exchange column, ChS had no protein and nucleic acid left and its purity was shown to be on a single elution peak. The yeild, purity and molecular weight of ChS were up to 91%, 99.82% and 44771, respectively. Moreover, the product was confirmed mainly to be 6-ChS by structural analysis of IR and NMR.3.The antioxidant function of shark chondroitin sulfate and its degraded products were determined.ChS from shark cartilage were degraded by the reaction system of ascorbate and hydrogen peroxide. Compared the antioxidant capacity of crude ChS, purified ChS and degraded ChS with different molecular weight, the results showed that ChS has good anti-oxidation activity. Impurities in the crude ChS affected their antioxidant capacity, and the scavenging ability of crude ChS on DPPH·,OH·were better than the purified ChS , but the reducing power on Fe3+ is just opposite. Moreover, the antioxidant capacity of degraded ChS were relevant to their molecular weight, lower the molecular weight of degraded ChS, better the antioxidant capacity.