不同提取水温对龙须菜多糖的得率、组成和免疫活性的影响

Effect of Water-Extracting Temperature on the Extraction Rate,Chemical Composition and Immune Activity of Polysaccharides From Red Seaweed Gracilariales lemaneiformis

系统研究了不同提取水温(30～100℃,温度梯度10℃,共8组)对龙须菜非胶体粗多糖的得率、多糖、蛋白、硫酸基、3,6内醚半乳糖、半乳糖含量的影响,并进一步比较了各组多糖的体外免疫活性和抗病毒能力。结果表明:不同提取水温对龙须菜非胶体粗多糖的得率影响显著(P<0.01),50℃提取水温组的粗多糖得率较高,蛋白含量较低(P<0.01),在30～50℃提取水温范围内,总糖含量显著上升;50℃水温组非胶体粗多糖的硫酸基含量显著高于40℃组,各组非胶体多糖的3,6内醚半乳糖含量在15%～20%之间,而半乳糖的含量则在30%～40%;各组非胶体多糖均表现出显著的体外免疫活性,其中50℃提取水温组的免疫活性显著高于其它各组,各组非胶体多糖均没有表现出抗疱疹病毒(HSV-Ⅰ和Ⅱ)活性。因此,综合多糖得率、生化组成及免疫活性,建议龙须菜免疫多糖的最佳提取水温为50℃。

Red seaweed Gracilariales lemaneiformis a commercially important seaweed with high nutritional and pharmic value. G. lemaneiforrn is widely cultured in the coastal area of Shangdong, Zhejiang, Fujian, Guangdong and Hainan province. Previous studies have shown that polysaecharides form G. lemaneiformis has many pharmic functions, such as antitumor, antioxidation, antivirus and antimutagenic. Then, exploration andultilization of polysaccharides form G. lemaneiform have attracted more and more attention for the reserch cylce, aquaculture and pharmacy industry. Although imcreasing temperature will facilitate the improvement of extraction rate of polysaccharide and agar production from G. lemaneiformis, high water-extracting temperature will destroy immune activity and antiviral activity of seaweed polysaccharides. Therefore, the identification of appropriate water-extracting temperature is very important for the extraction and ultilization of polysaccharides form G. lemaneiform. Up to date, no available information could be found on the optimization of water-extracting temperature for the polysaccharides extraction form G. lemaneiform. Our previous study have found that the water-extracts of G. lemaneiform has two fractios, i.e. soft-gelling fraction （SGF） and non-gelling fraction （NGF）. NGF has dramatic higher immune activity than SGF. The experiments were conducted to investigate the effects of water-extracting temperature （30-100 ℃, interval 10 ℃, 8 treatments） on the extraction rate, chemical composition and immune activity of polysaccharides of NGF from red seaweed G. lemaneiformis. The results showed that, there was significant effect for the water-extracting temperature on the extraction rate of crude NGF polysaccharides from G. lemaneiformis （P〈0.01）. The highest extraction rate and lowerest protein level of crude NGF polysaccharides were found on the 50 ℃ treatment（P〈0.01） among all treatments. From 30 ℃ to 50 ℃, the polysaccharides content of NGF increased significantly with the water-extracting temperature. The sulfate group content of 50 ℃ treatment was significantly higher than that of 40 ℃ treatment. The 3, 6-anhydrogalactopyranoseunit content ranged from 15%-20% while Galactopyranoseunit levels were 30%-40% for all treatments. Although the crude polysaccharides of NGF from all treatments had significant higher immunoactivity than that of the negative control treatment, the crude polysaccharides of NGF from 50 ℃ treatment had the highest immune activity among all treatments（P〈0.01）. However, no antiviral activity for virus of HSV-I and II was found for the crude polysaccharides of NGF from all treatmens. Therefore, these results idicates that the optimal waterextracting temperature was 50 ℃ for the extraction of immunoactivity polysaccharides of NGF from red seaweed G, lemaneiformis.