紫菜多糖硫酸化修饰及生物活性分析

Sulfated Modification and Bioactivity Analysis of Polysaccharide from Porphyra

以紫菜为原料,采用微波辅助酶法制备紫菜多糖,浓硫酸法合成硫酸化紫菜多糖,通过单因素及正交试验对紫菜多糖硫酸化修饰工艺条件进行优化,利用傅里叶红外光谱仪鉴定修饰结果,并比较浓硫酸法与氯磺酸-吡啶法对硫酸化多糖抗氧化与降血糖活性的影响。结果表明:浓硫酸法进行硫酸化的最佳条件为料液比1:80 g/mL,紫菜多糖与硫酸铵质量比10:9 g/g,反应时间33 min,最高取代度为2.94;红外光谱指征修饰后的紫菜多糖在801、1123 cm^(-1)处有硫酸基团的特征吸收峰,硫酸基团的可能取代位置为C-6;硫酸化后的紫菜多糖对DPPH、O_(2)^(-)和OH自由基的清除作用及α-葡萄糖苷酶的抑制作用均显著高于硫酸化前(P<0.05);浓硫酸法修饰紫菜多糖的抗氧化活性及降血糖活性均显著高于氯磺酸-吡啶法(P<0.05),说明浓硫酸法更适用于紫菜多糖的硫酸化修饰。研究结果为开展食源性紫菜多糖的进一步利用提供了参考。

The polysaccharides were obtained by microwave-assisted enzymatic extraction from Porphyra,and then modified by sulphate method.Single factor and orthogonal experiments were used to optimize the sulfated modification process of polysaccharides,which were identified by Fourier transform infrared spectroscopy(FT-IR).The antioxidant and hypoglycemic activity changes of the polysaccharides modified by sulphate and chlorosulfonic acid-pyridine method were also studied.Results showed that the optimal technology parameters were the ratio of solid to liquid 1:80 g/mL,the mass ratio of Porphyra polysaccharide to ammonium sulfate 10:9 g/g,reaction time 33 min,and the maximum degree of substitution was 2.94.FT-IR showed that the characteristic absorption peaks of sulfate radical group appeared near 801 and 1123 cm^(−1),and the possible substitution position of sulfate radical group was C-6.The sulfate modification could significantly improve the scavenging ability of DPPH,O_(2)^(-)and OH free radicals and the inhibitory effect onα-glucosidase activity of the polysaccharides(P<0.05).The antioxidant and hypoglycemic activity of the polysaccharides modified by sulphate method were both higher than that by chlorosulfonic acid-pyridine method(P<0.05),indicating that sulphate method was applicable to modify the Porphyra polysaccharide.This study provides a theoretical basis for the further development of polysaccharides from Porphyra as a functional food.