不同纯化程度香菇柄多糖的乙酰化修饰及降血糖活性

Acetylation Modification and Hypoglycemic Activity of Lentinus edodes Stipe Polysaccharide with Different Purification Degrees

摘要:

以香菇柄为原料,采用乙酸酐法制备乙酰化香菇柄多糖,考察不同纯化程度对多糖乙酰化修饰取代度以及多糖结构特性的影响,并对多糖及其乙酰化多糖的降血糖活性进行评价。结果表明,经纯化后,香菇柄多糖及其对应乙酰化多糖纯度分别由纯化前的36.42%和41.87%提高到88.57%和81.27%,多糖得率则分别由纯化前的83.25%和48.83%显著降低到21.85%和35.42%。纯化对多糖乙酰化修饰的乙酰基取代度无显著影响,不同纯化多糖的乙酰基取代度均在0.3左右。傅里叶红外光谱表明,纯化未造成多糖结构的破坏,且多糖经乙酰化修饰后具有乙酰基的特征吸收峰。刚果红实验结果表明,经不同程度纯化后香菇柄多糖及其对应的乙酰化多糖均具有三螺旋结构,但其红移幅度随着纯化的不断进行而逐渐减小。香菇柄多糖及其乙酰化多糖对α-淀粉酶和α-葡萄糖苷酶具有剂量依赖性抑制活性,且乙酰化可显著提高多糖对α-葡萄糖苷酶的抑制活性,表明乙酰化修饰可提高多糖的降血糖活性。研究结果表明,纯化可显著提高香菇柄多糖及其对应乙酰化多糖的多糖纯度,而对多糖结构无显著影响,乙酰化修饰可进一步提高多糖的降血糖活性。

Abstract:

Taking Lentinus edodes (L. edodes) stipe as raw material, acetylated L. edodes stipe polysaccharide was prepared by acetic anhydride modification method. The effects of different purification degree on degree of acetylated substitution and structural characteristics of polysaccharides were studied, and the hypoglycemic activities of polysaccharides and acetylated polysaccharides were evaluated. The results showed that after purification, the purity of the polysaccharide extracted from L. edodes stipe and its corresponding acetylated polysaccharide increased from 36.42% and 41.87% before purification to 88.57% and 81.27%, respectively, while the yield of polysaccharide significantly decreased from 83.25% and 48.83% before purification to 21.85% and 35.42%, respectively. There was no significant effect of purification on the degree of acetylated substitution of polysaccharides, and the degree of acetylated substitution of different purified polysaccharides were about 0.3. Fourier transform infrared spectrum showed that the structure of polysaccharide was not destroyed by purification, and the characteristic absorption peak of acetyl group was found after acetylation modification. Congo red experiment showed that different purified polysaccharides and their corresponding acetylated polysaccharides had triple helix structure, but the red shift amplitude decreased with the continuous purification. Polysaccharides of L. edodes stipe and their corresponding acetylated polysaccharides had dose-dependent inhibitory activity on α-amylase and α-glucosidase, and acetylation could significantly increase the inhibitory activity of polysaccharides on α-glucosidase, indicating that acetylation modification improved the hypoglycemic activity of polysaccharides. In conclusion, purification could significantly improve the purity of polysaccharide and its corresponding acetylated polysaccharide extracted from L. edodes stipe and had no significant effect on the structure of the polysaccharide. Acetylation modification could further improve the hypoglycemic activity of polysaccharides.