碱提甘蔗皮多糖提取工艺、初步结构及其对α-葡萄糖苷酶的抑制作用

【目的】建立碱提甘蔗皮多糖的优化工艺,进一步探究其结构特征,并评价其对α-葡萄糖苷酶的抑制作用。【方法】采用单因素试验和响应面分析法（RSM）对碱提甘蔗皮多糖（SPAP）提取工艺进行优化,采用苯酚硫酸法测定多糖含量。SPAP经Sevag法除蛋白、AB-8除色素后进行结构表征,主要包括高效液相色谱法（HPLC）检测多糖分子量分布,气相-质谱色谱仪（GC-MS）进行单糖分析及傅里叶红外光谱仪（FT-IR）对官能团进行分析。采用4-硝基苯基-D-吡喃葡糖苷（PNPG）法测定多糖提取物对α-葡萄糖苷酶抑制作用。【结果】SPAP的最佳提取条件为提取温度37℃、氢氧化钠（NaOH）浓度5%、料液比1∶46（g·mL^-1）、提取次数4次,在此条件下SPAP得率达到10.84%。经除蛋白、色素后,SPAP含量达到86.54%,主要由阿拉伯糖、木糖、葡萄糖和半乳糖4种单糖组成,分子量为3.03×10³ kD,可能为吡喃型杂多糖,呈现α或β构型。此外,SPAP表现出良好的α-葡萄糖苷酶抑制作用,其抑制率达到78.31%。【结论】对碱提甘蔗皮多糖进行工艺优化,可有效利用原料、提高产出和效率;由HPLC、FT-IR、GC-MS等方面初步阐述了SPAP的结构特性,同时SPAP对α-葡萄糖苷酶表现出良好的抑制作用,具有一定的降糖潜力,研究结果为进一步研究SPAP的构效关系提供了理论依据。

Extraction Technology,Preliminary Structure and α-glucosidase Inhibition of Polysaccharide with Alkaline-Extracted from Sugarcane Peel

【Objective】 The objectives of this research were to establish the optimized technology, further explore the structural characteristics and evaluate α-glucosidase inhibitory effect of polysaccharide with alkaline-extracted from sugarcane peel.【Method】Single factor experiment and response surface methodology (RSM) were used to optimize the extraction process of alkali-extracted sugarcane peel polysaccharide (SPAP). The method of phenol sulfuric acid was used to determine the content of polysaccharide. After deproteinization by Sevag method and depigmentation by AB-8, the structure of SPAP was characterized. The molecular weight distribution, monosaccharide compositions and characteristic functional groups of SPAP were detected by HPLC, GC-MS and FT-IR, respectively. Finally, the method of 4-nitrophenol-2-β-D-glucopyranoside (PNPG) was used to determine the α-glucosidase inhibitory effect of polysaccharide extract. 【Result】 The optimum extraction conditions were as follows: extraction temperature 37℃, sodium hydroxide concentration 5%, ratio of material to solvent 1﹕46 (g·mL^-1), and extraction times 4 times. Under these conditions, the yield of SPAP reached 10.84%. After removing protein and pigment, the content of SPAP reached 86.54%. Furthermore, SPAP was mainly composed of arabinose, xylose, glucose and galactose, with molecular weight of 3.03×10³ kD. It might be a pyran hetero-polysaccharide with α or β configuration. In addition, SPAP showed good inhibitory effect on α-glucosidase. The inhibition rate of SPAP reached 78.31%.【Conclusion】 The process optimization of alkali-extracted of polysaccharides from sugarcane peel could effectively utilize raw materials and improve the yield and efficiency. The structural characteristics of SPAP were preliminarily described by HPLC, FT-IR and GC-MS. At the same time, SPAP showed good inhibitory effect on α-glucosidase and potential hypoglycemic activity. These results provided a theoretical basis for further study on the structure-activity relationship of SPAP.