桦褐孔菌多糖的乙酰化修饰及其抗氧化活性

采用乙酰化修饰方法对桦褐孔菌多糖进行结构修饰,并评价其抗氧化活性,为桦褐孔菌多糖结构修饰提供新的思路和方向。以桦褐孔菌为原料,采用水提醇沉法提取桦褐孔菌多糖,过AB-8大孔吸附树脂,得纯化后的桦褐孔菌多糖。在氢氧化钠水溶液中以不同体积的乙酸酐制备乙酰化桦褐孔菌多糖,盐酸羟胺比色法测定其取代度。在此基础上,对3种不同取代度的乙酰化桦褐孔菌多糖进行抗氧化活性研究。结果表明,桦褐孔菌多糖经纯化后,通过乙酰化修饰得到三个取代度分别为0.2810、0.3136、0.4072的乙酰化产物,随着乙酰化试剂的体积增加,多糖取代度逐渐增大;三个不同取代度的乙酰化产物对DPPH自由基最大清除率分别为71.8%、74.9%、78.5%;对超氧阴离子的最大清除率分别为71.8%、74.9%、78.5%;对羟基自由基的最大清除率分别为74.5%、79.9%、81.1%。随着取代度的增加,乙酰化桦褐孔菌多糖抗氧化活性逐渐增强。桦褐孔菌多糖经乙酰化修饰后,可显著提高体外抗氧化活性,且抗氧化活性的强弱与乙酰基取代度有关。

Acetylated Modification and Antioxidant Activity of Polysaccharides from Inonotus obliquus

Acetylated modification was applied to modify the structure of polysaccharide from Inonotus obliquus,and the antioxidant activity of polysaccharides were evaluated,which was expected to provide the new ideas and directions for the structural modification of Inonotus obliquus. Inonotus obliquus was used as raw materials. Polysaccharides from Inonotus obliquus were obtained by water extraction and alcohol precipitation. Using inonotus obliquus as raw material, the polysaccharide of inonotus obliquus was extracted by water extraction method,and was purified after AB-8 macroporous adsorption resin. The polysaccharides of inonotus obliquus were prepared by acetic anhydride with different volume in sodium hydroxide aqueous solution,and the substitution degree was determined by hydroxylamine hydrochloride colorimetric method. On this basis,the antioxidant activities of three different acetylated degrees of acetylated Inonotus obliquus polysaccharides were studied. Results:After acetylation modification,three acetylated derivatives were obtained with different degrees of substitution 0.2810,0.3136,0.4072.With the increase of the volume of acetylation reagent,the degree of substitution of polysaccharides increased gradually. With the increase of substitution degree,the antioxidant activity of polysaccharides gradually enhanced. The maximum scavenging rates of DPPH were 71.8%,74.9% and 78.5% for three acetylated products with different degrees of substitution,respectively. The maximum scavenging rates of O-2 was 71.8%,74.9% and 78.5%,respectively. The maximum scavenging rates for OH- were 74.5%,79.9% and 81.1%,respectively. In conclusion,in vitro antioxidant activity of polysaccharides from Inonotus obliquus is significantly enhanced by acetylation. In addition,the strength of antioxidant activity was related to the degree of acetyl substitution.