不同醇沉米糠多糖的体外抗氧化和降血糖活性研究

Antioxidant and Hypoglycemic Activities in vitro of Rice Bran Polysaccharides with Different Ethanol Precipitation Treatment

为分离纯化米糠粗多糖(RBP),提高其纯度及生物活性,对RBP进行分级醇沉,得到RBP-40、RBP-60、RBP-80、RBP-80S四组醇沉RBP,并将其与RBP对比进行理化性质、抗氧化活性、降血糖活性分析。结果表明:RBP-80S的总糖、可溶性蛋白质、糖醛酸含量均显著高于其他各组多糖(P<0.05);5组多糖的抗氧化活性和降血糖活性均随多糖纯度的提高而增强,RBP-80S对1,1-二苯基-2-苦肼基自由基(DPPH·)、羟基自由基(·OH)、超氧阴离子自由基(O_(2)^(-)·)的清除率,总抗氧化活性和Fe^(2+)还原力均最高;RBP-80S对α-葡萄糖苷酶和α-淀粉酶的抑制率最高可达90.69%和74.56%,且显著优于其他4组多糖(P<0.05)。以上结果说明,分级醇沉可提高RBP的纯度,从而提高其体外抗氧化和降血糖活性,为提高米糠粗多糖价值提供了新途径。

To isolate and purify rice bran crude polysaccharide(RBP) and improve its purity and biological activity,the RBP was precipitated by graded alcohol precipitation and four groups of ethanol precipitated RBP including RBP-40、RBP-60、RBP-80、RBP-80S were obtained,and the physical-chemical properties,antioxidant and hypoglycemic activities were analyzed and compared with RBP.The results indicated that,the contents of polysaccharide,soluble protein and uronic acid in RBP-80S group was significantly higher than that in other RBP groups(P<0.05).The antioxidant activity and hypoglycemic activity of 5 groups of polysaccharide increased with the increase of polysaccharide purity.RBP-80S had the highest scavenging rate of DPPH·,·OH and O_(2)^(-)· radicals,total antioxidant activity and Fe^(2+)reducing power.The inhibition rate of RBP-80S on α-glucosidase and α-amylase was up to 90.69% and 74.56%,and significantly better than other four groups of polysaccharides(P<0.05).Which indicated that the graded alcohol precipitation could increase the purity of RBP,and therefore improve the antioxidant and hypoglycemic activities in vitro,and provide a new way for improving the value of rice bran crude polysaccharide.