银杏果多糖的物化性质及抗氧化活性研究

Physicochemical properties and Antioxidant Activity of Ginkgo biloba L. Nut

摘要:

以银杏果为原料，采用水提醇沉法提取，Sevag法除蛋白，大孔树脂法脱色制备多糖，利用紫外光谱（UV）、高效液相色谱（HPLC）、红外光谱（IR）并对多糖的结构进行了分析；通过对DPPH自由基、超氧自由基和羟基自由基的清除作用，研究银杏果多糖体外抗氧化活性；用银杏果多糖对高脂小鼠进行干预后，测定血清和肝脏中SOD、GSH-PX、MAD和CAT含量，以此评定体内抗氧化活性。结果表明，银杏果多糖中不含蛋白质和花色苷等物质，主要是由葡萄糖、半乳糖和木糖三种单糖组成，其摩尔比为2.26:19.60:4.29，是一种含有α-糖苷键的吡喃糖；银杏果多糖对DPPH自由基、超氧自由基和羟基自由基的清除效果显著，其IC50分别为0.15 mg/L、0.30 mg/L、0.47 mg/mL；体内实验显示，银杏果多糖能显著提高血清和肝脏中SOD、GSH-Px和CAT的含量、降低血清和肝脏中MDA的含量。因此可知，银杏果多糖有显著的抗氧化功能。

Abstract:

The polysaccharides extracted by water-extract and ethanol-precipitation from Ginkgo nuts were purified by Sevag method for protein removing and macroporous adsorption resin for the de-colorization. The composition of the polysaccharide was analyzed by Ultraviolet spectrum (UV), high-performance liquid chromatography (HPLC), and infrared spectra (IR). The in vitro antioxidant activities of the polysaccharide were determined by DPPH, superoxide radicals and hydroxyl radicals scavenging assays. The effect of the polysaccharide on the content of SOD, GSH-PX, MAD and CAT in the serum and liver of the hyperlipemia mice were measured to determine the antioxidant activity in vivo. It was found that the ginkgo polysaccharide consisted of 3 kinds of monosaccharide, including glucose, galactose and xylose, with the molar ratio of 2.26:19.60:4.29, in the form of pyranose containing α-glycosidic bond. The Ginkgo polysaccharide showed the significant DPPH, superoxide radicals and hydroxyl radicals scavenging activities, with IC50 values being of 0.15 mg/L, 0.30 mg/L and 0.47 mg/mL, respectively. The antioxidant in vivo showed that the ginkgo polysaccharide could evidently increase the concentrations of SOD, GSH-Px and CAT, and decrease the concentration of MDA in serum and liver.