硒化枯草芽孢杆菌肽聚糖的结构表征及体外抗氧化活性研究

Structural characterization and antioxidant activity in vitro of selenized Bacillus subtilis peptidoglycan

为探究硒化肽聚糖(Se-PG)的结构与抗氧化能力,以枯草芽孢杆菌(Bacillus subtilis)胞壁肽聚糖(PG)和亚硒酸钠为原料,利用HNO_(3)-Na_(2)SeO_(3)法对PG进行硒化修饰,制备Se-PG复合物。通过紫外光谱、傅里叶红外光谱及核磁共振研究Se-PG结构特征,从对DPPH、ABTS、·OH自由基的清除能力评价其体外抗氧化活性。结果表明:Se-PG的硒含量为369.32μg/g,傅里叶红外光谱在890 cm_(-1)有吸收峰,表明形成亚硒酸酯键;Se-PG对DPPH、ABTS和·OH自由基清除率具有质量浓度依赖效应,当质量浓度达到5 mg/mL时,自由基清除率分别为39.51%±0.26%、39.47%±0.98%、48.38%±1.42%,显著高于亚硒酸钠和PG(P<0.05)。结构表征表明B.subtilis PG可进行硒化修饰且不改变PG的基本结构。Se-PG具有优越的体外自由基清除能力和抗氧化活性,可作为功能性抗氧化剂进行开发。

The objective of the research was to analyze the structure of the selenizing peptidoglycan(Se-PG)and examine the antioxidant capacity.Selenizing peptidoglycan was prepared by using Bacillus subtilis peptidoglycan and HNO_(3)-Na_(2)SeO_(3).The properties of structural changes were analyzed by UV,FT-IR and NMR.Taking scavenging effects on DPPH,ABTS and·OH free radicals as indicators,the antioxidative function of raw materials and selenium-modified products were evaluated in vitro.The results showed that the selenium content was 369.32μg/g and a new absorption peak appeared at 890 cm^(-1) FT-IR spectroscopy in Se-PG,which was due to the form of selenite ester in Se-PG.Compared with the Na_(2)SeO_(3) and PG,the DPPH,ABTS and·OH scavenging rates of Se-PG were increased,showing a concentration-dependent.in the dependent manner of concentration.When the concentration reached 5 mg/mL,the radical scavenging rates were the highest,which were 39.51%±0.26%,39.47%±0.98%,and 48.38%±1.42%,respectively(P<0.05).The structural characterization showed that the PG had been successfully selenized,selenidation did not change the basic structure of PG and the Se-PG,and selenization showed an excellent ability in scavenging free radicals in vitro.Therefore,Se-PG could be used as potential antioxidants in the development of functional products.