螺旋藻转化纳米元素硒的制备及其体外清除自由基活性的初步研究

Nano Elemental Selenium Bio-transformed from S.platensis and Scavenging Activity on Oxygen Free Radicals in vitro

研究利用高密度富硒螺旋藻(Se-SP)细胞通过生物转化制备纳米元素硒(Nano-Se)的可行性,观察Nano-Se在体外对氧自由基的清除作用。用梯度离心分选Nano-Se,原子力显微镜(AFM)、透射电镜(TEM)及X-射线能谱(EDX)联用表征纳米粒中的元素硒形态,电感耦合等离子质谱仪(ICP-MS)测定Nano-Se中的硒含量,化学发光方法检测Nano-Se在体外对超氧自由基和羟自由基的清除作用。结果发现,Nano-Se主要由元素硒构成,形态呈球形,73%的纳米粒子直径大小分布在(61±17)nm范围。Nano-Se在体外对两种氧自由基的最大清除率分别为:30.1%和27.6%,相应的EC50分别为:0.8μg/ml和2.2μg/ml。相同剂量时,Nano-Se对氧自由基的清除作用比硒代蛋氨酸(Se-Met)及Se-SP中其它含硒活性成分更强。结果提示,利用高密度Se-SP可诱导Nano-Se的大量生成,Se-SP转化的Nano-Se可能是一种新的抗氧化硒形态,其作用机制和体内生物活性有待深入研究。

Preparation of Nano elemental selenium（Nano-Se） bio-transformed from Se enriched S.platensis（Se-SP） and scavenging activity on oxygen free redicals was investigated.Nano-Se was harvested from high cells density cultures of Se-SP with total Se supplementation of 600 μg/ml in form of sodium selenite.The shape and size of Nano-Se was characterized by atomic force microscope（AFM）,transmission electron microcope（TEM） and energy-dispersive X-ray（EDX）.Se contents were detected by inductively coupled plasma mass spectrometry（ICP-MS）.The scavenging activities of Nano-Se on superoxide anions and hydroxyl radicals were detected by chemiluminescence method.The data showed that the bio-transformed Nano-Se was constructed mainly by elemental Se.A 73% fraction of Nano-Se was collected by gradient centrifugation,in which it was spherical in shape and uniform in size with average diameter of（61±17）nm.In vitro maximum scavenging rates of Nano-Se on superoxide anions and hydroxyl radicals were 30.1% and 27.6%,and the correspondence EC50 were 0.8 and 2.2 μg/ml,respectively.The scavenging activities of Nano-Se on oxygen free radicals were much higher than that of selenomethinoine and other Se containing compounds isolated from Se-SP at the same dosages.In conclusion,present results suggested that Nano-Se produced by high cells density cultures of Se-SP is a novel Se species with anti-oxidative activity in vitro.