Development of Novel Apparatus for Singlet Oxygen Detection and Its Application as Biological Tool

单线态氧是一种高反应性和毒性的中间体，在许多光化学和光生物过程中起着重要作用，被认为是生物系统中介导光化学作用的主要物质。在各种光敏反应和酶促系统中，人们已经做了许多尝试来寻找单线态氧生成的证据。与已知的单线态氧检测的非特异性技术相比，直接观测1268 nm的发射已被证明是最可靠的单线态氧检测方法。我们构建了一个灵敏的锗探测器近红外发射光谱仪，扫描范围为1000 ~ 1600 nm。我们将该仪器应用于激光激发光敏染料产生的单线态氧的检测。例如，有关新型喹诺酮类药物的数据如下所示。新型喹诺酮类药物以抑制细菌DNA旋切酶为基础，具有较强的抗菌活性，已被广泛用作抗菌药物。然而，有报道称其中一些药物会引起光敏性皮肤病。我们研究了如下图所示的新喹诺酮类药物介导的活性氧（ROS）的产生，以及ROS在光毒性中的参与。采用近红外（1268 nm）发射光谱仪检测单线态氧比发射，采用NBT还原法检测超氧化物。我们定量比较了新喹诺酮类药物的ROS形成能力。由于已知新喹诺酮类药物能够与DNA相互作用，我们还研究了光动力DNA链断裂活性，可以估计新喹诺酮类药物的光毒性。本研究所研究的新型喹诺酮类药物均产生单线态氧，除SPFX外均产生超氧化物。无色或淡色化合物作为光敏剂产生活性氧的报道很少。它们还具有光动力DNA链断裂活性。主要活性物质可能是单线态氧，因为NaN对活性有强烈的抑制作用。少

Singlet oxygen, a highy reacive and toxic intermediate, plays an important role in many photochemical and photobiological processes and has been postulated to be a major species mediating photochemical action in biological systems. Many attempts have been made to find evidence of singlet oxygen generation in various photosensitized reactions and enzymatic systems. Compared with the known nonspecific techniques for the detection of singlet oxygen, direct obervation of the emission at 1268 nm has proven to be the most reliable approach for singlet oxygen detection. We have constructed a sensitive near-infrared emission spectrometer with germanium detector, which scans from 1000 nm to 1600 nm. We applied this apparatus for detection of singlet oxygen produced by laser-excited photosensitive dyes. For example, the data about new quinolones will be shown below.New quinolones have potent anti-bacterial activity based on the inhibition of bacterial DNA gyrase and have been widely used as a cu … More rative medicine. However, some of them have been reported to induce photodermatosis as side effect. We have examined 1)the production of reactive oxygen species (ROS) mediated by new quinolones shown below and 2)participation of ROS in the phototoxicity. We employed the near-infrared (1268 nm) emission spectrometer to detect singlet oxygen specific emission, and NBT reduction method to detect superoxide. We compared ROS formation ability of the new quinolones quantitatively. Since it is known that new quinolones are able to interact with DNA,we also investigated the photodynamic DNA strand breaking activity that can estimate the phototoxicity of the new quinolones. All the new quinolones investigated in this study were found to produce singlet oxygen, and they also produced superoxide except SPFX.It has been little reported that colorless or pale color compounds act as photosensitizer that produces ROS.They also had photodynamic DNA strand breaking activity. The main active species was probably singlet oxygen, because NaN,inhibited the activity strongly. Less