焦脱镁叶绿酸-a光敏助氧化生物学效应研究

Biological effects of pyropheophorbide-a as photosensitizer and prooxidant.

通过对焦脱镁叶绿酸-a紫外可见吸收、化学发光以及电子自旋共振(ESR)等特性的研究,证实焦脱镁叶绿酸-a具有良好的光敏助氧化作用,其光敏化作用沿Ⅱ型机制进行.通过光照条件下焦脱镁叶绿酸-a对Tn-5B1-4细胞存活率的测定和饲毒法对鳞翅目害虫的胃毒作用研究发现:焦脱镁叶绿酸-a在浓度为10μmol·L-1处理48 h光照30 min时细胞存活率仅为6.29%;用焦脱镁叶绿酸-a处理48 h并经紫外灯和可见光照1 h后,小菜蛾(Plutella xylostellaL.)3龄幼虫的死亡率各为60%和100%,明显高于对照组,证明焦脱镁叶绿酸-a对Tn-5B1-4细胞和鳞翅目害虫的生长有严重影响.说明焦脱镁叶绿酸-a具有极好的光敏助氧化生物活性.

UV-visible absorption, chemiluminescence and ESR （electron spin-resonance） were employed to investigate characteristics of pyropheophorbide-a. The results showed that pyropheophorbide-a was photosensitized and prooxidated as the way of model Ⅱ ; By estimating the viability of Tn-5B1-4 cells and mortality of third instar larvae of Plutella xylostella L. under illumination, it was found that pyropheophorbide-a significantly influenced on the viability of Tn-5B1-4 cells and the mortality of third instar larvae of P. xylostella L. The cell viability of Tn-5B1-4 was reduced to 6.29%, disposed with pyropheophorbide-a for 48 h with 30 min light irradiation at the concentration of 10 μmol· L^-1 . After fed with pyropheophorbide-a 48 h with irradiation of ultraviolet and sunlight for 1 h, the death rate of third instar larvae of P. xylostella L. , was 60% and 100%, respectively, significantly different with control. It was indicated that pyropheophorbide-a is an excellent photosensitizer and prooxidant in biological applications.