| abstract |
A method and a pharmaceutical composition for killing mammalian tumour cells is disclosed and entails cells being exposed to light in the presence of a photoactivatable tetrapyrrole, the improvement consisting in the fact that these cells are treated with a compound which inhibits the enzymatic conversion of protoporphyrinogen to protoporphyrin IX by protoporphyrinogen oxidase in these cells, which brings about an accumulation of protoporphyrin IX in these cells. A process for the preparation of protoporphyrin IX is also disclosed and comprises the cultivation of eukaryotic microalgae in the presence of a protoporphyringen oxidase inhibitor. |