Photohemolytic activity of lichen metabolites.

Irradiation of pannarin 1'-chloropannarin and antranorin with 366 nm light leads to significant hemolysis in a red cell suspension. However, their mechanism of action is different. Hemolysis induced by pannarin and 1'chloropannarin increases in the presence of oxygen, whereas hemolysis induced by atranorin is higher in nitrogen-purged solutions. The effect of free radical scavengers, and the lack of effect of D2O in the medium, suggest that the hemolysis induced by pannarin and 1'chloropannarin is not mediated by (1)O2. Both the hemolytic and photohemolytic activities of the depsidones, particularly 1'-chloropannarin, increase when the temperature increases from 21 to 37 degrees C.