Usnea barbata (L.) F.H.Wigg. is a fruticose lichen widespread in coniferous forests in the temperate zone of Europe and North America. The special dual structure of lichens, the result of the symbiosis between a fungus and an alga / cyanobacteria and the specific conditions in which they live, determine the synthesis of many special organic compounds - secondary metabolites - which ensure optimal protection against disturbing physical and biological factors.
The present study aims to evaluate the cytotoxic activity of the extract of Usnea barbata (L.) F H Wigg. The cytotoxic activity was evaluated on the swimming larvae of Artemia salina L. The results was appreciated by the larvae mortality in contact with solutions of different concentrations of extract in dimethyl sulfoxide, comprised in the range 30 - 266 μg/mL; the highest mortality rate was obtained at 266 μg/mL. In conclusion, the present study shows that the extract of Usnea barbata (L.) F.H.Wigg. has cytotoxic properties; the cytotoxicity is directly proportional to the concentration of the applied extract solution.