Antiproliferative activity of three lichen species belonging to the genusPeltigera

The results of antiproliferative activity against murine myeloma cells (line P3X63-Ag8.653) of water, ethanol, and methanol crude extracts of three lichen species belonging to the genus Peltigera (P. canina, P. elisabethae, and P. praetextata) are reported. Cell proliferation was evaluated by means of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test, which is commonly used to assess the activity of living cells through mitochondrial dehydrogenases. The results showed that water extracts were the most effective in reducing cell proliferation; however, 40 μl of all Peltigera extracts, irrespective of water, ethanol, or methanol, induced a consistent reduction in cell proliferation. It is suggested that this important biological activity is due to antioxidant properties, possibly linked with phenolic compounds. A possible role of quaternary ammonium compounds is also discussed.