Polypodium leucotomos is a type of fern which grows in tropical and sub-tropical regions of America. It has a long history of use in traditional medicine in the Honduras, to treat a range of health problems, particularly inflammation of the skin. Its photoprotective effects have been demonstrated in animal models and humans.

¤ Cell and animal studies have shown Polypodium leucotomos to have antioxidant, anti-inflammatory and immunomodulatory effects, which explains its capacity for protecting the skin from the harmful effects of exposure to the sun’s UV rays :
• it eliminates free radicals and reactive oxygen species, particularly superoxide anion ;
• it inhibits depletion of Langerhans cells ;
• it reduces the number of cells burned by the sun. Pre-treatment of human keratinocytes before exposure to UV rays has a cytoprotective effect against radiation-induced damage and increases cell survival rates ;
• it protects DNA by inhibiting the formation of UVB-induced cyclobutane pyrimidine dimers (which cause cell cancers) ;
• it preserves the structure of cutaneous tissue by inhibiting mastocyte infiltration into the skin. (Mastocytes release chemicals in the body which cause inflammation, redness and itching.)

¤ Other research suggests that Polypodium leucotomos may be beneficial for certain skin diseases. Polypodium leucotomos extract has been used for over 30 years in Europe and Central and South America to treat psiorasis.

¤ Studies have also shown that Polypodium leucotomos extract :
• decreases the severity of sunburn, helps prevent skin aging and lowers the risk of UV-associated cancer ;
• reduces skin reactions and subjective symptoms in sufferers of idiopathic photodermatitis ;
• reduces the side-effects, and duration, of PUVA therapy in psoriasis ;
• in cell and animal studies, it inhibits the action of cytokines, immune factors present in auto-immune diseases ;
• increases repigmentation in vitiligo-sufferers treated with UVB or PUVA therapy. When given Polypodium leucotomos extract, repigmentation is twice that from PUVA therapy alone, with a more pronounced effect in pale-skinned individuals.