Immunological protection

Orally administered Polypodium leucotomos extract decreases psoralen-UVA-induced phototoxicity, pigmentation, and damage of human skin, MA Middelkamp-Hup, MA Pathak, C Parrado, T Garcia-Caballero, F Rius-Díaz, TB Fitzpatrick, S González, J Am Acad Dermatol 2004

Background: The use of psoralen-UVA (PUVA) in patients of skin phototype I to II is limited by side effects of acute phototoxicity and possible long-term carcinogenesis.

Objective: We sought to assess oral Polypodium leucotomos (PL) extract in decreasing PUVA-induced phototoxicity of human skin on a clinical and histologic level.

Methods: A total of 10 healthy patients with skin phototypes II to III were exposed to PUVA alone (using 0.6 mg/kg oral 8-methoxypsoralen) and to PUVA with 7.5 mg/kg of oral PL.

Results: Clinically, phototoxicity was always lower in PL-treated skin after 48 to 72 hours (P.005), and pigmentation was also reduced 4 months later. Histologically, PL-treated skin showed a significant numeric reduction of sunburn cells (P .05), preservation of Langerhans cells (P .01), decrease of tryptasepositive mast cell infiltration (P .05), and decrease of vasodilation (P .01). No differences were found in Ki-67 proliferating cells.

Conclusion: PL is an effective chemophotoprotector against PUVA-induced skin phototoxicity and leads to substantial benefits of skin protection against damaging effects of PUVA as evidenced by histology. (J Am Acad Dermatol 2004;50:41-9.)