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 tryptase-positive mast cell infiltration (P < .05), and decrease of vasodilation (P ≤ .01). No differences were found in Ki-67+ proliferating cells. Conclusions: 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.
Middelkamp-Hup, M. A., Pathak, M. A., Parrado, C., Garcia-Caballero, T., Rius-Díaz, F., Fitzpatrick, T. B., & González, S. (2004). Orally administered Polypodium leucotomos extract decreases psoralen-UVA-induced phototoxicity, pigmentation, and damage of human skin. Journal of the American Academy of Dermatology, 50(1), 41–49. https://doi.org/10.1016/S0190-9622(03)02732-4