Photosensitization of Trichophyton with 8-methoxypsoralen to UV-A light radiation

The photosensitization effect of 8-methoxypsoralen (8-MOP) and subsequent long-wavelength ultraviolet(UV-A) irradiation on Trichophyton mentagrophytes was examined by in vitro, semi-in vivo, and in vivo experiments. A marked fungicidal effect of 8-MOP plus UV-A (PUVA) on suspensions of fungal spores was observed in vitro as measured by loss in colony-forming ability of T. mentagrophytes. 8-MOP application or UV-A irradiation alone did not show such an ability. The antifungal effect of PUVA was also observed on the infected scales obtained from experimental and clinical dermatophytosis. The in vivo activity of PUVA treatments was also demonstrated on the lesions of experimentally induced dermatophytosis in guinea-pigs. These observations suggest possible clinical applications of photochemotherapy on superficial fungal infections.