Protective effect of isoflavone derivative against photocarcinogenesis in a mouse model.

Plant-derived isoflavones are currently receiving much attention because of their phyto-estrogenic and antioxidant activities. In this study, we describe novel photoprotective effects of one isoflavone derivative from red clover (NV07), following its application topically in Skh:HR-1 hairless mice. We found that in mice irradiated in the short-term (3 days) with minimally erythemal solar simulated UV radiation, topical lotions containing NV07 dose-responsively reduced the erythema-associated oedema, the induction of ornithine decarboxylase, and the suppression of contact hypersensitivity. In mice irradiated chronically (50 days), daily application of topical NV07-lotion reduced photocarcinogenesis significantly, and appeared to be actively protective during both the initiation phase and the later promotion phase of tumour induction.