Inhibitory Effects of the Aerial Parts of Epimedium koreanum on TPA-Induced Inflammation and Tumour Promotion in Two-Stage Carcinogenesis in Mouse Skin

Cancer prevention by supplements offers the most cost-effective long-term health strategy. Methanol extracts from the aerial parts of Epimedium koreanum were previously found to inhibit 12- O -tetradecanoylphorbol-13-acetate (TPA)-induced inflammatory ear oedema and tumour promotion by TPA in the two-stage mouse skin carcinogenesis model. Four prenyl flavonol glycosides ( 1 ‒ 4 ) were isolated from the active fraction of this extract, and were identified. The isolated compounds showed inhibitory activity against TPA-induced ear inflammatory ear oedema. The 50% inhibitory dose (ID 50 ) of icariin ( 1 ), epimedin A ( 2 ), epimedin B ( 3 ) and epimedin C ( 4 ) for TPA-induced inflammation ranged from 114 to 255 nmol/ear, suggesting greater potency than indomethacin (ID 50 : 908 nmol/ear), an anti-inflammatory drug. Thus, the epimedium herb may be useful in cancer prevention.