Cancer chemopreventive activity of 3,5,6,7,8,3′,4′-heptamethoxyflavone from the peel of citrus plants

Abstract Nobiletin and 3,5,6,7,8,3′,4′-heptamethoxyflavone (HPT), isolated from the peel of Citrus plants, were examined for the anti-tumor-initiating activity on two-stage carcinogenesis of mouse skin tumors induced by a nitric oxide donor, (±)-( E )-methyl-2-[( E )-hydroxyimino]-5-nitro-6-methoxy-3-hexenamide, as an initiator and 12- O -tetradecanoylphorbol-13-acetate as a promoter. HPT exhibited the remarkable anti-tumor-initiating effect on mouse skin and it suggested the possibility of HPT being a chemopreventive agent against nitric oxide (NO) carcinogenesis.