Potent anti-tumor promoting effects of Daucus carota oil extract in mice

Abstract

Daucus carota, commonly known as wild carrot, is an annual or biannual herb confined to temperate regions of Europe, Asia and South Africa. In view of biochemical and pharmacological actions, it was shown that the plant has significant protective effects on inflammation and gastric ulcer without being harmful to different body functions [1]. The present study investigates the chemopreventive effects of Daucus carota oil extract upon skin papilloma initiated by 7,12,dimethylbenza-anthracene (DMBA) and promoted by 12-O-tetrad-ecanoylphorbol-13-acetate (TPA). The extract was either applied topically to mouse skin at concentrations of 5, 50, 100% in acetone, or injected intraperitoneally at a concentration of 20% in saline, or given by gavage at 100% twice per week for 20 weeks, 20 minutes prior to each promotion treatment with TPA [2]. At week 20, the topically applied 100% extract delayed tumor appearance by 3-weeks, and inhibited tumor incidence and yield by 40 and 89% respectively. Topical application of 50% extract inhibited tumor incidence and yield by 30 and 83% respectively, while topical application of 5% extract inhibited tumor yield by 36%. Tumor volume was decreased by 99, 91 and 70% following topical treatments with 100, 50 and 5% oil extract respectively. Inraperitoneal treatment inhibited tumor yield by 43%, and decreased the tumor volume by 85% at week 20. Gavage treatment failed to inhibit the promotion of tumors but decreased tumor volume by 20%. The results suggest that Daucus carota oil extract has potent suppressive activity against tumor promotion in mouse skin, and can be an effective chemopreventive agent against skin cancer.