Potent Chemopreventive/Antioxidant Activity Detected in Common Spices of the Apiaceae Family

Abstract

Spices are used worldwide, particularly in the Asian and Middle Eastern countries, and considered protective against degenerative diseases, including cancer. Here, we report the efficacy of aqueous and non-aqueous extracts of 11 Apiaceae spices for free radical-scavenging activity and to inhibit cytochrome P450s in two separate reactions involving: 1) 4-hydroxy-17ß-estradiol (4E₂), DNA, and CuCl₂ and 2) 17ß-estradiol, rat liver microsomes, cofactors, DNA and CuCl₂. Oxidative DNA adducts resulting from redox cycling of 4E₂ were analyzed by ³²P-postlabeling. Aqueous (5 mg/ml) and non-aqueous extracts (6 mg/ml) substantially inhibited (83–98%) formation of DNA adducts in the microsomal reaction. However, in nonmicrosomal reaction, only aqueous extracts showed the inhibitory activity (83–96%). Adduct inhibition was also observed at five-fold lower concentrations of aqueous extracts of cumin (60%) and caraway (90%), and 10-fold lower concentrations of carrot seeds (76%) and ajowan (90%). These results suggests the presence of 2 groups of phytochemicals: polar compounds that have free radical-scavenging activity and lipophilic compounds that selectively inhibit P450 activity associated with estrogen metabolism. Because most of these Apiaceae spices are used widely with no known toxicity, the phytochemicals from the Apiaceae spices used in foods may be potentially protective against estrogen-mediated breast cancer.

Funding

This work was supported from the USPHS grant CA-125152, and Agnes Brown Duggan Endowment. R.C.G. holds the Agnes Brown Duggan Chair in Oncological Research.