Genotoxicity and carcinogenicity of herbal products

In 2012, the World Health Organization (WHO) recorded 14 million new cases of cancer and 8.2 million cancer-related deaths. Remarkably, the WHO estimates that 30 % of cancer mortalities are due to lifestyle choices and environmental factors that can and should be avoided. In line with these recommendations, this chapter discusses the genotoxicity and carcinogenicity of herbal products. Although often perceived as innocuous by the general public, many herbs harbor phytochemicals that are either directly reactive towards DNA or likely to disturb cellular homeostasis, cell cycle, and/or genome maintenance mechanisms; this may translate into genotoxicity, carcinogenicity, or co-carcinogenicity. Genotoxicity refers to the deleterious effect of a chemical compound or a physical event on the genetic material; such genotoxic events are considered hallmarks of cancer risk. Nevertheless, much of the damage to the genetic material can be efficiently bypassed and/or repaired by the numerous genome maintenance mechanisms of the cell and may not lead to cancer. The long-term safety evaluation is probably better investigated through carcinogenicity, which denotes the capacity of a chemical substance or a mixture of chemical substances to induce cancer or increase its incidence. The major mechanisms of carcinogenicity are discussed along with biomarkers and approved regulatory guidelines. The recent development of innovative carcinogenicity testing strategies, especially based on functional genomics, are debated and evaluated for possible application to the precocious evaluation of herbal products’ long-term safety. Finally, this chapter provides some examples of proven or suspected carcinogenic herbal products reported in the current literature.SCOPUS: ch.b