Role of Qat Chewing and Mate Consumption in Human Oral Carcinogenesis

Oral cancer is one of the most common noncommunicable diseases worldwide. This cancer is considered one of the most frequent types of malignancies in the head and neck particularly in males. Major causes of oral cancer are tobacco in its many different forms, excessive alcohol consumption, and viral and bacterial infection, in addition to gene mutations and lifestyle factors that include oral hygiene, betel quid/shamma/Qat chewing, as well as excessive consumption of certain hot beverages, such as mate. Thus, Qat and mate consumption are considered to have an important impact on the development of human oral cancer. In this regard, it has been pointed out that raw consumption of Qat leaves makes human oral and general health liable to the effects of pesticides and insecticides, such as dichlorodiphenyltrichloroethane (DDT). In parallel, the mode of processing of mate leaves can allow its contamination with polycyclic aromatic hydrocarbons that have been found in some commercial samples. Thus, methods of Qat and mate growing and preparing, respectively, could also play an important role in enhancing human oral carcinogenesis, in addition to their excessive consumption by their users. In this chapter, we will review the chemical composition of these two herbs and their role in the development of human oral cancer, based on the limited number of investigations.