Role of beetal quid and areca nut in oral cancer

Much of the tobacco in the world is consumed without combustion, by being placed into contact with mucous membranes through which the nicotine is absorbed to provide the pharmacological “benefit”. From the early days itself, beetal quid is mainly used for chewing. It usually consists of four main ingredients: betel leaf (Piper betel), areca nut (Areca catechu), slaked lime [Ca (OH)2] , and catechu (Acacia catechu). Since the introduction of pan, tobacco has become an important ingredient of it and most of the habitual pan-chewers include tobacco along with pan. Tobacco is also prepared in blocks and flakes for chewing, where North Americans use the term smokeless tobacco for thes products.
The use of betel quid, containing both areca nut and tobacco, is associated with a much higher relative risk of oral cancer, between 8-15 times as compared to that of 1-4 times, associated with using the quid, without tobacco. Betel quid chewing produces reactive oxygen species (ROS) that is detrimental to oral mucosa and can be directly involved in tumor initiation process, by inducing mutation, or by making the mucosa susceptible to betel quid ingredients and environmental toxicants. Betel quid chewing produces reactive oxygen species (ROS), that have multiple detrimental effects upon the oral mucosa. The production and release of ROS occurs under alkaline conditions during the autooxidation of areca nut (AN) polyphenols, in the betel quid chewer’s saliva. The ROS can be directly involved in the tumour initiation process, by inducing genotoxicity and gene mutation, or by attacking the salivary proteins and oral mucosa, leading to structural change in the oral mucosa, that may facilitate the penetration by other Betel quid ingredients and environmental toxicants. The nitrosation of areca alkaloids to AN-specific nitrosamines occurs in the saliva of betel quid chewers. These AN-specific nitrosamines are mutagenic, genotoxic and capable of inducing tumours in animal models. Studies have shown that beetal quid chewing without tobacco can also cause precancerous conditions in the oral cavity in the form of erythroplakia and OSF.
Areca nut contains potent cholinergic muscurinic alkaloids, notably arecoline and guavacaline, with a wide range of parasymphatheticomimetic effects. They promote salivation and the passage of wind through the gut; they rise blood pressure and pulse rate; and they elicit a degree of euphoria by virtue of their GABA receptor inhibitory properties which contribute to dependence and habituation. There are also bronchoconstrictor effects, and evidence for a role in precipitating and exacerbating asthama and diabetes. Areca nut is certainly the main etilogical agent in OSMF.