Therapeutic Role of Phytochemicals in the Prevention of Oral Potentially Malignant Disorders and Oral Cancer – A Review

BACKGROUND Medicinal plants and their extracts have been found to possess potent antiinflammatory, antioxidant and anti-cancer properties that slow down the cellular proliferation and malignant transformation rate of orally potential malignant disorders such as oral leukoplakia, oral submucous fibrosis and oral lichen planus. They are a potential source of antioxidants such as vitamin A, E, and C that neutralize the free radicals produced in various oral mucosal lesions thereby preventing the mucosal damage. They have been found to modulate cellular signalling pathways and, this activation influences the cellular defence mechanisms that protect the normal cells against reactive oxygen species or reactive metabolites and induces apoptotic death of cancerous cells, thus chemoprevention ensues to prevent, reverse or delay carcinogenesis. They have been studied to enhance tumour cell killing and inhibition of metastasis by increasing number of immunocompetent cells such as macrophages, cytotoxic T lymphocytes, natural killer cells and by recruitment of antibodies at the tumour site. Now a days, natural herbs or phytochemicals are gaining attention due to side effects and increased antimicrobial resistance that often occur with prolonged use of chemotherapeutic agents. Therapeutic effect of phytochemicals in oral PMDs is very promising as they prevent the progression of dysplasia from mild to severe. Literature has revealed significant reduction in burning sensation, difficulty in swallowing and speech, and pain associated with the oral mucosal lesion. However, more research should be conducted in future to establish their use as an adjunctive therapy in oral potentially malignant disorders. By this review, an attempt has been made to highlight therapeutic potential of diverse herbs such as aloe vera, tulsi, neem, curcumin, lycopene, green and black tea, peppermint etc. in the reduction of clinical symptoms of burning sensation and pain associated with the oral mucosal lesions, and discusses their indispensable role in prevention of oral cancer. KEY WORDS Antioxidants, Chemoprevention, Phytochemicals, Oral Cancer