Topical application of green tea polyphenol (−) epigallocatechin-3-gallate for prevention of recurrent oral neoplastic lesions

Abstract

Objective: A preliminary study was conducted to investigate the feasibility of using an oral cancer chemopreventive agent (−)-epigallocatechin-3-gallate (EGCG), the most biologically active component in the green tea extract, in a form of "swish-and-spit" mouthwash. Such application of EGCG is beneficial as it maximizes exposure of the oral mucosa to the agent but minimizes systemic side effect. Materials and Methods: The study was conducted on individuals suspected to have oral field cancerization who are at a high risk for developing recurrent oral precancerous and carcinomatous lesions. EGCG was used as a daily mouthwash for 7 days. EGCG′s ability to modulate target molecules implicated in oral carcinogenesis was assessed by measuring the change in the expression levels of biomarkers. Results: Immunohistochemical expressions of phosphoactivated epidermal growth factor receptor (pEGFR), cyclooxygenase-2 (cox-2), and ki-67 were evaluated at baseline and at the endpoint (day 8). Although not statistically significant, overall decrease in expression levels of pEGFR (27.5%), cox-2 (15.9%), and ki-67 positive cells (51.8%) was observed following EGCG treatment. Moreover, a detectable level of EGCG was found in saliva but not in plasma after the 1-week treatment regime, demonstrating local availability of EGCG in oral mucosa without significant systemic absorption. Conclusion: To the best of our knowledge, this is the first study to explore use of oral cancer chemopreventive agent in the form of mouthwash in patients with oral field cancerization. Although a definitive conclusion was not reached due to limited sample size, if proven effective, EGCG therapy may offer a non-invasive preventive modality for oral field cancerization.

Keywords

• (−)-Epigallocatechin-3-gallate, feasibility trial, oral field cancerization, topical chemopreventive agent