Therapeutic Effects of Green Tea Catechin Ointment on Oral Leukoplakia and Its Penetration into the Oral Mucosa

been shown to possess various bioactivi-ties, including anti-carcinogenic activity（anti-tumor-promoting activity, suppression of cancer cell growth, induction of apoptosis）, anti-mutagenicity（anti-initiation activity, anti-cancer agent, suppression of DNA adduct formation）, and inhibition of angiogene-sis. This study aimed to investigate the therapeutic effects of applying GTE as a topical agent for oral leukoplakia and the subsequent histopathological changes. We examined the absorption of GTE in rat oral mucosa. In addition, we examined 30 patients diagnosed with oral leukoplakia between April 2009 to March 2011. We administered an oral ointment composed of 1% GTE kneaded into a base material. A single dose（0.5 g） was applied to the affected area thrice a day for 90 days. Macroscopic observations and serum catechin levels were examined before, during, and after administration. The comparative histological effects and Ki-67-positive cell rates were examined using hematoxylin and eosin（H-E）staining and Ki-67 immunohistochemical staining. Nine patients in the treatment group exhibited disappearance, shrinkage, or thinning of the leukoplakia. After administration, effective cases exhibited histopathological normalization of the mucosa, and Ki-67 immunohistochemical staining suggested normalization of epithelial growth dynamics. GTE ointment applied to the dorsum of the rat tongues were examined for tissue permeability of GTE in frozen sagittal sections. Imaging of the rat tongue sections showed GTE penetrating the epithelium over time. Together, our results indicate that topical administration of GTE may be effective against oral leukoplakia. verify its inhibitory effect on cell growth in human oral squamous cell carcinoma lines（HSC - 4, Ca9 - 22）. After confirming a decrease in cell activity, we examined its application as a therapeutic agent for oral leukoplakia. immunohistochemical suggested the GTE ointment into oral mucosa acts on - related factors（5）. We that ointment may have clinical effect on oral leukoplakia（5）. MALDI-MS analysis of substances in the treatment of Sprague-Dawley with tea catechin（GTE）. The substance detected was thought to be caffeine [m/z = 195,（MH）+], which permeated and diffused into the epithelium over time.