Therapeutic effect of green tea catechin on oral leukoplakia.

B148

Research is being conducted to clinically utilize tea extracts (green tea catechin, or GTE for short) for cancer prevention. Basic studies have proven that GTE possesses various biological effects such as anticancer activities (promotion of anticarcinogenesis, suppression of cancer cell proliferation, and induction of apoptosis), antimutagenic activities (anti-initiation and suppression of anticancer agent/DNA adduct formation), and anti-angiogenesis activities. Here, we administered GTE as a liniment for oral leukoplakia and investigated efficacy and histopathological changes. Subjects and Methods: Subjects were 10 consenting patients who consulted our department and were diagnosed with oral leukoplakia after histopathologic examination of biopsy material between August 2005 and January 2006. For at least 60 days, 0.5 g of a 1% GTE liniment prepared by mixing GET into an oral ointment was applied to the affected area four times a day. Each lesion was monitored macroscopically. The serum concentration of catechin was measured before, during, and after administration. In addition, biopsy was performed before and after administration, and immunohistochemical techniques Ki-67LI was used to ascertain changes in cellular proliferation. Results: No clinical or laboratory adverse reactions were seen during or after administration. Macroscopic observations revealed resolution, reduction or thinning of leukoplakia in four patients. When leukoplakia disappeared histopathologically, the new oral tissue was histologically nomal, and even when leukoplakia did not disappear, favorable changes in Ki-67LI occurred before and after administration. These findings suggest the effectiveness of local GTE administration in the treatment of oral leukoplakia.