Suppressive effect of the herbal medicine Oren-gedoku-to on cyclooxygenase-2 activity and azoxymethane-induced aberrant crypt foci development in rats

The present study is part of a program to obtain effective chemopreventive agents with low toxicity from medicinal herbs and traditional herbal medici nes. We previously reported that Oren (Coptidis rhizoma) and Ogon (Scutella riae radix) inhibit azoxymethane (AOM)-induced aberrant crypt foci (ACF) fo rmation. In the present investigation, we found Sanshishi (Gardeniae fructu s) and the traditional herbal medicine Oren-gedoku-to (OGT), composed of Og on, Oren, Sanshishi and Obaku, also have preventive potential. Sanshishi an d OGT decreased the numbers of ACF to 25.2 and 59.4% of the control Value a t 2% in the diet, respectively. Adverse effects, evidenced by body weight l oss, were weaker with OGT than component herbs. To investigate their mechan isms of action, the influence on cyclooxygenase-l (COX-1) and cyclooxygenas e-2 (COX-2) activities was studied. Both OGT and Sanshishi inhibited COX-2 but not COX-1, this presumably contributing to their suppressive effects on ACF development. The results suggest that OGT may be useful for colon canc er chemoprevention in terms of efficacy and toxicity. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.