Mechanisms by which Hange-shashin-to reduces prostaglandin E2 levels

To determine the mechanisms by which Hange-shashin-to (TJ-14) reduces prost aglandin E2 (PGE2) levels, the effects on blood corticosterone levels were examined in vivo and the effects on cyclooxygenase (COX) activity in vitro assessed, TJ-14, orally administered to rats at dose levels between 125 and 1000 mg/kg, caused a dose-dependent increase in blood corticosterone level s. We also showed that Glycyrrhizae Radix and Ginseng Radix, constituents o f TJ-14, are involved in the increase in blood corticosterone, The activity of COX-1 was not inhibited by TJ-14 even at a dose of 1000 mu g/ml, while COX-2 was inhibited at dose levels between 10 and 1000 mu g/ml. The constit uents Scutellariae Radix, Glycyrrhizae Radix and Coptidis Rhizoma were beli eved to be involved in COX-2 inhibition. These results suggest that the effect of TJ-14 in decreasing PGE2 is partia lly mediated by corticosterone and inhibition of COX-2.