Abstract
Glycyrrhetic acid (GA), aglycone of glycyrrhizin (GL), inhibited potently (I50=7×10-6 M) and non-competitively the activity of NAD(P)+-linked 3α-hydroxysteroid dehydrogenase of rat liver cytosol. The inhibition was slightly weaker than that of indomethacin, a potent anti-inflammatory agent, but stronger than that of dexamethasone, another anti-inflammatory agent. GL, GA monoglucuronide, and 3-epi-glycyrrhetic acid also inhibited this enzyme activity, but did so less effectively (I50=5-8×10-5 M). Carbenoxolone (GA 3-hemisuccinate) and 3-keto-glycyrrhetic acid showed potent inhibitory effects similar to GA, and 18α-GA showed the most powerful inhibition of the activity.
