Inhibition of Adenosine 3', 5'-Cyclic Monophosphate Phosphodiesterase by Components of Sophora flavescens AITON

Abstract

Adenosine 3', 5'-cyclic monophosphate (cAMP) phosphodiesterase inhibitiors contained in the roots of Sophora flavescens AITON were identified as flavonoids, kushenol A (9), kurarinone (5), and kuraridin (22). The structure-inhibitory activity relationships were studied in 30 flavonoids. O-Methylation of a hydroxyl group on an aromatic ring decreased the activity. The prenyl group is important for high inhibitory activity. A kinetic study revealed that nor-kurarinone, kurarinol and kurafidin non-competitively inhibit cAMP phosphodiesterase.