Dehydrodicaffeic acid dilactone, an inhibitor of catechol-O-methyl transferase.

Abstract
In the screening of catechol-O-methyltransferase inhibitors, 3 compounds were isolated from the culture filtrate of a mushroom, Inonotus sp. One was 3,4-dihydroxycinnamic acid (caffeic acid) which was reported as an inhibitor of this enzyme. The others were the d-2,6-bis-(3'',4''-dihydroxyphenyl)-3,7-dioxabicyclo-[3,3,0]-octane 4,8-dione (dehydrodicaffeic acid dilactone) and its antipode. These new compounds inhibited both dopamine .beta.-hydroxylase and dopa decarboxylase and showed hypotensive activity in the spontaneously hypertensive rat.