Isolation of Isoflavones Inhibiting Dopa Decarboxylase from Fungi and Streptomyces

Abstract

By screening of culture filtrates of fungi and streptomyces for activity to inhibit dopa decarboxylase the following isoflavone compounds were obtained: psi-tectorigenin (I), genistein (II), orobol (IV), 8-hydroxygenistein (V) and a new compound (III). III was elucidated to be 3′, 4′, 5, 7-tetrahydroxy-8-methoxy isoflavone. Among these isoflavones. IV and III showed the strongest activity in inhibiting dopa decarboxylase. All these isoflavones also inhibited histidine decarboxylase and catechol-O-methyltransferase. Activities of these compounds to inhibit tyrosine hydroxylase and dopamine β-hydroxylase were examined. Orobol which showed no or only slight inhibition of tyrosine hydroxylase and dopamine β-hydroxylase exhibited a significant hypotensive effect on spontaneously hypertensive rats. © 1975, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.