Inhibitors of angiotensin converting enzyme in crude drugs. I.

Abstract

Hot 50% MeOH [methyl hydroxide] extracts of crude drugs considered to have a hypotensive effect were tested for inhibitory effects on hog kidney angiotensin converting enzyme. Of 65 samples tested, 14 showed reproducible inhibition in the preliminary screening. The extracts of 8 potent samples were fractionated by MCI gel and Sephadex LH-20 gel chromatographies to concentrate the inhibitors. The most potent fractions of Arecae Semen, Ephedrae Herba, Epimedii Herba, Polygoni avicularis Herba, Potentillae Herba and Rhei Rhizoma showed > 90% inhibition at the concentration of 20 .mu.g/ml. Those of Moutan Cortex and Cinnamomi Cortex showed 86 and 78% inhibitions, respectively, at the same concentration. All of these fractions consisted of tannin-type compounds.