Inhibitory Effects of Condensed Tannins on Angiotensin Converting Enzyme

[摘要] References(15)Cited-By(16)Effects of condensed tannins isolated from Rhei Rhizoma on the activities of angiotensin converting enzyme (ACE) and various proteases were examined in vitro. Among the various condensed tannins tested, procyanidin B-5 3, 3' di-O-gallate and procyanidin C-1 3, 3', 3''-tri-O-gallate strongly inhibited the activity of ACE. The concentration of procyanidin B-5 3, 3'-di-O-gallate required for 50% inhibition of ACE was 1.3×10-6 M. The inhibition of ACE by condensed tannins was reversible and non-competitive, according to dialysis and to Dixon plots. However, over one hundred times the concentration was required to inhibit activities of other proteases such as trypsin, chymotrypsin, leucine aminopeptidase, carboxypeptidase A and urinary kallikrein. These results suggest that the inhibitory effects of condensed tannins on the activities of ACE are specific.

[学科分类] 药理学