Inhibition of renin-angiotensin system related enzymes (renin, angiotensin converting enzyme, chymase, and angiotensin converting enzyme 2) by water shield extracts.

We screened for the inhibitory activities of 19 wild vegetable and fruit extracts for renin-angiotensin system (RAS)-related enzymes, including renin, angiotensin- converting enzyme (ACE), chymase, and angiotensin-converting enzyme 2 (ACE2). Among them, a hot water extract of Brasenia schreberi (Water shield, Junsai) strongly inhibited renin and chymase activities and significantly inhibited ACE and ACE2 activities. We also tested the RAS-related enzyme inhibitory activities of 13 polyphenols isolated from Brasenia schreberi. The polyphenols mostly had little effect on ACE and ACE2 activities. Among them, hypolaetin 7-O-glucoside showed the strongest chymase inhibitory activity with an IC50 value of 3.8 μM. Some other polyphenols also inhibited renin and chymase activities.