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.
This report describes the high-sensitivity measurements of immunoglobulin (IgG) with the help of a phospholipid polymer conjugate, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer-IgG-horseradish peroxidase (HRP) conjugate. The phospholipid polymer, poly(MPC-co-2-aminoethyl methacrylate) (PMAE), was synthesized. To prepare the 1-step conjugate, IgG and PMAE were chemically modified with HRP at the same time. To prepare the 2-step conjugate, PMAE was first chemically modified with HRP, and then IgG was chemically modified. The activities of 1-step and 2-step conjugates significantly decreased compared with that of a conventional IgG conjugated with HRP (conventional conjugate) (p 0.05). The detection sensitivity of the 1-step and 2-step conjugates was also compared with that of conventional conjugate. When 0.5 µg/mL anti(goat IgG)IgG was used as an analyte, compared with a conventional conjugate, the values of Δ absorbance of the 1-step and 2-step conjugates were 4.8 and 9.8 times respectively. These results demonstrate that high-sensitivity measurements are possible using HRP-IgG-PMAE conjugate.