Isolation of Angiotensin Converting Enzyme Inhibitors from Compositae Plants

Thirty plants of the Compositae family were screened for inhibitory activity of angiotensin converting enzyme (ACE). Among them, Chrysanthemum boreale Makino and Ixeris dentate Nakai were selected for further investigation since they had the highest inhibitory activity. Crude water extracts of the flowers of Chrysanthemum boreale Makino and the roots of Ixeris dentate Nakai were prepared by heating at 95$^{\circ}C$ and 6$0^{\circ}C$ for 2 hr, respectively, followed by centrifugation at 8000$\times$ g far 30 min. Crude extracts were then filtered using YM-3 and YM-1 membranes. The ACE inhibitors were isolated using consecutive chromatographic methods including: Sephadex G-15, ion exchange, FPLC, and reverse phase HPLC. The inhibitors were identified to have molecular masses of 204 and 283 daltons, respectively, by mass spectrometry. These results demonstrate that crude extracts of Compositae plants may be useful as functional food ingredients with anti-hypertensive properties.